Tuesday, March 17, 2015, 08:30-12:00

T01: Isolated DC-DC Converters  
Chair(s): Wenduo Liu – International Rectifier; Wisam Moussa – International Rectifier;
Track: DC-DC Converters
Location: Room 1

T02: Three-Phase & Higher Power AC-DC Converters  
Chair(s): Gerry Moschopoulos – Western University, Canada; Laszlo Balogh – Fairchild Semiconductor;
Track: AC-DC Converters
Location: Room 2

T03: Magnetic Devices and Components I  
Chair(s): Stephen M. Carlsen – Raytheon; Matt Wilkowski – Altera;
Track: Devices and Components
Location: Room 3

T04: Photovoltaic Applications  
Chair(s): Robert Pilawa-Podgurski – University of Illinois; Tiefu Zhao – Eaton;
Track: Power Electronics for Utility Interface
Location: Room 4

T05: Machines and Inverters  
Chair(s): Alexis Kwasinski – University of Texas – Austin; Yingying Kuai – Caterpillar Inc.;
Track: Motor Drives and Inverters
Location: Room 5

T06: Modeling of DC Energy Converters and Systems  
Chair(s): Jaber Abu Qahouq – The University of Alabama; Leo Wang – Cree Power Application;
Track: Power Electronics Applications
Location: Room 6

T07: DC-DC Converter Control I  
Chair(s): Shamim Choudhury – Texas Instruments; Akshay Kumar Rathore – National University of Singapore;
Track: Renewable Energy Systems
Location: Room 7

Wednesday, March 18, 2015, 08:30-10:10

T08: Integrated and HF DC-DC Converters  
Chair(s): Zhigang Liang – International Rectifier; David Perreault – Massachusetts Institute of Technology;
Track: DC-DC Converters
Location: Room 1

T09: Single Phase AC-DC Converters  
Chair(s): Dusty Becker – Emerson; Pritam Das – National University of Singapore;
Track: DC-DC Converters
Location: Room 2

T10: Miscellaneous Grid Topics  
Chair(s): Thomas Gietzold – United Technologies Aerospace Systems; Ali Bazzi – University of Connecticut;
Track: Modeling, Simulation, and Control
Location: Room 3

T11: Inverter Control I  
Chair(s): Iqbal Husain – North Carolina State University; Kent Wanner – John Deere;
Track: Packaging and Material Science
Location: Room 4

T12: Conductive and Inductive Chargers for Electric Vehicles  
Chair(s): Omer Onar – Oak Ridge National Laboratory; Khurram Afridi – University of Colorado Boulder;
Track: System Integration
Location: Room 5

T13: DC-DC Converter Control II  
Chair(s): Bilal Akin – University of Texas at Dallas; Yilmaz Sozer – Univ of Akron;
Track: Power Electronics Applications
Location: Room 6

T14: Renewable Circuits I  
Chair(s): Jason Stauth – Dartmouth College; Bulent Sarlioglu – University of Wisconsin – Madison;
Track: Renewable Energy Systems
Location: Room 7

Wednesday, March 18, 2015, 14:00-17:30

T15: Renewable Microgrids  
Chair(s): Behrooz Mirafzal – Kansas State University; Haihua Zhou – International Rectifier;
Track: Renewable Energy Systems
Location: Room 1

T16: WBG Device Performance & Circuit Interactions  
Chair(s): Alex Q. Huang – North Carolina State University; Juan Carlos Balda – University of Arkansas;
Track: Devices and Components
Location: Room 2

T17: Inverter Topologies  
Chair(s): Babak Nahidmobarakeh – University of Lorraine; Yichao Tang – University of Maryland;
Track: Motor Drives and Inverters
Location: Room 3

T18: LED Drivers  
Chair(s): Jim Spangler – Spangler Prototype Inc.; Zobair Roohani – International Rectifier;
Track: Power Electronics Applications
Location: Room 4

T19: Non-Isolated DC-DC Converters  
Chair(s): Cahit Gezgin – International Rectifier; Qiang Li – Virginia Tech;
Track: AC-DC Converters
Location: Room 5

T20: Multilevel Converters and Power Transformers  
Chair(s): Daniel Ludois – University of Wisconsin – Madison; Julia Zhang – Oregon State University;
Track: Power Electronics for Utility Interface
Location: Room 6

T21: Component Modeling  
Chair(s): Sheldon Williamson – University of Ontario Institute of Technology; Vahidreza Nasirian – University of Texas-Arlington;
Track: Modeling, Simulation, and Control
Location: Room 7

Thursday, March 19, 2015, 08:30-11:20

T22: DC-DC Converter Applications  
Chair(s): Olivier Trescases – University of Toronto; Xin Zhou – Maxim Integrated;
Track: DC-DC Converters
Location: Room 1

T23: System Integration  
Chair(s): Ernie Parker – Crane Aerospace & Electronics; John Vigars – Allegro Microsystems;
Track: Modeling, Simulation, and Control
Location: Room 2

T24: Modeling of AC Energy Converters and Systems  
Chair(s): Zobair Roohani – International Rectifier; Ali Davoudi – University of Texas at Arlington;
Track: Modeling, Simulation, and Control
Location: Room 3

T25: What’s in the Can, Combinational Semiconductors  
Chair(s): Yang Xu – NC State University; Paul Schimel – International Rectifier;
Track: Power Electronics for Utility Interface
Location: Room 4

T26: Renewable Wind I  
Chair(s): William Erdman – Cinch LLC; Haoyu Wang – Shanghai Tech University;
Track: Motor Drives and Inverters
Location: Room 5

T27: Power Electronics for Transportation Electrification  
Chair(s): Omer Onar – Oak Ridge National Laboratory; Sheldon Williamson – University of Ontario Institute of Technology;
Track: Power Electronics Applications
Location: Room 6

T28: WBG Power Device Based Applications  
Chair(s): Jin Wang – Ohio State University; Yifeng Wu – Transphorm, Inc.;
Track: Power Electronics Applications
Location: Room 7

Thursday, March 19, 2015, 14:00-17:30

T29: Resonant and Soft-Switching DC-DC Converters  
Chair(s): Bulent Sarlioglu – University of Wisconsin – Madison; Xin Zhou – Maxim Integrated;
Track: DC-DC Converters
Location: Room 1

T30: Power Converter Control  
Chair(s): Bilal Akin – University of Texas at Dallas; Mahshid Amirabadi – University of Illinois at Chicago;
Track: Devices and Components
Location: Room 2

T31: Inverter Control II  
Chair(s): Keith Corzine – Clemson; Dimitri Torregrossa – École polytechnique fédérale de Lausanne;
Track: Motor Drives and Inverters
Location: Room 3

T32: Wireless Power Transfer  
Chair(s): Juan Rivas – Stanford University; Sheldon Williamson – University of Ontario Institute of Technology;
Track: Power Electronics Applications
Location: Room 4

T33: Utility & Mixed Applications of Power Electronics  
Chair(s): Paul Schimel – International Rectifier; Omer Onar – Oak Ridge National Laboratory;
Track: Vehicular Electronics
Location: Room 5

T34: Photvoltaics  
Chair(s): Brandon Pierquet – Tesla Motors; Haoyu Wang – Shanghai Tech University;
Track: Renewable Energy Systems
Location: Room 6

T35: Grid and Microgrid Interfaces  
Chair(s): Fernando Briz – University of Oviedo, Spain; Haihua Zhou – International Rectifier;
Track: Modeling, Simulation, and Control
Location: Room 7

Thursday, March 19, 2015, 11:30-14:00

D01: AC-DC Converters  
Chair(s): Nathan Weise – University of Maine; Daniel Costinett – University of Tennessee;
Track: AC-DC Converters
Location: Poster Area

D02: DC-DC Converters I  
Chair(s): Dave Freeman – Texas Instruments; Haihua Zhou – International Rectifier;
Track: DC-DC Converters
Location: Poster Area

D03: DC-DC Converters II  
Chair(s): Akshay Kumar Rathore – National University of Singapore; William G. Dunford – The University of British Columbia;
Track: DC-DC Converters
Location: Poster Area

D04: Power Electronics for Utility Interface I  
Chair(s): Babak Parkhideh – University of North Carolina, Charlotte; Jing Xu – ABB Inc;
Track: Power Electronics for Utility Interface
Location: Poster Area

D05: Power Electronics for Utility Interface II  
Chair(s): Dong Cao – North Dakota State University; Davide Giacomini – International Rectifier;
Track: Power Electronics for Utility Interface
Location: Poster Area

D06: Power Electronics for Utility Interface III  
Chair(s): Ali Bazzi – University of Connecticut; Julia Zhang – Oregon State University;
Track: Motor Drives and Inverters
Location: Poster Area

D07: Drives and Inverters I  
Chair(s): Jonathan Kimball – Missouri University of Science and Technology; Tianjun Fu – John Deere;
Track: Motor Drives and Inverters
Location: Poster Area

D08: Drives and Inverters II  
Chair(s): Maryam Saeedifard – Georgia Tech; Kent Wanner – John Deere;
Track: Devices and Components
Location: Poster Area

D09: High Performance Devices and Components  
Chair(s): H Zhang – Transphorm; Jason Kulick – Indiana Integrated Circuits, LLC;
Track: Devices and Components
Location: Poster Area

D10: Magnetic Devices and Components II  
Chair(s): Ed Herbert; Stephen M. Carlsen – Raytheon;
Track: Devices and Components
Location: Poster Area

D11: Power System Solutions  
Chair(s): John Vigars – Allegro Microsystems; Ernie Parker – Crane Aerospace & Electronics;
Track: System Integration
Location: Poster Area

D12: Modeling and Simulation  
Chair(s): Jaber Abu Qahouq – The University of Alabama; Sheldon Williamson – University of Ontario Institute of Technology;
Track: Modeling, Simulation, and Control
Location: Poster Area

D13: Control  
Chair(s): Ali Davoudi – University of Texas at Arlington; Pietro Scalia – Texas Instruments;
Track: Modeling, Simulation, and Control
Location: Poster Area

D14: Manufacturing, Quality, and Business Issues  
Chair(s): Bulent Sarlioglu – University of Wisconsin – Madison;
Track: Modeling, Simulation, and Control
Location: Poster Area

D15: Renewable Grid  
Chair(s): Babak Nahidmobarakeh – University of Lorraine; Chris Siegl – Fairchild Semiconductor International, Inc.;
Track: Manufacturing, Quality, and Business Issues
Location: Poster Area

D16: Renewable Wind II  
Chair(s): Ali Mehrizi – Washington State University; Huai Wang – Aalborg University;
Track: Renewable Energy Systems
Location: Poster Area

D17: Renewable Circuits II  
Chair(s): Akshay Kumar Rathore – National University of Singapore; Huai Wang – Aalborg University;
Track: Renewable Energy Systems
Location: Poster Area

D18: Renewable PV Systems  
Chair(s): Ali Mehrizi – Washington State University; Liming Liu – ABB;
Track: Vehicular Electronics
Location: Poster Area

D19: Transportation Power Electronics  
Chair(s): Farborz Musavi – CUI; Jing Xu – ABB Inc;
Track: Power Electronics Applications
Location: Poster Area

D20: Power Electronics Applications I  
Chair(s): Pradeep Shenoy – Texas Instruments; Abhijit Pathak – International Rectifier;
Track: Power Electronics Applications
Location: Poster Area

D21: Power Electronics Applications II  
Chair(s): Dimitri Torregrossa – École polytechnique fédérale de Lausanne; Abhijit Pathak – International Rectifier;
Track: Packaging and Material Science
Location: Poster Area

T01-DC-DC Converter Applications
Track: DC-DC Converters

Title: A Hybrid Resonant Converter Utilizing a Bidirectional GaN AC Switch for High-Efficiency PV Applications
Abstract: This paper introduces a novel isolated hybrid resonant converter with smooth transition between multiple operating modes to obtain high efficiency over a wide input-voltage and output-power operating range. The proposed converter achieves high efficiency through low circulating losses, ZVS and near ZCS of the primary-side switching devices, and ZCS of the output diodes regardless of input voltage and output power. Closed-loop input-voltage controllers are designed for the different operating modes and a smooth transition between operating modes is achieved using a two-carrier modulation scheme. Experimental results verify the proposed system using a 300-W prototype that achieved 97.5% CEC efficiency at 30-V input including all auxiliary and control losses.
Presenters:
Thomas Labella, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University

Title: Output Rectifier Analysis in Parallel and Series-Parallel Resonant Converters with Pure Capacitive Output Filter
Abstract: This paper analyzes the behavior of a pure capacitive output filter in parallel and series-parallel resonant converters. This work provides detailed analysis of, and design equations for, pure capacitive output filters to cover the characteristic behavior of this rectifier. These valuable equations can be employed in the design of both low and high voltage power supplies for a variety of applications such as telecom power supplies and medical therapy instruments. Experimental results of a 10kVDC, 1.1kW power supply are presented to validate the analysis, along with other comparative experimental examples.
Presenters:
Navid Shafiei, University of British Columbia
Martin Ordonez, University of British Columbia
Wilson Eberle, University of British Columbia

Title: Three-Level Frequency-Doubling LLC Resonant Converter with High Step-Down Ratio for High Input Voltage Applications
Abstract: A frequency-doubling LLC resonant converter with high step-down voltage gain for high input voltage applications is proposed. The three-level structure is adopted to reduce the voltage stresses of the power devices. On the other hand, a single conventional resonant tank is shared by both half bridges, and the input capacitor voltage unbalance is suppressed effectively. By adopting the proposed control scheme, the resonant tank operating frequency is twice as the device switching frequency, which largely reduces the switching loss and increases power density. An 800W prototype is built to demonstrate the effectiveness of the proposed converter.
Presenters:
Sheng Zong, Zhejiang University
Qingjing Luo, Zhejiang University
Chushan Li, Zhejiang University
Wuhua Li, Zhejiang University
Xiangning He, Zhejiang University
Senliang Su, Hangzhou State Power Energy and Environment Institute

Title: Series Resonant Converters with an Adaptive Secondary-Side Digital Control for MHz 48V VRs: Circuit Analysis and Modeling
Abstract: An adaptive secondary-side digital control is proposed for the series resonant converter to solve the loss of ZVS under certain input and load conditions, making it a good candidate for MHz 48V voltage regulators (VRs). By means of varying AC equivalent resistance, the output voltage regulation is achieved by controlling the duty cycle of the synchronous MOSFET. An additional control variable has added complexity to circuit analysis, modeling and controller design, since the state variables such as the inductor current and capacitor voltage are AC domain. A sine-cosine transformation is applied to these AC resonant state variables, correspondingly, the resonant circuit can be decomposed into two subcircuits under sine and cosine axes at each harmonics frequency of interest. The transformed state space model can be used for the large signal and small signal analysis for the series resonant converter with the secondary-side control. A power circuit is designed based on the large signal analysis and a feedback controller is designed based on the derived small signal model. Simulation and experimental results verify the validation of the design.
Presenters:
Shangzhi Pan, Queen’s University
Majid Pahlevaninezhad, Queen’s University
Praveen Jain, Queen’s University

Title: Online Efficiency Optimization Technique for Digitally Controlled Resonant DC/DC Converters
Abstract: This paper proposes a digital online efficiency optimization technique for DC/DC Dual Half-Bridge Series Resonant Converters. The proposed technique implements an advanced modulation scheme which exploits the degrees of freedom inherently available in the converter modulation space in order to simultaneously regulate the output voltage and maintain the system in its maximum efficiency point. Furthermore, the proposed multivariable control technique robustly brings the converter back to maximum efficiency even in presence of abrupt load changes. The proposed efficiency optimization approach is first discussed theoretically, then via simulation and experimental tests. Experimental results on a 5 V, 1.2 A, 200 kHz series resonant converter prototype are in line with the theoretical predictions and confirm both the feasibility and the effectiveness of the approach. Experimental efficiency measurements indicate an efficiency improvement from 30% to more than 80% in light load conditions.
Presenters:
Luca Scandola, Università degli Studi di Padova
Luca Corradini, Università degli Studi di Padova
Giorgio Spiazzi, Università degli Studi di Padova
Cristian Garbossa, Infineon Technology
Pietro Piersimoni, Infineon Technology
Andrea Vecchiato, Infineon Technology

Title: CCM and DCM Operation of the Integrated-Magnetic Interleaved Two-Phase Boost Converter
Abstract: This paper presents the different discontinuous conduction modes of an integrated magnetic boost converter. The integrated magnetic used in the experimental set-up, the CCTT IM, is discussed. The different waveforms of an IM boost converter operating in DCM are shown, along with the sub-modes of conduction of the converter. Novel approaches to finding the boundaries of three different DCM modes are included. Importantly, the results are validated with a low power IM boost converter test set up.
Presenters:
Brendan Barry, University College Cork
John Hayes, University College Cork
Michael Egan, University College Cork
Marek Rylko, dtw
Jerzy Maslon, dtw
Kevin Hartnett, University College Cork

Title: Analysis of MOSFET Failure Modes in Bi-Directional Phase-Shift Full-Bridge Converters
Abstract: This paper presents the analysis of the mechanism of failure modes in bi-directional phase-shift full-bridge converters, composed of MOSFET, based on the circuit operation and parameters considering parasitic components of MOSFET. In addition, the relation between circuit operation and parameters are suggested through the experimental comparison. Using the relation, the suitable ranges of parameters for the stable performance are analyzed. The design criteria of the bi-directional phase-shift full-bridge converter are presented and evaluated by the experimental verification.
Presenters:
Chang-Yeol Oh, Sungkyunkwan University
Yun-Sung Kim, Sungkyunkwan University
Won-Yong Sung, Sungkyunkwan University
Nam-Jin Cho, Sungkyunkwan University
Byoung-Kuk Lee, Sungkyunkwan University

Title: Transformer-Flux-Balancing Control in Isolated Bidirectional DC-DC Converters
Abstract: The paper presents transformer flux-balancing control in isolated buck-boost and dual-active bridge (DAB) bidirectional converters. The control is based on the sensed transformer magnetizing current. It is shown that in the isolated buck-boost converter the magnetizing current peak values necessary for flux balancing control can be recovered based on a single sensed transformer current waveform. In the DAB converter, the flux-balancing control requires sensing of both transformer primary and secondary currents. Direct flux-balancing control in the DAB converter based on the magnetizing current extraction from the primary and secondary currents prevents transformer saturation but has a drawback of potentially high dc currents flowing through the transformer windings. To overcome this drawback, extra feedback loop is proposed which minimizes dc components of the primary and secondary currents. Operation of proposed controls for buck-boost and DAB converters were verified by simulations. The paper also includes experimental results for the 2-kW high-voltage buck-boost converter operating with proposed flux-balancing control.
Presenters:
Yuri Panov, Delta Products Corporation
Milan Jovanovic, Delta Products Corporation
Liu Gang, Delta Electronics
Meng Yueyong, Delta Electronics

Title: A Full-Bridge Three-Port Converter for Renewable Energy Application
Abstract: Multi-port DC/DC converters have been widely employed in stand-alone renewable power systems to provide stable and continuous power to the electrical loads. A full-bridge three-port converter (FB-TPC) interfacing a renewable source, a storage battery, and a load is proposed. The FB-TPC integrates two Buck-boost converters into the primary side of the full-bridge topology, and the magnetizing inductor of the transformer functions as an inductor. Single stage power conversion, between any two of the three ports, and zero-voltage-switching for all the primary switches are achieved. As a result, high power density and high efficiency can be implemented with the proposed converter. The duty cycle of the buck”boost converter is adopted to realize the maximum power point tracking of the PV panel and the charging control of the battery, while the phase angle between the two switching legs is employed as another control freedom to achieve the output voltage regulation. The operational principles of the proposed converter are analyzed in detail and verified with experimental results.
Presenters:
Wenfei Hu, Nanjing Aeronautics and Astronautics University
Hongfei Wu, Nanjing Aeronautics and Astronautics University
Yan Xing, Nanjing Aeronautics and Astronautics University
Kai Sun, Tsinghua University

T02-Single-Phase AC-DC Converters
Track: AC-DC Converters

Title: A Digitally Controlled DCM Flyback Converter with a Low-Volume Dual-Mode Soft Switching Circuit
Abstract: This paper introduces a dual-mode hybrid zero-voltage/zero-current switching (ZVS/ZCS) circuit and a ?complementary controller for flyback converters operating in discontinuous conduction mode (DCM). The new ?ZVS/ZCS solution provides soft switching feature and high efficiency throughout the whole operating range and ?requires smaller components than other soft switching solutions [1]-[6]. To achieve these benefits, the solution ?combines a low power passive snubber circuit and a novel secondary side circuit that provides ZCS on the primary ?side and ZVS on the secondary. A digital controller governs the operation of this circuit. At light loads the ZVS/ZCS ?is disabled to minimize conduction losses. At medium and heavy loads ZVS/ZCS provides soft switching and at the ?same time minimizes power losses of the snubber by recapturing the energy that would have been lost otherwise. ?
Presenters:
Behzad Mahdavikhah, University of Toronto
Aleksandar Prodic, University of Toronto

Title: Enhanced Constant-on-Time Control for DCM/CCM Boundary Boost PFC Pre-Regulators: Implementation and Performance Evaluation
Abstract: The paper will focus on an innovative improvement of the constant on time (COT) control of transition mode boost PFC. An overview and the enhancements of this method will be presented in comparison to the standard COT. The algorithms, the equations, the analog and digital implementations will be detailed for both improved methods. The comparison of the standard, enhanced COT (eCOT) and ramp enhanced COT (reCOT), in terms of THD, PF and computational load, will be shown with physical measures based on real implementations. The measures will confirm the analysis and the good performance reached. Moreover the benefits of the methods will show up.
Presenters:
Alberto Bianco, STMicroelectronics
Claudio Adragna, STMicroelectronics
Giuseppe Scappatura, STMicroelectronics

Title: Combining Peak Current Mode Control with Average Current Mode Control Using Digitally Assisted Analog
Abstract: Analogue peak current mode control, CPM, is combined with a new digital average current mode control, ACM, to provide the benefits of both control modes in a “Hybrid Current Controller” (HCM). The averaging and compensation functions traditionally implemented within an ACM compensated amplifier are separated out and implemented digitally. The digital control is designed to operate on the basis of one analog to digital conversion per PWM switching cycle. Results in a 250W Boost Power Factor Correction Stage, employing this new HCM, are presented.
Presenters:
Seamus O’Driscoll, Texas Instruments
David A. Grant, Texas Instruments

Title: A Novel Active Power Decoupling Single-Phase PWM Rectifier Topology
Abstract: Single-phase Pulse Width Modulation (PWM) rectifier has the inherent problem that there is second-order ripple power on the DC-link. The ripple power is normally filtered using a bulk capacitor connected on the DC-link of conventional H-bridge circuit, which results in low power density. Active power decoupling method, using an active circuit to divert the low-frequency power into another energy-storage component, is an alternative way to solve this problem. This paper presents a novel single-phase PWM rectifier topology with active power decoupling function. The proposed circuit divides the AC inductor of the conventional H-bridge circuit into two parts and only an auxiliary decoupling capacitor is added. In this paper, modulation strategy of the circuit is formulated. Control scheme is proposed for the circuit working as unity power factor rectifier. This circuit has the same advantage as other decoupling circuits such as high power density. Due to no additional switches, the proposed circuit has higher efficiency. Effectiveness of the circuit is validated by simulation. The proposed circuit is more suitable for higher DC-link voltage application.
Presenters:
Wenlong Qi, Shandong University
Hui Wang, Shandong University
Xingguo Tan, Shandong University
Guangzhu Wang, Shandong University
Khai D. T. Ngo, Virginia Polytechnic Institute and State University

Title: Decoupling of Fluctuating Power in Single-Phase Systems Through a Symmetrical Half-Bridge Circuit
Abstract: Single-phase AC/DC or DC/AC systems inherently subject to harmonic disturbance which is caused by the well-known double line frequency ripple power. This issue can be eased by installing bulky electrolytic capacitors in the dc-link, but such passive filtering approach may inevitably lead to low power density and limited system operation lifetime. An alternative approach is to use active power decoupling so that this ripple power can be diverted into other energy storage devices to gain improved performance. Nevertheless, all existing active methods have to introduce extra inductors or film capacitors to absorb the ripple power, and this again leads to increased component costs. In view of this, this paper presents a symmetrical half-bridge circuit which utilizes the dc-link capacitors to absorb the ripple power, and the only additional components are a pair of switches and a small filtering inductor. A design example is presented and the proposed circuit concept is also verified with both simulation and experimental results. It shows that at least ten times capacitance reduction can be achieved with the proposed method, which proves its practicality and effectiveness.
Presenters:
Yi Tang, Aalborg University
Frede Blaabjerg, Aalborg University
Poh Chiang Loh, aalborg University

Title: A Soft-Switching Bridgeless AC-DC Power Factor Correction Converter for Off-Road and Neighborhood Electric Vehicle Battery Charging
Abstract: This paper presents a high efficiency, continuous conduction mode zero voltage switching (ZVS) bridgeless ac-dc power-factor-correction (PFC) converter for neighborhood electric vehicle (NEV) battery charging. The converter operates in both pulse-width-modulation (PWM) mode and resonant mode each switching cycle and utilizes standard average-current-mode control.
Presenters:
Md Muntasir Ul Alam, University of British Columbia
Wilson Eberle, University of British Columbia
Deepak Gautom, Delta-Q Technologies Corp.
Fariborz Musavi, Delta-Q Technologies Corp.

Title: A GaN Transistor Based 90W AC/DC Adapter with a Buck-PFC Stage and an Isolated Quasi-Switched-Capacitor DC/DC Stage
Abstract: This paper presents a GaN Transistor based 90W ac/dc adapter with a Buck-PFC stage and an isolated Quasi-Switched-Capacitor dc/dc stage. In the dc/dc stage, two different QSC converters are proposed. Compared to Flyback and LLC resonant converters, the QSC converters feature: 1) reduced voltage stress on the primary-side switches to 2/3 of the input voltage; 2) reduced voltage stress on the transformer to 1/3 of the input voltage and a lower transformer turns ratio; 3) a wide range for soft-switching operation and high efficiency; 4) a simple control strategy. The operation principles and simulation results are presented. A 90 W, 85 V/19 V, 1 MHz QSC resonant converter is built, using 100 V EPC eGaN FETs for all switches. This prototype achieves: 1) a high power density of 10.5 W/cm3; 2) wide-range soft switching and a peak efficiency of 92.8% at 900 kHz in preliminary test results. A Buck-PFC evaluation module from TI is tested with a GaN HEMT and a SiC Schottky diode. The peak efficiency reached 97.1%, and the experimental results are compared with those from the Si based version.
Presenters:
Xuan Zhang, Ohio State University
Chengcheng Yao, Ohio State University
Xintong Lu, Ohio State University
Ernest Davidson, Ohio State University
Markus Sievers, Technische Universität München
Mark Scott, Ohio State University
Pu Xu, Ohio State University
Jin Wang, Ohio State University

Title: Using the Loss-Free Resistor Concept to Design a Simple AC-DC HB-LED Driver for Retrofit Lamp Applications
Abstract: Nowadays, it is known that High-Brightness Light”Emitting Diodes (HB-LEDs) are a fast emergent technology due to its high efficiency, low maintenance and durability. It is evident that to achieve these advantages the HB-LED driver must be durable and efficient. Also, in the case of replacing incandescent bulbs, the ac-dc HB-LED driver needs low cost and high Power Factor (PF). This digest presents a new proposal to design a simple and low-cost ac-dc HB-LED driver for retrofit lamps. Two 12W experimental prototypes have been built and tested in order to validate the theoretical results presented in this digest.
Presenters:
Diego G. Lamar, Universidad de Oviedo
Manuel Arias, Universidad de Oviedo
Marta Hernando, Universidad de Oviedo
Javier Sebastian, Universidad de Oviedo

Title: A Novel Bridgeless High-Frequency Resonant AC-DC Converter
Abstract: This paper introduces a novel bridgeless resonant AC-to-DC converter to efficiently convert arbitrary input voltages into a regulated DC voltage. The proposed topology features small size of passive components, high light-load efficiency and wide input AC voltage ranges. High frequency quasi-resonant or full-resonant operation owing to LC resonance allows small footprint for passive components, thereby increasing the circuit power density without sacrificing its efficiency. A resonant gate drive circuit is designed and utilized to further reduce gating losses under high-frequency switching and light-load conditions. The converter operates at maximum efficiency condition with fixed switching frequency, while it regulates the output voltage by using on-off hysteretic control with fast transient response. A 5mm×6mm, 100mg prototype is fabricated, which is operating at 2MHz switching frequency. The maximum efficiency of the prototype is 61.8% at its rated output power of 600mW.
Presenters:
Yichao Tang, University of Maryland
Alireza Khaligh, University of Maryland

T03-High Speed Devices & Gate Drives
Track: Devices and Components

Title: Investigation of 600 V GaN HEMTs for High Efficiency and High Temperature Applications
Abstract: This paper investigates the fast switching characteristics and high temperature performance of the 600 V GaN HEMT for high efficiency applications. First, the inherent switching performance of the GaN HEMT is demonstrated in the double pulse test. The GaN HEMT exhibits superior switching capability, with a di/dt reaching 9.6 A/ns and dv/dt reaching 140 V/ns. Then, the limitations of the fast switching capability by the device packaging and application circuit are analyzed. The inference between the current and gate thorough common source inductance limits the inherent switching speed. Packaging and circuit layout with small parasitics is critical in achieving fast switching. Finally, the high temperature static and switching characteristics up to 200 ?C are also tested and given. The switching performance of the device is independent of temperatures.
Presenters:
Zhuxian Xu, University of Tennessee
Weimin Zhang, University of Tennessee
Fan Xu, University of Tennessee
Fred Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee
Benjamin J. Blalock, University of Tennessee

Title: Internal Self-Damping Optimization in Trench Power FETs for High-Frequency Conversion
Abstract: The impact of the shield resistance (Rsh) on the waveform ringing and system efficiency is assessed in this work for 30V trench power FETs with shielded”gate (TP-FETs). Two different approaches, named distributed and local Rsh, are extensively investigated by experimental and numerical simulation tools. A layout distributed Rsh emerges as the ultimate solution to maximize the self-damping without penalization on the switching power losses or the product cost. The practical implementation of a TP-FET with distributed Rsh in a 12V-to-1.2V buck converter results in one of the best trade-offs ever reported between overvoltage (<3.5V) and peak efficiency (~88%) when operating at 1.3MHz.
Presenters:
Jaume Roig, ON Semiconductor
Chin-Foong Tong, ON Semiconductor
Filip Bauwens, ON Semiconductor
Renaud Gillon, ON Semiconductor
Hal Massie, ON Semiconductor
Charles Hoggatt, ON Semiconductor

Title: Ultrafast Switching Superjunction MOSFETs for Single Phase PFC Applications
Abstract: This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive current measurement method, which enables reaching the switching speed limits of these devices. Due to the intrinsic low and non-linear capacitances in vertical SJ MOSFETs, special attention needs to be paid to the gate drive design to minimize oscillations and limit the maximum dv/dt at turn off. This paper investigates the latest SJ devices in order to set a reference for future research on improvement over silicon (Si) attained with the introduction of wide bandgap devices in single phase PFC applications. The obtained results show that the latest generation of SJ devices set a new benchmark for its wide bandgap competitors.
Presenters:
Juan C. Hernandez, Technical University of Denmark
Lars P. Petersen, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark
Niels H. Petersen, Grundfos Holding A/S

Title: Coss Related Energy Loss in Power MOSFETs Used in Zero-Voltage-Switched Applications
Abstract: This paper presents a general method to measure the output capacitance (Coss) related energy loss per switching cycle in power MOSFETs used in zero-voltage-switched (ZVS) applications. It is shown that a simple model using Coss in series with a resistance Ross is inadequate for describing the observed energy loss and a different model is needed. This work also shows that the traditional hard-switched test methods for measuring the dynamic performance of power MOSFETs are inadequate for describing the dynamic performance of power MOSFETs used in ZVS applications. Finally, this study proposes a new power MOSFET figure of merit suitable for differentiating the performance of MOSFETs for use in ZVS applications.
Presenters:
Jeffrey Fedison, Enphase Energy, Inc.
Martin Fornage, Enphase Energy, Inc.
Michael Harrison, Enphase Energy, Inc.
Donald Zimmanck, Enphase Energy, Inc.

Title: Common Source Inductance (CSI) of Power Devices and the Impacts on Synchronous Buck Converters
Abstract: Common Source Inductance (CSI) is the inductance shared by the main current loop and the gate drive loop in a synchronous converter. Any voltage induced on CSI will change the effective gate-source voltage of the FET and has significant impacts on converter performance. This paper explores the impacts of High Side (HS) CSI on converter switch node ringing and power loss. The proposed equations provide more accurate power loss estimations and help converter designs. Power MOSFET example with advanced package design is given to demonstrate converter efficiency improvement brought by minimized CSI. The paper also analyzes and verifies the switch node ringing difference due to different HS CSIs.
Presenters:
Bo Wang, Texas Instruments
Rengang Chen, Texas Instruments
David Jauregui, Texas Instruments

Title: A High Efficiency Inverter Based on SiC MOSFET Without Externally Anti-Paralleled Diodes
Abstract: This paper analyzes a high efficient SiC MOSFET based inverter without externally antiparalleled diodes. Steady-state performances of MOSFET channel and its body diode are demonstrated; proper control and modulation technique is applied to realize synchronous rectification of the inverter and to minimize the conduction loss of body diodes. Power loss analysis of the inverter under various junction temperatures is performed. Calculated results show it is unnecessary to antiparallel external diodes for the less than 0.15% efficiency improvement since external diodes will inevitably increase the system volume and harm the power density. At last, a 10 kW SiC MOSFET based prototype is built. A full load efficiency greater than 98% is achieved. Experimental results show that the three phase inverter exhibits high efficiency under various working conditions even without antiparalleled diodes. By removing the external diodes, system volume and cost of the inverter can be reduced and power density improved. This paper shows the possibility of utilizing body diodes and provides references for tradeoff making between power efficiency and power density of the inverter.
Presenters:
Huawu Liu, Nanjing Aeronautics and Astronautics University
Hongfei Wu, Nanjing Aeronautics and Astronautics University
Yangjun Lu, Nanjing Aeronautics and Astronautics University
Yan Xing, Nanjing Aeronautics and Astronautics University
Kai Sun, Tsinghua University

Title: Evaluation of High-Voltage Cascode GaN HEMT in Different Packages
Abstract: This paper presents the evaluation of high-voltage cascode gallium nitride (GaN) high-electron-mobility transistors (HEMT) in different packages. The GaN HEMT in traditional package has high turn-on loss in hard-switching turn-on condition, and severe parasitic ringing in hard-switching turn-off condition, due to package related parasitics. To solve this problem a stack-die package is introduced, which is able to eliminate all the critical common-source inductances in traditional package, avoiding side effects caused by the package, and thus could be more suitable for MHz high frequency operation. A prototype of this stack-die package is fabricated in the lab, experimental results are shown to verify the analysis and to demonstrate the strength of the stack-die package.
Presenters:
Zhengyang Liu, Virginia Polytechnic Institute and State University
Xiucheng Huang, Virginia Polytechnic Institute and State University
Wenli Zhang, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: Dynamic Performances of GaN-HEMT on Si in Cascode Configuration
Abstract: This paper describes dynamic characteristics and power loss analysis of a high-voltage GaN-HEMT in cascode. The GaN-HEMT is “normally-on” and fabricated on 6-inch Si substrate using our Si mass-production line. Simple switching characteristics with resistive load and power efficiency measurements with a power factor correction (PFC) circuit driven from 100 kHz to 800 kHz were performed for the evaluation. The switching times (tr/tf) are about 4 times faster than those of conventional Si-MOSFET. An analytical method of power losses including temperature dependence of component parameters is also demonstrated.
Presenters:
Tatsuya Hirose, Fujitsu Laboratories Ltd.
Miki Imai, Fujitsu Laboratories Ltd.
Kazukiyo Joshin, Fujitsu Laboratories Ltd.
Keiji Watanabe, Fujitsu Laboratories Ltd.
Tsutomu Ogino, Fujitsu Laboratories Ltd.
Yasumori Miyazaki, Fujitsu Laboratories Ltd.
Ken Shono, Fujitsu Laboratories Ltd.
Tsutomu Hosoda, Fujitsu Laboratories Ltd.
Yoshimori Asai, Fujitsu Laboratories Ltd.

Title: Feasibility and Performances of BOOST Converter in Automotive Application Using Silicon Power Transistors Operating at 200°C
Abstract: This study investigates the feasibility to use conventional silicon power semiconductor devices (Si-IGBT, Si-CoolMOS.TM) at 200°C junction temperature in a BOOST converter topology (200V to 450V) for automotive application. Based on severe specifications, dice have been selected and nano-scale silver sintered die-attach process has been used in order to guaranty an optimum heat transfer between the chip and the DBC substrate. Static electrical characteristics (breakdown voltage, leakage current, threshold voltage and on-state voltage) have been investigated as well as dynamic ones (turn-on, turn-off and switching losses) for a wide range of temperature (from -50°C up to 200°C). In each case, a comparison is made with a SiC-MOSFET taken as reference. At least, as a preliminary approach, each device is tested in a 200V-450V @200W (power scale reduction) BOOST converter to evaluate its performance and feasibility under 200°C operation.
Presenters:
Raphaël Roder, University of Bordeaux
Stephane Azzopardi, University of Bordeaux
Francois Le Henaff, University of Bordeaux
Olivier Briat, University of Bordeaux
Jean-Michel Vinassa, University of Bordeaux
Serge Bontemps, Microsemi Corporation

T04-Multilevel Converter Modulation & Control Strategy
Track: Power Electronics for Utility Interface

Title: Switching-Frequency Ripple on DC Link Voltage in a Modular Multilevel Converter with Circulating Current Suppressing Control
Abstract: This paper investigates the dc link voltage ripple in a modular multilevel converter (MMC). It is found that switching-frequency ripple occurs on the dc link voltage in MMC when circulating current suppressing control is implemented. The mechanism of the switching-frequency voltage ripple is investigated and explained. Circulating current suppressing control will manipulate the average values for the three phase-leg voltages to be equal in order to reduce the low frequency circulating current. However, switching-frequency harmonics appear on the phase-leg voltages as a result, introducing the switching-ripple voltage on the dc link. By modeling the dc link voltage, switching-ripple voltage is derived. Experimental results of a three-phase MMC are presented to verify the theoretical analysis.
Presenters:
Yalong Li, University of Tennessee
Edward Jones, University of Tennessee
Fred Wang, University of Tennessee

Title: Unifying and Generating of Space Vector Modulation Sequences for Multilevel Converter
Abstract: In this paper, the popular modulation sequences used for the three-level neutral point clamped converter (3L-NPC) are unified from a new and intuitive perspective. Based on the discovered correlation and pattern, a general method for modulation sequences generating is proposed, and a series of new modulation sequences are deducted according to several easily applied rules.
Presenters:
Ke Ma, Aalborg University
Frede Blaabjerg, Aalborg University

Title: Phase-Shifted Modulation Strategy for Voltage Balancing in Neutral-Point Clamped Converter
Abstract: This paper suggests a new method to balance the voltage of the two capacitors in the three-level neutral-point clamped (NPC) converter. The proposed method only needs the information about the voltage of the two capacitors. The two capacitor voltages are fed back to the controller and then the control loop generates the appropriate value of phase shifting based on which the sinusoidal modulation signals are adjusted. The new voltage balancing technique is verified by simulation and experimental results.
Presenters:
Sangin Lee, Missouri University of Science and Technology
Mehdi Ferdowsi, Missouri University of Science and Technology

Title: Design of H-Bridge Based Converter Module Used in Cascaded DSTATCOM
Abstract: In this paper a type of “plug and play” HCM was discussed about the design of electrical parameters of the main circuit and physical structure. A universal module controller integrates with functions of control, communication, DC voltage sampling, fault detection and module protection was developed on complex programmable logic device (CPLD). Module functions and of stability is verified by experiment carried out on the HCM experimental platform.
Presenters:
Kun Yang, Zhejiang University
Yue Wang, Zhejiang University
Hua Yang, STSAIL Science-technology Co., LTD.
Haijun Tao, Zhejiang University
Guozhu Chen, Zhejiang University

Title: Modulation Strategies Suitable for a Large Power Voltage Source Converter Combining 3-Level Neutral Point Clamped Power Electronic Building Blocks
Abstract: This paper presents a review of modulation strategies that can be applied to a novel large power voltage source converter arrangement. This arrangement has been used in a 47 MVAR SSSC demonstrator connected to the 220 kV Spanish transmission network, for power flow control purposes. It employs four standard 3-Level Neutral-Point Clamped (3L-NPC) Power Electronic Building Blocks (PEBB), of well-proven reliability and share a common dc-bus. The 12 resulting inverter poles, are combined by means of a low VA-rating magnetic arrangement to provide open-end output terminals. In this paper four out of all possible modulation strategies are shown. These obtain a clean output waveform that is unlikely to require any filter to meet power quality regulations The converter components and its operation are explained, and experimental results are provided
Presenters:
Javier Chivite-Zabalza, Ingeteam Power Technology
Gorka Calvo, Ingeteam Power Technology
Danel Madariaga, Ingeteam Power Technology
Pedro Izurza, Ingeteam Power Technology
Miguel Angel Rodriguez, Ingeteam Power Technology
Alberto Guerrero, Ingeteam Power Technology

Title: Analysis of the Relationship Between Switching Frequency and Sub-Module Capacitor Unbalanced Voltage for a Modular Multilevel Converter
Abstract: With voltage-balancing control, the voltage difference among sub-module (SM) capacitors in a modular multilevel converter can be reduced. However, this comes at the cost of increased device switching frequency. In this paper, the relationship between the switching frequency and SM capacitor unbalanced voltage is investigated. As the relationship depends on the voltage-balancing control schemes, a popular scheme using a modified sorting method is considered. The switching frequency is found to be inversely proportional to the SM capacitor unbalanced voltage due to the voltage-balancing control and an analytical relationship is derived for the first time. As the SM capacitors voltage-unbalance increases the voltage fluctuation for each SM, the impact of switching frequency on the SM capacitance design is further investigated. The developed analytical relationship can thus be used for the SM capacitance design. Finally, the theoretical analysis is verified by simulation.
Presenters:
Yalong Li, University of Tennessee
Edward Jones, University of Tennessee
Fred Wang, University of Tennessee

Title: Capacitor Voltage Balancing Using Minimum Loss SVPWM for a Five-Level Diode-Clamped Converter
Abstract: DC capacitor voltage imbalance is an inevitable technical concern for the multilevel diode-clamped converters with number of levels higher than two. This paper addresses the balancing of the capacitor voltages based on the capacitor current equalization considering a minimum loss space vector pulse width modulation (MLSVPWM) algorithm for five-level diode-clamped converters. In diode-clamped converter topology, individual capacitors are connected in series on the DC side of the converter. By choosing appropriate switching pattern and their duration in a combined manner, the current passing through each capacitor can be controlled very competently. Using the redundant switching patterns for the proposed control strategy, number of switching that is required for the operation can also be minimized in addition to capacitor voltage balancing, without the requirement of complex calculations. The proposed MLSVPWM modulation technique for voltage balancing is verified using circuit simulations.
Presenters:
Aparna Saha, University of Akron
Yilmaz Sozer, University of Akron

Title: Reduction of DC-Link Capacitor in Case of Cascade Multilevel Converters by Means of Reactive Power Control
Abstract: A new method to selectively control the amount of dc-link voltage ripple by processing the desired reactive power by a DC/DC converter in an isolated AC/DC or AC/DC/AC system is proposed. The concept can reduce the dc-link capacitors used for balancing the input and output power and thereby limiting the voltage ripple. It allows the use of a smaller dc-link capacitor and hence a longer lifetime and at the same time high power density and low cost can be achieved. The isolated DC/DC converter is controlled to process the desired reactive power in addition to the active power. The control system to achieve this selective degree of compensation is proposed and verified by Simulations.
Presenters:
Ghanshyamsinh Gohil, Aalborg University
Huai Wang, Aalborg University
Marco Liserre, Aalborg University
Tamas Kerekes, Aalborg University
Remus Teodorescu, Aalborg University
Frede Blaabjerg, Aalborg University

Title: A KARNAUGH Mapping Technique for the Modeling of Single Phase Multi String Multi Level Inverter
Abstract: The objective of this paper is to study a seven level multi string converter topology for distributed energy resources based DC-AC conversion system. The modeling of this type of multi-level converter has not been showed before. This paper proposes the Karnaugh mapping technique used for modeling of the converter with three input DC sources. This paper also proposes the double Fourier series analysis to analyze the converter with particular reference to seven level design. The studied multi string inverter topology offers strong advantages such as less switching losses, improved output voltage waveforms, lower EMI and lower THD.
Presenters:
Bhanu Naga V Angirekula, Tennessee Technological University
Olorunfemi Ojo, Tennessee Technological University

T05-Multilevel Inverters
Track: Motor Drives and Inverters

Title: Optimal Control of Modular Multilevel Converters for Low-Speed Operation of Motor Drives
Abstract: This paper proposes two new techniques to reduce the SubModule capacitor voltage ripple magnitude in a Modular Multilevel Converter at low-frequencies when used in a medium-voltage adjustable-speed motor drive application since the capacitor voltage ripple is large at low-frequencies. The paper presents a comprehensive analysis of the proposed techniques and provides a comparison between the proposed and the existing techniques. Furthermore, the paper formulates an optimization problem to establish a tradeoff between the performance indices and, subsequently, to find the Pareto-optimal solutions. The effectiveness and performance of the proposed techniques are verified by simulation studies in the PSCAD/EMTDC environment.
Presenters:
Suman Debnath, Purdue University
Maryam Saeedifard, Purdue University

Title: A Modified Voltage Balancing Sorting Algorithm for the Modular Multilevel Converter: Evaluation for Staircase and Phase-Disposition PWM
Abstract: This paper proposes a simple voltage balancing algorithm to reduce the switching frequency of power devices and evaluates the performance of staircase modulation and phase disposition pulse-width-modulation (PD-PWM) in the modular multilevel converter (MMC). The performance of the converter is demonstrated based on the weighted total harmonic distortion of the common voltage and the amplitude of the capacitor voltage ripples. With the circulating current control, PD-PWM technique yields better performance compared to the staircase modulation technique. The test condition for this comparison is such that the power devices operate at a similar switching frequency in both modulation techniques. The results are verified through extensive simulations and experimentally using a phase-leg MMC laboratory prototype.
Presenters:
Rosheila Darus, University of New South Wales
Josep Pou, University of New South Wales
Georgios Konstantinou, University of New South Wales
Salvador Ceballos, Tecnalia Corporación Tecnológica
Vassilios G. Agelidis, University of New South Wales

Title: A Modified Two-Level Three-Phase Quasi-Soft-Switching Inverter
Abstract: A traditional Voltage Source Inverter (VSI) has higher efficiency than a Current Voltage Source (CSI) due to the less conduction power loss. However, the reverse recovery of the free-wheeling diode limits the efficiency improvement for the silicon devices based hard-switching VSI. The traditional quasi-soft-switching inverter can alternate between VSI and CSI by using a proper control scheme and thereby reduce the power losses caused by the reverse recovery of the free-wheeling diode. Nevertheless, slightly extra conduction power loss of the auxiliary switch is also introduced. In order to reduce the extra conduction power loss and the voltage stress across the DC-link capacitor, a modified two-level three-phase quasi-soft-switching inverter is proposed by using a SiC MOSFET instead of an IGBT. The principle of the modified two-level three-phase quasi-soft-switching inverter is analyzed in detail. And the performance is verified through simulations and experiments on a 5 kW/380 V three-phase prototype.
Presenters:
Yusheng Liu, Shanghai Maritime University
Weimin Wu, Shanghai Maritime University
Frede Blaabjerg, Aalborg University
Henry Shu-Hung Chung, City University of Hong Kong

Title: Modelling and Implementation of SVPWM Technique for a Thirteen-Phase Voltage Source Inverter-Sinusoidal Output Waveform
Abstract: In this paper comprehensive space vector model of a thirteen-phase voltage source inverter (VSI) and this work discusses the space vector Pulse Width Modulation (SVPWM) of a thirteen-phase voltage source inverter (VSI) with the aim of producing sinusoidal output waveform. Generalized space vector theory is used to achieve the SVPWM. As per the general inverter switching theory there are 213 = 8192 switching states are possible that yield 8190 active space voltage vectors and two zero voltage vectors at the origin. Out of the total 8190 active voltage vectors, 156 voltage vectors are utilized for the implementation of SVPWM. The sinusoidal voltage is obtained by controlling the duty cycle the voltage space vectors of d-q plane when voltage space vectors of other five x-y planes are set to zero. Maximum modulation index is used to get balanced sinusoidal output. The theoretical results are verified by simulation and experimental results with R-L load
Presenters:
Shaikh Moinoddin, Texas A&M University at Qatar
Haitham Abu-Rub, Texas A&M University at Qatar
Atif Iqbal, Qatar University

Title: A Fault-Tolerant T-Type Three-Level Inverter System
Abstract: Field experiences have demonstrated that semiconductor devices are vulnerable to failures (open- & short-circuit). In many critical applications, such failures are unacceptable and high system reliability is required. In this paper, a topology modification for the T-type 3-level inverter is explored to achieve the fault-tolerant operation and enhance the system reliability in the case of device open-circuit or short-circuit failures. With the proposed topology modification (via fewer additional switches), the device failure ride-through performance can be dynamically achieved without degradation of output capacity. Furthermore, the transition principles from normal operations to post-fault operations are detailed, and the reliability enhancement is calculated. The simulation results are included to verify the validity of the modified topology.
Presenters:
Wenping Zhang, Zhejiang University
Guangyuan Liu, Zhejiang University
Dehong Xu, Zhejiang University
Joshua Hawke, Texas A&M University
Pawan Garg, Texas A&M University
Prasad Enjeti, Texas A&M University

Title: Loss Balancing SVPWM for Active NPC Converters
Abstract: This paper presents a novel loss balancing modulation method for more evenly distributing semiconductor losses in multilevel active neutral-point-clamped (ANPC) converters. The presented method is achieved by optimally utilizing the redundant switching states of space vector pulse width modulation (SVPWM) in ANPC converters. A comparison of the effect of losses distribution between the proposed loss balancing SVPWM (LB-SVPWM) method and the conventional phase-shifted PWM (PS-PWM) methods is carried out in simulation. The effectiveness of the presented LB-SVPWM method is also verified in ANPC converters based on all-SiC MOSFETs. The results show that the proposed method can distribute the device losses more evenly, especially for all-SiC based ANPC converters, which can in turn improve the output power capacity and switching frequency. In addition, with utilization of the introduced loss balancing SVPWM method in ANPC converters, 15% higher output voltage and lower harmonic distortion can be achieved compared to PS-PWM modulated ANPC converters.
Presenters:
Xin Jing, Marquette University / General Motors
Jiangbiao He, Marquette University
Nabeel Demerdash, Marquette University

Title: A High Resolution Output Voltage Multilevel Inverter Topology with Few Cascade-Connected Cells
Abstract: This paper discusses a study of a generalized multilevel inverter asymmetric Cell-based H-Bridge with one Arm in Series (CHB-as), five switches. The study shows various asymmetrical arrangements for combinations of input sources that produce equally spaced voltage levels using fewer components. Equations for calculating the switching frequency used in the high resolution settings proposed in this paper demonstrate the operation of the inverter at low frequency. Simulations implemented in the program Orcad Pspice V. 16.5 to 1 kW-220V prototype have validated, the analyzes for the inverter operating with only two cells, resulting in output voltage with 25 levels. The results presented show that it is possible to obtain with only three cells, 85 levels for the first proposed configuration, or 125 levels to the second one without redundant states in the output voltage.
Presenters:
Samuel de Mesquita, Universidade Federal do Ceará
Fernando Antunes, Universidade Federal do Ceará
Sergio Daher, Universidade Federal do Ceará

Title: A PWM Control Strategy for Low-Speed Operation of Three-Level NPC Inverter Based on Bootstrap Gate Drive Circuit
Abstract: This paper proposes the pulse width modulation (PWM) control strategy for low-speed operation in the three-level neutral-point-clamped (NPC) inverters based on the bootstrap gate drive circuit.For low-speed operation, the dipolar and partial-dipolar modulations can be the effective solution. However, these modulations have drawbacks in terms of the switching loss and THD. Therefore, this paper proposes the PWM control strategy to operate the inverter at low-speed and to minimize the switching loss and harmonics.
Presenters:
Jun Hyung Jung, Pusan National University
Hyun-Keun Ku, Pusan National University
Won-Sang Im, Pusan National University
Jang-Mok Kim, Pusan National University

Title: Engineering Design for Structure and Bus Bar of 1.2MVA Hybrid Clamped Five- Level Converter Module
Abstract: Engineering design of structure and bus bar for a 1.2MVA hybrid clamped five-level (HCFL) converter module is presented in this paper. Firstly, the commutation coupling characteristics of the HCFL topology are analyzed and a decoupling structural design is proposed to eliminate the negative effect of high frequency current. Secondly, a laminated design for bus bar is employed to decrease the overshoot voltage of switching devices. Finally, a prototype is built to verify the effectiveness of the proposed design method for the 1.2MVA HCFL.
Presenters:
Yufei Dong, Zhejiang University
Haoze Luo, Zhejiang University
Pengfei Sun, Zhejiang University
Chushan Li, Zhejiang University
Wuhua Li, Zhejiang University
Xiangning He, Zhejiang University

T06-Utility Interface Converters
Track: Power Electronics Applications

Title: Loss Comparison of Different Nine-Switch and Twelve-Switch Energy Conversion Systems
Abstract: Nine-switch converter is a recently proposed reduced-switch equivalence of the twelve-switch back-to-back converter. The usual expectation is thus for the nine-switch converter to face some switching constraints and hence performance trade-offs. However, this might not always be the case with an answer only available after performing a thorough analysis. For that, it is the intention now to compare the nine-switch and twelve-switch converters when they are used in ac-ac, ac-dc, dc-ac or dc-dc energy conversion systems. Their losses will be compared to identify when the nine-switch converter will have an advantage or face only a slight constraint, which can hence better justify its usage to save switches. Simulation results are presented, while experimental loss measurements are presently ongoing.
Presenters:
Amir Sajjad Bahman, Aalborg University
Poh Chiang Loh, Aalborg University
Zian Qin, Aalborg University
Frede Blaabjerg, Aalborg University

Title: A New Voltage-Balancing Method for Split-Capacitor Inverters Using Split-Output Front-End Rectifiers in AC-DC-AC Applications
Abstract: In this paper, a new method to balance the DC bus capacitor voltages of two-stage AC-DC-AC converters with split-capacitor inverters is proposed. Converters use such split-capacitor inverters for various reasons such as cost, improved harmonic content and lower switch voltage stresses than those of conventional two-level, six-switch inverters, but the effectiveness of such inverters is limited by the need to perform voltage balancing. The proposed method frees the inverter from having to do such voltage balancing by using a novel approach that involves the front-end AC-DC converter. The paper introduces the new method, explains its basic operating principles and show how certain potential drawbacks are avoided. The feasibility of the proposed voltage balancing method is confirmed with results obtained from an experimental prototype
Presenters:
Mehdi Narimani, University of Western Ontario
Dunisha Wijeratne, University of Western Ontario
Gerry Moschopoulos, University of Western Ontario

Title: Shunt Active Power Filter with Reduced Number of Inductors
Abstract: In this paper is presented a shunt active power filter with a reduced number of inductors for harmonic and reactive power compensation in three-phase three-wire electrical systems. The proposed configuration is based on two single-phase shunt active power filters connected to a three-phase three- wire grid. The two single-phase cells can be achieved by a three-leg single-phase to single-phase ac-dc-ac converter, therefore resulting in a three-phase shunt active power filter with one inductor less than the typical three-phase active power filter. As a result the proposed configuration has reduced losses and weight.
Presenters:
Isaac Freitas, Universidade Federal da Paraíba
Zariff Gomes, Universidade Federal da Paraíba
Marcos Meira, Universidade Federal da Paraíba
Fabiano Salvadori, Universidade Federal da Paraíba
Lucas Hartmann, Universidade Federal de Campina Grande
Cursino Jacobina, Universidade Federal de Campina Grande
Euzeli dos Santos Jr., Purdue School of Engineering and Technology

Title: High Efficiency Switching Sequence and Enhanced Dynamic Regulation for Dab Converters in Solid-State Transformers
Abstract: This paper presents an advanced switching sequence based on boundary control for the Dual Active Bridge (DAB) DC-DC converter applied in a Solid-State Transformer (SST). The implementation of the switching sequence follows the recent advancements in curved switching surfaces for DAB converters and contributes to higher efficiency and transient regulation. The proposed switching sequence improves the overall efficiency of the converter. Dynamic regulation, is also addressed by the proposed boundary-based sequence. As a result, excellent dynamic response is obtained by taking advantage of all the possible switching structures of the converter. Simulation and experimental results are presented.
Presenters:
Germán Oggier, Universidad Nacional de Río Cuarto
Martin Ordonez, University of British Columbia

Title: Investigation of Transformer Winding Architectures for High Voltage Capacitor Charging Applications
Abstract: The transformer parameters such as leakage inductance and self-capacitance are rarely calculated in advance during the design phase, because of the complexity and huge analytical error margins caused by practical winding implementation issues. Thus choosing one transformer architecture over another for a given design is usually based on experience or a trial and error approach. This work presents equations regarding calculation of leakage inductance and self-capacitance in transformer winding architectures, ranging from the common non-interleaved primary/secondary winding architecture, to an interleaved and sectionalized secondary and/or primary winding architecture. The analytical results are evaluated experimentally, and different transformer winding architectures are investigated in terms of the losses caused by the transformer parasitics in a bi-directional high-voltage (~1500 V) flyback converter used to drive a dielectric electro active polymer (DEAP) based incremental actuator.
Presenters:
Henrik Schneider, Technical University of Denmark
Prasanth Thummala, Technical University of Denmark
Lina Huang, Technical University of Denmark
Ziwei Ouyang, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Zhe Zhang, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: Design, Measurement and Equivalent Circuit Synthesis of High Power HF Transformer for Three-Phase Composite Dual Active Bridge Topology
Abstract: High voltage high frequency (HF) transformer provides the isolation between high and low dc link voltages in dual active bridge (DAB) converters. Such DAB converters are finding wide applications as an intermediate DC-DC converter in transformer-less intelligent power substation (TIPS), which is proposed as an alternative for conventional distribution-transformer connecting 13.8 kV and 480 V grids. The design of HF transformer used in DAB stage of such application is very challenging considering the required isolation, size and cost. In this paper, the specification generation, design, characterization, test and measurement results on a 10 kHz HF transformer are presented, highlighting the above challenges.
Presenters:
Krishna Mainali, North Carolina State University
Awneesh Tripathi, North Carolina State University
Dhaval Patel, North Carolina State University
Subhashish Bhattacharya, North Carolina State University
Tony Challita, IAP Research, Inc

Title: Feasibility Study and Design of Hybrid AC/DC High Power Transmission Considering Unbalanced Line Impedances
Abstract: In this paper, a hybrid ac/dc approach is studied to increase power capacity of existing ac lines. The line current can be pushed close to its thermal rating by superposing dc current on ac current through existing ac lines without alternations of insulators, towers. The feasible topology is shown. The design methodology of zigzag transformer as the key component for dc injection is proposed. And saturation issue when considering unbalanced AC line impedance is firstly investigated. Experimental results on a prototype validate this design. Economical comparison with scheme of converting AC line to pure DC shows that within certain ranges, LCC based hybrid ac/dc can be a cheaper solution to upgrade HVAC power capacity.
Presenters:
Bo Liu, University of Tennessee
Xiaojie Shi, University of Tennessee
Fred Wang, University of Tennessee

Title: Start-Up and Integration of DFIG-Based Wind Farm Using Modular Multilevel VSC-HVDC Transmission System
Abstract: This paper describes the start-up and integration of a doubly fed induction generatorbased wind farm into the ac network through a voltage source converter-based HVDC transmission system. A control strategy based on the closed-loop control of rotor current is proposed to limit the overcurrents of DFIG during cut-in process. In normal operation, an additional feedback signal is introduce to the passive voltage tracing control system of the wind farm side modular multilevel convertto eliminate the output current ripples of the wind farm. Primary simulation waveforms and field tests results are presented to validate the effective performances of the proposed control strategies in this digest.
Presenters:
Wenjin Li, Huazhong University of Science and Technology
Yong Kang, Huazhong University of Science and Technology
Guangfu Tang, State Grid Company of China
Ming Kong, State Grid Company of China

Title: Unsymmetrical Fault Correction for Sensitive Loads Utilizing a Current Regulated Inverter
Abstract: Many industrial applications involve loads which are very sensitive to electrical disturbances in the supply. These instances involve both various types of voltage unbalance as well as more serious disturbances such as symmetrical and asymmetrical faults. This paper proposes a voltage unbalance and an unsymmetrical fault correction technique for a three phase load, utilizing an industry-standard current regulated voltage source inverter by connecting it parallel to the associated three phase transformer. The inverter regulates the current for the load and never allows the current to exceed to a prescribed value under any type of unsymmetrical condition. To support the proposed technique simulation results have been obtained by using Simulink.
Presenters:
Syed Sabir Hussain Bukhari, Hanyang University
Byung-Il Kwon, Hanyang University
Thomas A. Lipo, University of Wisconsin-Madison

T07-Renewable Energy System Integration
Track: Renewable Energy Systems

Title: Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements
Abstract: Reactive power injection strategies for single-phase PV systems are explored in this digest. The possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those proposed strategies comply with the current active grid codes, but are with different control objectives. The thermal optimized control strategy is demonstrated on a 3 kW single-phase PV system. The constant peak current control strategy is verified on a 1 kW singe-phase system in LVRT operation. Those results show the effectiveness and feasibility of the proposed strategies in terms of reactive power injection.
Presenters:
Yongheng Yang, Aalborg University
Huai Wang, Aalborg University
Frede Blaabjerg, Aalborg University

Title: Constant Power Generation of Photovoltaic Systems Considering the Distributed Grid Capacity
Abstract: In order to reduce the requirement of grid capacity expansion and increase the photovoltaic penetration level, a Constant Power Generation (CPG) control concept is proposed in this digest. Accordingly, it is worth investigating into two main issues: a) analyzing the reduction of the energy yield to study its feasibility and b) developing robust CPG control methods. Thereby, the possibilities of CPG control are explored in this digest. Examples are presented to show its effectiveness. In addition, the loss of energy is calculated to reveal the rationality of CPG control. More experimental verifications will be included in the final paper.
Presenters:
Yongheng Yang, Aalborg University
Frede Blaabjerg, Aalborg University
Huai Wang, Aalborg University

Title: Fast Voltage Detection Method for the Voltage Ride Through Operation of Grid-Tied Renewable Energy Generation Systems
Abstract: As the scale of renewable energy resources connected to the grid is increasing remarkably, the strict gird codes are formulated in order to ensure the grid safety. Among the grid codes, the low voltage ride through (LVRT) regulation is important because it defines the acquired response to support the grid stability. This paper proposed a new voltage detection method, which consists of the traditional three-phase phase lock loop and a new low voltage detection procedure for the low voltage ride through operation of grid-tied renewable energy generation systems. This method can detect the amplitude of voltage sag within 5ms by tracking either the maximum point or the zero point.
Presenters:
Cong Ma, Shandong University
Feng Gao, Shandong University
Guo-Qing He, China Electric Power Research Institute
Guang-Hui Li, China Electric Power Research Institute

Title: An Active Damping Method Based on Biquad Digital Filter for Parallel Grid-Interfacing Inverters with LCL Filters
Abstract: In this paper, the resonance phenomenon involved by the multiple LCL-filtered interfacing inverters in a distributed renewable energy system is studied. The frequency domain characteristics of the parallel LCL-filtered inverters are presented. It is shown that additional resonance peak appears compared to the single inverter system, which further challenges the system stability. In order to facilitate efficient damping of the above multiple resonance peaks, the biquad filter based active damping method is proposed. The biquad filter based active damping method does not require additional sensors and control loops. Meanwhile, the multiple instable closed-loop poles of the parallel inverter system can be moved to the stable region simultaneously. Real-time simulation based on dSPACE 1103 and the preliminary experimental test based on 2×2.2 kW prototype are performed to validate the proposed damping approaches. Further experimental results will be shown in the final paper.
Presenters:
Xiaonan Lu, University of Tennessee
Kai Sun, Tsinghua University
Lipei Huang, Tsinghua University
Marco Liserre, Aalborg University
Frede Blaabjerg, Aalborg University

Title: Comparison of Control Strategies for Doubly Fed Induction Generator Under Recurring Grid Faults
Abstract: The new grid codes demand the wind turbine systems to be able ride through recurring grid faults. Many control strategies have been proposed for the Doubly Fed Induction Generator under grid faults, but their performance under recurring grid faults have not been studied yet. In this paper, a series of control strategies for DFIG under grid faults are presented, and their performance under recurring grid faults are analyzed. Their controllable range, damping time constant of the stator natural flux and the torque fluctuations are compared. The result is verified by simulations and will be verified by experiments in the final paper.
Presenters:
Wenjie Chen, Zhejiang University
Frede Blaabjerg, Aalborg University
Nan Zhu, Zhejiang University
Min Chen, Zhejiang University
Dehong Xu, Zhejiang University

Title: Analysis of the Electromagnetic Transient Time in DFIG During Grid Faults
Abstract: To care the rapid response of reactive support in LVRT, the electromagnetic transient time of DFIG is systematically studied for the first time. Under crowbar protection, larger crowbar or lower speed will slow down transition process. Under RSC control, a reversed rotor current to transient stator flux is conducive to accelerate transient and restore the free control to DFIG. Considering typical MW-level DFIG parameters, the fault transient would last 100ms at least.
Presenters:
Qingjun Huang, Huazhong University of Science and Technology
Xudong Zou, Huazhong University of Science and Technology
Li Tong, Huazhong University of Science and Technology

Title: Virtual Series Impedance Emulation Control for Remote PV or Wind Farms
Abstract: This paper proposes a virtual series impedance emulation control strategy for current controlled remote PV or wind farms, in order to enhance the power transfer capability of the transmission line. First, the virtual series impedance emulation control strategy for both the operation mode with P and Q control and the operation mode with P and V control is described. Then the capability of virtual impedance emulation is analyzed. Comparison with physical series capacitors is carried out to investigate the impact on the grid-side converter design. The effectiveness of the proposed methods is verified by both simulation and experiments.
Presenters:
Wenchao Cao, University of Tennessee
Yiwei Ma, University of Tennessee
Jingxin Wang, University of Tennessee
Fred Wang, University of Tennessee

Title: A Mode Switching, Multiterminal Converter Topology with Integrated Fluctuating Renewable Energy Source Without Energy Storage
Abstract: An important functionality of the Solid State Transformer (SST) is the integration of renewable energy sources in the topology itself. Due to the fluctuating nature of the renewable energy source, such integration becomes a challenge and energy storage becomes a requirement. In this paper a topology variant of single phase SST is proposed which directly integrates the renewable energy source in the high frequency magnetic stage and uses the grid as the energy buffer, eliminating the requirement of energy storage.
Presenters:
Sumit Dutta, North Carolina State University
Sudhin Roy, North Carolina State University
Subhashish Bhattacharya, North Carolina State University

Title: A Novel Real-Time and on-Line Computation Algorithm for Characteristic Parameters of Micro-Grids
Abstract: The characteristic parameters of the micro-grids determine its transient response and the stability. The generation, the grid structure and the electric loads of all the whole micro-grids are always changing randomly due to the random load changes and the integration of large-scale batch energy, indicating that the characteristic parameters of the micro-grids also changes. A novel real-time and on-line computation algorithm for the characteristic parameters of the micro-grids is presented in this paper. This new method can calculate the key characteristic parameters of the micro-grids according to the measured transient currents. And hence the response character and the stability of the transient, the important information for the regulation and dispatching of the micro-grid system, can be pre-estimated quickly and accurately.
Presenters:
Liansong Xiong, Xi’an Jiaotong University
Chen Li, Xi’an Jiaotong University
Fang Zhuo, Xi’an Jiaotong University
Minghua Zhu, Xi’an Jiaotong University
Baoquan Liu, Xi’an Jiaotong University
Hailong Zhang, Xuji Group

T08-Non-isolated DC-DC Converters
Track: DC-DC Converters

Title: FIVR – Fully Integrated Voltage Regulators on 4th Generation Intel® Core™ SoCs
Abstract: Intel’s® 4th generation Core™ microprocessors are powered by Fully Integrated Voltage Regulators (FIVR). These 140 MHz multi-phase buck regulators are integrated into the 22nm processor die, and feature up to 80 MHz unity gain bandwidth, non-magnetic package trace inductors and on-die MIM capacitors. FIVRs are highly configurable, allowing them to power a wide range of products from 3W fanless tablets to 300W servers. FIVR helps enable 50% or more battery life improvements for mobile products and more than doubles the peak power available for burst workloads.
Presenters:
Edward Burton, Intel Corporation
Gerhard Schrom, Intel Corporation
Fabrice Paillet, Intel Corporation
Jonathan Douglas, Intel Corporation
William Lambert, Intel Corporation
Kaladhar Radhakrishnan, Intel Corporation
Michael Hill, Intel Corporation

Title: Adaptive Ripple-Based Constant on-Time Control with Internal Ramp Compensations for Buck Converters
Abstract: This paper presents an adaptive ripple-based constant on-time control architecture for buck converter ICs with wide applications. An internal ramp compensation with emulating inductor current ripple is implemented to solve the ripple oscillation instability issue when using low-ESR output capacitors in buck converters. However, in order to guarantee the stability margin and the jitter performance for wide duty-ratio applications with different switching frequencies, a large internal ramp is normally applied, but it may not be optimal for all different applications. Hence, the internal ramp must be carefully designed to guarantee the stability margin while maintaining fast load transients and adequate phase margins for wide duty-ratio applications. In this paper, an adaptive ripple tuning algorithm is proposed to fine tune the internal ramp compensation automatically based on the duty ratio, output voltage, and the switching frequency. The preliminary analyses and experimental results are given to verify the effectiveness of the proposed adaptive ripple tuning algorithm. More detailed analyses and experimental verification will be given in the final paper.
Presenters:
Brian Cheng, Texas Instruments
Fred C. Lee, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University

Title: 1MHz Switching Frequency POL with a Fast Response Digital Controller
Abstract: This paper will discuss about the proposed hardware logic type digital controller for on-board SMPS which has a very small time-delay in control loop. Experimental results of the load current change experiment and the frequency characteristic of open loop transfer function has been described respectively. These results reveal the validity of the proposed technique.
Presenters:
Yoichi Ishizuka, Nagasaki University
Kenji Mii, Nagasaki University
Fumiaki Takenami, Nagasaki University
Daisuke Kanemoto, University of Yamanashi

Title: Optimized Phase Positioning for Minimizing Input Filter Requirements in Single-Input Multiple-Output DC-DC Switch-Mode Power Supplies
Abstract: In order to comply with regulations, reduce EMI, and ensure that input transients are properly handled, an input filter is usually required in a power supply system. In systems with a single input power supply and multiple output converters, the phase positioning of the converters affects the input current/voltage ripple as well as the magnitude of the input harmonics. Optimizing the phase positioning of each converter can reduce the required size of the input filter capacitor, in turn reducing cost and physical dimensions. An algorithm is presented for selecting the optimal phase positioning based on each converter parameters and operating conditions. This method is verified using the Exar’s XRP7724 4-channel controller and 4 buck converters.
Presenters:
Jason Weinstein, Exar Corporation
Santa Huerta, Exar Corporation
Zhenyu Zhao, Exar Corporation
Jeff Mincey, Exar Corporation
Zaki Moussaoui, Exar Corporation

Title: Constant on-Time DC-DC Converter Using Ripple Injection Filter with Inherent Adaptive Voltage Positioning
Abstract: A constant on-time DC-DC converter using ripple injection filter with inherent adaptive voltage positing function is proposed. By using the proposed filter, voltage positioning is realized without current-sensing mechanism and the droop voltage can be controlled by a resistor within the filter. The droop voltage is calculated and the filter design methodology to obtain optimal transient response is described. A test chip is fabricated using 0.25um CMOS process. The experimental results show that the line regulation of the designed DC-DC converter is consistent with the calculation. With a load-current transient of 500mA, the designed DC-DC converter showed voltage disturbance of 15mV.
Presenters:
Takayuki Miyazaki, Toshiba Corporation
Taichi Ogawa, Toshiba Corporation

T09-Wide Bandgap Devices in DC-DC Converters
Track: DC-DC Converters

Title: Evaluation of Gallium Nitride Transistors in High Frequency Resonant and Soft-Switching DC-DC Converters
Abstract: The emergence of GaN power devices offers the potential to achieve performance not possible with Si power MOSFETs. This paper will demonstrate the ability of GaN to improve performance in resonant and soft-switching applications. A figure of merit is proposed to compare the critical device parameters between GaN and Si technologies that influence the in-circuit performance of resonant and soft-switching applications. The benefits of GaN transistors are experimentally verified in high frequency 48V to 12V resonant bus converter prototypes with Si and GaN power devices operating at 1.2MHz and output power up to 400W.
Presenters:
David Reusch, Efficient Power Conversion Corporation
Johan Strydom, Efficient Power Conversion Corporation

Title: A 130 W 95%-Efficiency 1 MHz Non-Isolated Boost Converter Using PWM Zero-Voltage Switching and Enhancement-Mode GaN FETs
Abstract: A PWM zero-voltage-switching (ZVS) non-isolated boost converter using enhancement-mode GaN (eGaN) FETs is proposed in this paper. The new converter topology requires small number of passive components, minimizes the capacitive switching loss under high-voltage high-frequency operation, and offers low-voltage stress across power transistors. A transformer-based floating gate driver with 30ns propagation delay and 3ns rising/falling time enables high-speed high-side gate driving of the eGaN power FET and thus high-frequency operation of the proposed ZVS converter. A 1MHz switching frequency 130W output power prototype circuit of the proposed boost converter has been implemented and the measured peak power efficiency achieves 95%.
Presenters:
Jing Xue, University of Texas at Dallas
Lin Cong, University of Texas at Dallas
Hoi Lee, University of Texas at Dallas

Title: Advantages of GaN in a High-Voltage Resonant LLC Converter
Abstract: LLC Resonant converters have been popular in recent years by providing highly-efficient, compact isolated power conversion for numerous applications. 48V to 12V and 400V to 12V step-down isolated converters are often required in server, telecom and automotive applications. While the switching losses in LLC converters are eliminated due to zero-voltage switching, the primary-side switch output capacitance limits switching frequency and thus places a lower-bound on the converter size. This switch-node capacitance can be significantly reduced by the use of high-voltage Gallium Nitride (GaN) power transistors. This paper demonstrates a 500W, 380V to 12V LLC converter using GaN transistors which achieves 97.85% efficiency with a 308 W/in3 power density.
Presenters:
Michael Seeman, Texas Instruments
Sandeep Bahl, Texas Instruments
David Anderson, Texas Instruments
Gaurang Shah, Texas Instruments

Title: Normally-Off GaN-on-Si Multi-Chip Module Boost Converter with 96% Efficiency and Low Gate and Drain Overshoot
Abstract: A high-efficiency, normally-off GaN, synchronous half-bridge boost converter is designed with fast switching and low overshoot. A half-bridge Multi-Chip Module is designed with a power-loop inductance of ~4nH using transmission-line techniques to minimize inductance. The gate circuit inductance is reduced to 1nH using bare MOSFET die for driving the GaN gates and a 0.5mil flexible substrate gate transmission-line. Critically damping the gate turn-on reduces overshoot to safe levels of 1V gate overshoot and ~20V drain overshoot. The resulting synchronous boost converter has an efficiency of 96%, switching 300V at 1MHz with 50% duty cycle and an output power of 2.4kW.
Presenters:
Brian Hughes, HRL Laboratories LLC
James Lazar, HRL Laboratories LLC
Stephen Hulsey, HRL Laboratories LLC
Marcel Musni, HRL Laboratories LLC
Daniel Zehnder, HRL Laboratories LLC
Austin Garrido, HRL Laboratories LLC
Raghav Khanna, HRL Laboratories LLC
Rongming Chu, HRL Laboratories LLC
Sameh Khalil, HRL Laboratories LLC
Karim Boutros, HRL Laboratories LLC

Title: Design and Experimental Analysis of a 1 kW, 800 kHz All-SiC Boost DC-DC Converter
Abstract: This paper presents the design, prototype development, operation and testing of a 1kW, 800V output all-SiC boost dc-dc converter module utilizing SiC MOSFET and SiC Shottky diode chips. The switching frequency is raised up to as high as 800 kHz and a 230 degree?C SiC MOSFET junction temperature has been reached by switching-loss dominant self-heating. High frequency switching operation of the proposed converter is evaluated in detail and a Critical Conduction Mode (CrCM) Zero Voltage Switching (ZVS) soft-switched control method is experimentally proposed to reduce the switching loss of SiC MOSFET.
Presenters:
Xueqian Zhong, Zhejiang University
Xinke Wu, Zhejiang University
Weicheng Zhou, Zhejiang University
Shidong Cheng, Zhejiang University
Kuang Sheng, Zhejiang University

T10-Device and Thermal Modeling
Track: Modeling, Simulation, and Control

Title: Advanced SPICE Models Applied to High Power GaN Devices and Integrated GaN Drive Circuits
Abstract: The paper describes SPICE models and the use of SPICE models that have been developed for a CMOS/GaN cascode. The device is compared to a conventional discrete MOSFET/GaN cascode and a Super Junction MOSFET. The GaN devices provide a high speed 650V/50m?/50A switching capability. The DC and AC simulations of the high power structures use the new SPICE models which produce accurate simulations over a wide temperature range and width load currents ranging from 2-47A. Measured results are compared to the SPICE simulations and show that the high speed performance is maintained at the higher operating currents.
Presenters:
John Roberts, GaN Systems Inc.
Hugues Lafontaine, GaN Systems Inc.
Cameron McKnight-MacNeil, GaN Systems Inc.

Title: An Inductive-Switching Loss Model Accounting for Source Inductance and Switching Loop Inductance
Abstract: It is well known that that source inductance could significantly increase turn-on and turn-off time, and therefore increase switching power losses. Also, it is well understood that switching loop inductance could reduce voltage stress during turn-on and increase voltage stress during turn-off. In this paper, a new inductive switching loss model that includes source inductance and switching loop inductance has been derived and thoroughly analyzed. The new model shows that source inductance contributes a “visual gate charge”, which is equivalent to “physical gate charge”, when look from the driver. For high current switching conditions, the visual source charge dominates total gate charge and is the main factor for switching time. Simulations and experiments show that the model has very good accuracy.
Presenters:
Zhiyang Chen, ON Semiconductor

Title: Analytical Solution for Temperature Distribution of Power Semiconductor Devices Mounted on Rectangular Base Plate
Abstract: Thermal performance is a major design consideration for power electronics systems. Power semiconductor devices are temperature limited and to satisfy application reliability considerations it is necessary to limit the junction temperature during operation through design. Hence it is desirable to have a procedure that can accurately calculate the temperature distribution of the system under actual operation condition. This paper presents an analytical technique that estimates the temperature distribution of devices mounted on rectangular base plates without the lengthy computation required by finite element analysis (FEA). The procedure enables the designer to estimate the temperature distribution due to power dissipation on the base plate which could be heat sinks or printed circuit board, and to utilize this information to optimize the number of devices and their layout. This procedure can also be used to evaluate different cooling solutions to meet system level objectives, e.g. size and cost.
Presenters:
Xin Wu, United Technologies Research Center
Shashank Krishnamurthy, United Technologies Research Center

Title: An Effective Heat Propagation Path-Based Online Adaptive Thermal Model for IGBT Modules
Abstract: This paper proposes an Effective Heat Propagation Path (EHPP)-based online adaptive thermal model for IGBT modules, where the EHPP is proposed to quantify the impact of substrate solder cracks on the heat propagation inside the IGBT modules. A straightforward relationship between substrate solder crack and the degree of nonuniformity of case temperature distribution is established. Based on the EHPP, the parameters of a thermal network, e.g., a Cauer thermal network, are adjusted online to track the thermal behavior changes of the IGBT modules caused by substrate solder cracks, leading to an adaptive thermal model. The proposed adaptive thermal model is validated by comparing with finite element analysis (FEA) simulation results for a commercial IGBT module.
Presenters:
Ze Wang, University of Nebraska-Lincoln
Wei Qiao, University of Nebraska-Lincoln
Bo Tian, University of Nebraska-Lincoln
Liyan Qu, University of Nebraska-Lincoln

Title: Modeling, Design and Performance of Integrated Power Electronics Using MEMS Toroidal Inductors
Abstract: This paper presents the design and optimization of MEMS-microfabricated toroidal inductors targeted for use in integrated power electronics. The process is based on Monte- Carlo inductor synthesis, performance evaluation based on analytic inductor models and circuit simulation, and Pareto-optimal filtering. The models and simulation are verified through comparison with magnetic finite element analysis and measurements. The design process is illustrated through the development of a buck converter in a 25-W LED driver that uses air-core toroidal inductors and GaN transistors. Design results indicate that efficiencies higher than 90% and power densities higher than 100 W/in3 are possible. In the resulting designs the inductors are no longer the physically largest part of the converter.
Presenters:
Mohammad Araghchini, Massachusetts Institute of Technology
Jeffrey Lang, Massachusetts Institute of Technology

T11-Packaging for Higher Performance
Track: Packaging and Material Science

Title: Double-Sided Nickel-Tin Transient Liquid Phase Bonding for Double-Sided Cooling
Abstract: This paper is the first time presentation of double-sided nickel-tin transient liquid phase (Ni-Sn TLP) bonding and its application to double-sided cooling structures used in automotive power modules. Double-sided cooling is an emerging solution for heat dissipation problems inside compact power modules (used in electrified vehicles) and requires high-level reliability. This requirement is satisfied by the high re-melting temperature of Ni-Sn TLP bonding technology. Double-sided Ni-Sn TLP bonded (conventional) power diodes exhibited (1) consistent and reproducible bonding quality and (2) excellent high temperature reliability, demonstrated by electrical characterizations, high temperature storage (at 300C), and thermal cycling (-40 to 200C) evaluations.
Presenters:
Sang Won Yoon, Toyota Research Institute of North America
Koji Shiozaki, Toyota Research Institute of North America
Takehiro Kato, Toyota Motor Corporation

Title: Critical Design Issues of Retrofit Light-Emitting Diode (LED) Light Bulb
Abstract: For retrofit applications, some high-brightness (HB) light-emitting diode (LED) products have the same form factor restrictions as existing light bulbs. Such form factor constraints may restrict the design and optimal performance of the LED technology. In this paper, some critical design issues for a commercial LED bulb designed for replacing an E27 incandescent lamp are quantitatively analyzed. The analysis involves a power audit on such densely packed LED system so that the amounts of power consumption in (1) the LED driver, (2) the LED wafer, (3) the phosphor coating, and (4) the bulb translucent cover are quantified. The outcomes of such an audit enable R&D engineers to identify the critical areas that need further improvements in a compact LED bulb design.
Presenters:
Sinan Li, University of Hong Kong
Huanting Chen, University of Hong Kong
Siew-Chong Tan, University of Hong Kong
Shu Yuen Ron Hui, University of Hong Kong
Eberhard Waffenschmidt, Fachhochschule Köln

Title: Design Considerations for GaN HEMT MultiChip Half-Bridge Module for High-Frequency Power Converters
Abstract: This paper discusses the design of a multichip Gallium-Nitride (GaN) power module for high frequency power conversion. The module is designed with HRL 600 V Gallium-Nitride (GaN) enhancement mode HEMT device. To unleash the capability of fast switching with low loss from high voltage GaN devices, different layout structures have been analyzed to reduce power loop parasitic inductance and improve switching performance. The approach investigated in this paper is based on a multi-chip module where small current rated dies are placed in parallel to achieve higher current handling capability. Moreover, a transmission-line type gate structure has been proposed to minimize the gate loop inductance and reduce the gate voltage ringing. Finite-Element-Analysis (FEA) simulation and switching circuit simulation show that the multi-layer power loop design can effectively reduce the gate loop inductance and voltage overshoot on the devices.
Presenters:
Fang Luo, Virginia Polytechnic Institute and State University
Zheng Chen, Virginia Polytechnic Institute and State University
Lingxiao Xue, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Brian Hughes, HRL Laboratories LLC

Title: Misconception of Thermal Spreading Angle and Misapplication to IGBT Power Modules
Abstract: This paper analyzes the widely used 45 degree thermal spreading model in IGBT package design and quantifies error in application to both single and multi-layer package structures. The results are compared with finite element analysis (FEA). For single-layer heat transfer problem; the spreading angle model with a 45 degree assumption provides less than 20% conservative error of thermal resistance for a certain substrate layer thickness range. However, a more accurate modified spreading-angle model should be used for thicker single layer structures. For two or more layer structures, as commonly found in direct bonded copper (DBC) substrates used in multiple-chip power modules (MCPMs), the fixed-angle method cannot capture the behavior of the heat transfer problem and cannot accurately predict the temperature of critical points for design. The method introduces significant detrimental error dependent on layer thickness ratios. An in-depth literature review was conducted and little, if any, concrete basis for the 45 degree assumption was found.
Presenters:
Yang Xu, North Carolina State University
Douglas Hopkins, North Carolina State University

T12-System Integration I
Track: System Integration

Title: Noise Susceptibility of Delta-Vbe Temperature Sensors in Highly Integrated Power Converters
Abstract: This paper introduces the detrimental effects of voltage regulator noise on high precision “VBE analog temperature sense circuits. The work is based on a severe issue observed on a commercial power module. In the paper, the observed problem will be discussed, and a Spice model presented which allows the issue to be simulated. The main part of the work, however, concentrates on a very comprehensive experimental investigation of the problem. The paper concludes by offering important design guidelines for both analog and applications engineers when these high precision temperature sense circuits are used on power conversion circuits.
Presenters:
Derek Murray, Powervation Ltd.
Karl Rinne, Powervation Ltd.

Title: A Flexible and Cost Effective Gate Drive Platform for Rapid Prototyping
Abstract: Most electronics makers are familiar with hardware offerings ArduinoTM and XbeeTM, which are user friendly prototyping platforms for microcontrollers and wireless networks respectively; however an equivalent solution for power electronics is not available at comparable cost. This paper presents a low cost, flexible gate driver capable of interfacing with a variety of IGBT and MOSFET discrete or module packages over a wide operating space. The gate driver provides more than 2kV of isolation with an isolation capacitance of less than 5pF while supporting gate drive powers of up to 5W with bipolar 15V rails in ambient temperatures up to 40C.
Presenters:
Adam Shea, University of Wisconsin-Madison
Daniel Ludois, University of Wisconsin-Madison

Title: Analysis and Reduction of Common Mode EMI Noise for Resonant Converters
Abstract: This paper analyzes and compares the EMI characteristic and performance of three popular topologies of resonant converter (LLC, CLL and LCL). A state-of-art LLC resonant converter with matrix transformer is used as an example to illustrate the CM noise problem. The CM noise model of LLC resonant converter is provided. The CM noise of LLC converter is reduced significantly by a novel shielding technique for matrix transformer. The loss of shielding is analyzed and minimized using FEA tool. There is very little efficiency sacrifice for LLC converter with shielding according to the experiment result.
Presenters:
Yuchen Yang, Virginia Polytechnic Institute and State University
Daocheng Huang, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: On-Chip Integrated Cell-Level Power Manangement Architecture with MPPT for PV Solar System
Abstract: This paper presents the design of an on-chip integrated power management architecture with Maximum Power Point Tracking (MPPT) for Photovoltaic (PV) solar system. The system is developed in order to extract higher power for PV system under partial shading and other mismatching conditions. The MPPT circuit is implemented in 0.35µm Complementary Metal”Oxide”Semiconductor (CMOS) technology. The on-chip system utilizes a high-efficiency synchronous DC-DC boost power converter and analog Ripple Correlation Control (RCC) circuit for MPPT control. The 2400µm×5000µm developed Integrated Circuit (IC) is connected to a solar cell with 0.5V nominal output voltage and 5A output current. A peak efficiency of 92% is achieved. The design of the power stage and analog RCC MPPT algorithm circuit are presented and examined in this paper.
Presenters:
Ahmed Shawky, Aswan University
Fatma Helmy, Aswan University
Mohamed Orabi, Aswan University
Jaber Abu Qahouq, University of Alabama
Zhigang Dang, University of Alabama

Title: Terminal Admittance Based Stability Criterion for Multi-Module DC Distributed System
Abstract: In this paper, the stability issues of multi-module DC distributed power system are studied. Physical understanding of terminal characteristics of each module is focused. All the modules are divided into two groups based on the different terminal property type and different equivalent circuit is selected for each group. Equivalent circuits of total system are established to analyze the stability issue. Then, mathematical equations of total system are derived. Because the DC bus voltage of the total system is unique, the DC bus voltage is treated as response variable caused by the interaction among different modules. A generalized criterion based on the terminal admittance for multi-module distributed system is proposed. It’s clear that the proposed criterion is independent of the power flow direction.
Presenters:
Fangcheng Liu, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Haodong Zhang, Xi’an Jiaotong University
Danhong Xue, Xi’an Jiaotong University
Qinyun Dou, Xi’an Jiaotong University

T13-Multilevel/Matrix Conv
Track: Power Electronics Applications

Title: Realization of a SiC Module-Based Indirect Matrix Converter with Minimum Parasitic Inductances
Abstract: The use of new wide bandgap power semiconductor devices, like those based on silicon carbide (SiC), for different power converter applications is becoming more prevalent due to advantages realized at the system level when compared to conventional silicon (Si) devices. The small footprint and low switching losses of SiC devices allow an increase in the power density of power converters, but packaging them into a module is a challenge. As power converters with higher volumetric densities are being pursued, an IMC based on SiC semiconductor devices provides a more than viable solution for exceeding current power density limits. The development of a 10kVA, 480Vrms IMC module based on SiC 1200V, 40A MOSFETs and 1200V, 20A Schottky diodes to achieve a power density of 15 kW/liter is presented in this paper. The power converter is implemented in an interleaved input/output phase leg arrangement to reduce parasitic inductances in the critical dc-bus path by 30%. Experimental results of the IMC prototype are given to demonstrate the advantages and functionality of the proposed IMC system.
Presenters:
Jonathan K. Hayes, University of Arkansas
Andrés Escobar-Mejía, University of Arkansas
Juan Balda, University of Arkansas
Atanu Dutta, University of Arkansas
Simon Ang, University of Arkansas

Title: Space Vector Pulse Width Modulation Scheme for Three to Seven Phase Direct Matrix Converter
Abstract: In this paper a generalized multi-phase space vector theory is considered for developing the space vector modulation of a seven-phase direct matrix converter (DMC). The modulation is based on the control of the voltage vectors in the first d-q plane, while imposing the remaining voltage vectors in the second and the third planes (x1-y1, x2-y2), being zero. The duty cycles of the bidirectional switches are obtained using space vector modulation theory. The output to input voltage transfer ratio is obtained as 0.7694. The proposed matrix converter system offers full control of the input power factor, no limitation on the output frequency range and nearly sinusoidal output voltage. The proposed space vector algorithm can be fully implemented on a digital platform. The theoretical analysis is confirmed by digital simulations which is further verified using real time implementation.
Presenters:
Khaliqur Rahman, Qatar University
Atif Iqbal, Qatar University
Ahmad Anad Abduallah, Qatar University
Rashid Al-ammari, Qatar University
Haitham Abu-Rub, Texas A&M University at Qatar

Title: A Comprehensive Cell Capacitor Energy Control Strategy of a Modular Multilevel Converter (MMC) Without a Stiff DC Bus Voltage Source
Abstract: Cell capacitor energy control of a Modular Multilevel Converter (MMC) is conventionally done by controlling leg current and modulation strategy. In most of literatures, leg current transient is analyzed under an assumption that the DC bus is a stiff DC voltage source. In a real MMC-based HVDC transmission system, however, there’s no such virtual stiff DC voltage source and the conventional regulation method can lead to poor dynamics of cell capacitor energy control and even make system unstable. In this paper, the MMC model is revised for circulating current transient analysis. Based on the revised model, a new comprehensive cell capacitor energy control strategy is proposed by updating leg capacitor energy reference on-line and injecting positive and negative sequence circulating currents. Validity of the proposed method is verified by a 7-level scaled version prototype experimental setup.
Presenters:
Shenghui Cui, Seoul National University
Sungmin Kim, Seoul National University
Jae-Jung Jung, Seoul National University
Seung-Ki Sul, Seoul National University

Title: Principle, Conrol and Comparison of Modular Multilevel Converters (MMCs) with DC Short Circuit Fault Ride-Through Capability
Abstract: Lack of DC short circuit fault blocking and ride through capability is one of main issues in applications of Modular Multilevel Converter (MMC) to actual HVDC transmission system. Recently, several topologies have been proposed to provide DC short circuit fault blocking capability and/or DC fault ride through capability. In this paper, the operation principles, functionalities, and characteristics of several topologies are compared. And, it’s revealed that the conventional leg capacitor energy balancing strategy by regulating DC component of leg current fails under DC short circuit fault. A corresponding new leg capacitor energy balancing method by common mode voltage injection is proposed. Validity of the proposed method is verified by computer simulation.
Presenters:
Shenghui Cui, Seoul National University
Sungmin Kim, Seoul National University
Jae-Jung Jung, Seoul National University
Seung-Ki Sul, Seoul National University

Title: 1200V Cascaded HVIC Gate Driver for Three-Level Neutral-Point-Clamped Inverter IPM
Abstract: This paper proposes a new 1200V cascaded high voltage IC (HVIC) gate drive circuit for a 1200V three-level NPC inverter intelligent power module (IPM). The proposed single-ground IGBT gate driver of the 1200V three-level NPC inverter is based on a bootstrap capacitor charging method and a cascaded 600V HVIC configuration which can dramatically improve its integration for practical use, especially system air conditioner application. The proposed approach possibly enables high-volume production, low cost, and increased reliability of the 1200V three-phase inverter IPMs. Simulation and experimental results of a 1200V 30A three-level NPC inverter prototype and its IPM are provided to verify the effectiveness of the proposed 1200V cascaded HVIC gate driver for the 1200V three-level NPC inverter IPM.
Presenters:
In Wha Jeong, Samsung Electro-Mechanics
Bum Seok Suh, Samsung Electro-Mechanics
Keyue Smedley, University of California, Irvine

T14-PV Micro-Inverters
Track: Renewable Energy Systems

Title: Enhancing Micro-Inverter Energy Capture with Sub-Module Differential Power Processing
Abstract: In this paper, DPP converters are combined with micro-inverters to perform sub-module-level maximum power point tracking in micro-inverter systems. We present a DPP converter design that achieves substantial hardware miniaturization that allows for the converters to be fitted in a PV module junction box. The control of DPP converters to interface with the MPPT operation of the micro-inverter was analysed. A hardware prototype was built and tested with a commercial off-the-shelf micro-inverter and the effectiveness of the proposed solution has been experimental verified.
Presenters:
Shibin Qin, University of Illinois at Urbana-Champaign
Andrew Morrison, University of Illinois at Urbana-Champaign
Robert Pilawa-Podgurski, University of Illinois at Urbana-Champaign

Title: Fast Reconfigurable Photovoltaic Switching Cell Integrated Within DC-DC Converters
Abstract: This paper proposes a method to merge PV cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies. This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. As an example, reconfigurable PV-buck converter topology is presented. Its analysis, simulation and experimental verification are presented. Benefits and drawbacks of the new approach are discussed.
Presenters:
Jen-Hung Huang, Northeastern University
Ye Zhao, Northeastern University
Brad Lehman, Northeastern University

Title: A High Voltage-Gain LLC Micro-Converter with High Efficiency in Wide Input Range for PV Applications
Abstract: This paper proposes a novel high voltage-gain LLC micro-converter for PV applications. The converter has simple structure and minimum components with low cost. It can realize high voltage gain based on the voltage doubler rectifier with the optimal turns ratio. The main power switches can achieve ZVS and the output diodes can realize ZCS in wide input and load range. By utilizing the voltage doubler in the secondary side, the voltage stress over the output diodes can be reduced by half compared to the conventional center-tapped full-wave rectifier. A 24-48 V input, 380 V output and 200W prototype was built to verify the benefits of the proposed converter. The achieved efficiency of the converter peaks at 96.6% and the CEC weighted efficiency reaches 95.4%.
Presenters:
Han-Dong Gui, Nanjing Aeronautics and Astronautics University
Zhiliang Zhang, Nanjing Aeronautics and Astronautics University
Xiao-Fei He, Nanjing Aeronautics and Astronautics University
Yan-Fei Liu, Queen’s University

Title: A Dual-Active-Bridge Based Bi-Directional Micro-Inverter with Integrated Short-Term Li-Ion Ultra-Capacitor Storage and Active Power Smoothing for Modular PV Systems
Abstract: This work targets modular nanogrids for remote locations, where photovoltaic modules can be introduced to grow the renewable energy capacity at minimal capital cost, while reducing diesel fuel consumption. Today’s grid-tied micro-inverters provide a modular solution for ac power generation in nanogrids but battery storage remains centralized, requiring an additional ac-dc converter. A new micro-inverter platform and control scheme with bi-directional power flow between the nanogrid, the photovoltaic module and integrated Li-Ion Capacitor storage is proposed and implemented. In addition, an efficient real-time power smoothing algorithm based on the low-latency Hull moving average is demonstrated.
Presenters:
Shahab Poshtkouhi, University of Toronto
Miad Fard, University of Toronto
Husam Hussein, University of Toronto
Lucas Marcelino Dos Santos, University of Toronto
Olivier Trescases, University of Toronto
Mihai Varlan, Solantro Semiconductor
Tudor Lipan, Solantro Semiconductor

Title: Variable Boundary Dual Mode Current Modulation Scheme for Three-Phase Micro-Inverter
Abstract: A traditional half-bridge three-phase inverter topology can achieve zero voltage switching by implementing BCM operation which requires no additional power devices or magnetic components. In this paper a variable boundary dual-mode current modulation method that combines ZVS and ZCS is proposed in order to improve the efficiency of the BCM current controlled micro-inverter. Decreasing output current moves the ZVS/ZCS boundary toward the peak of the line half cycle which reduces the switching losses at light loads. Increasing output current will move this boundary toward the line zero crossing which reduces conduction losses at heavier loads. The experimental results show that using the proposed current modulation scheme peak efficiency of 98.7% for a 400W three-phase micro-inverter can be achieved with no additional cost.
Presenters:
Ahmadreza Amirahmadi, University of Central Florida
Utsav Somani, University of Central Florida
Lin Chen, University of Central Florida
Nasser Kutkut, University of Central Florida
Issa Batarseh, University of Central Florida

T15-PV MPPT and Battery Storage
Track: Renewable Energy Systems

Title: Single-Output-Sensor on-Chip Integrated MPPT for PV Solar System Power Management
Abstract: This paper presents the design and HSPICE simulation results of an on-chip integrated Single-Output-Sensor Maximum Power Point Tracking (SOS MPPT) PV solar system architecture. The cell-level on-chip integrated analog SOS MPPT circuit is designed to track the maximum power point of PV system under different conditions including changes in irradiation levels. The MPPT circuit is implemented using 0.35µm CMOS technology. Results are presented for a two PV solar cells connected in series and exposed to different solar irradiation levels, which show the ability of each cell to extract its MPP. The proposed cell-level integrated system is a step forward to overcome the effects of mismatches and/or partial shading phenomena in PV solar systems which affects efficiency. In addition, the system cost is reduced as a result of using one MPPT controller with only one sensor for N-cell PV solar system with cell-level MPPT control.
Presenters:
Eman Goma, Aswan University
Mohamed Orabi, Aswan University
El-Sayed Hasaneen, Aswan University
Jaber Abu Qahouq, University of Alabama

Title: A Global MPPT Algorithm for PV System Under Rapidly Fluctuating Irradiance
Abstract: A two-step global maximum power point GMPP tracking algorithm for photovoltaic (PV) system powered by a string of series-connected solar panels will be presented. The proposed algorithm has been evaluated on a 3kW grid-tie PV system with a PV simulator connected. The two different power-voltage characteristics are programmed and switched in order to test and compare the tracking performances of traditional perturb-and-observe (P&O) and proposed MPPT algorithms. Results show that the proposed algorithm can locate the GMPP in one second and its speed is three times faster than the P&O algorithm.
Presenters:
Ryan Shun-Cheung Yeung, City University of Hong Kong
Henry Shu-Hung Chung, City University of Hong Kong
Steve Tzu-Hsiung Chuang, ProVista Technology Limited

Title: Individual MPPTs of Single-Phase Three-Level Split DC-Bus Inverter
Abstract: This paper proposes a single-phase three-level split DC-bus inverter for individual maximum power point tracking (MPPT) controls. With only eight switches and one filter inductor, the proposed system provides compact and cost-effective circuits in comparison with conventional single-phase individual MPPTs topologies. The proposed system has two split DC-buses from conventional single-phase three-level inverter, thus it is possible that total four DC-link voltages are separately controlled for individual MPPTs. In the control method, proposed system uses two types of voltage controller: DC-bus voltage controller and voltage-difference controller. The formal conducts power distribution and the latter regulates the voltages in each DC-bus. For the voltage-difference controller, offset voltage and switching pattern change methods are presented. Two methods for the proposed system which differs from that of conventional three-level system are analyzed and the proper controllers are designed. In experiments, a prototype circuit is utilized and the feasibility of the proposed method is verified.
Presenters:
Hojoon Shin, Seoul National University
Jung-Ik Ha, Seoul National University

Title: A Multi-Stage MPPT Algorithm for PV Systems Based on Golden Section Search Method
Abstract: This paper proposes a complete maximum power point tracking (MPPT) solution for grid-connected photovoltaic (PV) systems. The proposed MPPT algorithm is a multi-stage algorithm combining the golden section search (GSS) method with other two commonly used methods: the perturb and observe (P&O) and the incremental conductance (INC). The GSS method is used for its fast convergence and robustness. The GSS mechanism, as well as the whole multi-stage MPPT strategy, is described in this paper. Finally, the results of simulations and experiments are given to verify the good performance of the system.
Presenters:
Riming Shao, University of New Brunswick
Rong Wei, University of New Brunswick
Liuchen Chang, University of New Brunswick

Title: A New Power Stage Architecture and Control Scheme to Optimize Maximum Power Point Tracking for Photovoltaic Systems
Abstract: This paper proposes a new approach to efficiently track the desired maximum power point for photovoltaic systems under partial shading conditions. The power stage architecture achieves fast input current change rate by combining a current adjustable converter with a few converters operating at a fixed current. By taking advantage of fast current change, the control scheme effectively combines P&O tracking and periodical global maximum power point searching, and fulfills fast tracking as well as maintaining ease of implementation.
Presenters:
Chung-Ti Hsu, Northeastern University
Brad Lehman, Northeastern University
Ting Qian, Tongji University

Title: Distributed PV- Battery Architectures with Reconfigurable Power Conversion Units
Abstract: This paper presents a family of single-stage converters called Reconfigurable Solar Converter (RSC) for integration of energy storage to the PV system where ramp-rate control is desired. An algorithm designed to reduce the variability of photovoltaic (PV) power output by using a battery shows the PV power output smoothing. The purpose of the battery is to add power to the PV output (or subtract power from the PV output) to smooth out the fast variations of the PV power that occur during periods with transient cloud shadows on the PV array. Therefore, one power conversion system named RSC with multi-mode capability may be used at different times of the day. The proposed solution potentially requires minimal complexity and modifications to the PV converter for PV-battery systems application, and it will provide new architectures and utilization methods for achieving more efficient and more controllable PV farms. These architectures will potentially create flexible, retrofit and expandable platforms for current and future PV power plants that can accommodate efficient PV arrays and economical battery systems.
Presenters:
Iman Mazhari, University of North Carolina, Charlotte
Manohar Chamana, University of North Carolina, Charlotte
Badrul Chowdhury, University of North Carolina, Charlotte
Babak Parkhideh, University of North Carolina, Charlotte

Title: A Comprehensive Study of Autonomous PV System with Battery Storage Providing Power for a General AC Load
Abstract: In this paper, an autonomous photovoltaic (PV) power generation/storage system connected to an AC nonlinear load is investigated. Depending on the load demand, the PV output power and the battery condition, five modes of operation are feasible with the changing load power. The steady-state analysis of the system for the entire operating modes is presented. Based on the concept of controllability sensitivity, the influence of the input variables on the state variables is obtained. How the estimated states for feedback control contribute in the measured variables is also explored using the observability sensitivity concept. In view of these findings, an input-output nonlinear PID controller scheme is designed to control the overall system. A computer simulation of the controlled power system using the MATLAB/Simulink software demonstrates the effectiveness of the control method.
Presenters:
Mehdy Khayamy, Tennessee Technological University
Olorunfemi Ojo, Tennessee Technological University
Eseme Sota, Tennessee Technological University

Title: Coordinate Control of Parallel Connected Power Conditioning System for Battery Energy Storage System in Microgrid
Abstract: This paper concentrates on the control of the integrated battery storage Power Conditioning Systems (PCS) parallel system in Microgrid (MG). To improve the power sharing accuracy during the islanded operation, an enhanced droop controller is introduced. The proposed approach is not only able to ensure accurate power sharing but also restore voltage drops due to droop effect and load effect. Moreover, a novel active islanding detection method based on active phase shift with positive feedback (APSPF) is presented in the parallel connected PCSs application.
Presenters:
Minghui Lu, Huazhong University of Science and Technology
Shanxu Duan, Huazhong University of Science and Technology
Changsong Chen, Huazhong University of Science and Technology
Jiuqing Cai, Huazhong University of Science and Technology
Lei Sun, Huazhong University of Science and Technology

Title: Capacitor-Less Photovoltaic (PV) Cell-Level Power Balancing Using Diffusion Charge Redistribution
Abstract: This paper presents a new strategy, diffusion charge redistribution (DCR), for balancing power among photovoltaic cells to increase energy extraction and to improve maximum power point tracking (MPPT) efficiency under partial shading conditions. With DCR, testing and binning during cell manufacturing can be eliminated, and significant cost savings can be achieved during production. The proposed technique performs power balancing by taking advantage the intrinsic diffusion capacitance of the solar cells and requires no external passive components for energy storage, thereby minimizing power electronics cost and complexity. Strings balanced by this technique exhibit power versus current curves that are convex, which also greatly reduces the cost and complexity of the required MPPT algorithm.
Presenters:
Arthur H. Chang, Massachusetts Institute of Technology
Al-Thaddeus Avestruz, Massachusetts Institute of Technology
Steven B. Leeb, Massachusetts Institute of Technology

T16-Magnetic Components, Design and Characterization
Track: Devices and Components

Title: Method for Introducing Bias Magnetization in Ungaped Cores: “The Saturation-Gap”
Abstract: Inductors intended for DC applications present their working point on the load line restricted to the first quadrant and their energy storage capability on the third quadrant remains unused. A known technique for equilibrating the inherent asymmetry of DC inductors consists on introducing a negative bias flux by means of permanent magnets. This technique can help to draw upon the storage capability on the third quadrant and thus reduce the size of a given DC inductor. This paper analyzes the pros and cons of different permanent magnet inductors configurations found in the scientific literature. It will also present a new biasing configuration termed: The Saturation-Gap and test it experimentally.
Presenters:
Andres Revilla Aguilar, Aalborg University
Stig Munk-Nielsen, Aalborg University

Title: Gapped Transformer Design Methodology and Implementation for LLC Resonant Converters
Abstract: In the LLC resonant converter, the air gap is generally positioned in the core of the transformer for proper magnetizing inductance. Traditional transformer design methods assume infinite permeability of the core and no energy stored in the core. The improved design methodology for the gapped transformer is proposed with the optimum relative permeability and gap selection to meet the temperature rise and the magnetizing inductance requirements. The magnetizing current influences the magnetic flux in the core leading to the core saturation and core loss, while the resonant current contributes to the winding loss. The transformer design for a 200 W, 90 kHz LLC resonant converter is presented and experimental results validate the proposed methodology.
Presenters:
Jun Zhang, National University of Ireland, Galway
W. G. Hurley, National University of Ireland, Galway
W. H. Wolfle, Convertec Ltd.

Title: Design and Implementation of PCB Inductors with Litz-Wire Structure for Conventional-Size Large-Signal Domestic Induction Heating Applications
Abstract: Induction cookers are usually designed to deliver up to several kilowatts per burner, working above 20 kHz. These appliances are arranged by means of planar-spiral inductors, made of conventional multi-stranded litz-wire, whose size can reach up to tens of centimeters. In this work, a PCB implementation of such inductors is proposed in order to replace the conventional windings, considering the induction efficiency as the figure of merit. With this purpose, a finite-element analysis FEA-aided design and a planar litz-wire structure has been used for implementing the windings. The design was validated by means of experimental measurements on a prototype.
Presenters:
Ignacio Lope, Universidad de Zaragoza
Claudio Carretero, Universidad de Zaragoza
Jesus Acero, Universidad de Zaragoza
Rafael Alonso, Universidad de Zaragoza
José Miguel Burdío, Universidad de Zaragoza

Title: Realistic Litz Wire Characterization Using Fast Numerical Simulations
Abstract: The losses of realistic litz wires are characterized while explicitly accounting for their construction, using a procedure that computes the current-driven and magnetic-field–driven copper losses using fast numerical simulations. We present a case study that examines loss variation in one- and two-level litz wires as a function of twisting pitch, over a wide range of values and in small increments. Experimental confirmation is presented for predictions made by numerical simulations. Results confirm the capability and efficiency of numerical methods to provide valuable insights into the realistic construction of litz wire.
Presenters:
Richard Zhang, Massachusetts Institute of Technology
Jacob White, Massachusetts Institute of Technology
John Kassakian, Massachusetts Institute of Technology
Charles Sullivan, Dartmouth College

Title: New Core Loss Measurement Method with Partial Cancellation Concept
Abstract: As an essential part in a power converter, the magnetic cores and their design play an important role in achieving high efficiency and high power density. Accurate measurement of the core loss is important to their optimization. To improve the measurement accuracy, previous methods were proposed to cancel the reactive voltage of the testing core by a cancellation capacitor or inductor. However, the value of the cancellation component is critical, and a small variation may induce a big measurement error, so extra effort is required to fine-tune the cancellation component value. This paper presents a new measurement method with partial cancellation concept that enables accurate core loss measurement at high frequency without requirement to fine-tune the cancellation component value.
Presenters:
Dongbin Hou, Virginia Polytechnic Institute and State University
Mingkai Mu, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: Wire Bonded MEMS-Scale on-Chip Transformers
Abstract: We present a novel wafer-level fabrication method of 3D solenoidal microtransformers using an automatic wire-bonder. Automatic wire bonders allow to precisely shape 25 ?m diameter wire around prefabricated yokes or magnetic cores within seconds. Former reports of wire bonded micro coils treated individual solenoids with low mutual inductance, whereas in this study transformers with strongly coupled micro solenoids are presented. The process is fully compatible with standard microelectronic manufacturing and, therefore, enables the direct integration of transformers into a given electronic circuit. Two different prototypes are presented here. A non-magnetic core transformer with power efficiency of 67% and resonance frequency of 312 MHz and a magnetic core transformer with more than 1 ?H inductance and 74% power efficiency at 29 MHz. Both prototype’s feasibility with view to power conversion in miniaturized circuits are evaluated.
Presenters:
Ali Moazenzadeh, Albert-Ludwigs-Universität Freiburg
Nils Spengler, Albert-Ludwigs-Universität Freiburg
Vlad Badilita, Albert-Ludwigs-Universität Freiburg
Jan G. Korvink, Albert-Ludwigs-Universität Freiburg
Ulrike Wallrabe, Albert-Ludwigs-Universität Freiburg

Title: A New Model for Designing Multi-Hole Multi-Permeability Nonlinear LTCC Inductors
Abstract: A new model for designing multi-hole multi-permeability nonlinear inductors. The proposed model significantly simplified the complicated electromagnetic analysis of the nonlinear inductors by breaking down the inductor into three basic units. The calculation results of the proposed model highly agree with the simulation results. By using a nonlinear inductor, the efficiency of a DC/DC converter can be improved.
Presenters:
Laili Wang, Queen’s University
Zhiyuan Hu, Queen’s University
Yajie Qiu, Queen’s University
Hongliang Wang, Queen’s University
Yan-Fei Liu, Queen’s University

Title: Silicon-Embedded Toroidal Inductors with Magnetic Cores: Design Methodology and Experimental Validation
Abstract: An approach to the ultimate integration and miniaturization of MEMS-based 3-D magnetic components involves embedding the volume of the magnetic structures within the volume of the silicon wafer itself, exploiting lithographically-patterned windings to create current paths, and utilizing embedded magnetic cores within the limited footprint of these components to boost the magnetic performance. However, this embedding approach imposes volumetric and microfabrication constraints that require an unusual magnetic component optimization methodology compared to wire-wound inductors and PCB inductors. A design methodology encompassing these constraints is therefore needed. For a targeted inductance value within a given footprint, our design methodology addresses an inductor with a maximized quality factor based on the trade-offs between winding loss and core loss. To illustrate this methodology, silicon-embedded inductors with drop-in iron powder cores are designed and fabricated, where a quality factor of 24 is achieved at 30 MHz.
Presenters:
Xuehong Yu, Georgia Institute of Technology
Jungkwun Kim, Georgia Institute of Technology
Florian Herrault, Georgia Institute of Technology
Mark Allen, Georgia Institute of Technology

Title: Optimization of Windings in PFC Boosts and PWM Inverters to Maximize Converter Efficiency
Abstract: Optimization of the inductors and transformers in switching power converters is presented in the paper. Inductive components of different core ” coil geometries and wire technologies are taken into account. Rigorous analytical modeling was applied to achieve minimization of the losses, using homogenization of the stack of wires in equivalent conductive layers of the coils. The resolution has been carried out for many different shapes of conductors. Comparative study by complementary FEM approach shows and explains varied physical phenomena as e-mag interactions between the turns. Focus is done on skin and proximity effects and possible solutions to reduce their harmful influence on converter efficiency decreasing. Several new technologies by improved winding geometries and novel coil structures are discussed. The necessity of the optimization process to find the best industrial solution has been proven.
Presenters:
Timothe Delaforge, Schneider Electric
Herve Chazal, Université de Grenoble / G2Elab
Robert Pasterczyk, Schneider Electric

T17-AC Motor drives
Track: Motor Drives and Inverters

Title: Switched Doubly-Fed Machine Propulsion Drive
Abstract: Variable speed drives (VSD) constructed with doubly-fed machines (DFM) offer interesting flexibility for power electronic drive design. They also offer opportunities for controlling interactions with an ac grid. Design options are most flexible for the VSD DFM when the machine stator can be operated from an ac or dc source, selected “on-the-fly” as appropriate. This paper presents a SCR-based transfer switch that can connect the stator of the DFM either to an ac source or a dc source “on-the-fly”. Current commutations of the SCRs and a “bumpless” transition in shaft behavior is controlled from the rotor.
Presenters:
Arijit Banerjee, Massachusetts Institute of Technology
Arthur H. Chang, Massachusetts Institute of Technology
Kawin Surakitbovorn, Massachusetts Institute of Technology
Steven B. Leeb, Massachusetts Institute of Technology
James L. Kirtley Jr., Massachusetts Institute of Technology

Title: Impact of Stator Grounding in Low Power Single-Phase EC-Motors
Abstract: Bearing currents cause a reduction of ball bearing lifetime in electronically commutated permanent magnet motors. To compensate the lifetime decreasing factors, a tradeoff between special bearings and additional changes in the machine design have to be found, since e.g. stator grounding, which keeps the bearing voltage low and thus guarantees a long fan system’s lifetime, results in a higher input filter effort. Instead of reducing the bearing voltage, hybrid bearings could be deployed, which feature a high dielectric strength. However, hybrid bearings are much more expensive than conventional metal bearings, thus the extra cost for the hybrid bearings has to be weighed up against the higher filter effort. This paper deals with the impact of stator grounding to avoid bearing currents in low power single-phase motors by analyzing the bearing damage mechanism. Based on the presented filter design procedure, the additional filter effort for stator grounded motors is determined, which shows that hybrid bearing are undesirable in mass application.
Presenters:
Sebastian Schroth, Eidgenössische Technische Hochschule Zürich
Dominik Bortis, Enertronics GmbH
Johann Walter Kolar, Eidgenössische Technische Hochschule Zürich

Title: Inverter Characterization for Intermittent and Peak Duty Motor Drives
Abstract: This paper investigates inverter short-time ratings, electrical limitations and proper sizing under peak duty applications. Previous electro-thermal models rely on proprietary dimensional data, thus for a generic investigation transient thermal characteristics are used. A well-established inverter transient thermal model that relies only on manufacturer data is developed. Using this model, maximum allowable output current and associated time ratings are obtained for the maximum temperature rise. The inverter model is experimentally validated using a three-phase IGBT inverter. The validated model is also tested for several motor-drive overload scenarios using a real-time hardware-in-the-loop test bed run using a MATLAB XPC target.
Presenters:
Veysel Buyukdegirmenci, University of Illinois at Urbana-Champaign
Philip Krein, University of Illinois at Urbana-Champaign

Title: Saturation Controller-Based Ripple Reduction for Direct Torque Controlled Permanent-Magnet Synchronous Machines
Abstract: This paper proposes a novel direct torque control (DTC) scheme to reduce the torque and stator flux ripples for permanent-magnet synchronous motor (PMSM) drives using a relatively low sampling frequency. Unlike the conventional DTC in which the voltage vectors are determined by hysteresis controllers, the proposed DTC uses nonlinear saturation comparators and a duty ratio modulation scheme for switch selection and switching duration determination. Compared to the conventional DTC, the proposed DTC scheme significantly reduces the steady-state torque and flux ripples of PMSMs while preserving most of the intrinsic properties of the conventional DTC, e.g. fast dynamic, robust to disturbances, no coordinate transformation, etc. The effectiveness of the proposed DTC scheme is verified by simulation and experimental results on a 200W PMSM drive system.
Presenters:
Zhe Zhang, University of Nebraska-Lincoln
Wei Qiao, University of Nebraska-Lincoln
Liyan Qu, University of Nebraska-Lincoln

Title: EMI Noise Mode Transformation Due to Propagation Path Unbalance in Three-Phase Motor Drive System and its Implication to EMI Filter Design
Abstract: In this paper, the analysis of the intrinsic unbalance existing in the EMI noise propagation path of the dc-fed three-phase motor drive system is carried out. Unbalance in the circuit model is investigated with different switching statuses in three-phase space vector pulse-width-modulation (SVPWM). The transformation between the common-mode (CM) and differential-mode (DM) noises due to the unbalance is then studied theoretically and verified by simulation and experimental results in prototype system. Influence of the unbalance and noise mode transformation on the EMI filter design is discussed and a comprehensive design procedure for high density EMI filter is proposed.
Presenters:
Jing Xue, University of Tennessee
Fred Wang, University of Tennessee
Ben Guo, University of Tennessee

Title: Space-Vector-Based Hybrid PWM Technique to Reduce Peak-to-Peak Torque Ripple in Induction Motor Drives
Abstract: Special switching sequences involving division of active state time are used in space-vector-based generation of pulse width modulation (PWM) waveforms. This paper proposes a hybrid PWM technique which is a combination of the conventional and special switching sequences. The proposed hybrid PWM technique reduces the peak-to-peak torque ripple at high speeds of an induction motor drive. Supporting simulation and experimental results are presented from a closed-loop controlled motor drive.
Presenters:
Pavan Kumar Hari, Indian Institute of Science, Bangalore
Gopalaratnam Narayanan, Indian Institute of Science, Bangalore

Title: Bidirectional PMSM Drive Employing a Three Level ANPC Inverter and a Multi-Phase Interleaved DC/DC Converter for Hybrid Electric Vehicles
Abstract: A proposal for a two-stage bidirectional electric drive for hybrid electric vehicles is presented. A synchronous PM electric machine is directly connected to a Diesel internal combustion engine. The machine is fed by a three-level active neutral point clamped inverter connected to a bi-directional multi-phase interleaved DC/DC converter interfacing the high voltage dc-link with a low voltage battery. Design issues and control topics are fully investigated. Simulation and experimental results are based on a prototype test bench, composed by two external rotor PMSMs having same speed/torque/power ratings and connected to the same shaft, intended to emulate a hybrid traction system.
Presenters:
Silverio Bolognani, Università degli Studi di Padova
Mattia Morandin, Università degli Studi di Padova
Sandro Calligaro, Università di Udine
Roberto Petrella, Università di Udine
Alessandro Pevere, Università di Udine

Title: Maximum Torque Per Ampere Control for Interior Permanent Magnet Motors Using DC Link Power Measurement
Abstract: Maximum torque per ampere (MTPA) control scheme for internal permanent magnet (IPM) machine is presented in this paper. Proposed control scheme was developed based on measurement of only DC link quantities eliminating the necessity of 3-phase current feedback. The scheme employs an online search algorithm with initial condition computed from a-priory system information. Hybridization of search based algorithm with pre-computed control coefficients ensures robustness against parameter variations while maintaining good dynamic performance.
Presenters:
Adeeb Ahmed, University of Akron
Yilmaz Sozer, University of Akron
Marv Hamdan, Bendix CVS

Title: Novel Topology and Control of Single Inverter System for Two Permanent Magnet Synchronous Machines
Abstract: This paper proposes a novel topology which is capable of operate two permanent-magnet synchronous machines (PMSM) using a single 6-bridge inverter and its control method. In the conventional parallel connection method for this application, two motors can operate only at the same speed and have a high risk of loss of synchronism since the single voltage is applied to both motors. In other inverter topologies, the number of switches increases or implementation of inverter is complicated. On the other hand, the proposed topology can employ the conventional six bridge power module without any modification or addition and operate two motors at the different speeds using the superposition principle. The analysis of the proposed system is presented and the control method to independently operate two motors is proposed. It is verified through experimental results.
Presenters:
Youngnam Kim, Seoul National University
Jung-Ik Ha, Seoul National University

T18-Industrial Converters
Track: Power Electronics Applications

Title: Online Frequency Response Analysis: a Powerful Plug-in Tool for Compensation Design & Health Assessment of Digitally Controlled Power Converters
Abstract: This paper presents a cycle efficient software frequency response analyzer (SFRA), that is added to the software of the digital controller being used to control the power converter. SFRA needs no extra hardware connections and hence can be run periodically. The gathered frequency response data can be used to correlate with the health and changes in stability margins of the power converter; which can change due to aging and degradation of components caused by electrical and thermal stresses. The paper compares fixed and floating point implementation of SFRA and discusses a dual core approach to run SFRA for high switching frequency power converters. A bi-directional buck boost converter is used as a case study to demonstrate the SFRA, where first SFRA is used to extract the plant TF, which is then used to design the compensation and the designed compensation is then verified using SFRA.
Presenters:
Manish Bhardwaj, Texas Instruments
Shamim Choudhury, Texas Instruments
Richard Poley, Texas Instruments
Bilal Akin, University of Texas at Dallas

Title: Uniform Single-Sided Induction Heating Using Multiphase, Multi-Resonant Halbach Windings
Abstract: Traditional induction heating cooktops typically employ a circular planar coil in resonance excited by a switching inverter. This configuration results in stray magnetic fields below the coil and non-uniform heating profile on the top. This paper presents the concept of multiphase, multi-resonant induction heating using a Halbach winding arrangement to eliminate the shortcomings of the traditional cooktop. A multiphase winding structure enables a traveling magnetic field at the target, which results in uniform heating profile. Operating the phases at different resonances deliver power at different frequencies. The winding and drive structure developed in this paper can be applied to many other applications, including chargers and wireless power delivery systems.
Presenters:
Arijit Banerjee, Massachusetts Institute of Technology
Al-Thaddeus Avestruz, Massachusetts Institute of Technology
Kawin Surakitbovorn, Massachusetts Institute of Technology
Arthur H. Chang, Massachusetts Institute of Technology
Steven B. Leeb, Massachusetts Institute of Technology

Title: SiC BJT-Based Full-ZCS Quasi-Resonant Converter with Improved Efficiency for Induction Heating Applications
Abstract: This paper analyzes the impact and opportunities of using high-voltage SiC switching devices in a pulsed power supply oriented to domestic induction heating applications. Considering the converter requirements, SiC BJT devices results the most appropriated technology, improving the efficiency and the reliability. The proposed converter has been experimentally verified and, additionally, a specific activation circuit to improve its efficiency is proposed.
Presenters:
Hector Sarnago, Universidad de Zaragoza
Oscar Lucía, Universidad de Zaragoza
Arturo Mediano, Universidad de Zaragoza
José Miguel Burdío, Universidad de Zaragoza

Title: General Optimal Design Method for Series-Series Resonant Tank in Loosely-Coupled Wireless Power Transfer Applications
Abstract: Conventionally in wireless power transfer applications, symmetrical resonant tank (SRT) type, which employs an identical physical geometry for transmitter coil (Tx) and receiver coil (Rx), has been popular. However, for portable applications it is desirable to minimize size and weight of Rx, while Tx should provide stronger and more uniform magnetic field. Consequently, asymmetrical resonant tank (ART) type, which employs different physical geometries for Tx and Rx, is quite attractive. In this paper, a general optimal design method is proposed for series-series resonant tank in loosely-coupled wireless power transfer applications. Various simulation results and experimental results are presented to validate that the optimized resonant tank exhibits approximately equal values for voltage gain and current gain under magnetic coupling variation at a desirably fixed frequency. It is also shown that under this condition circulating current gain is approximately at its absolute minimum, which translates in reduced losses in an inductive coupler. Therefore, an optimal compromise between power delivery robustness and coil-to-coil efficiency can be achieved.
Presenters:
Isaac Nam, University of South Carolina
Roger Dougal, University of South Carolina
Enrico Santi, University of South Carolina

Title: Resonant Switched-Capacitor Voltage Regulator with Ideal Transient Response
Abstract: A new, small and efficient voltage regulator realized using a resonant switched capacitor converter (RSCC) technology is introduced. Voltage regulation is implemented by means of simple digital pulse density modulation (PDM). It displays an ideal transient response with a zero-order response to all disturbance types. The newly developed RSCC acts as a gyrator with a wide range of voltage conversion ratios (below as well as above unity) with constant efficiency characteristics for the entire operation range. The operation of the voltage regulator is verified on a 20W experimental prototype, demonstrating ideal transient recovery without over/undershoots in response to load and line transients. Simple design guidelines for the voltage regulation system are provided and verified by experiments.
Presenters:
Alon Cervera, Ben-Gurion University of the Negev
Mor Mordechai Peretz, Ben-Gurion University of the Negev

Title: A Current-Fed Asymmetric LLCC Resonant Converter for DBD Applications
Abstract: The current-fed asymmetric full-bridge LLCC resonant converter proposed in this paper has less components and simpler circuit structure compared with a previous design. Only two reverse-voltage blocking diodes and no front-end buck circuit are required. The magnetic integration technique is utilized to form the LLCC resonant tank. The power regulation is achieved by employing the phase-shift control. The leading switches realize ZCS and the lagging switches achieve ZVS, reducing the switching losses. A mathematical description based on RCFHA is effective and accurate enough for this design. The operation principle is verified by the experimental results.
Presenters:
Shiqiang Hao, Zhejiang University
Chi Zhang, Zhejiang University
Tangtang Guo, Zhejiang University
Xingliang Liu, Zhejiang University
Sideng Hu, Zhejiang University
Jun Liu, Zhejiang University
Xiangning He, Zhejiang University

Title: A New High Efficiency Isolated Bi-Directional DC-DC Converter for DC-Bus and Battery-Bank Interface
Abstract: A new bi-directional DC-DC converter is designed and analyzed in this paper. This new topology and its control strategy have completely solved the voltage spike issue in the bi-directional DC-DC converter which has limited its power level and efficiency, while most of the other existing solutions could only make improvements instead of a fundamental solution. This converter can serve as battery bank and DC-bus interface in uninterruptible power system (UPS) and work in both directions (charging-battery direction and supporting-bus direction) with high efficiency. Operation principles of each block of the circuit and system implementation have been analyzed. Experimental results show high efficiency is able to be achieved in both directions. A 300W in (charging battery) 1500W out (supporting bus) prototype proposed is able to charge battery at 93.0% efficiency (300W) and support bus at 93.6% efficiency (1500W). Higher power level can be easily achieved by re-configuration or paralleling.
Presenters:
Xiaoyan Yu, Vicor Corporation
Paul Yeaman, Vicor Corporation

Title: Adaptive DC-DC Converter for 4G Macro-Cell Base Station
Abstract: Despite the constant improvement in power efficiency of macro-cell base stations, the continuous capacity expansion increases considerably the global power consumption of the mobile network. This article presents a new concept of managing the DC-to-DC converter supplying power amplifiers in base stations, targeting a factor two reduction in power consumption. Details of the concept and the practical implementation of a 500 kHz and zero to 112W buck converter are discussed. The prototype achieves 94% power efficiency and a good stability over the complete power range.
Presenters:
Jean-Marie Retrouvey, NXP Semiconductors
Philippe Maugars, NXP Semiconductors
Nguyen Trieu Luan Le, NXP Semiconductors
Philippe Descamps, LaMIPS

Title: A Negative Voltage Supply for High-Side Switches Using Buck-Boost Bootstrap Circuitry
Abstract: The unipolar gate driving method provides a low cost and simple solution for inverter system design. However, the unipolar gate driving can cause issues like ‘parasitic oscillation’ during turn-on of power switches and ‘unintended parasitic turn-on’ caused by the Miller-effect of power semiconductors. Hence the maximum value of gate resistance has to be limited. To overcome the above mentioned issues, a negative gate voltage can be applied to the switch. Unfortunately the standard method for bootstrapping a positive gate voltage cannot be extended to negative voltages without increasing the complexity. The proposed bootstrap circuit can generate a negative gate voltage with minimal increase of components. For this purpose a buck-boost converter is merged with a standard bootstrap topology which can generate a negative as well as a positive gate voltage for high-side switches without additional power supply.
Presenters:
Jongmu Lee, Infineon Technology
Stephan Chmielus, Infineon Technology
Chung-Yuen Won, SungKyunKwan University

T19-Three-Phase AC-DC Converters
Track: AC-DC Converters

Title: A New Interleaved Three-Phase Single-Stage PFC AC-DC Converter with Flying Capacitor
Abstract: A new interleaved three-phase PFC ac-dc single-stage multilevel is proposed in this paper. The proposed converter uses flying capacitor structure with standard phase-shift PWM to improve efficiency of the converter particularly at light load conditions. In the paper, the operation of the converter is explained, the steady-state characteristics of the new converter are determined and its design is discussed. The feasibility of the new converter is confirmed with experimental results obtained from a prototype converter and its efficiency is compared to that of another multilevel converter of similar type
Presenters:
Mehdi Narimani, University of Western Ontario
Gerry Moschopoulos, University of Western Ontario

Title: High Efficiency Paralleled Three-Phase Current Source Front-End Rectifiers for Data Center Power Supplies with Current Balancing and Hot-Swap
Abstract: This paper develops a 19 kW three-phase front-end power conversion stage for data center power supplies based on 400 Vdc power delivery architecture. The front-end stage is based on three paralleled three-phase current source rectifiers (CSRs), which have several benefits for this application. A control method will be introduced for paralleled CSRs to achieve balanced output power and individual rectifier module hot-swap, which are required by power supply systems. By using SiC devices, the power conversion efficiency of front-end stage is improved and the whole efficiency of the data center power supply system can be further increased too.
Presenters:
Fan Xu, University of Tennessee
Ben Guo, University of Tennessee
Zhuxian Xu, University of Tennessee
Leon M. Tolbert, University of Tennessee
Fred Wang, University of Tennessee
Benjamin J. Blalock, University of Tennessee

Title: Power Distribution in a 13 kW Three-Phase Rectifier System: Impact on Weight, Volume and Efficiency
Abstract: The impact of using distributed or centralized power processing to supply isolated loads on weight or efficiency is not clear. This paper addresses the evaluation of these metrics on an aircraft application consisting on seven isolated DC loads to be supplied from the AC grid. Additionally the rectifier switching frequency has to be synchronized with an external frequency clock to minimize the interference of the converter harmonics with the loads
Presenters:
Jose Maria Molina, Universidad Politécnica de Madrid
Sisi Zhao, Universidad Politécnica de Madrid
Marcelo Silva, Universidad Politécnica de Madrid
Jesús Angel Oliver, Universidad Politécnica de Madrid
Pedro Alou, Universidad Politécnica de Madrid
Javier Torres, INDRA
Fernando Arévalo, INDRA
Oscar García, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Input Impedance Improvement by Using Digital Compensation Strategy for High Power Density Rectifiers with Wide Load Operation
Abstract: In this paper, an improved control loop based on feedforward is proposed to reduce the total harmonic distortion of the input current (THDi), realizing power factor correction (PFC) in MCM. The frequency responses of the input impedance for a wide frequency range are improved and unified by adding feedforward duty-ratio to the output of the original current-loop. A 5 kW experimental prototype is built to verify the validity of this strategy. The experimental results show that the system has close to unity power factor (PF), and THDi is significantly reduced.
Presenters:
Shengbao Geng, Shanghai Jiao Tong University
Fei Wang, Shanghai Jiao Tong University
Lijun Hang, Shanghai Jiao Tong University
Yong Wang, Shanghai Jiao Tong University

Title: Design and Experimental Verification of a Third Harmonic Injection Rectifier Circuit Using a Flying Converter Cell
Abstract: The proposed active three-phase rectifier circuit utilizing a Flying Converter Cell (FCC) based on the concept of third harmonic injection allows the extension of a passive three-phase diode bridge rectifier to a low-harmonic input stage (THDi < 5%) for applications where dc-link voltage control is not required. In this work the design and experimental verification of a 10 kW laboratory prototype using the proposed concept is addressed. Based on the analysis of the rectifier system a control concept is developed which is implemented in a digital signal processor. It is shown that the proposed rectifier system shows several degrees of freedom which can be used for system optimization. Several implementation details are discussed and experimental results taken from the constructed 10 kW laboratory prototype demonstrate the good performance of the proposed rectifier system and verify the proper operation of the developed control concepts.
Presenters:
Michael Hartmann, Schneider Electric
Rudolf Fehringer, Schneider Electric
Markus Makoschitz, Technische Universität Wien
Hans Ertl, Technische Universität Wien

Title: Three-Phase Unidirectional Buck-Type Third Harmonic Injection Rectifier Concepts
Abstract: This work introduces three-phase unidirectional buck-type unity power factor rectifiers. The proposed rectifiers are assembled by incorporating auxiliary circuit branches into standard three-phase buck-type PFC topologies, each comprising an active switch and three diodes. These circuits can operate as active third harmonic current injection PFC systems. The characteristics of the buck-type converters, including their operation principle, appropriate modulation strategy and control structure, are described. The proposed converters are compared to state-of-the-art buck-type rectifiers. According to the results, the proposed rectifiers can achieve the highest efficiency and thus are the topology of choice for a 2.5 kW three-phase buck-type PFC rectifier.
Presenters:
Thiago Soeiro, ABB Switzerland Ltd.
Gean de Sousa, Universidade Federal de Santa Catarina
Márcio Ortmann, Universidade Federal de Santa Catarina
Marcelo Heldwein, Universidade Federal de Santa Catarina

Title: Performance Comparison of PI and P Compensation in Average-Current-Controlled Three-Phase Six-Switch Boost PFC Rectifier
Abstract: In this paper it is shown that in the three-phase six-switch boost PFC rectifier with average-current control and mismatched input-voltage and/or input-current sensing gains, the current controller with proportional (P) compensation exhibits better performance, i.e., lower THD and higher PF, compared with that of the proportional and integral (PI) compensation. It is also shown that the P compensation with the input-voltage feedforward is effective in improving output-voltage transient response with respect to input-voltage changes only if the duty-cycle feedforward is also implemented. The operation of the three-phase six-switch boost PFC rectifier with average current control implemented with PI and P compensation is illustrated with Matlab/Simulink simulation waveforms. Experimental results, which are in good agreement with the simulation results, are also provided.
Presenters:
Laszlo Huber, Delta Products Corporation
Misha Kumar, Delta Products Corporation
Milan Jovanovic, Delta Products Corporation

Title: Three-Level TAIPEI Rectifier
Abstract: A new low-cost, three-phase, four-switch, three-level, zero-voltage-switching (ZVS), discontinuous-current-mode (DCM), power-factor-correction (PFC) boost rectifier, for short named the three-level TAIPEI rectifier, that achieves a low input-current total-harmonic-distortion (THD) and features ZVS of all the switches is introduced. In the proposed rectifier, the voltage stress of the four switches is equal to one-half of the output voltage. Consequently, the rectifier can utilize switches with a lower voltage rating, which, generally, have lower conduction losses. The performance was evaluated on a three-phase 6-kW prototype for the line-to-line voltage range from 340 V to 520 V. The proposed rectifier exhibits efficiency in the 96-98% range, achieves less than 5% input-current THD over the entire input and above 10% load range.
Presenters:
Yungtaek Jang, Delta Products Corporation
Milan Jovanovic, Delta Products Corporation
Juan Ruiz, Delta Products Corporation

Title: Isolated Swiss-Forward Three-Phase Rectifier for Aircraft Applications
Abstract: A new trend of DC distribution is emerging employing a 270 Vdc grid. This yields the need for high-efficiency and high power-density AC-DC converters, connecting the two grids while providing galvanic isolation. This paper presents a new isolated single-stage PWM rectifier system, based on the recently presented non-isolated Swiss rectifier topology, called the Swiss-Forward rectifier. The principle of operation of this converter topology is presented together with detailed design guidelines and experimental validation on a 3.3kW 115Vac to 270Vdc prototype.
Presenters:
Marcelo Silva, Universidad Politécnica de Madrid
Nico Hensgens, Universidad Politecnica de Madrid
Jesús Angel Oliver, Universidad Politécnica de Madrid
Pedro Alou, Universidad Politécnica de Madrid
Oscar García, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

T20-Improved Power Quality & Stability Approaches in Power Converter Application
Track: Power Electronics for Utility Interface

Title: Indirect Voltage Control Method for Single Phase DC/AC Converters
Abstract: A controller for single phase DC/AC converters is proposed that is analogous with the droop control method used in synchronous generator technology. Its approach is different from the existing droop techniques adopted for power electronic inverters where consistently the output voltage is controlled through an explicit voltage control loop. The proposed method indirectly controls the output voltage of the inverter by controlling its immediate (or internal) voltage. Therefore, when operating in parallel with other inverters, it can offer a more robust and stable operation by avoiding direct competition of the inverters. This paper presents the derivations and numerical results of the proposed controller.
Presenters:
Masoud Karimi-Ghartemani, Mississippi State University

Title: A Unified Control Scheme for Harmonic Elimination in the Front End Converter of a 13.8 kV, 100 kVA Transformerless Intelligent Power Substation Grid Tied with LCL Filter
Abstract: This paper proposes a simple control scheme to eliminate lower order harmonics in the line currents of FEC of a 100kVA TIPS connected to 13.8 kV grid using an LCL filter. Due to medium voltage and low power specification for the FEC, control technique needs to be specially designed to control very low magnitude of line current. Lower order harmonics are present in grid current due to dead time in the FEC and grid voltage harmonics. The control scheme eliminates harmonics by regulating the harmonics in the filter capacitor voltage and inductor currents both on grid side and converter side.
Presenters:
Sachin Madhusoodhanan, North Carolina State University
Subhashish Bhattacharya, North Carolina State University
Kamalesh Hatua, Indian Institute of Technology Madras

Title: Efficient Single Phase Power Factor Improvement Strategy for Microgrid Operation
Abstract: A strategy to improve the power factor (PF) at the point of common coupling (PCC) for microgrid applications is presented in this paper. The position of the compensating unit is selected to correct the power factor and reduce the harmonic levels of the grid current and PCC voltage in microgrid connected distributed renewable energy sources. The proposed compensation system for power factor improvement (PFI) can be operated dynamically for both linear and nonlinear loads. Fast and efficient algorithm for phase detection in the presence of harmonics has been incorporated to the proposed system. Finally simulation and experimental results are presented to verify the effectiveness of proposed compensation unit.
Presenters:
Saeed Anwar, University of Akron
Ali Elrayyah, University of Akron
Yilmaz Sozer, University of Akron

Title: New Current Control Strategy for Local Converter Under Distorted Grid Conditions
Abstract: This paper proposes a novel current control method for reducing the rms current of converters in the distorted grid. The proposed strategy can reduce the conduction losses of both local converter itself and overall power system. Practically, the grid may be distorted by various non-linear loads, but conventional regulations assume ideal grid voltages. Therefore, this paper considers distortion conditions and mathematically calculates an optimal current of the local converter. The corresponding control scheme is implemented, and the analysis for the effects on the grid by the proposed strategy is also presented. Experimental results verify the outperformance of the proposed control.
Presenters:
Kyung-Hwan Lee, Seoul National University
Yongjae Lee, Seoul National University
Jung-Ik Ha, Seoul National University

Title: A Single-Phase Shunt Active Power Filter with an Improved Modulated Carrier Control
Abstract: This paper proposes an improved modulated carrier control for single-phase active power filter. This control method directly shapes input current to be sinusoidal and in phase with input voltage by comparing a modulated carrier signal to the average input current and making duty ratio doubled. Since the input current value compared to the carrier signal is average, dc-offset issue is effectively addressed. The proposed control technique extirpates the harmonic currents and solves the dc-offset problem. The operation of a shunt active power filter with the proposed control is discussed and experimental results verify its performance.
Presenters:
Gibong Son, Seoul National University Power Electronics Center
Hyejin Kim, Seoul National University Power Electronics Center
Bo-Hyung Cho, Seoul National University Power Electronics Center

Title: Distributed Power Balance Strategy for DC/DC Converters in Solid State Transformer
Abstract: A distributed power balance strategy for DC/DC converters in Solid State Transformer (SST) is presented in this paper. Unbalanced power in dc/dc stage of SST is analyzed theoretically and an adapted droop method is developed accordingly. The proposed strategy can not only balance power distributed, but also eliminate the voltage drop caused by the conventional droop control. In the end, simulation and experimental results are provided for verifying the proposed method.
Presenters:
Xunwei Yu, North Carolina State University
Xu She, North Carolina State University
Alex Huang, North Carolina State University
Liming Liu, ABB Inc.

Title: A Distribution System Harmonic Compensation Approach Using DG-Grid Interfacing Converters at Low Switching Frequency
Abstract: In recent years, embedding ancillary functions of distributed generation (DG) has drawn great attention due to the increasing penetration of renewable energy based DG. When controlled properly, the DG-grid interfacing converters can provide effective harmonic compensation for the distribution power system. However, the conventional harmonic control methods used for active power filters (APFs) may not be suitable for DG units, where the flow of real and reactive power limits the switching frequency to be lower than APFs. In this paper, a harmonic compensation approach suitable for DG-grid interfacing converters at low switching frequency is proposed.
Presenters:
Xiaohan Wen, University of Alberta
Yun Wei Li, University of Alberta
Jinwei He, University of Alberta

Title: Single-Phase Active Power Filter for Selective Harmonic Elimination Based on Synchronous Frame Control System
Abstract: In this paper is presented a synchronous reference frame control strategy for single-phase active power filter. The presented system is based on a selective harmonic elimination approach and allows for the fundamental reactive power compensation and harmonic elimination. The control system is carried out on a synchronous frame, which brings robustness and simplicity to the whole system.
Presenters:
Isaac Freitas, Universidade Federal da Paraíba
Zariff Gomes, Universidade Federal da Paraíba
Marcos Meira, Universidade Federal da Paraíba
Fabiano Salvadori, Universidade Federal da Paraíba
Lucas Hartmann, Universidade Federal da Paraíba
Flavio Carvalho, Universidade Federal da Paraíba
Darlan Fernandes, Universidade Federal da Paraíba
Euzeli dos Santos Jr., Purdue School of Engineering and Technology

Title: Small-Signal Modeling of a Three-Phase Isolated Inverter with Both Voltage and Frequency Droop Control
Abstract: In conventional power system operation, droop control methods are used to facilitate load sharing among different generation sources. This method compensates for both active and reactive power imbalances by adjusting the output voltage magnitude and frequency of the generating unit. Both P-? and Q-V droops have been used in synchronous machines for decades. Similar droop controllers were used in this study to develop a control algorithm for a three-phase isolated (islanded) inverter. Controllers modeled in a synchronous dq reference frame were simulated in PLECS and validated with the hardware setup. A small-signal model based on an averaged model of the inverter was developed to study the system’s dynamics. The accuracy of this mathematical model was then verified using the data obtained from the experimental and simulation results. This validated model is a useful tool for the further dynamic analysis of a microgrid.
Presenters:
Md. Rasheduzzaman, Missouri University of Science and Technology
Jacob Mueller, Missouri University of Science and Technology
Jonathan Kimball, Missouri University of Science and Technology

T21-Control Loops for Dc-Dc Converters
Track: Modeling, Simulation, and Control

Title: Unified Equivalent Circuit Model of V² Control
Abstract: V2 control is a popular control scheme in point-of-load Buck converters and Voltage Regulators for microprocessor. This control scheme is elegant when output capacitors with sufficient ESR are employed, such as OSCON caps. However, with small-ESR caps, such as ceramic caps, instability problem will occur in many cases. Previous equivalent circuit model based on current mode control is only applicable to V2 control with large-ESR caps and can not predict instability issue since the effect of the capacitor voltage ripple is not considered. This paper proposes a unified equivalent circuit model which is suitable to all kinds of capacitors by considering the effect of the capacitor voltage ripple. The equivalent circuit model is a simple yet complete model and can be used to investigate all transfer functions. The proposed equivalent circuit model is applicable to both variable frequency modulation and constant frequency modulation. Furthermore, the model can be extended to enhanced V2 control and muti-phase V2 converters. The equivalent circuit model is verified with simulation and experimental results.
Presenters:
Shuilin Tian, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University
Yingyi Yan, Virginia Polytechnic Institute and State University

Title: Frequency Compensation and Power Stage Design for Buck Converters to Meet Load Transient Specifications
Abstract: This paper derives an analytical expression for the peak transient output voltage due to a load step in a buck converter considering bandwidth of its control loop. Utilizing this, a simple design method is developed for a current-mode controlled buck converter with type II compensator that meets the time domain voltage transient specification. The compensator design is illustrated using a critically damped pole/zero cancellation method. The approach is extended to include a design method for voltage-mode buck converters. The results are verified using time and frequency domain simulations as well as experimental data.
Presenters:
Santu Bag, Indian Institute of Technology, Kharagpur
Siddhartha Mukhopadhyay, Indian Institute of Technology, Kharagpur
Robert Sheehan, Texas Instruments
Susovon Samanta, National Institute of Technology Rourkela
Tanushree Roy, University of Central Florida

Title: Small-Signal Modeling and Controller Design of an Isolated Quasi-Switched-Capacitor DC/DC Converter
Abstract: This paper presents the small-signal modeling and controller design of an isolated Quasi-Switched-Capacitor (QSC) dc/dc converter. The converter serves as an auxiliary power supply in automotive applications, connecting the high-voltage battery and the 14 V power net. It employs a front-stage QSC dc/ac circuit with a 3:1 voltage step-down ratio, and a post-stage synchronous-rectifier, current-doubler circuit. The output power of the converter is regulated by the switching frequency control. A small-signal model of the converter is derived by the method of state-space averaging. Comparison of the open-loop simulation results from the derived small-signal model and a detailed circuit model showcases the effectiveness of the small-signal model. A closed-loop voltage controller with feed-forward compensation is designed to regulate the output voltage. Closed-loop simulation results from both the small-signal model and the detail circuit model, and experiment results from a 1-kW prototype are provided to verify the closed-loop control.
Presenters:
Xuan Zhang, Ohio State University
Feng Guo, Ohio State University
Chengcheng Yao, Ohio State University
He Li, Ohio State University
Pu Xu, Ohio State University
Jin Wang, Ohio State University

Title: Design Considerations and Small Signal Modeling of the Flyback Converter Using Second Stage LC Filtering Circuit
Abstract: This paper analyzes the stability issue of the Flyback converter which utilizes a second stage LC filtering circuit at its output side. The small signal models of the Flyback converter using second stage filter, in both DCM and CCM, are presented with experimental data collected to verify the theoretical analysis. Finally, guidelines for designing the second stage LC filter are derived to facilitate the procedure.
Presenters:
Lei Hua, Fairchild Semiconductor
Jason Guo, Fairchild Semiconductor
Richard Chung, Fairchild Semiconductor

Title: State-Trajectory Control of LLC Converter Implemented by Microcontroller
Abstract: The major contribution of this paper is integrating 3 stat-trajectory control functions (SOTC, burst mode, soft start-up) in one low-cost MCU. The problem of complex calculation process is solved by simplifying calculation of SOTC. The large oscillation problem between burst mode and normal operation is solved by optimizing transient processes between burst mode and normal operation. Besides, soft start-up is implemented by only sensing output voltage. With proposed methods, it is shown that commercial MCU is suitable for state-trajectory control of LLC resonant converter. Experiment results are demonstrated on a 130kHz 300W 380V/12V half-bridge LLC resonant converter with an low-cost MCU TMS320F2808.
Presenters:
Chao Fei, Virginia Polytechnic Institute and State University
Weiyi Feng, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: A Multivariable Auto-Tuning Digital Controller for Switching Power Converters
Abstract: This paper presents an online multivariable auto-tuning digital controller for DC-DC switching power converters. In the proposed scheme, all the variables/parameters (i.e. gain, zero(s) and pole(s)) of a digital PID compensator are auto-tuned simultaneously during system operation in order to achieve an optimized compensator that results in improved dynamic performance for a given power converter design. The proposed multivariable auto-tuning scheme is based on observing the time-domain characteristics of the compensated error signal, namely the output of the compensator, and it does not require the accurate knowledge of the power stage parameters and/or the measurement of the control loop frequency response. Experimental results are presented in order to illustrate and verify the multivariable auto-tuning scheme.
Presenters:
Wangxin Huang, University of Alabama
Jaber Abu Qahouq, University of Alabama

Title: Autotuning Technique for Digital Constant on-Time Controllers
Abstract: This paper addresses the design and practical implementation of a digital constant on-time controller for switched-mode DC-DC converters with self-tuning capabilities. The proposed tuning techniques are based on the sinusoidal signal injection in the control loop in order to measure the linear gain-loop transfer function at the desired crossover frequency. This autotuning method is applied in close loop condition hence the stability and the regulation are assured during the tuning process. The proposed tuning technique is presented and the complexity of the control and tuning blocks is analyzed. The proposed approach is simple, accurate, and robust. Experimental results on a 100 A, 1.8 V multiphase buck converter with a constant on-time controller are provided to show the effectiveness of the discussed system.
Presenters:
Stefano Saggini, Università di Udine
Mirko Loghi, Università di Udine
Osvaldo Zambetti, STMicroelectronics
Alessandro Zafarana, STMicroelectronics
Luca Corradini, Università degli Studi di Padova

Title: Modeling and Autotuning of AVP Control with Inductor DCR Current Sensing
Abstract: A new equivalent circuit model is presented to predict the small-signal characteristic of current-mode control with DCR current sensing accurately, and a novel autotuning method is proposed to solve the issue of time constant mismatch in DCR current sensing. The autotuning method uses a novel pole-zero compensation technique to maintain constant output impedance over wide mismatch condition, and provides simple implementation for monolithically integration into multiphase VRM. The SIMPLIS simulation with state-of-art output filter model of laptop VR and the experiment result on a commercial VR12 controller confirms the effectiveness of the proposed autotuning method.
Presenters:
Pei-Hsin Liu, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: Modeling, Dynamic Analysis and Digital Control Design of a New Current Auto Zero Master-Less Current Shared Converters
Abstract: This paper introduces a new modular master-less active control method for current share in digitally controlled DC-DC converters that communicate over single wire bus. Current balance among paralleled converters is achieved with new current error zeroing method. Experimental results show the new scheme exhibiting excellent static and stable dynamic current matching performance. The paper also includes correlated modeled and bench current loop frequency response results.
Presenters:
Basil AlMukhtar, Powervation Ltd.
Karl Rinne, Powervation Ltd.
Elaine Sheridan, Powervation Ltd.

T22-Soft Switching DC-DC Converters
Track: DC-DC Converters

Title: Modular Dual Active Bridge Converter Architecture
Abstract: This paper is focused on the assessment of a modular architecture based on the Dual Active Bridge (DAB) converter in input series, output parallel (ISOP) connection. Previous works have dealt with modeling and control techniques to ensure a proper voltage and power sharing among the modules. In this paper an experimental evaluation of the behavior of the DAB in ISOP connection is carried out in order to validate the previously proposed models.
Presenters:
Pablo Zumel, Universidad Carlos III de Madrid
Leonardo Ortega, Escuela Politécnica Nacional
Antonio Lazaro, Universidad Carlos III de Madrid
Cristina Fernández, Universidad Carlos III de Madrid
Andrés Barrado, Universidad Carlos III de Madrid
Alberto Rodriguez, Universidad de Oviedo
Marta Hernando, Universidad de Oviedo

Title: Hybrid Ps Full Bridge and LLC Half Bridge DC-DC Converter for Low-Voltage and High-Current Output Applications
Abstract: A hybrid phase shifted full bridge (PSFB) and LLC half bridge (HB) dc-dc converter for low-voltage and high-current output applications is proposed in this paper. ZVS for lagging leg switches under light loads can be realized. The PSFB undergoes most of the power while the LLC-HB working as an auxiliary part converts only a small portion of the total power. The design principle is given in view of ZVS realization for lagging leg switches and wide regulating range of converter’s output current. The proposed converter has been verified by experimental results of a 2.5kW prototype.
Presenters:
Mengyuan Yu, Beijing Institute of Technology
Deshang Sha, Beijing Institute of Technology
Zhiqiang Guo, Beijing Institute of Technology
Xiaozhong Liao, Beijing Institute of Technology

Title: A Variable Switching Frequency Hybrid Control for ZVS Dual Active Bridge Converters to Achieve High Efficiency in Wide Load Range
Abstract: The Dual Active Bridge (DAB) converter with the Conventional Phase-shift Modulation (CPM) and Triangular Current Modulation (TCM) are compared in terms of the power transfer and total loss. It is noted that there exists an optimal design trade off among the switching loss, conduction loss and drive loss according to different load current and switching frequency. A hybrid modulation strategy with variable switching frequency is proposed to reduce the dominant loss and improve the efficiency in wide load range. A 500 W prototype was built and an efficiency improvement of 3.1% is achieved under 10% load condition.
Presenters:
Xiao-Fei He, Nanjing Aeronautics and Astronautics University
Zhiliang Zhang, Nanjing Aeronautics and Astronautics University
Yong-Yong Cai, Nanjing Aeronautics and Astronautics University
Yan-Fei Liu, Queen’s University

Title: Phase Shift Controlled Modular DC/DC Converter with Input Voltage Auto Balance Ability
Abstract: A novel phase shift controlled modular DC/DC converter is proposed in this paper by integrating the fullbridge converters and three-level flying-capacitor circuit. Due to the series connection of the full-bridge modules, the high switch voltage stress in the primary side is effectively reduced. Therefore, the low-voltage rated power devices can be employed to obtain the benefits of low conduction losses. Moreover, the voltage auto-balance ability among the modules is achieved by the inherent flying capacitor, which removes the additional possible active components or control loops. In additional, zero-voltage-switching (ZVS) performance for all the active switches can be provided by the phase shift control scheme, which can reduce the switching losses. The circuit operation and converter performance are analyzed in detail. Finally, the performance of the presented converter is verified by the simulation and experimental results from a 2kW prototype.
Presenters:
Qun Jiang, Zhejiang University
Heya Yang, Zhejiang University
Chushan Li, Zhejiang University
Wuhua Li, Zhejiang University
Xiangning He, Zhejiang University

Title: A Fully Soft-Switched Single Switch Isolated DC-DC Converter
Abstract: This paper proposes a single switch soft switching isolated converter. The proposed converter is able to offer low cost and high power density in high step up application due to the following features: ZCS turn on and ZVS turn off of switch and ZCS turn-off of diodes regardless of voltage and load variation; simple gate driver circuit and low rated lossless snubber; reduced transformer volume compared to flyback or forward based converters due to low magnetizing current. Experimental results on a 100kHz, 250W prototype are provided to validate the proposed concept.
Presenters:
Minjae Kim, Seoul National University of Science and Technology
Daeki Yang, Seoul National University of Science and Technology
Sewan Choi, Seoul National University of Science and Technology

Title: A Soft-Switching Dual-Phase-Shift Controlled Full-Bridge Converter with Voltage-Doubler for Wide Voltage Range Applications
Abstract: A soft-switching full-bridge converter (FBC) with dual-phase-shift control strategy is proposed for high efficiency conversion in wide voltage range applications. The proposed FBC can either work in step-up mode or step-down mode.Soft-switching is achieved for all power devices in a wide load and voltage range due to unique structure and dual-phase-shift control scheme. Reverse recovery problem of rectifier diodes is eliminated, which helps to achieve high efficiency. Voltage stresses across the primary-side and secondary-side MOSFETs are clamped to the input voltage and half of output voltage, respectively. The operational principle analysis with experimental results is provided to verify the effectiveness and advantages of the proposed converter.
Presenters:
Yangjun Lu, Nanjing Aeronautics and Astronautics University
Hongfei Wu, Nanjing Aeronautics and Astronautics University
Yan Xing, Nanjing Aeronautics and Astronautics University
Tiantian Mu, Nanjing Aeronautics and Astronautics University
Huawu Liu, Nanjing Aeronautics and Astronautics University
Xudong Ma, Southeast University

Title: LLC Resonant Converter with Matrix Transformer
Abstract: In this paper, a high efficiency high power density matrix transformer structure for LLC resonant converters is proposed. Matrix transformer is help to reduce leakage inductance and the AC resistance of windings. Flux cancellation method is utilized to reduce core size and loss. Synchronous Rectifier (SR) devices and output capacitors are integrated into secondary windings to eliminate termination related winding losses, via loss and leakage inductance. A detail design procedure is proposed. A 1MHz 390V /12 V 1kW LLC resonant converter prototype is built.
Presenters:
Daocheng Huang, Virginia Polytechnic Institute and State University
Shu Ji, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University

T23-Control of Distributed Systems
Track: Modeling, Simulation, and Control

Title: Distributed Battery Energy Storage System Architecture with Energy Sharing Control for Charge Balancing
Abstract: This paper presents a distributed battery energy storage architecture where the cells in the battery pack are decoupled from each other by connecting each cell with a lower power (smaller) DC-DC power converter. In addition to providing voltage regulation for the DC bus, these small DC-DC power converters are utilized to achieve state of charge (SOC) balancing among the cells by employing a proposed charge balancing controller that is based on energy sharing concept. As a result, no additional charge balancing circuits and controllers are needed in order to transfer charges between the cells of the battery pack. A system simulation model based on the proposed energy storage system architecture is developed in Matlab®/Simulink® in order to verify the feasibility and functionality of the proposed charge balancing controller.
Presenters:
Wangxin Huang, University of Alabama
Jaber Abu Qahouq, University of Alabama

Title: Modeling Closed-Loop Input and Output Impedances of DC-DC Power Converters Operating Inside DC Distribution Systems
Abstract: This paper derives closed-loop input and output impedances of a number of dc-dc power electronic converters when operating in a dc distribution network. The derived impedances can be used for stability analysis and control design for dc distribution networks. In this paper, first the small-signal model of a power converter operating in a dc power system is introduced and the open-loop transfer functions are derived. Next, the closed-loop model of the converter is assembled based on the open-loop model and the type of the control scheme. Then, the closed-loop impedances are derived from the resulting closed-loop model. Finally, the derived impedances are verified using an experimental prototype converter.
Presenters:
Reza Ahmadi, Southern Illinois University Carbondale
Mehdi Ferdowsi, Missouri University of Science and Technology

Title: Stabilizing Positive Feed-Forward Control Design for a DC Power Distribution System Using a Passivity-Based Stability Criterion and System Bus Impedance Identification
Abstract: This paper presents how two recently proposed tools, i.e. the Passivity-Based Stability Criterion (PBSC) and the Positive Feed-Forward (PFF) control, can be used together with a System Identification technique to address system level stability issues in DC distribution systems. In particular, after the frequency-domain measurement of the system bus impedance is taken, a parametric model of the bus impedance can be obtained and used to design a stabilizing PFF control that imposes passivity of the overall bus impedance. If passivity of the overall DC bus impedance is ensured, stability is guaranteed as well. The method is experimentally validated on a system consisting of the cascade of two converters. Two series of results are presented: 1) when we have knowledge of the system model, and 2) when we treat the system as a “black box”.
Presenters:
Antonino Riccobono, University of South Carolina
Jonathan Siegers, University of South Carolina
Enrico Santi, University of South Carolina

Title: Distributed Adaptive Droop Control for DC Microgrids
Abstract: Conventional droop controls have been widely studied for dc Microgrids. However, unlike ac Microgrids, transmission line impedances can undermine the controller’s performance, and the droop control might fail to provide regulated rated voltage and proportional load sharing. Herein, a distributed control methodology is introduced that includes voltage compensation and current regulation modules. The voltage compensation module adjusts the voltage set point to keep it regulated at the rated value. Simultaneously, the current regulator module adjusts the droop virtual resistance to ensure proportional load sharing. Simulation results are provided to verify the performance of the proposed control methodology.
Presenters:
Vahidreza Nasirian, University of Texas at Arlignton
Ali Davoudi, University of Texas at Arlignton
Frank L. Lewis, University of Texas at Arlignton

Title: A Decoupled and Adaptive Power Sharing Strategy Based on Droop Method for Parallel Inverters
Abstract: This paper presents a decoupled and adaptive droop strategy to coordinate parallel operation of inverters. This strategy neatly combines a novel decouple method and an adaptive power sharing strategy. The decouple method guarantees the system stability by defining a pair of virtual power and utilizing a low pass filter to achieve dynamic decoupling. And the adaptive power sharing method is included to achieve accurate power sharing by updating voltage magnitude reference values according to output voltage magnitudes and modified reactive power. Both simulation and experimental results are presented to prove the validity and the improvements achieved by the proposed controller.
Presenters:
Zhiyuan You, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Xuan Zhang, Xi’an Jiaotong University
Xinyu Wang, Xi’an Jiaotong University

Title: Simulation Platform Development for the Analysis of Power Electronic Converter Systems with Plant and Network Coupling
Abstract: Integration of multi-converter systems into information-embedded power system infrastructures has been necessitated by the increasing popularity of microgrids, renewable energy systems and DC distribution systems. This work is motivated by the need for an autonomous simulation tool to perform system-wide analysis of static and dynamic behavior of multi-converter systems taking into account the underlying coupling between the power electronic converters and electromechanical equipment as well as the power system as a whole and the communication network. In this work, specific studies that can aid in static and dynamic analysis of these systems and the devised simulation algorithms are presented.
Presenters:
Juan Jimenez, Drexel University
Sachi Jayasuriya, Drexel University
Chika Nwankpa, Drexel University

Title: Monitoring of Multiple Loads in Wireless Power Transfer Systems Without Direct Output Feedback
Abstract: In this paper, a new computational method is proposed to use only the input current and input voltage to determine the impedance of multiple loads in wireless power transfer systems without any direct measurements on the load sides. This concept is verified by the practical results of an 8-ring wireless power domino-resonator system. A good degree of accuracy has been achieved in the practical verification. The proposal can greatly reduce the cost and complexity for input power control by eliminating the requirements of any output feedback circuitry, which may not be allowed or available in some important applications such as biomedical implants.
Presenters:
Jian Yin, University of Hong Kong
Deyan Lin, University of Hong Kong
Chi Kwan Lee, University of Hong Kong
Shu Yuen Ron Hui, University of Hong Kong

T24-Control of Novel Dc-Dc Converters
Track: Modeling, Simulation, and Control

Title: Discrete Time Modeling of Output Disturbances in the Dual Active Bridge Converter
Abstract: Small-signal modeling of dual active bridge converter dynamics in discrete time is useful due to the ability to incorporate behavior during ZVS intervals explicitly, and is advantageous for the direct design of digital compensators. While the control-to-output transfer function has been modeled previously, accurate models of the output impedance of the DAB converter have not been proposed which account for the converter behavior during ZVS intervals. A discrete time model of the DAB output impedance is developed and tested against experimental results for a 1 MHz, 50-to-4 V, 10 W DAB converter. The model is then extended to remain valid for the analysis of load current step changes which are asynchronous to the discrete time sampling instances.
Presenters:
Daniel Costinett, University of Tennessee
Regan Zane, Utah State University
Dragan Maksimovic, University of Colorado at Boulder

Title: Design of a Multi-Port Converter Using Dual-Frequency PWM Control for Satellite Applications
Abstract: In solar array-battery power system of satellites, new topology and control strategy have been studied to decrease the volume and weight. In this paper, a multi-port converter with the multimode control is introduced. The control strategy for the module is proposed, which contains domain control and dual-frequency PWM control, i.e. multi-mode control strategy. It is demonstrated that dual-frequency PWM control can use only one switch to regulate the bus voltage and battery charge current simultaneously. Input and output characteristics of different operation modes are analyzed in detail and the parameters design is given. At last, a 28V/4A prototype is built to verify the theoretical analysis.
Presenters:
Fang Li, Beijing Jiaotong University
Xiaojie You, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University

Title: Effect of Output Capacitor Structure on the Input Impedance of Stacked Boost Converter
Abstract: In order to improve the input impedance of stacked boost converter (SBC) that processes only a part of the total power delivery, the traditional three-capacitor structure is optimized as single-capacitor structure in this paper. Then small signal models of push-pull SBC based on these two capacitor structures are set up, the loop gain and input impedance are analyzed and compared. Finally, the effectiveness of theoretical analysis is verified by the experimental results.
Presenters:
Qian Chen, Beijing Jiaotong University
Trillion Q. Zheng, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University

Title: Average Natural Trajectories (ANTs) for Boost Converters: Centric-Based Control
Abstract: A novel control technique for boost converters combining fixed frequency PWM with geometrical analysis is presented in this work. The natural evolution of the converter averaged state variables is modeled in a geometrical domain and employed to develop a non-linear control scheme. The proposed technique is suitable for implementation with low bandwidth sensing stages and it features fixed switching frequency and enhanced dynamic response. Since the developed model predicts large-signal behaviour accurately, the control scheme behaves reliably and predictably in any operating point. The theoretical concepts are supported by detailed mathematical procedures and the controller implementation validated by experimental results.
Presenters:
Ignacio Galiano Zurbriggen, University of British Columbia
Martin Ordonez, University of British Columbia

Title: Improved Power Hardware-in-the-Loop Interface Algorithm Using Wideband System Identification
Abstract: The application of wideband system identification techniques to the Damping Impedance Method Power Hardware-in-the-Loop interface algorithm is investigated in this paper. Knowledge of the hardware under test impedance over a wide frequency range improves the simulation accuracy and ensures interface stability under dynamic and transient conditions. A small-signal, white noise perturbation is injected into the hardware under test using the switching converter acting as the power interface. Cross correlation methods are then used to construct a wideband estimation of the hardware impedance. This information is used to update the interface algorithm and guarantee simulation accuracy and stability.
Presenters:
Jonathan Siegers, University of South Carolina
Enrico Santi, University of South Carolina

Title: Phase Jump Technique for Minimization of Load Voltage Transients in SSSC-Based Voltage Regulator
Abstract: There is a large body of literature on modeling, design, and analysis of static-synchronous-series-compensator (SSSC) for voltage restoration and regulation. Most of them focus on investigating the impacts of source voltage disturbance only and give less emphasis on characterizing the whole system under load disturbances. This paper will derive a mathematical model to describe the static and dynamic characteristics of a capacitor-supported SSSC-based voltage regulator and will propose a phase jump technique that can minimize the load voltage fluctuation under load type and load value disturbances. The proposed technique has been applied to a 3kVA, 220V system.
Presenters:
Sui Pung Cheung, City University of Hong Kong
Henry Shu-Hung Chung, City University of Hong Kong
Wai Lun Lo, Chu Hai College of Higher Education

Title: A New Simple and High Performance Digital Peak Current Mode Controller for DC-DC Converters
Abstract: This paper introduces a novel digital peak current mode controller for dc-dc converters. In the proposed controller, the inductor current is reconstructed using the average value of inductor current, the input voltage, and the output voltage. All measured values for the controller are sampled at low sampling rate (equal to switching frequency), allowing use of low speed and low cost analog to digital converters; consequently high frequency noise cannot enter into the control loop. Also, a compensation slope can easily be added to the current loop to tune the controller and stabilize the system. The theory of controller operation is described in the paper, also the function of control blocks inside the controller are discussed briefly. The proposed controller is implemented in an FPGA, and an isolated full bridge boost converter is built to evaluate the controller performance. The experimental results verify the validity of proposed method.
Presenters:
Fazel Taeed, University of Southern Denmark
Morten Nymand, University of Southern Denmark

T25-Advanced Topology & Control for Three-phase Power Converters
Track: Power Electronics for Utility Interface

Title: Dyna-C: a Topology for a Bi-Directional Solid-State Transformer
Abstract: This paper presents a compact bi-directional solid state transformer (SST) based on a current-source topology, featuring high-frequency galvanic isolation and only two minimal power conversion stages. The topology, referenced as Dynamic Current or Dyna-C, can be configured for multi-terminal DC and/or multi-phase AC applications. The Dyna-C is robust, can be stacked for MV applications and be paralleled for high current/power applications. The paper will present some of the possible configurations of Dyna-C, and will discuss challenges associated with the control and operation. One core innovation presented in this paper is the management of transformer leakage energy when transitioning from one bridge to another while maintaining low device stresses and losses. Simulation and experimental results are used to validate operation of the topology.
Presenters:
Anish Prasai, Varentec, Inc.
Hao Chen, Georgia Institute of Technology
Deepak Divan, Varentec, Inc.

Title: Output Current Balancing Method for Three-Phase Interleaved LLC Resonant Converter Employing Y-Connected Rectifier
Abstract: This paper presents the output current balancing method for three-phase interleaved full-bridge LLC resonant converter which employs a Y-connected rectifier. The proposed Y-connected rectifier is capable of boosting the output voltage without increasing the transformer’s turn ratio. Especially, the frequency of the output ripple of the rectifier is six times higher than the switching frequency, thereby reducing the output capacitor and the secondary transformer’s RMS current. However, imperfections of resonant components cause the unbalance of output ripple current, and there are the limitations of individual control capability for each three-phase interleaving structure. To solve the current unbalance problem, a current balancing method is proposed for the output rectifying current. The performance of the proposed converter and the current balancing method has been verified through experiments using a 10 kW (300 V/33.3 A) prototype converter.
Presenters:
Hosung Kim, Korea Electrotechnology Research Institute
Juwon Baek, Korea Electrotechnology Research Institute
Jeehoon Jung, Ulsan National Institue of Science and Technology

Title: Impedance-Based Analysis of Grid-Synchronization Stability for Three-Phase Paralleled Converters
Abstract: Grid synchronization instability issue and low-frequency oscillation between synchronous generators exit in electric power system. This kind of stability issue had also been found between paralleled power electronic inverters. Analysis based on small-signal model of inverters’ phase-locked loops (PLL) has been proposed recently. Different from this approach, which needs detailed inverter control and PLL parameters, this paper proposes an impedance based analysis method of grid-synchronization stability issue for paralleled three-phase converter system. The proposed method shows that generalized inverse Nyquist stability criterion (GINC) can be used to predict system stability condition based on grid impedances and inverter output impedances in synchronous rotating d-q frame. Experimental results verify the proposed analysis method.
Presenters:
Bo Wen, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Zhiyu Shen, Virginia Polytechnic Institute and State University

Title: 3-Phase AC-DC Converter Topologies with Higher Frequency Transformer Isolation for Utility Grid Interface
Abstract: Two AC-DC converter topologies (say T-I and T-II) for 3-phase utility grid interface using high frequency (HF) transformer have been proposed. The line-frequency AC from the utility is first converted to HF AC using three 1-phase AC-AC converters. The secondary side of topology T-I consists of a 3-phase PWM rectifier, while topology T-II consists of three 1-phase boost PFC stages with a common output DC-bus. Both topologies avoid DC-link capacitors in the intermediate stages and allow for high density power conversion. Potential applications include electric vehicle battery charging, telecom power supply, adjustable speed drives, server power supplies, etc.
Presenters:
Harish Krishnamoorthy, Texas A&M University
Pawan Garg, Texas A&M University
Puspa Kunwor, Texas A&M University
Prasad Enjeti, Texas A&M University

Title: Experimental Studies on a Three Phase Improved Switched Z-Source Inverter
Abstract: This paper presents an experimental verification of the Improved Switched Inductor Z-Source Inverter (ISL-ZSI). The ISL-ZSI has been proposed to overcome the limitations of classical Z-Source Inverter (ZSI) such as lower voltage gain, higher capacitor voltage stress of Z-network and huge inrush current that appears in the case of traditional ZSI. In this paper, different aspects will be presented and analyzed such as the PWM control, relationships of voltage boosting gain versus modulation index, voltage stress versus modulation index and output voltage/current. Those important points will be analyzed in detail and verified by simulation and experimentally.
Presenters:
Mohamed Ismeil, Aswan University
Mohamed Orabi, Aswan University
Ralph Kennel, Technische Universität München
Omar Ellabban, Texas A&M University at Qatar
Haitham Abu-Rub, Texas A&M University at Qatar

Title: A New Delta Inverter System for Grid Integration of Large Scale Photovoltaic Power Plants
Abstract: A new grid-connected delta inverter system (DIS)for large scale solar photovoltaic (PV) energy systems is introduced. Two different configurations of the DIS are discussed. The proposed DIS topologies have many advantages over conventional grid connected PV systems, such as reduced component count, high voltage gain and higher energy yield. A detailed design example and simulation results of a 30 kW DIS based PV plant are presented to explore the feasibility of such a system. Experimental results on a scaled down laboratory delta inverter system are shown to demonstrate the feasibility of such topology.
Presenters:
Jose Sandoval, Texas A&M University
Jorge Ramos-Ruiz, Texas A&M University
Michael Daniel, Texas A&M University
Somasundaram Essakiappan, Texas A&M University
Prasad Enjeti, Texas A&M University

Title: Phase Locked Loop with Fast Tracking Over Wide Stability Range Under Grid Faults
Abstract: This paper introduces a PLL characterized by fast dynamics, wide stability range and minimal deviations. The proposed PLL is based on a frequency adaptive filtering stage to minimize the frequency and phase deviations under unbalanced conditions and harmonic distortions. Furthermore, a simple mathematical formula is introduced to modify the conventional synchronous frame based PLL to provide more stabilization points for the PLL. The advantages of the proposed PLL are verified through simulations.
Presenters:
Ahmed Morsy, Texas A&M University
Prasad Enjeti, Texas A&M University
Shehab Ahmed, Texas A&M University at Qatar
Ahmed Massoud, Qatar University

T26-Advances in Motor Drives and Inverters I
Track: Motor Drives and Inverters

Title: Single-Stage Soft-Switching AC-Link AC-AC and DC-AC Buck-Boost Converters with Unrestriced Load Power Factor
Abstract: Due to their remarkable merits, the soft-switching ac-link universal power converters have received noticeable attention during the last few years. These converters, which can appear as dc-dc, dc-ac, ac-dc, or ac-ac, are compact, reliable, and expected to offer longer life time compared to the other types of converters. These converters are an extension of the dc-dc buck-boost converters, in which the current of the link inductor is alternating. By adding a small capacitor to the link and by modifying the control scheme the switches can all be turned on at zero voltage, and they can also have a soft turn-off. In this paper it will be shown that soft-switching ac-link three-phase ac-ac or dc-ac configurations have some restrictions on the load power factor to operate properly. The range of the acceptable power factor will be calculated and a solution will be presented to overcome this problem.
Presenters:
Mahshid Amirabadi, University of Illinois at Chicago
Hamid A. Toliyat, Texas A&M University
William Alexander, Ideal Power Converters

Title: Modified Phasor Pulse Width Modulation Method for Three-Phase Single-Stage Boost Inverter
Abstract: Three-phase single-stage boost inverter requires narrow pulses, thus a low resolution can cause some pulse droppings which results in asymmetries in the output waveforms of the boost inverter. This leads to an increase in the total harmonic distortion (THD) of the output waveforms. In order to solve this problem, a modified version of the phasor pulse width modulation (PPWM) switching pattern is developed based on constant charging time over each sector and staircase pattern for the discharging durations. Also, the boost inverter needs a relatively large dc-link inductor to boost and convert a small dc voltage to a nominal ac voltage, all in one stage. Due to the existence of the large dc-link inductor, large voltage spikes appear across inverter switches. Thus, in the modified PPWM method an overlap-time is developed as a solution to suppress the voltage spikes. A 2kW 208/230V laboratory-scale three-phase boost inverter has been designed, built and tested using the modified PPWM switching pattern with the overlap-time, and the results are presented in this paper.
Presenters:
Akanksha Singh, Kansas State University
Alireza A. Milani, Kansas State University
Behrooz Mirafzal, Kansas State University

Title: LCL Filter Design for Grid-Connected Inverters by Analytical Estimation of PWM Ripple Voltage
Abstract: LCL filter is becoming an attractive choice over conventional L filters for grid-connected Voltage Source Inverters (VSI) due to smaller inductor size and better attenuation of the ripple components in the grid current. The modulation of the VSI generates switched voltages which results in distorted currents. In this paper, a simple closed form analytical expression is derived for the higher order switching components present in the inverter voltage. This is used in a systematic design procedure to design the LCL filter components for allowable grid current harmonics. A passive damping resistor is designed ensuring minimum power loss. The design is validated by simulations in MATLAB/Simulink and experiments on a laboratory prototype.
Presenters:
Ashish Kumar Sahoo, University of Minnesota
Arushi Shahani, University of Minnesota
Kaushik Basu, University of Minnesota
Ned Mohan, University of Minnesota

Title: A Power Loss Characterization Method for Semiconductor Switching Devices Based on Inverter-Level DC Measurements
Abstract: This paper presents an inverter-level method for power loss measurement of semiconductor switching devices at real inverter operation conditions. This method employs an H-bridge topology with dc-dc operation mode and a highly inductive load to improve the loss measurement accuracy. Since only dc measurement is involved, it is simpler and more accurate compared to traditional inverter-level loss measurement methods. Both switching and conduction loss can be measured with this method. Experimental results on a traction-drive inverter show that, the difference between the proposed method and device-level loss measurement methods is within 4% for the normal operation range of the inverter.
Presenters:
Ke Zou, Ford Motor Company
Chingchi Chen, Ford Motor Company

Title: A Novel FPGA Implementation of a Model Predictive Controller for Sic-Based Quasi-Z-Source Inverters
Abstract: This paper proposes a novel implementation of an FPGA-Based model predictive controller (MPC) for a SiC quasi-z-source inverter. To speed up computations and satisfy the control requirements, MPC algorithm is designed for parallel processing and is implemented on an FPGA. This is suitable for high-sampling/switching frequency operation which enables the use of MPC in fast systems as SiC-based converters. Proposed concepts are experimentally validated using a three-phase SiC quasi-z-source inverter. Experimental results show that the proposed FPGA-based controller attains a good performance at a very smaller calculation time, comparable to that consumed by conventional MPC sequential implementations.
Presenters:
Mostafa Mosa, Aswan University
Gamal Dousoky, Texas A&M University at Qatar
Haitham Abu-Rub, Texas A&M University at Qatar

Title: Full-Bridge Quasi-Resonant Class-DE Inverter for Optimized High Frequency Operation with GaN HEMT Devices
Abstract: In this paper a high-power density quasi-resonant converter is proposed in order to improve both the maximum output power and the maximum operating frequency with GaN HEMTdevices. Since the proposed converter operates as a class-E converter, there is no negative current flowing through the switching devices, perfectly matching with the GaN HEMT devices restrictions. Besides, the proposed converter reduces the component count by using the parasitic output capacitance for high switching applications. An analytical model of the resonant converter operation is proposed in this paper, with special emphasis in the design equations, and an experimental prototype has been built to prove the feasibility of the proposed converter.
Presenters:
Hector Sarnago, Universidad de Zaragoza
Oscar Lucía, Universidad de Zaragoza
Arturo Mediano, Universidad de Zaragoza
José Miguel Burdío, Universidad de Zaragoza

Title: The Extra L Opposed Current Converter
Abstract: In existing half/full-bridge high precision amplifiers the main output distortion is caused by the required switch blanking time. The OCC topology does not require this blanking time but has a much higher total inductor volume compared to the half-bridge. In this paper a new patent pending topology is introduced that has the advantages of the OCC but with a much lower total inductor volume. The basic operation and properties of the ELOCC topology are explained including an optimization for the total inductor volume and an average model for control design.
Presenters:
Erik Lemmen, Technische Universiteit Eindhoven
Jan Schellekens, Technische Universiteit Eindhoven
Korneel Wijnands, Technische Universiteit Eindhoven
Jorge Duarte, Technische Universiteit Eindhoven

T27-Wireless Power Applications
Track: Power Electronics Applications

Title: A Voltage Ratio-Based Efficiency Control Method for 3 kW Wireless Power Transmission
Abstract: This paper presents a novel control method for wireless power transmission (WPT). The proposed method can maximize the power efficiency only by controlling the voltage ratio between the primary and the secondary side. Experimental measurement results of the prototype system with 3 kW power transmission show the efficiency difference between the proposed control method and the available maximum value is less than 0.3 % even with a large variation of coil-to-coil distance and load voltage. The automatic controller for the proposed method provides the load-following operation, maintaining both constant power and high efficiency, using a WLAN connection.
Presenters:
Hiraoki Ishihara, Toshiba Corporation
Fumi Moritsuka, Toshiba Corporation
Hiroki Kudo, Toshiba Corporation
Shuichi Obayashi, Toshiba Corporation
Tetsuro Itakura, Toshiba Corporation
Akihisa Matsushita, Toshiba Corporation
Hiroshi Mochikawa, Toshiba Corporation
Shoji Otaka, Toshiba Corporation

Title: Modeling and Investigation of Magnetic Resonance Coupled Wireless Power Transfer System with Lateral Misalignment
Abstract: Lateral misalignment between the transmitter (Tx) and receiver (Rx) in a wireless power transfer (WPT) system significantly reduces its power transmission efficiency. This paper first investigates the lateral misalignment in the magnetic resonance coupled (MRC) WPT system and identifies the High Efficiency Range (HER). The HER is a high efficiency area on the transmission efficiency versus Rx lateral misalignment amount curve. In the HER, the transmission efficiency is nearly constant at a maximum value before it sharply drops down to zero (or a very small value). The identification of the HER is verified by simulation results obtained from a developed ANSYS® HFSS® 3-D physical model. Simulation results of the ANSYS® HFSS® 3-D physical model with 5-turn, 60cm outer diameter spiral shape MRC-WPT system show that when the vertical distance (DIS) between the Tx and Rx ranges from 0.1 m to 1m, an HER exists at each DIS value. When 0.3m ? DIS ? 0.6m, nearly constant high efficiency of ~90% could be maintained when the lateral misalignment is not larger than 50cm (83.3% of the Rx diameter).
Presenters:
Zhigang Dang, University of Alabama
Jaber Abu Qahouq, University of Alabama

Title: Design and Realization of a Four Coils Excited Wireless Power Transmission Region via Magnetic Resonances
Abstract: Wireless power transmission region stands out for its convenience in the applications where several terminals or movable terminals need to be charged. The conventional single coil excited charging region has the drawback of distance and angle limitation. To overcome the shortcoming, a charging region which is constructed by four emitting coils is proposed in this paper. This four emitting coils configuration can not only increase the transmission distance but also weaken the sensitivity to angle change. Magnetic field distributions and equivalent circuit of four windings connection types of these four coils are studied.
Presenters:
Juntao Huang, Nanjing Aeronautics and Astronautics University
Qianhong Chen, Nanjing Aeronautics and Astronautics University
Wenxian Chen, Nanjing Aeronautics and Astronautics University
Xiaoyong Ren, Nanjing Aeronautics and Astronautics University
Xinbo Ruan, Nanjing Aeronautics and Astronautics University
Huijuan Zhang, Nanjing Engineering Institute of Aircraft Systems

Title: Investigation for High Output of 2.5MHz Power Supply Constructed from Multi-Core Transformers and a Multi-Phase Inverter and Application for Wireless Power Transfer
Abstract: This paper discusses a development for high output of 2.5 MHz inverter without fast-switching semiconductor switches. This inverter consists of a multi-phase inverter and multiple core transformers. In this paper, a principle of drop in inverter output voltage which reduces the inverter output voltage due to a relationship between dead-time and a leakage inductance of a transformer is clarified. In addition, two methods which are bifilar wound transformers and a LC series resonance are applied to the proposed circuit in order to achieve higher output power. The validity of two methods for higher output power is confirmed by experiments.
Presenters:
Koji Orikawa, Nagaoka University of Technology
Yusuke Fujita, Nagaoka University of Technology
Jun-Ichi Itoh, Nagaoka University of Technology

Title: Active Resonance Wireless Power Transfer System Using Phase Shift Control Strategy
Abstract: In this paper, an active resonance circuit is proposed for wireless power transfer system. Comparing with conventional full-wave rectifier pick-up converter, a reversible rectifier is adopted in this case. With theoretical model based on the proposed system, the power delivery analysis is investigated. In addition, the impacts of parasitic resistors to the power delivery are also considered in the analysis. As a result, a different controlling strategy is employed to counteract the negative influence caused by those parasitic resistors, and maximum power could be delivered to the load. At last, a 100W prototype is built to verify the proposed system
Presenters:
Chongwen Zhao, Zhejiang University
Zhibo Wang, Zhejiang University
Jin Du, Zhejiang University
Jiande Wu, Zhejiang University
Sheng Zong, Zhejiang University
Xiangning He, Zhejiang University

Title: Contactless USB – a Capacitive Power and Bidirectional Data Transfer System
Abstract: This paper extends the Universal Serial Bus (USB) standard to the contactless domain by combining bidirectional data communication with a capacitive power transfer interface. This work first addresses the power transfer with analysis, simulations, and experiment, based on a secondary side phase feedback series resonant topology. This gives the advantage of simple circuitry to regulate output voltage over large parametric variations of the capacitive interface. Secondly this work presents the data communication analysis, simulations and experiment where differential mode voltage containing the data information rides on top of the larger power voltage. An experimental prototype was built to deliver 1.25W of power with 53% overall efficiency over a total of 300pF capacitance with an area of 52cm2, also realizing 100Mb/s bidirectional data communication.
Presenters:
Kun Wang, University of California, Berkeley
Seth Sanders, University of California, Berkeley

Title: Magnetic Couplers in Kickstands for Wireless Charging of Electric Bicycles
Abstract: Wireless charging is proposed for recharging electric bicycles, eliminating the need for direct connections. Charging stations could be installed in public areas and therefore stray magnetic fields must be kept to a minimum to ensure the safety of users and passersby. The magnetic coupler is proposed to be installed within the kickstand of electric bicycles where the couplers would be at ground level. Two proposed magnetic couplers have been simulated and one has been prototyped. Simulated and measured results are within 6% and system efficiency at 200W is 85%. Further simulations and discussions will be presented in the full paper.
Presenters:
Hui Zhi Beh, University of Auckland
Grant Covic, University of Auckland
John Boys, University of Auckland

T28-LED Lighting
Track: Power Electronics Applications

Title: A Novel Isolated Electrolytic Capacitor-Less Single-Switch AC-DC Offline LED Driver with Power Factor Correction
Abstract: Conventional AC-DC driver circuits for Light-Emitting Diode (LED) lamps require large output capacitance across the LED load to minimize the low frequency current ripple. This large capacitance is usually achieved by using an electrolytic capacitor, which has a lifetime that is at least two times less than that of a LED device. To match the potential lifetime of the LEDs, a new isolated single switch AC-DC high power factor LED driver without any electrolytic capacitors is proposed in this paper. In the proposed circuit, the energy storage capacitor is moved to the rectifier side, with a three-winding transformer used to provide isolation; power factor correction as well as to store and provide the required energy to the output. As a result, the energy storage capacitance is significantly reduced, which allows film capacitor to replace the unreliable electrolytic capacitors. The circuit’s operating principles and its characteristics are described in this paper. Simulation and experimental results confirm that a power factor of 0.96 is achieved on a 120Vrms, 12W prototype.
Presenters:
John Lam, Queen’s University
Praveen Jain, Queen’s University

Title: A Comparison Between Open- and Daisy-Chain Transformer Structures for Current-Balancing Multiple LED Strings
Abstract: A comparison between open-chain (OC) and daisy-chain (DC) transformer structures for current-balancing multiple LED strings is presented. The methodology starts with deriving a general analytical expression for describing the current distribution in both structures. The derived model is then used to study the differences in the string currents to the variations of LED string voltages, magnetizing and leakage inductances of the transformers. Results show that the required whole size of transformers for DC structure is smaller than that for OC structure with achieving the same level of current balancing, even if DC structure requires one more transformer than OC structure.
Presenters:
Ruihong Zhang, City University Of Hong Kong
Henry Shu-Hung Chung, City University Of Hong Kong

Title: Transformer-Isolated Resonant Driver for Parallel Strings with Robust Balancing and Stabilization of Individual LED Current
Abstract: This paper presents a transformer-isolated resonant driver for parallel strings with robust balancing and stabilization of individual LED current. The methodology is based on connecting multiple transformers in a daisy chain to balance the string currents. To ensure service continuity of all LEDs, each LED has a bypass thyristor. A 21W prototype with 7 strings has been built. Experimental results show that the LED current can still be regulated at the reference value within ±1% error even if the whole circuit has only one piece of LED in operation and all other LEDs fail short or open.
Presenters:
Ruihong Zhang, City University Of Hong Kong
Henry Shu-Hung Chung, City University Of Hong Kong

Title: A 25W 97%-Efficiency 3.5MHz Integrated Dimmable LED Driver with Lossless Synchronous Current Control and Floating NMOS-Sensing Scheme
Abstract: This paper presents an integrated buck-type dimmable LED driver for high-brightness lighting applications. A lossless synchronous current control is developed to enable the driver to operate at high frequencies and achieve high current accuracy over a wide range of input voltages and output LED loads. The driver power efficiency is benefited from realizing the synchronous rectification via a high-voltage (HV) dynamic-shifter-based gate driver and a HV floating NMOS sensing scheme. Implemented in a 0.5um HV CMOS process, the proposed 45V LED driver can operate at 3.5MHz and achieve a peak power efficiency of 97.2% when driving 12 series-connected output LEDs (25W output power). The worst-case current error is within 2.6% of 700mA average LED current under different conditions. The proposed LED driver outperforms other state-of-the-art counterparts.
Presenters:
Zhidong Liu, University of Texas at Dallas
Hoi Lee, University of Texas at Dallas

Title: A Resonant LED Driver with Capacitive Power Transfer
Abstract: A quasi resonant topology suitable for LED drivers, featuring power factor correction and dimming in a single stage is presented. It contains a single active switch, and operates in zero-voltage-switching zero-current-switching. This topology includes neither electrolytic capacitors nor transformer, and provides galvanic isolation between the AC mains and the DC side. Building on this new topology, a 15 W, 30 V, LED string driver with a typical operation frequency of 200 kHz was designed and experimented. Experimental results fully support the theoretical analysis and the simulation results. Measured efficiency exceeds 90% in the entire operation range and reached a peak efficiency of 96%. The driver is dimmable through the switching frequency. Dimming in the range of 4W-19W is demonstrated experimentally.
Presenters:
Doron Shmilovitz, Tel-Aviv University
Shaul Ozeri, Tel-Aviv University
Mark Ehsani, Texas A&M University

Title: Single Stage Dual Purpose Offline HB-LED Driver with Power Factor Correction for Illumination and Visible Light Communication
Abstract: In this paper a dual purpose offline LED driver using Single Stage Buck-Boost Buck (S2″B3) converter for illumination control and Visible Light Communications (VLC) with Power Factor Correction (PFC) is presented. The (S2″B3) converter is designed to operate buck-boost section in Discontinues Conduction Mode (DCM) with constant duty ratio to provide inherent power factor correction (PFC). The buck section of the converter is operated in Continuous Conduction Mode (CCM) with Average Current Mode Control (ACMC) to realize a constant current source for LED loads. LEDs when switched ON and OFF with megahertz frequencies will facilitate VLC along with illumination. Data transfer and illumination control are achieved through Variable Pulse Position Modulation (VPPM) and high frequency dimming respectively. Simulation and experimental results of the proposed dual purpose converter with PFC for a 500 lm output with 110/120V AC input are presented
Presenters:
Kumar Modepalli, Rensselaer Polytechnic Institute
Leila Parsa, Rensselaer Polytechnic Institute

Title: An Electrolytic Capacitor-Free Single Stage Buck-Boost LED Driver and its Integrated Solution
Abstract: This digest proposed a innovative single stage buck-boost LED driver which can achieve high power factor and tight output current regulation at the same time. Ceramic capacitor is allowed to use as output capacitor in our proposed technology, which remove the lifespan limitation of LED driver. A prospective integration solution has also illustrated in this digest, which aim for further reducing component cost.
Presenters:
Peng Fang, Queen’s University
Yan-Fei Liu, Queen’s University

T29-High Frequency DC-DC & Switched Capacitor Converters
Track: DC-DC Converters

Title: A VHF Interleaved Self-Oscillating Resonant SEPIC Converter with Phase-Shift Burst-Mode Control
Abstract: This paper presents design and implementation of the phase-shift burst-mode control method for interleaved self-oscillating resonant (ISOR) SEPIC converters for LED lighting applications. The proposed control method utilizes delays in the turn-on and turn-off of the power stage and control circuitry in order to reduce requirements for the comparator in the regulation loop. The control method is experimentally evaluated on a 49 MHz VHF ISOR SEPIC prototype, and the results are presented. The designed converter demonstrates peak efficiency of 81%, maintains efficiency above 75% from 20% to full load, and is implemented using low-cost switches and integrated circuits.
Presenters:
Milovan Kovacevic, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: Very High Frequency Half Bridge DC/DC Converter
Abstract: This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all components in the power stage are given. The circuit has been simulated to verify the accuracy of the presented equations and an efficiency of 89% has been shown. A prototype has been implemented with self-oscillating reso- nant gate drives driving the switches. The prototype has been used to drive an LED string and shows an efficiency of 85% at 29 MHz with 130 V input and 13.4 W output. The efficiency was above 82% in the range 110-150 V input with output power between 10.3 W and 16.5 W.
Presenters:
Mickey Madsen, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: A 30-W Flyback Converter Operating at 5 MHz
Abstract: A quasi-square-wave (QSW) flyback converter with zero-voltage switching (ZVS) ability was measured with peak efficiency of 88.4%. The coupled inductors were composed of a commercial planar ER core with a size of 18×3.2×10 mm3 in Nickel-zinc (NiZn) ferrite material which occupied 30% volume of the power stage. In addition, high dv/dt of 16 V/ns and high di/dt of 10 A/ns caused by the smaller output capacitance of GaN device together with the 0.7-nH common source inductance required -2-V between gate and source to turn the switches off without the shoot-through issue.
Presenters:
Zhemin Zhang, Virginia Polytechnic Institute and State University
Khai D. T. Ngo, Virginia Polytechnic Institute and State University
Jeff Nilles, Texas Instruments

Title: A VHF-Level Fully Integrated Multi-Phase Switching Converter Using Bond-Wire Inductors, on-Chip Decoupling Capacitors and DLL Phase Synchronization
Abstract: This paper presents a fully integrated, four-phase, DC-DC switching converter with fast transient response. By applying effective clock and phase synchronization schemes to a current-mode hysteretic control, the multiphase converter achieves ripple cancellation and fast transient response seamlessly. Thanks to the very high frequency (VHF) operation (200 MHz) and the multiphase interleaving topology, the inductance and the capacitance in the power stage are reduced significantly, allowing the use of bond-wires as main inductors and all fully on-chip capacitors. The output voltage of the converter can be regulated at any level between 0.6 V and 0.9 V, with an input source of 1.1 V. The converter achieves 89% maximum efficiency at 170 mW and 79% efficiency at the full load of 540 mW. The transient response times from no load to 300 mA are within 10 ns with 8.8% voltage droop (VOUT=0.82V).
Presenters:
Minkyu Song, University of Texas at Dallas
Mohsen Farahmand Dehghanpour, University of Texas at Dallas
Joey Sankman, University of Texas at Dallas
Dongsheng Ma, University of Texas at Dallas

Title: 5MHz PWM-Controlled Current-Mode Resonant DC-DC Converter with GaN-Fets
Abstract: In this paper, a new pulse width modulation (PWM) control method for the isolated current-mode resonant converter with a fixed switching frequency is presented. The circuit topology is the same as a conventional resonant converter and without any additional components. The control technique for the output voltage regulation is proposed with the unique PWM control for synchronously-rectifying switches. By using the transformer’s leakage inductance and the PWM control, the boost conversion can be realized. Also, the ZVS operation can be done for primary switches, simultaneously. Some experiments have been done with 5MHz isolated DC-DC converter which has GaN-FET.
Presenters:
Akinori Hariya, Nagasaki University
Yoichi Ishizuka, Nagasaki University
Ken Matsuura, TDK-Lambda Corporation
Hiroshige Yanagi, TDK-Lambda Corporation
Satoshi Tomioka, TDK-Lambda Corporation
Tamotsu Ninomiya, International Centre for the Study of East Asian Development

Title: A New 3X Interleaved Bidirectional Switched Capacitor Converter
Abstract: An interleaved bidirectional switched capacitor converter with regulation capability is proposed in this paper. This converter is able to step up input voltage from one to three times continuously with continuous input current and small output voltage ripple. Due to its natural interleaved structure, fewer components are required compared with previously reported interleaving topologies. The proposed topology can also function as unidirectional converter with much reduced number of switches. A PWM technique is also proposed to regulate the output voltage. A modeling method is presented that provides the voltage gain formula. Criterion for high efficiency switched capacitor converter design is presented. A 10W 5V to 14V prototype of proposed SC converter with more than 90% efficiency was built. The experimental results demonstrate the validity of proposed topology and regulation technique.
Presenters:
Bin Wu, University of California, Irvine
Keyue Smedley, University of California, Irvine
Sigmond Singer, Tel-Aviv University

Title: Primary Parallel Secondary Series Flyback Converter (PPSSFC) with Multiple Transformers for Very High Step-Up Ratio in Capacitive Load Charging Applications
Abstract: Flyback converters are widely used in several applications, however, with this topology it is very challenging to achieve high voltage operation especially with very high step-up ratio (>500). This paper presents a new flyback-based topology which utilizes primary parallel and secondary series transformer connection in order to achieve very high step-up ratios and high voltage operation (~2 kV). The topology is analyzed and presented. Experimental results are used to compare and analyze the advantages and disadvantages of the proposed topology. Measurements are performed on three converter prototypes designed for a step-up ratio of 650 (from 3 V to 2000 V).
Presenters:
Riccardo Pittini, Technical University of Denmark
Lina Huang, Technical University of Denmark
Zhe Zhang, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: A Deep Trench Capacitor Based 2:1 and 3:2 Reconfigurable on-Chip Switched Capacitor DC-DC Converter in 32 nm SOI CMOS
Abstract: On-chip switched capacitor (SC) converters for multicore microprocessor power delivery have the potential to reduce the overall energy consumption of future multicore microprocessor systems by independently regulating the voltage supply of each core. This paper describes an on-chip SC converter that can be reconfigured between a 2:1 and a 3:2 voltage conversion ratio to support a wide output voltage range from a single input supply. Regarding SC converter analysis and modeling, this paper extends an existing state space model framework to include the flying capacitors’ parasitic bottom plate capacitors, which for on-chip SC converters significantly influence both the capacitor currents and the converter efficiency. A reconfigurable SC converter that supports an output voltage range of 700mV to 1150mV from a 1.8V input supply is implemented in a 32 nm SOI CMOS technology that features the high-density deep trench capacitor. The converter achieves a maximum efficiency of 85.2% at 2.1W/mm2 power density in the 2:1 configuration and a maximum efficiency of 84.1% at 3.2W/mm2 in the 3:2 configuration.
Presenters:
Toke Meyer Andersen, Eidgenössische Technische Hochschule Zürich / IBM Research Zurich
Florian Krismer, Eidgenössische Technische Hochschule Zürich
Johann Walter Kolar, Eidgenössische Technische Hochschule Zürich
Thomas Toifl, IBM Research Zurich
Christian Menolfi, IBM Research Zurich
Lukas Kull, IBM Research Zurich
Thomas Morf, IBM Research Zurich
Marcel Kossel, IBM Research Zurich
Matthias Brändli, IBM Research Zurich
Peter Buchmann, IBM Research Zurich
Pier Andrea Francese, IBM Research Zurich

Title: A 30-MHz Isolated Push-Pull VHF Resonant Converter
Abstract: A new isolated push-pull VHF resonant DC-DC converter is proposed. The primary side of the converter is a push-pull topology derived from the Class EF2 inverter. The secondary side is a class E based low dv/dt full-wave rectifier. A two-channel multi-stage resonant gate driver is proposed to provide two complementary drive signals. The advantages of the converter are as follows: 1) the power isolation is achieved; 2) the MOSFET and diode are under soft-switching condition for high efficiency; 3) the voltage stress of the MOSFET is much reduced; 4) the parasitic inductance and capacitance can be absorbed
Presenters:
Wei Cai, Nanjing Aeronautics and Astronautics University
Zhiliang Zhang, Nanjing Aeronautics and Astronautics University
Xiaoyong Ren, Nanjing Aeronautics and Astronautics University
Yan-Fei Liu, Queen’s University

T30-Semiconductor Devices
Track: Devices and Components

Title: A Compact Drive-by-Microwave Gate Driver with Coupler Integrated in a Package
Abstract: A low cost and compact isolated gate driver with Drive-by-Microwave technology is developed, which consists of 2.4GHz GaN/Si transmitter and receiver chips and the butterfly isolation coupler that integrated in a printed circuit board based package. The fabricated DBM gate driver successfully demonstrated that it drove a GaN power switching device with a very fast switching. The fabricated DBM gate driver was implemented the multi-level output function, which realizes the gate voltage profile control for a waveform shaping of a power switching device. And this function can contribute the power consumption saving of the gate driver by low power output at on and off-states other than turn-on and turn-off.
Presenters:
Shuichi Nagai, Panasonic Corporation
Yasufumi Kawai, Panasonic Corporation
Osamu Tabata, Panasonic Corporation
Hideaki Fujiwara, Panasonic Corporation
Nobuyuki Otsuka, Panasonic Corporation
Daisuke Ueda, Panasonic Corporation
Noboru Negoro, Panasonic Corporation
Masahiro Ishida, Panasonic Corporation

Title: Self-Contained Control for Turn-on Transition of an Optically Driven IGBT
Abstract: This paper presents a photonic control mechanism to control the turn-on transition of insulated gate power semi-conductor devices. In contrast to other works, the proposed control method independently adjusts the turn-on di/dt and dv/dt in different operating conditions using a single circuit. The onset of transition between di/dt and dv/dt control regions is determined using a self-contained control circuit, which uses the data from previous cycle to initiate the transition. Another Feature of the proposed work is using an optical beam to directly control the turn-on transition. The proposed control operation and advantages are presented and verified by experimental results.
Presenters:
Hossein Riazmontazer, University of Illinois at Chicago
Sudip Mazumder, University of Illinois at Chicago

Title: Active Compensation of Current Unbalance in Paralleled Silicon Carbide MOSFETs
Abstract: Current unbalance in paralleled devices can affect their performance and reliability. In this paper, the factors causing current unbalance in parallel SiC MOSFETs are analyzed, and the major factor is identified. The distribution and temperature dependence of SiC MOSFETs’ threshold voltage are measured. A novel active current balancing scheme is presented, which measures the unbalance current, and eliminates it in closed loop by varying the gate delay to each device. The turn-on and turn-off current unbalance are independently compensated to yield an optimal performance. The proposed scheme provides robust compensation of current unbalance while keeping circuit complexity and cost low.
Presenters:
Yang Xue, University of Tennessee
Junjie Lu, University of Tennessee
Zhiqiang Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee
Benjamin J. Blalock, University of Tennessee
Fred Wang, University of Tennessee

Title: Dynamic and Static Behavior of Packaged Silicon Carbide MOSFETs in Paralleled Applications
Abstract: There is little work done to study the nuances related to paralleling the higher speed SiC Mosfet devices when compared to Si devices. This paper deals with the parallel operation of packaged silicon carbide (SiC) MOSFETs. The parameters that affect the static and dynamic current sharing behavior of the devices have been studied. We also investigate the sensitivity of those parameters to the junction temperature of the devices. The case temperature difference for paralleled MOSFETs has been experimentally measured on a SEPIC converter for different gate driver resistance and different switching frequency, the results show the current and temperature can be well balanced for the latest generation of SiC MOSFETs with low gate driver resistance.
Presenters:
Gangyao Wang, Cree, Inc.
John Mookken, Cree, Inc.
Julius Rice, Cree, Inc.
Marcelo Schupbach, Cree, Inc.

Title: Gate Drive Design Considerations for High Voltage Cascode GaN HEMT
Abstract: This paper investigates gate drive design for high voltage gallium nitride (GaN) high electron-mobility transistors (HEMT) in a cascade structure. High dv/dt and di/dt switching characteristics of GaN device and its influences on high-side gate drive are analyzed on an 8.4kW bidirectional multi-channel buck/boost battery charger operating in critical conduction mode (CRM). Driving candidates for high-side gate drive are reviewed, and digital isolator based driving architecture is proposed with discussion of PCB layout and package parasitics. Experimental results are conducted in each step for concepts validation.
Presenters:
Wei Zhang, Virginia Polytechnic Institute and State University
Xiucheng Huang, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Qiang Li, Virginia Polytechnic Institute and State University

Title: 4A Isolated Half-Bridge Gate Driver with 4.5V to 18V Output Drive Voltage
Abstract: This paper presents an isolated half-bridge gate driver which supports 4.5V to 18V gate drive voltages. The gate drive outputs can switch capacitive loads up to 2nF in 12ns with 4A peak currents, at frequencies up to 1MHz, with no constraints on duty-cycle variation. Coreless micro-transformers are used for transmitting gate drive signals from input to isolated outputs. The optimized encoding/decoding scheme enables sub 40ns propagation delay and less than 1ns delay matching, which are designed to improve the performance and efficiency of AC-to-DC and DC-to-DC power supplies, solar-power inverters and motor-control designs. Up to 5kV isolation is achieved through 20?m polyimide layers sandwiched in between the primary coils and the second coils. Also with two independent isolation channels, the half-bridge gate driver provide 800V galvanic isolation between the drivers’ high-side and low-side outputs, which minimizes the potential for cross conduction and makes it ideal for providing reliable control over a wide range of bus voltages. An example application of the half-bridge gate drivers in a motor driver will also be discussed.
Presenters:
Shaoyu Ma, Analog Devices Inc.
Tianting Zhao, Analog Devices Inc.
Baoxing Chen, Analog Devices Inc.

Title: Design Considerations and Development of Gate Driver for 15 kV SiC IGBT
Abstract: The 15kV SiC IGBT presents unprecedented design challenges for gate driver development due to high dv/dt generated from its punch-through design. From the switching characteristics of the IGBT shown at 11kV, dv/dt over 100kV/µs is observed in the turn-on transition. Such high dv/dt requires low coupling capacitance in the isolation power supply of the gate driver to limit the common mode currents. A gate driver prototype with ultra-low coupling capacitance has been developed for the 15kV IGBT. The results of the gate driver validation at 8kV, 5kHz operation; and 11kV on double-pulse tests are presented.
Presenters:
Arun Kadavelugu, North Carolina State University
Subhashish Bhattacharya, North Carolina State University

Title: Recent Developments in GaAs Power Switching Devices Including Device Modeling
Abstract: A new GaAs power switching device, the gFET™ switch was introduced at APEC 2013. This paper describes devices developed since APEC 2013 including depletion mode devices with nominal on resistances of 7, 14 and 40 mOhms as well as an enhancement mode device with a nominal on resistance of 40 mOhms. The enhancement mode device is particularly well suited for use as a control switch in buck converters. The paper also describes the development of SPICE models from the experimental data.
Presenters:
Robert White, University of Colorado at Boulder
Greg Miller, Sarda Technologies
Bogdan Duduman, Sarda Technologies
Robert Erickson, University of Colorado at Boulder

Title: Design and Evaluation of a 10 MHz Gallium Nitride Based 42 V DC-DC Converter
Abstract: Gallium nitride (GaN) based power devices are becoming common place due to their ability to achieve higher efficiencies and higher switching frequencies than is possible with silicon (Si) power MOSFETs. With discrete GaN devices capable of switching at slew rates up to 40V/ns, the system performance is greatly impacted by aspects outside the power devices, such as high speed gate drivers and printed circuit board (PCB) layout. In this paper, these limitations are identified and discussed while demonstrating the ability of a new high frequency enhancement mode gallium nitride power transistor (eGaN®FET). This device was designed to address high-frequency hard-switching power applications not practical with Si MOSFETs, thus enabling applications requiring high-frequency at higher voltages. The final demonstration is a 42V, 10MHz, 20W buck converter suitable for envelope tracking.
Presenters:
Johan Strydom, Efficient Power Conversion Corporation
David Reusch, Efficient Power Conversion Corporation

T31-Advances in Motor Drives and Inverters II
Track: Motor Drives and Inverters

Title: Induction Motor Drive Design for Traction Application Based on Drive-Cycle Energy Minimization
Abstract: Typical AC traction drive electrical components include a motor, inverter, dc link and filter elements. Drive design parameters and component values are chosen to minimize the system-level drive losses. This paper presents a systematic approach for selecting rotor flux magnitude and passive component values in an induction motor drive using a comprehensive loss-minimization algorithm. The proposed approach is implemented for a standard extra urban drive cycle to illustrate the overall cycle-energy loss minimization. Simulation and experimental studies are conducted to validate the presented design scheme for a rotor-flux-oriented-control based induction motor drive.
Presenters:
Srikanthan Sridharan, University of Illinois at Urbana-Champaign
Philip Krein, University of Illinois at Urbana-Champaign

Title: A Post-Fault Modulation Strategy to Control the Matrix Converter Under an Open-Switch Failure
Abstract: This paper proposes a new post-fault modulation strategy to control the direct 3×3 Matrix Converter (MC) under an open-circuit switch failure. The proposed strategy uses the remaining eight healthy switches of the converter and their corresponding switching states to control the output voltages at their reference values. The duty cycles of the selected switching states are determined by formulating and solving an optimization problem which minimizes the error between the reference voltage and the voltage generated by the switching states. Based on the Karush-Khun-Tucker (KKT) conditions, the solution to the optimization problem is found. As compared with the existing post-fault strategies, the proposed strategy ensures continuous operation of the MC with improved harmonic performance. Performance of the proposed strategy for an MC, based on simulation studies in the MATLAB/Simulink environment is evaluated.
Presenters:
Jaya Deepti Dasika, Purdue University
Maryam Saeedifard, Purdue University

Title: Flux Vector Modulation for Single-Phase Inverter with LC Output Filter
Abstract: The inverter often connects to load or grid through inductor-capacitor (LC) filter for feeding the filtered voltage and current. The carrier based modulation techniques, such as sinusoidal pulse width modulation (SPWM) and space vector modulation (SVM), require some kind of current control in LC filter connected inverter to damp out the LC resonance. The major advantage of flux vector modulation for the inverter with output LC filter is that the voltage control loop alone can damp out the resonance of LC filter. Hence, there is no need to use extra passive components or active damping controller. In this paper, the flux vector modulation for single-phase voltage source inverter (VSI) is proposed. The theoretical development and the digital implementation steps of flux vector modulation are described. The synchronously rotating reference frame (SRRF) proportional-integral (PI) controller is used for output voltage control for stand-alone operation of inverter. The single-phase inverter with output LC filter in stand-alone mode controlled by only voltage control loop with the flux vector modulation is validated through laboratory experiments.
Presenters:
Dhaval Patel, North Carolina State University
Ritwik Chattopadhyay, North Carolina State University
Sachin Madhusoodhanan, North Carolina State University
Subhashish Bhattacharya, North Carolina State University
Rajendra Sawant, Khurana Sawant Institute of Engineering and Technology-Hingoli
Mukul Chandorkar, Indian Institute of Technology Bombay

Title: Control of an Open-End Winding Induction Machine via a Two-Output Indirect Matrix Converter
Abstract: A two-output Indirect Matrix Converter feeding an open-end winding induction machine is presented. The machine currents are vector controlled and the modulation strategy for the converter outputs aims to reduce the common mode voltage and compensate the zero sequence currents. The converter has the advantage of having no bulky energy storage elements and with the two outputs up to 1.5 times the input phase voltage can be obtained across the machine windings without overmodulation. Simulation results showing the performance of the control scheme and the reduction of zero sequence and common mode voltages are presented. Preliminary experimental results are also shown.
Presenters:
Javier Riedemann, Universidad de Concepción
Rubén Peña, Universidad de Concepción
Roberto Cárdenas, University of Chile
Marco Rivera, Universidad de Talca
Ramón Blasco-Gimenez, Universitat de València
Jon Clare, University of Nottingham
Pat Wheeler, University of Nottingham

Title: A Correction to the State-Machine-Decoder for Stacked Multicell Converters
Abstract: Natural capacitor voltage balancing for Flying Capacitor and Stacked Multicell converters require uniform distribution of switching transitions among cells. The state-machine-decoder has been known as the optimal technique to achieve this goal. In this paper, however, it is shown that the conventional state-machine-decoder may not generate the optimal balancing scheme for Stacked Multicell converters. The reason behind the suboptimal distribution is investigated and a correction to the state-machine-decoder is proposed to achieve the optimal distribution. Simulation results are included to support the proposed correction.
Presenters:
Roozbeh Naderi, University of California, Irvine
Abdolreza Rahmati, Iran University of Science and Technology

Title: Accurate Modeling, Compensation and Self-Commissioning of Inverter Voltage Distortion for High-Performance Motor Drives
Abstract: Dead-times, power devices voltage drops and total output capacitance represent the most important sources of distortion of the output voltage in voltage-fed PWM inverters. Their effect is often intolerable in many drives applications and requires a proper compensation strategy. An accurate physical model of the power converter is proposed and a novel self commissioning identification of the compensation model parameters is proposed and verified on a commercial general purpose drive. Comparison with standard compensation techniques demonstrate the superior characteristics of the proposal. Dramatic performance improvements of a sensorless drive system are also shown for an additional validation of the method.
Presenters:
Nicola Bedetti, Gefran s.p.a.
Sandro Calligaro, Università di Udine
Roberto Petrella, Università di Udine

Title: An Improved Single-Phase Active Front End Rectifier System for Use with Three-Phase Variable Frequency Drives
Abstract: In many rural areas, due to unavailability of three-phase AC power, three-phase Variable Frequency Drives (VFDs) are often required to operate from single-phase AC source. Powering up three-phase VFDs from single-phase AC source requires addressing many issues – higher rms value of input diode current, higher ripple voltage across the DC bus capacitor, higher peak input current, higher input current distortion, lower power factor, and poorer system efficiency. All of this leads to severe de-rating of VFDs for single-phase applications. A new low-cost, single-phase active circuit based on injecting current into the mid-point of the DC bus employing only one bidirectional switch is proposed here. The bidirectional switch carries current for less than a quarter-cycle and is rated accordingly. The presence of a three phase diode bridge rectifier lends itself better to distribute the higher input rms current so that the diodes need not carry current higher than their nominal rating. The proposed method shows that VFDs need not be de-rated to achieve rated output power. Test results from a 10hp, 230V system are given to prove the concept.
Presenters:
Mahesh Swamy, Yaskawa America, Inc.
Chaitanya Guddanti, Yaskawa America, Inc.

Title: Analysis and Calculation of DC-Link Current and Voltage Ripple for Three-Phase Inverter with Unbalanced Loads
Abstract: In this paper, the analysis and calculation of the dc-link current and voltage ripple are presented for three-phase inverter with unbalanced load. The average and rms values of the dc-link current are derived. It is found that the rms value is independent of the modulation strategy and switching frequency. Apart from the high frequency harmonics, the current and voltage ripple consists of double fundamental frequency harmonic, which is different from the balanced load. Moreover, the peak-to-peak value of the dc-link ripple voltage caused by the double fundamental harmonic is calculated. Experimental results are shown to verify the accuracy of the theoretical analysis. The analytical and calculated results can be used to guide the dc-link capacitor design.
Presenters:
Xuejun Pei, Huazhong University of Science and Technology
Yong Kang, Huazhong University of Science and Technology
Jian Chen, Huazhong University of Science and Technology

Title: Design and Analysis of Analog Filtering Method for Signal Injection Based Sensorless Control
Abstract: In this paper, the angle estimation error in the sensorless control using analog band pass filter is analyzed and the consideration for the filter design is proposed. According to the quality factor of the BPF, the filtered and sampled current signals are distorted differently. Even though the angle of the injection voltage is on the real rotor position, the sampled q-axis error current has the fluctuating components at three times per rotation or six times and the dc constant component. Also, this paper proposes the filter design guide to minimize the rotor position estimation error.
Presenters:
Sungho Jung, Seoul National University
Jung-Ik Ha, Seoul National University

T32-Power Electronics Applications
Track: Power Electronics Applications

Title: Assisting Converter Based Integrated Battery Management System for Low Power Applications
Abstract: This paper introduces a new battery management system for portable electronics applications based on the flyback converter. This new architecture integrates the voltage step-up and balancing functions inside a single converter. The step-up function is obtained using an assisting concept, where the flyback output is placed at the top of the battery pack and is therefore only processing a portion of the output power. As a result, high power processing efficiency and small converter volume are achieved. The operation of the system is regulated by a hardware-efficient digital controller that provides voltage regulation and charge balancing of the battery cells at the same time.
Presenters:
Mahmoud Shousha, University of Toronto
Timothy McRae, University of Toronto
Aleksandar Prodic, University of Toronto
Victor Marten, Sendyne Corp

Title: Parallel Operation of Three-Phase Bi-Directional Isolated Interleaved DC-DC Converters for Battery Test System
Abstract: Parallel operation of dc-dc converters is widely used in today`s distributed power systems. In this paper, parallel control method of 2.5kW three-phase bi-directional isolated interleaved dc-dc converters for the battery test system is discussed. The battery test system consists of battery charger/discharger, three-phase bi-directional isolated interleaved dc-dc converter and three-phase inverter. In discharge mode, energy from battery is delivered to grid and in charge mode, energy from grid is delivered to battery. Average current sharing control method and feed forward compensation through communication are used maintaining each three-phase dc-dc converter current equal. By using this method, unbalance factor is improved to 1% from 8%. Two 2.5kW three-phase bi-directional dc-dc converter prototype are assembled and the proposed methods are verified through simulations and experiments.
Presenters:
Hyunsik Jo, Chungnam National university
Hanju Cha, Chungnam National university

Title: Design and Control of Battery Charger for Portable Human Powered Generator
Abstract: The developmental process and the battery charging strategy of a 100W battery charging circuit using a three-phase permanent magnet synchronous generator are presented. It is assumed that a typical male can comfortably generate over 100W using cranking motions with two feet. Using a portable and manual generator, human cranking motions are converted to three-phase ac electric power, and the electric power is efficiently harvested and stored in a battery pack using a battery charging circuit consists of a three-phase boost rectifier and a buck converter. The boost rectifier utilizes a mechanical sensorless method to estimate the generator’s rotor position to reduce size and increase reliability. The overall development processes that include topology selection, parameter selection criteria, battery charging strategy with controller gain values, and experimental results, are presented. The experimental results demonstrate the battery charging capability over 100W using a sensorless algorithm.
Presenters:
Seungryul Moon, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University
Byounggun Park, Korea Electrotechnology Research Institute
Jiyoung Lee, Korea Electrotechnology Research Institute
Dae-Hyun Koo, Korea Electrotechnology Research Institute

Title: Finite-Element-Based Computationally-Efficient Electric Machine Model Suitable for Use in Electrified Vehicle Powertrain Design Optimization
Abstract: Electric machines and their corresponding power electronic drives are key components of electric/hybrid electric vehicle (EV/HEV) powertrains. Thus, computationally-efficient models for electric machines and drives are essential for powertrain-level design, simulation, and optimization. In this paper, a finite-element-based method for quickly generating torque-speed curves and efficiency maps for electric machines and drives is presented. First, magneto-static finite element analysis (FEA) is conducted on a “base” machine design. This analysis produces normalized torque, flux linkage, current, and losses for the operating points of interest. These values are then adjusted based upon changing the size of the machine and the effective number of turns of the machine windings to quickly generate a variety of new machine designs and their corresponding efficiency maps. Results suggest that the proposed techniques can be useful for EV/HEV powertrain design and optimization.
Presenters:
Kan Zhou, University of Michigan
Andrej Ivanco, Clemson University
Zoran Filipi, Clemson University
Heath Hofmann, University of Michigan

Title: Detection of EVs on IPT Highways
Abstract: Electric Vehicles (EVs) are quickly gaining widespread interest as attractive alternatives to conventional petrol driven vehicles, to help reduce global dependence on fossil fuels. Inductive power transfer (IPT) is a method that can transfer power to EVs over an air-gap without physical contact. If IPT systems are incorporated into the highway networks, then EVs can be charged dynamically as they travel. This will dramatically increase the range, convenience and safety of EV charging, and reduce range anxiety and battery bank capacities. One of the major difficulties involves detecting an EV. A novel three coil detection system is proposed to allow the primary power supply to detect the approaching secondary IPT coupler (mounted on the EV) and energize the primary IPT coupler buried in the roadway to enable power transfer. The proposed detection method is tested on a laboratory scale prototype and can detect EVs approaching at different speeds, road clearances and horizontal misalignments.
Presenters:
Ganesh Nagendra, University of Auckland
Liang Chen, University of Auckland
Grant Covic, University of Auckland
John Boys, University of Auckland

Title: An on-Line Fast Model Predictive Control of High-Power Ultracapacitors Charging Current for Renewable Energy Urban Rail Vehicle
Abstract: Ultracapacitors have been supplied as main power in urban rail vehicle for the characteristic of high efficiency. Given the model complexity and hard constraints of the ultracapacitors, the charging current control of ultracapacitors under this condition is challenging as fast charging is required. In this paper, an on-line fast model predictive control is proposed to address the problem based on extended interior-point method. By utilizing fixed barrier parameter and warm start, the on-line MPC substantially simplifies the solving process and regulates the charging current of ultracapacitors rapidly and precisely. Meanwhile, a Kalman filter is integrated to observe the state and to adapt the load uncertainty. Experiment results are presented to demonstrate the effectiveness of the proposed control method.
Presenters:
Zhiwu Huang, Central South University
Hao Li, Central South University
Jia Hu, Central South University
Weirong Liu, Central South University
Jianfeng Liu, Central South University

Title: Double-Coupled Systems for Roadway IPT Systems
Abstract: Dynamic powering of in-motion Electric Vehicles (EV) using Inductive Power Transfer (IPT) can potentially solve many of the problems currently faced by EVs. However there is currently limited research focused on the suitable IPT primary supply side infrastructure, and most proposed systems so far have serious limitations. This paper presents a new roadway IPT system called “Double-Coupled System” which allows individual power sections on the roadway to be controlled independently and only turned on when required, and as such minimizes unwanted leakage fields. The proposed system is highly reliable and fault tolerable, allows high power transfer ability at high frequency, and is also potentially efficient and cost effective.
Presenters:
Liang Chen, University of Auckland
Ganesh Nagendra, University of Auckland
John Boys, University of Auckland
Grant Covic, University of Auckland

Title: Fault Tolerant Drive Module via Electromechanical Alteration of Circuit Topology
Abstract: The current technology applied to design power electronic converters, based on stationary placement of power switches, require additional switches (redundancy approach) for most fault tolerant realizations. This paper introduces application of inverse piezoelectric phenomenon to create dynamic circuit topology thereby elevating the size, cost, and complexity issues associated with current technology. Along with introduction to such dynamic circuit topology, this paper also discusses the process of model development, and practical aspects and limitations under different load conditions. The presented model will generate new opportunities in effective thermal management and reduced part converter topologies.
Presenters:
Lizon Maharjan, University of Texas at Dallas
Nasim Arbab, University of Texas at Dallas
Babak Fahimi, University of Texas at Dallas

Title: Design and Development of Autonomous High Voltage Driving System for DEAP Actuator in Radiator Thermostat
Abstract: In radiator thermostat application, DEAP (Dielectric Electro Active Polymer) actuator tends to be good candidate. The capacitive property and high voltage driving demand of DEAP actuator make a high voltage capacitive load driving system to be necessary.The only energy source battery determines it needs to be an autonomous system. The system level design as well as the detailed design and implementation information has been provided. The experimental results have been provided to validate the capability and performance of the driving system.
Presenters:
Lina Huang, Technical University of Denmark
Zhe Zhang, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

T33-Vehicular Electronics I
Track: Vehicular Electronics

Title: A Hybrid Resonant Bridgeless AC-DC Power Factor Correction Converter for Off-Road and Neighborhood Electric Vehicle Battery Charging
Abstract: A new hybrid-resonant bridgeless ac-dc PFC boost converter operating in continuous-conduction-mode (CCM) is proposed for neighborhood electric vehicles (NEVs). This hybrid-resonant boost converter has two active switches that operate in pulse-width-modulation (PWM) and hybrid-resonant modes of operation. This combined modulation technique is called hybrid resonant PWM (HRPWM). The proposed converter with HRPWM features several benefits, which include the following. The gates of the two active switches are tied together; hence, the proposed converter does not need any extra circuitry to sense the positive, or negative line-cycle operation. The semiconductor devices operate with a voltage stress close to the output voltage.
Presenters:
Md Muntasir Ul Alam, University of British Columbia
Wilson Eberle, University of British Columbia
Fariborz Musavi, Delta-Q Technologies Corp.

Title: Accurate Finite-Element Modeling and Experimental Verification of Inductive Power Transfer Coil Design
Abstract: Inductive Power Transfer (IPT) is a promising technology for the charging of the batteries of electric and hybrid electric vehicles. Typically, Finite-Element (FE) methods are used to predict the power loss, equivalent circuit parameters, and magnetic stray field of IPT coils. This paper gives insight into the FE modeling of IPT coils of a 5 kW prototype IPT system with a dc-to-dc efficiency of more than 96%. In the paper, modeling of IPT coils is discussed and the calculation methods to predict power loss, equivalent circuit, and stray fields are presented. The main part of the paper is an experimental verification of the obtained FE results.
Presenters:
Roman Bosshard, Eidgenössische Technische Hochschule Zürich / IBM Research Zurich
Johann Walter Kolar, Eidgenössische Technische Hochschule Zürich
Bernhard Wunsch, ABB Corporate Research Center

Title: Analysis and Parameters Optimization of a Contactless IPT System for EV Charger
Abstract: For SS IPT system in battery charger application, general characteristics is discussed based on calculation and prototype test verification, initial efficiency curves are reported. Relationship between resonant frequencies and coupling coefficient is first reported. A parameters sweeping based design method is proposed to optimize charger efficiency. Future work would focus on building new prototype based on the designed parameters and verifing the validity of optimization method.
Presenters:
Rui Chen, Virginia Polytechnic Institute and State University
Cong Zheng, Virginia Polytechnic Institute and State University
Zaka Ullah Zahid, Virginia Polytechnic Institute and State University
William Eric Faraci, Virginia Polytechnic Institute and State University
Wensong Yu, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University
Matthew Senesky, Texas Instruments
David Anderson, Texas Instruments
Gianpaolo Lisi, Texas Instruments

Title: Bi-Directional PHEV Battery Charger Based on Normally-Off GaN-on-Si Multi-Chip Module
Abstract: A high frequency, high efficiency bi-directional battery charger for Plug-in Hybrid Electric Vehicle (PHEV) is built with high voltage normally-off GaN-on-Si HFETs. The battery charger topology consists of a 500 kHz Full Bridge (FB) AD/DC stage and a 500 kHz Dual Active Bridge (DAB) DC/DC stage. The system functionality is verified and measured efficiency is 97% for the AC/DC stage and 97.2% for the DC/DC stage, which leads to a total efficiency 94.2%. By doing sinusoidal charging, the DC link capacitance can be reduced to much less than one third but efficiency will drop to 92.0%.
Presenters:
Lingxiao Xue, Virginia Polytechnic Institute and State University
Zhiyu Shen, Virginia Polytechnic Institute and State University
Mingkai Mu, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Brian Hughes, HRL Laboratories LLC
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University

Title: SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications
Abstract: Wireless Power Transfer (WPT) charging technology is one of the key emerging technologies that continues to evolve as the PEVs and EVs are being pursued as the next generation vehicles. WPT technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow the grid to the vehicle RESS. WPT regulation approaches can be secondary side only, primary side only or a combination of both. The change in the impedance of the resonant circuit because of the gap or the misalignment between the coils may significantly affect the power transferred to the load. There are different control parameters that can be utilized to compensate for the change in the impedance. This paper will discuss the impact of different control parameters on the load power and identify the critical parameters. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed here.
Presenters:
Lixin Tang, Oak Ridge National Laboratory
Madhu Sudhan Chinthavali, Oak Ridge National Laboratory
Omer Onar, Oak Ridge National Laboratory
Steven Campbell, Oak Ridge National Laboratory
John Miller, Oak Ridge National Laboratory

Title: Feasibility Study on Bipolar Pads for Efficient Wireless Power Chargers
Abstract: This paper presents the feasibility study of bipolar pads for efficient wireless power chargers used in electric vehicle (EV) and plug-in hybrid electric vehicle (PHEV) applications. Due to the unconventional flux distribution in this system, a 3D finite element method was employed for the design and analysis. The importance of misalignment tolerance in this system is analyzed and discussed. The distinct features of the proposed rectangular bipolar topology have been exploited to develop the pads for wireless power chargers for EV applications. An 8kW wireless charger with a 200mm gap and a 300mm horizontal misalignment tolerance has been fabricated and tested. From the optimal to critical points of horizontal misalignments, the coupling coefficient of this system can maintain from 18.8% to 31.1%. With a 200mm gap, the charger efficiently transfers energy with an efficiency of 95.66% (overall DC to DC) at the desired position while still maintains at 95.39% efficiency with a 300mm horizontal misalignment.
Presenters:
Trong-Duy Nguyen, University of Michigan-Dearborn
Siqi Li, University of Michigan-Dearborn
Weihan Li, Hefei University of Technology
Chris Mi, University of Michigan-Dearborn

Title: A Novel Approach to Design EV Battery Chargers Using SEPIC PFC Stage and Optimal Operating Point Tracking Technique for LLC Converter
Abstract: In this paper, full bridge LLC topology is investigated for plug-in electric vehicle battery charging applications. Maximum efficiency point phenomenon of LLC converter is introduced and analyzed. A unique actively controlled dc link voltage technique is proposed to optimize the conversion efficiency of LLC converter over the wide voltage range of the high voltage battery pack. Comprehensive circuit modeling and loss analysis at maximum efficiency point of LLC converter are carried out. A 3.3 kW charger, charging the Li-ion battery with an output voltage range of 100 V to 420 V from variable dc link voltage, is designed and simulated. In comparison to conventional approaches, designed LLC converter demonstrates 4.4% efficiency improvement at the heaviest load condition and 16.5% efficiency improvement in the lightest load condition.
Presenters:
Haoyu Wang, University of Maryland
Serkan Dusmez, University of Maryland
Alireza Khaligh, University of Maryland

Title: A SiC MOSFET Based Inverter for Wireless Power Transfer Applications
Abstract: In this paper, a high power density SiC high efficiency wireless power transfer converter system via inductive coupling has been designed and developed. The detailed power module design, cooling system design and power stage development are presented. The successful operation of rated power converter system demonstrates the feasible wireless charging plan.
Presenters:
Omer Onar, Oak Ridge National Laboratory
Madhu Sudhan Chinthavali, Oak Ridge National Laboratory
Steven Campbell, Oak Ridge National Laboratory
Puqi Ning, Institute of Electrical Engineering, Chinese Academy of Sciences
Clifford P. White, Oak Ridge National Laboratory
John M. Miller, Oak Ridge National Laboratory

Title: Bidirectional Power Flow with Constant Power Load in Electric Vehicles: a Non-Linear Strategy for Buck+Boost Cascade Converters
Abstract: This paper proposes a simple and practical non-linear control, using Circular Switching Surfaces, to address constant power load instability in electric vehicle’s power systems. The proposed control technique provides a solution in the geometrical domain to constant power loading conditions while achieving outstanding dynamic response. The controller is implemented in a bidirectional Buck+Boost cascade converter as a battery charge/discharge unit and ensures reliable system operation. Simulation and experimental results on a scaled 2kW Buck+Boost cascade converter validate the proposed switching surfaces and predictions regarding the converter’s behavior under constant power loading conditions.
Presenters:
Matias Anun, University of British Columbia
Martin Ordonez, University of British Columbia
Ignacio Galiano Zurbriggen, University of British Columbia
German Oggier, Universidad Nacional de Rio Cuarto

T34-PV Inverters and Wind Generation
Track: Renewable Energy Systems

Title: Dual Multi-String PV Topology Fed Three Level Grid Connected Inverter
Abstract: Presently, multi-string topology is considered the state of the art for grid integration of high power photovoltaic (PV) systems. In this paper, an improvement of the basic multi-string topology is presented which uses a three -level neutral point clamped (3L-NPC) converter as central grid tied inverter. Each of the two capacitors of the split dc link in 3L-NPC converter is fed from a separate multi-string PV configuration. This modified topology is referred as dual multi-string (DMS) topology. Compared to basic multi-string topology, the dual multi-string topology doubles the number of distributed maximum power point (MPP) trackers, increases modularity and reduces the step-up effort required by the dc-dc stage to half. The control design for grid integration of DMS topology is presented and the limitation of implemented control algorithm is derived. Simulations are done on scaled-down model to validate the control strategy and hardware implementation is done using a 3 kWp roof top PV installation.
Presenters:
Dorai Babu Yelaverthi, Indian Institute of Technology Kanpur
Shyama P Das, Indian Institute of Technology Kanpur

Title: Performance Characteristics of Grid-Tie Solar Inverter with Series Voltage Compensator for Reduction of High-Voltage DC Link Capacitance
Abstract: The performance characteristics of grid-tie solar inverter with capacitor-supported series voltage compensator for reduction of high-voltage dc-link capacitance will be presented in this paper. The compensator generates a voltage to counteract the voltage ripple on the dc-link capacitor. As the magnitude of the voltage ripple is much smaller than the dc-link voltage, the voltage-current rating of the compensator is small. Detailed mathematical analysis on the static and dynamic behaviors of the overall system, and the control method will be discussed. The performance characteristics of a 2kW grid-tie solar inverter system with the compensator will be discussed.
Presenters:
Wenchao Liu, City University of Hong Kong
Kewei Wang, City University of Hong Kong
Henry Shu-Hung Chung, City University of Hong Kong
Steve Tzu-Hsiung Chuang, Provista Technology Limited

Title: Independent Control Strategy of Two DC-Link Voltages for Separate MPPTs in Transformerless Photovoltaic Systems Using Neutral-Point-Clamped Inverters
Abstract: To improve the efficiency of the photovoltaic (PV) system, the centralized topology using three-level inverters are widely used. In this system, PV modules are separately connected to the split DC-links. This causes a decrease in the maximum power point tracking (MPPT) efficiency under the partial shading condition. This paper proposes an independent control of two DC-link voltages for separate MPPT of each PV module in three-level inverters. The proposed method is simply implemented by adding the time-offset to the three-phase turn-on times and modifying the reference voltages without using complex calculations or any additional hardware. Simulations and experimental results verify the validity and feasibility of the proposed method.
Presenters:
Ui-Min Choi, Aalborg University
Frede Blaabjerg, Aalborg University
Kyo-Beum Lee, Ajou University

Title: A Soft-Switched Highly Reliable Grid-Tied Inverter for PV Applications
Abstract: This paper introduces a soft-switched high-frequency-link inverter for grid-tied PV systems. This single-stage inverter can perform the step-up/down operation and also has the ability to effectively harvest the highest possible power from the PV array. The high-frequency link is formed by an ac inductor and a small ac capacitor without the use of bulky short-life electrolytic capacitors. The link inductor is responsible for transferring the PV power to the grid while the link capacitor facilitates zero-voltage switching for the power devices. Galvanic isolation can be realized by replacing the link inductor with an air-gapped high-frequency transformer. This novel topology has seven total switches, making it suitable for low and medium power PV applications. Furthermore, the converter has a high power density and reliability due to the minimization of passive component sizes and the requisite number of power switches. The proposed PV inverter’s control scheme and operating algorithm are presented, followed by a detailed design analysis. Experimental results are also provided to demonstrate the effectiveness of the proposed topology under different operating conditions.
Presenters:
Hamidreza Keyhani, Texas A&M University
Matthew Johnson, Texas A&M University
Hamid A. Toliyat, Texas A&M University

Title: An Effective Control Method for Quasi-Z-Source Cascade Multilevel Three-Phase Grid-Tie Photovoltaic Power System
Abstract: An effective control method for a three-phase quasi-Z-source cascade multilevel inverter (qZS-CMI) based grid-tie photovoltaic (PV) power system is proposed. The control scheme achieves distributed maximum power point tracking (MPPT) and independent dc-link voltage balance for all quasi-Z-source H-bridge inverter (qZS-HBI) based PV modules, and balanced three-phase grid-injected power for the qZS-CMI based PV system. A system-level modeling, which can be used to design the controllers, is also disclosed. Simulation and experiment are carried out on a 7-level qZS-CMI based PV system to validate the proposed scheme.
Presenters:
Yushan Liu, Texas A&M University at Qatar
Haitham Abu-Rub, Texas A&M University at Qatar
Baoming Ge, Beijing Jiaotong University
Fang Zheng Peng, Michigan State University

Title: Dithering Digital Ripple Correlation Control with Digitally-Assisted Windowed Sensing for Solar Photovoltaic MPPT
Abstract: This work demonstrates the use of windowed current and voltage measurements for high accuracy PV maximum power point tracking using dithering digital ripple correlation control (DDRCC) at voltage and current levels typical of PV panels. Prior work has demonstrated that DDRCC can be used to obtain high tracking accuracy at fast speeds in low-power applications, however the measurement resolution required for DDRCC is non-trivial at typical panel power levels. In this work a circuit configuration is demonstrated which allows high resolution measurements using a basic microcontroller and analog circuitry. Using this technique, we experimentally demonstrate a 3.5X reduction in tracking error compared to conventional perturb and observe on the same hardware.
Presenters:
Christopher Barth, University of Illinois at Urbana-Champaign
Robert Pilawa-Podgurski, University of Illinois at Urbana-Champaign

Title: An Energy Stored Quasi-Z Source Cascaded Multilevel Inverter Based Photovoltaic Power Generation System
Abstract: This paper proposes an energy stored quasi-Z source (qZS) cascaded multilevel inverter (ES-qZS-CMI) based photovoltaic (PV) power generation system. The system combines advantages of both the qZS inverter and the cascaded multilevel inverter; moreover, the system uses a battery in each module to balance the stochastic fluctuations of PV power injected to the grid. This paper also proposes an effective control scheme for the ES-qZS-CMI based PV system, using which the system can achieve the distributed maximum power point track (MPPT) for each PV panel, balance the power between different modules, and provide the desired power for the grid. Simulation and experimental results verify the proposed system and the control scheme.
Presenters:
Dongsen Sun, Beijing Jiaotong University
Baoming Ge, Beijing Jiaotong University
Hao Zhang, Beijing Jiaotong University
Xingyu Yan, Beijing Jiaotong University
Daqiang Bi, Tsinghua University
Haitham Abu-Rub, Texas A&M University at Qatar
Fang Zheng Peng, Michigan State University

Title: A Wind Energy Conversion System with Enhanced Power Harvesting Capability for Low Cut-in Speeds
Abstract: This paper proposes a new technique for enhancement of energy extraction capabilities in wind energy conversion systems with low cut-in speed. The dc-link voltage is maintained by the grid-side converter in wind energy systems equipped with back-to-back three-phase bridge converters. This voltage is required to be higher that a certain value to ensure proper operation of the grid-side converter. Accordingly, the system cannot harvest energy at low cut-in speeds. This issue is addressed and alleviated in this paper. Excellent power extraction capability has been achieved at low speeds. Experimental and simulation results verify the effectiveness of the proposed solution.
Presenters:
Ali Moallem, Queen’s University
Alireza Bakhshai, Queen’s University
Praveen Jain, Queen’s University

Title: Adaptive Passivity-Based Nonlinear Controller for Wind Energy Conversion Systems
Abstract: This paper presents a control method to improve the efficiency and dynamic response of wind energy control systems (WECS) that use a permanent magnet synchronous generator (PMSG) operating under a wide input and load range. An adaptive passivity-based nonlinear controller (APBC) is developed and tested. This controller is designed to overcome the limitations of conventional dq-control methods, which exhibit slow performance and uncertain stability. The APBC controller increases performance and guarantees stability under all operating conditions. This controller is simulated and its performance is compared to that of a conventional controller. Experimental results are presented.
Presenters:
Jonathan Mash, Queen’s University
Majid Pahlevaninezhad, Queen’s University
Praveen Jain, Queen’s University

T35-Control of Grid-tied Systems
Track: Modeling, Simulation, and Control

Title: New Hysteresis Current Control for Grid Connected Single-Phase Three-Level Quasi-Z-Source Inverter
Abstract: This paper proposes a new hysteresis current control technique for a grid connected single-phase three-level quasi-Z-source inverter. This control algorithm could be applied in any three-level inverter with Z- or quasi-Z-source network where reference current control signal along with shoot-through states is used. To explain the operation principle of the algorithm the steady state analysis is presented. As a result, the band ratio of the hysteresis current controller as a function of the input voltage and the preliminarily defined DC-link voltage were obtained. A simple closed loop control system for a grid connected inverter is described. Simulation results prove all theoretical predictions. Future applications are discussed.
Presenters:
Oleksandr Husev, Tallinn University of Technology
Dmitri Vinnikov, Tallinn University of Technology
Carlos Roncero-Clemente, University of Extremadura
Enrique Romero-Cadaval, Universidad de Extremadura

Title: Dynamic Characteristics of Boost Inverter with Waveform Control
Abstract: The input current of single-phase inverter typically has an AC ripple component at twice the output frequency. The low-frequency current ripple can cause a bad effect on the system. In this paper, a proposed waveform control method which can eliminate such a ripple current in boost inverter system is discussed. The characteristics of the waveform control method in boost inverter under input voltage or wide range load variations are studied. Analysis, simulation and experimental results are presented to support the investigation.
Presenters:
Guo-Rong Zhu, Wuhan University of Technology
Cheng-Yuan Xiao, Wuhan University of Technology
Hao-Ran Wang, Wuhan University of Technology
Wei Chen, Wuhan University of Technology
Siew-Chong Tan, University of Hong Kong

Title: Model Predictive Control of Modular Multilevel Converter with Reduced Computational Load
Abstract: Based on MMC topology, a reduced computation load MPC is proposed in this paper. The proposed MPC is aimed to solve the heavy computation load brought by prediction in traditional MPC. The submodule work mode is further classified into three kinds with consideration of capacitor charge state. In this way, the control object of submodule capacitor voltage balance is separated from the cost function by using sorting. After submodule sorting, the number of possible actuations decreased to N+1 for an N+1 level MMC. Therefore, the computation load in prediction is well reduced, especially when N increases.
Presenters:
Yue Wang, Xi’an Jiaotong University
Wulong Cong, Xi’an Jiaotong University
Ming Li, Xi’an Jiaotong University
Ning Li, Xi’an Jiaotong University
Mu Cao, Xi’an Jiaotong University
Wanjun Lei, Xi’an Jiaotong University

Title: Space Vector Modulation for 3-Level NPC Converter with Neutral Voltage Balancing and Switching Loss/Noise Reduction
Abstract: This paper proposes an improved space vector modulation (SVM) method for the 3-level neutral point clamped (NPC) inverter that serves as a bidirectional power conversion system for renewable energy micro-grid. Conventional SVM for the NPC converter majorly deals with neutral point (NP) balance issue without considering switching loss. The proposed SVM method balances the NP voltage and minimize the switching loss/noise simultaneously. The coordinately selected redundant vectors consider both the NP charge and the pulse sequence so that the minimized NP ripple and switching events is guaranteed in one switching cycle. In addition, the switching events between switching cycles are also considered to reduce the total switching loss and noise. This method also guarantees evenly distributed phase leg loss and constant system efficiency under different power factors (PF). The control result for NP balance and loss reduction is verified by both simulation model and experiment on a 200kVA converter hardware.
Presenters:
Yang Jiao, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University
Sizhao Lu, Virginia Polytechnic Institute and State University

Title: Control of Electrolyte-Free Microinverter with Improved MPPT Performance and Grid Current Quality
Abstract: This paper presents a control technique to improve the MPPT performance and grid current quality for double-stage electrolyte-free microniverter. The proposed method rejects the PV-side double-line frequency oscillation and reduces the grid current distortion with the PV dc-dc converter controlled with a high loop gain while intermediate dc bus voltage loop of grid-tie dc-ac inverter controlled with a low loop gain both at the double-line frequency. The dc-bus film capacitors with the small capacitance allow to have high ripple voltage to buffer the double-line energy while the PV-side could not see this double-line frequency oscillation due to the control of dc-dc converter with high double-line frequency ripple rejection capability. As a result of high reduction of double-line frequency of dc bus voltage loop, the distortion of grid current reference is reduced and the total harmonic distortion (THD) of the grid current is improved.
Presenters:
Bin Gu, Virginia Polytechnic Institute and State University
Jason Dominic, Virginia Polytechnic Institute and State University
Jingyao Zhang, Virginia Polytechnic Institute and State University
Lanhua Zhang, Virginia Polytechnic Institute and State University
Baifeng Chen, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University

Title: A Single-Stage Three-Phase Grid-Connected Photo-Voltaic System with Fractional Order MPPT
Abstract: This paper propose a new maximum power point tracker called fractional order extremum seeking control for grid-connected photovoltaic (PV) systems tasks to better accommodate rapid varying solar irradiance for photovoltaic (PV) arrays. The new algorithm is benchmarked against the integer order extremum seeking control and incremental conductance algorithms. Our extensive simulation results show that the proposed maximum power point tracker has faster convergence speed in comparison to integer order and incremental conductance algorithm and also less total harmonic distortion (THD) in the injected current to the grid.
Presenters:
Hadi Malek, WAVE Inc.
Yangquan Chen, University of California, Merced

Title: Modeling the Output Impedance Negative Incremental Resistance Behavior of Grid-Tied Inverters
Abstract: Small-signal stability in balanced three-phase systems can be analyzed using Generalized Nyquist stability Criterion (GNC), which is based on source and load impedances in synchronous rotating (d-q) frame. This paper models the d-q impedance of three-phase grid-tied inverter with current feedback control and Phase-Locked Loop (PLL). The result unveils a very interesting and important feature of three-phase grid-tied inverter that its qq channel impedance behaves as a negative incremental resistance. Further, the paper shows that this behavior is a consequence of grid synchronization. Bandwidth of PLL determines the frequency range of the negative incremental resistance behavior, power rating of inverter determines the magnitude of the resistance. Simulation and experimental results verify the analysis.
Presenters:
Bo Wen, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Zhiyu Shen, Virginia Polytechnic Institute and State University

Title: High Quality Output Current Control for Single Phase Grid-Connected Inverters
Abstract: This paper presents a method for current controller design in a single phase grid-connected inverter (GCI). The proposed controller addresses the following items: transient performance; steady state tracking; output current distortions and dc; active damping; and start-up transient. The proposed controller is based on various extensions of the linear quadratic regulator (LQR) method and it inherits the optimality and robustness features of the LQR. A design algorithm is proposed that offers a very systematic method of designing controller gains to achieve all the above control objectives. Simulation and experimental results are presented to illustrate performance of the proposed method.
Presenters:
Sayed Ali Khajehoddin, University of Alberta
Masoud Karimi-Ghartemani, Mississippi State University
Alireza Bakhshai, Queen’s University
Praveen Jain, Queen’s University

Title: A State Space Model of Paralleled Inverters Based on Droop Control in Grid-Connected Microgrid
Abstract: Droop control and some improved droop control methods are adopted to control microgrid inverters not only in island mode, but also in grid-connected mode. This paper presents a state space model of three phase paralleled inverters in grid-connected microgrid based on droop control to facilitate the control design and stability analysis. This model is established in rotation framework based on modern control theory and can be very easily used in microgrid composed by any arbitrary number of parallel-connected inverters. An universal state matrix for any number of inverters is derived in this paper in very compact and clear form. The stability analysis and design of the system is simplified by using the root locus. Simulation results are shown to prove the validity of the proposed state model.
Presenters:
Xuan Zhang, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Zhiyuan You, Xi’an Jiaotong University

D01-AC-DC Converters
Track: AC-DC Converters

Title: Input Current Control for Bridgeless PFC Converter Without Sensing Current
Abstract: This paper presents a new control method for bridgeless single-phase power-factor-correction (PFC) converter. A bridgeless PFC converter is more efficient than the conventional boost-type PFC converter by eliminating one semiconductor device in the main current path but is more difficult to control using the existing PFC control method due to the need to sense input current. The proposed control method yields acceptable current waveform without sensing current. Control characteristics and performance of the new method are analyzed using average model and verified by experiment results from a 600W prototype.
Presenters:
Hung-Chi Chen, National Chiao Tung University
Chao-Chiang Chung, National Chiao Tung University
Jhen-Yu Liao, National Chiao Tung University
Sheng-Yang Yu, Texas Instruments

Title: Efficiency of Converters and Amorphous Core AC-Filters in an LVDC Distribution
Abstract: The low voltage direct current (LVDC) distribution is a promising solution, which brings new opportunities to electricity distribution development. The targets of the LVDC distribution are typically high cost-efficiency, reliability and high power quality. This paper studies the efficiencies of line and load converters and their amorphous core AC-filter inductors for a bipolar 750 V DC distribution network by electrical and calorimetric measurements. Measured results are compared with simulations and analytical calculations.
Presenters:
Jenni Rekola, Tampere University of Technology
Heikki Tuusa, Tampere University of Technology

Title: Fully SiC Based High Efficiency Boost Converter
Abstract: Wide band-gap semiconductors (WBG) have recently drawn a lot of interest as main switches for power conversion processes. Owing to their inherent properties, materials such as Silicon Carbide (SiC) offer some advantages over silicon in the 1200V voltage range representing a solution to the quest for increased power density, safer thermal operation, better efficiency and reduced system form factor. In this paper we show the main benefits of ST 1200V SiC MOSFETs as an “ideal” high voltage switch through the results found in a 5 kW boost converter. The most relevant aspect of this work consists in exploiting the SiC MOSFET reverse mode capability through its extremely fast intrinsic body diode as well as with the synchronous rectification technique.
Presenters:
Luigi Abbatelli, STMicroelectronics
Michele Macauda, STMicroelectroincs
Giuseppe Catalisano, STMicroelectronics

Title: Power Conversion Architecture for Grid Interface at High Switching Frequency
Abstract: This paper presents a new power conversion architecture for single-phase grid interface. The proposed architecture is suitable for realizing miniaturized ac-dc converters operating at high frequencies (HF, above 3 MHz) and high power factor, without the need for electrolytic capacitors. It comprises of a line-frequency rectifier, a stack of capacitors, a set of regulating converters, and a power combining converter. The regulating converters are connected to capacitors on the capacitor stack, and provide regulated outputs while achieving high power factor and twice-line-frequency energy buffering on the capacitor stack. The power-combining converter combines power from the individual regulated outputs to a single output. We introduce circuit implementations that enable efficient operation at 5-10 MHz. The circuit is demonstrated for an LED driver operating from 120 Vac, and supplying a 35 V, 30 W output. The prototype converter operates at a (variable) switching frequency of 5-10 MHz and an efficiency of > 93%. The converter achieves a displacement power density of 130 W/in^3, while providing a 0.89 power factor.
Presenters:
Seungbum Lim, Massachusetts Institute of Technology
David Otten, Massachusetts Institute of Technology
David Perreault, Massachusetts Institute of Technology

Title: Tolerance Controls for Open-Switch Fault in a Grid-Connected T-Type Rectifier at Low Modulation Index
Abstract: Multi-level rectifier topologies are widely used in applications of the wide-power range. T-type topology, which is one of many three-level topologies, has an advantage in terms of an efficiency compared to a neutral-point clamped (NPC)-type. In applications using T-type rectifier topology, the interest in reliability has been increased recently. Therefore, a tolerance control for T-type rectifiers is necessary to improve reliability of applications. When an open-switch fault of switches connected to the neutral-point occurs, the NPC-type rectifier cannot restore distorted input currents; however, the T-type rectifier is able to eliminate input current distortion completely. In this paper, two tolerance controls for the T-type rectifier at low modulation index are proposed and their characteristics are analyzed. The effectiveness and performance of two proposed tolerance controls are verified by simulations results.
Presenters:
June-Seok Lee, Ajou University
Kyo-Beum Lee, Ajou University

Title: Start-Up Procedure for Three-Phase Six-Switch Boost PFC Rectifier
Abstract: In three-phase application, the six-switch boost PFC rectifier is the most widely employed topology because of its good performance and cost effectiveness. A vast amount of literature that deals with this circuit is exclusively focused on various control schemes aimed at optimizing different aspects of its steady-state and/or transient performance. However, no literature is available on its start-up procedure which is an indispensable part of control design of any practical circuit. To fill this gap, in this paper, a detailed start-up procedure is described. This three-step start-up procedure ensures that the inrush currents stay below a specified level and that the output voltage increases monotonically to its regulated value, i.e., it does not exhibit any overshoot. The proposed start-up procedure is illustrated with Matlab/Simulink simulation waveforms and also experimentally verified.
Presenters:
Misha Kumar, Delta Products Corporation
Laszlo Huber, Delta Products Corporation
Milan Jovanovic, Delta Products Corporation

Title: A Novel Single Stage AC/DC Converter for Fast Charging Applications with Unity Power Factor
Abstract: This paper proposes a single stage AC/DC converter for fast charging application with unity power factor, most suitable for high voltage level. By having a varying dc link voltage, the capacitor size can be reduced. And by PWM operation of the following DAB, input average current can be regulated with reduced-size high frequency transformer. The PWM operation of DAB is analyzed and verified in this paper. A prototype is built and shows that direct rectifying ac input to dc output with unity power factor can be achieved
Presenters:
Fei Wang, North Carolina State University
Alex Huang, North Carolina State University

Title: A New Control Scheme for an AC-DC Single-Stage Buck-Boost PFC Converter with Improved Output Ripple Reduction and Transient Response
Abstract: The main objective of this paper is to minimize the 120 Hz output ripple component and improve the dynamic response of an AC-DC single-stage power factor correction (PFC) buck-boost converter that has a clamping mechanism to limit the DC bus voltage. In the paper, the operation of the single-stage converter is reviewed and the control method is explained in detail. Key design considerations for the design of the converter controller are discussed and the converter’s ability to operate with fixed DC bus voltage, low output ripple and fast dynamic response is confirmed with experimental results obtained from a prototype converter.
Presenters:
Kamran Rezaei, University of Western Ontario
Navid Golbon, University of Western Ontario
Gerry Moschopoulos, University of Western Ontario

Title: A Generalized DQ Impedance Model of ATRU System
Abstract: Three-phase ac systems can be transferred into dq axis, where stability analysis becomes much simpler. In order to apply the stability criterion in AC system, an equivalent DQ admittance model for the ATRU system has been developed in this paper, based on the ABC impedance model in paper [1]. Compared to the literature work, this model has two better features: (1) it is valid in a wide frequency range, which is from below fundamental frequency to high number times of fundamental frequency; (2) it considers the effect of the ac line impedance and output dc impedance. At different circuit parameters, including the extreme cases, the analytical modeling results and the numerical simulation results present excellent agreement, which demonstrates the accuracy of the analytical model.
Presenters:
Qin Lei, Michigan State University / United Technology Research Center
Miaosen Shen, United Technology Research Center
Vlado Blasko, United Technology Research Center
Sisheng Liang, Michigan State University
Fang Zheng Peng, Michigan State University

Title: Novel Techniques to Suppress the Common Mode EMI Noise in Class II Off-Line SMPS Applications
Abstract: A novel Y-cap. connection structure for Class ? off-line SMPS applications is proposed to supress the commmon mode (CM)noise. With the proposed concept, the size of the CM choke can be greatly reduced while satisfying the EMC standard. Furthermore, the inner shielding layer inside power transformer which is normally a must in product design to comply with the EMC standards can be eliminated for higher conversion efficiency and easier manufacturing. Sucessful implemantation of this concept leads to the smallest 65W adaptor in the world.
Presenters:
Chao Sun, FSP-Powerland Technology Inc.
Ming Xu, FSP-Powerland Technology Inc.

Title: DQ Current Control of a Bidirectional, Isolated Single-Stage AC-DC Converter
Abstract: Electric vehicles provide portable energy storage that can be used in Vehicle-to-Grid (V2G) applications. In order to source power to the grid, the power electronics on-board these vehicles must be bidirectional. A single stage bidirectional isolated AC-DC converter is discussed. A modulation scheme for this topology is proposed to provide control of real and reactive power. A control scheme is coupled with the modulation and allows the topology to act as an inductive, capacitive or resistive load. The proposed modulation scheme can charge the electric vehicle battery as well as provide ancillary services to the grid.
Presenters:
Nathan Weise, University of Maine
Lance Doiron, University of Maine

Title: A Two-Stage AC/DC SST Based on Modular Multilevel Converterfeasible to AC Railway Systems
Abstract: This paper proposes the use of the modular multilevel converter (MMC) for ac-dc conversion using medium frequency transformers in a two-stage topology with unidirectional switches. The medium frequency links provided by each module of the MMC are used to supply the windings of the transformer. A full-bridge rectifier connected to the dc side supplies the secondary side such as the power flow is controlled by the phase-shift angle between the primary and secondary voltages. The resulting topology is fault tolerant since a short-circuit in the dc side causes low additional stress in the semiconductors. The basic description of the topology and some simulation results are presented, followed by a comparative losses study.
Presenters:
Demercil Oliveira, Universidade Federal do Ceará
Dalton de A. Honório, Universidade Federal do Ceará
Luiz Henrique S. C. Barreto, Universidade Federal do Ceará
Paulo Praca, Universidade Federal do Ceará
Andreas Kunzea, Universität Kassel
Samuel Carvalho, Universidade Federal do Ceará

Title: Quantification Analysis of Input / Output Current of Interleaved Power Factor Correction (PFC) Boost Converter
Abstract: Quantification Analysis of input/output current facilities the optimal design of the interleaved PFC boost converter. This paper presents a method to calculate these currents both in every switching cycle and over a main half cycle, which is valid for the interleaved PFC boost converter with arbitrary number of phases operating at continuous conduction mode (CCM) and discontinuous conduction mode (DCM). Compared to the other existing methods, it yields a significant reduction of calculation time and is straightforward. Moreover, this method can be applied to all of the interleaved PFC converters with other topologies such as flyback, Sepic. In addition, the further application of the derived results is discussed. Experimental results validate the proposed method.
Presenters:
Saijun Zhang, Osram Sylvania
Richard Garner, Osram Sylvania
Yuting Zhang, Osram Sylvania
Shashank Bakre, Osram Sylvania

Title: Efficiency Evaluation of Two-Level and Three-Level Bridgless PFC Boost Rectifiers
Abstract: In this paper, a comprehensive efficiency evaluation of several single-phase bridgeless Power Factor Correction (PFC) boost rectifier topologies is conducted. Both two-level and three-level bridgeless PFC boost rectifier topologies are considered; including paralleled and interleaved variants of each. To improve efficiency, a three-level bridgeless PFC boost rectifier with an AC switch is proposed. Loss analysis of the topologies are provided, which shows the advantage of three-level converters and interleaved systems in achieving high efficiency.
Presenters:
Qiong Wang, Virginia Polytechnic Institute and State University
Bo Wen, Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Adam White, United Technology Aerospace Systems

Title: A New Phase Shedding Scheme for Improved Transient Behavior of Interleaved Boost PFC Converters
Abstract: This paper proposes a new phase shedding scheme for interleaved Boost PFC converter to improve the light load efficiency. In the proposed scheme, the power level in the slave channels is reduced linearly as the output loading drops for optimization of light load efficiency. The proposed scheme also prevents the PFC slaves from switching between the ON and OFF states immediately after phase shedding, thereby improving the transient behavior of the system. The proposed scheme is verified on a universal input, 390V output, 2.5KW 3-phases interleaved Boost PFC converter and experimental results are presented to demonstrate the improved light load efficiency and output voltage stability during load transient.
Presenters:
Ying-Chi Chen, Fairchild Semiconductor
Jhih-Da Hsu, Fairchild Semiconductor
Yong-Ann Ang, Fairchild Semiconductor
Ta-Yung Yang, Fairchild Semiconductor

D02-DC-DC Converters I
Track: DC-DC Converters

Title: A Passive Level-Shifter for Elimination of Spurious Turn-on in the Bridge-Leg Configuration
Abstract: Eliminating spurious turn-on in the bridge-leg configuration plays an important role in preventing excessive switching loss and shoot-through. A passive level-shifter is proposed to superimpose a negative gate voltage to bring down the spurious triggering pulse and thereby avoid spurious turn-on. The merits of the devised auxiliary circuit lie not only in that it consists only of passive components and can easily be integrated into the existing gate driver, but also in that the negative voltage level is tunable and independent of the duty cycle of the converter. The effectiveness of this circuit will be verified by experimental results.
Presenters:
Jianjing Wang, City University of Hong Kong
Henry Shu-Hung Chung, City University of Hong Kong

Title: System Optimization of a High-Power and High-Step-Down Accessory Power Module for Electric Vehicles
Abstract: In previous work, a novel design of a 2.5kW 400V/12V 93.2%-efficiency DC/DC converter with a triggering angle tracking synchronous rectifier was proposed for use in an electric vehicle to replace the electric alternator. This paper is focused on the further enhancement of the DC/DC converter to improve the system efficiency and wide-range input/output performance.
Presenters:
Zhong Nie, Chrysler Group, LLC
W. David Williams, Chrysler Group, LLC
Chen Duan, Kettering University
Wei Guo, Kettering University
Kevin Hua Bai, Kettering University

Title: A 600 mA, Constant on-Time Controlled DC-DC Converter with 67% Conversion Efficiency at an Output Current of 23 µA
Abstract: This paper describes a constant-on time controlled dc-dc converter that realizes high efficiency at a light-load condition. To realize a low power operation, a combination of a simple common source amplifier and a very-low power differential amplifier is used instead of a power-hungry differential comparator. In addition, background calibration for a zero-cross comparator (ZCC) is proposed. The calibration guarantees correct discontinuous-current mode (DCM) operation and minimize power loss at switching. Experimental results for a 600mA, 3.6V to 1.2V dc-dc converter are shown. The measured efficiencies is 67% at the output current of 23uA.
Presenters:
Takeshi Ueno, Toshiba Corporation
Takayuki Miyazaki, Toshiba Corporation
Taichi Ogawa, Toshiba Corporation
Tetsuro Itakura, Toshiba Corporation

Title: On High Frequency High Voltage Generators with Planar Transformers
Abstract: In this paper a planar high frequency transformer suitable for resonant high voltage generators has been described. Next to the general generator and transformer design winding layout options have been described. The experimental verification point out, that the planar transformer can fulfil the high voltage isolation requirements and the operation at high frequencies and high power densities. The planar transformer investigated operates successful at power levels up to 50kW at frequencies at 250kHz.
Presenters:
Christoph Loef, Rheinisch-Westfaelische Technische Hochschule Aachen
Rik W. De Doncker, Rheinisch-Westfaelische Technische Hochschule Aachen
Bernd Ackermann, Philips Research

Title: Bidirectional Secondary LLC Resonant Converter Using Auxiliary Switches and Inductor
Abstract: For achieving the high gain characteristics of LLC resonant converters in both of the power flow directions for bidirectional power transfer applications, a bidirectional Secondary LLC resonant converter with auxiliary switches and inductor is proposed. Auxiliary switches and an inductor, a resonant capacitor are connected in the high voltage secondary side of the proposed converter. A 1kW prototyped bidirectional Secondary LLC resonant converter for interfacing the 400VDC buses is built and tested to verify the validity and applicability of the proposed converter.
Presenters:
Eun-Soo Kim, Jeonju University
Jun-Hyoung Park, Jeonju University
Yong-Seog Jeon, Jeonju University
Young-Su Kong, National Forensic Service
Seung-Min Lee, KACO new-energy
Kwangseob Kim, KACO new-energy

Title: Low-Volume Stackable Flyback Converter with Near Minimum Deviation Controller
Abstract: This paper introduces a flyback-based low-volume modular converter and complementary mixed-signal controller that provide input voltage and output current sharing as well as near optimal transient response. This serial-input parallel-output switch-mode power supply (SMPS) is well suited for high-step down ratio applications where, compared to a conventionally used multi-phase buck, it requires a smaller output filter volume, lower MOSFET blocking voltages, and provides better dynamic response. The stackable flyback also has better power processing efficiency and provides inherent passive current sharing. These advantages are achieved by utilizing low-voltage flyback cells and a novel implementation of minimum deviation control method. Experiments with a 12-to-1-V, 4-A, 500kHz 2-cell stacked flyback converter prototype show that, compared to an equivalent 12-V 2-phase conventional buck with approximately the same inductor volume, the introduced converter has 14% smaller output capacitor, up to 40% lower power losses, and 33% faster transient response.
Presenters:
Aleksandar Radic, University of Toronto
Adrian Straka, University of Toronto
Aleksandar Prodic, University of Toronto

Title: Dual-Frequency SIMO Power Converters for Low-Power on-Chip Power Grids in SoCs
Abstract: This paper introduces the Dual-Frequency SIMO (DF-SIMO) power converter topology as a cost-effective and power-efficient method for implementing on-chip power grids in System-on-Chip (SoCs). The proposed topology decouples the rate of energy conversion at the input of the converter from the rate of energy distribution to the outputs, and thus, output bandwidth and dynamic behavior become no longer limited by the switching frequency at the input side. Low switching frequency at the input side preserves high power conversion efficiency, while high switching frequency for energy distribution reduces the output capacitors to integrate-able levels where they can be implemented on-chip.
Presenters:
Chih-Wei Chen, Iowa State University
Jeffrey Morroni, Texas Instruments
David Anderson, Texas Instruments
Ayman Fayed, Iowa State University

Title: Modular DC/DC Converter with Improved Efficiency for Electric Vehicles Applications
Abstract: A modular approach for DC/DC converters to obtain desired voltages and currents is presented in this paper. A high efficiency low switch count isolated push-pull DC/DC converter is used as a unit module. The converters are connected in input series or parallel and output series or parallel configuration to meet the desired power level. The aim is to obtain a flexible DC/DC converter block which can be used to cover a wide power range as well as a wide input and output voltage range. The converters and the communication topologies are designed in such a way that the numbers of unit modules can be connected in several different configurations to achieve the desired requirements with a minimum effort. The experimental details of a configuration with two and four converters are considered in this work.
Presenters:
Marek Galek, Siemens AG
Gopal Mondal, Siemens AG

Title: Open-Circuit Fault Detection and Tolerant Operation for a Parallel-Connected SAB DC-DC Converter
Abstract: This paper presents an open-circuit fault detection method and its tolerant control strategy for a Parallel-Connected Single Active Bridge (PCSAB) dc-dc converter. The proposed fault diagnosis method identifies the location and type of a fault using one current sensor in the output. Depending on the type of the fault, the proposed fault-tolerant strategy tries to keep the capability of the converter unaffected by the fault or to improve the quality of the output current under the fault condition. The feasibility of the proposed fault detection and fault-tolerant methods are verified by simulations and experiments.
Presenters:
Kiwoo Park, Aalborg University
Zhe Chen, Aalborg University

Title: Improved Modulation Technique for Voltage Fed Quasi-Z-Source DC/DC Converter
Abstract: A new shoot-through pulse width modulation (PWM) technique for voltage fed quasi-Z-source DC/DC converters is presented. One advantage of the technique is it minimises switching losses in the converter by minimising the number of switching commutations of the active devices. Additionally, the duration of the active and shoot-through states are independently controllable, allowing the shoot-through duty cycle to reach its maximum limit (Dst,max = 0.5), thus enabling a high voltage gain suitable for applications with renewable energy sources (fuel cells, photovoltaics) and other applications requiring a large voltage boost. A 500W prototype converter was implemented demonstrating improved performance with the new modulation technique.
Presenters:
Yam Siwakoti, Macquarie University
Graham Town, Macquarie University

Title: Distributed Multi-Agent Control of Parallel Cúk Converters Using Feedback Linearization
Abstract: A distributed control scheme, based on feedback linearization, is proposed for proper current sharing in parallel Cúk converters. Compared to the conventional master-slave control method used in parallel converters, the proposed distributed scheme enjoys modularity, improved reliability, and more design flexibility; it also eliminates the necessity for a central master controller. The nonlinear state-space average model of the multiphase Cúk converter is developed. Feedback linearization is used to transform the nonlinear average model to an equivalent single-integrator dynamics. A distributed control protocol is developed for the single-integrator dynamic model and numerical switch-level simulations are presented to verify the performance of the proposed method.
Presenters:
Hamid Behjati, University of Texas at Arlignton
Ali Davoudi, University of Texas at Arlignton
Frank L. Lewis, University of Texas at Arlignton

Title: Sneak Circuit Analysis of Boost Converter Considering Parasitic Parameters
Abstract: Sneak circuit in power electronic circuit is a newly discovered phenomenon. Analysis of sneak circuit is essential for power electronics converters because of its unpredictable feature and various influences.This paper selects Boost converter considering the parasitic parameters as the research object,and the sneak circuit phenomenon is found in this kind of converter for the first time. This paper deduces the major exciting conditions of sneak circuits and their effects on power electronic converters. The simulation results and the experimental results agree well with the theoretical results.
Presenters:
Min Li, South China University of Technology
Bo Zhang, South China University of Technology
Dongyuan Qiu, South China University of Technology

Title: High Step-Up Active-Clamp Converter with Input Current Doubler and Output Switched-Capacitor Circuit: Analysis, Design, Experiment
Abstract: The proposed converter consists of an input current doubler, a switched-capacitor doubler and an active-clamp circuit. The input doubler makes input current ripple minimized. The switched-capacitor doubler is composed of two symmetrical quasi-resonant switched-capacitor circuits, which share the leakage inductance of the transformer as resonant inductor. The rectifier diodes are turned off at zero current switching (ZCS) condition, so that the reverse-recovery problem of diodes is removed. And symmetrical structure results in output voltage ripple reduction because the voltage ripple of charge/pump capacitors will be cancelled out with each other. Meanwhile, the voltage stress of the rectifier diodes is clamped to be half of output voltage. In addition, the active-clamp circuit clamps the voltage surge of switches and recycles the energy of transformer leakage inductance. Furthermore, the control strategy of pulse-width modulation plus phase angle shift (PPAS) is employed to control output voltage.
Presenters:
Liangzong He, Xiamen University
Wei Zhou, Xiamen University
Jiazhi Lei, Huazhong University of Science and Technology

Title: Asymmetrical Interleaving Strategy and AVP Concept for Interleaved LLC Resonant DC/DC
Abstract: Against conventional wisdom, asymmetrical interleaving strategy is proposed for two-phase interleaved LLC resonant DC/DC running at the same switching frequency to guarantee the equilibrium point of current sharing under all operation condition. Basing this strategy, adaptive-voltage-positioning (AVP) concept is further proposed for passive current sharing realization, while satisfying output voltage regulation with better dynamic performance. These concepts can also be applied into other resonant converters. The experimental result in a 1KW interleaved LLC DC/DC has verified the theoretical analysis.
Presenters:
Feiyue Duan, Xi’an Jiaotong University
Ming Xu, FSP-Powerland Technology Inc.
Xu Yang, Xi’an Jiaotong University
Yuan Yao, FSP-Powerland Technology Inc

Session: D03-DC-DC Converters II
Track: DC-DC Converters

Title: Seamless Operation of Bi-Directional LLC Resonant Converter for PV System
Abstract: This paper proposes the simple and seamless operation technique for bi-directional LLC converter. Generally, bi-directional operation of LLC converter is complicated and difficult to control. Because, the switching frequency has to be changed across fsr (series resonant frequency) and the switching sequences has to be also changed due to resonant characteristics. In order to simplify the switching scheme, the switching frequency is moved to higher frequency than fsr where ZVS condition is maintained and simple switching sequence is achieved for both direction. The experimental results for 400Vin, 48Vo, 300W board achieves 93% efficiency and validated this method is useful practically.
Presenters:
Seiya Abe, International Center for the Study of East Asian Development
Tamotsu Ninomiya, International Centre for the Study of East Asian Development
Toshiyuki Zaitsu, Texas Instruments
Junichi Yamamoto, Texas Instruments
Shinji Ueda, Texas Instruments

Title: Optimal Negative Current Control for Four-Phase Interleaved Bi-Directional Buck/Boost Converters to Achieve ZVS and ZCS
Abstract: This paper presents an optimal negative current control for four-phase interleaved bi-directional converters to achieve soft-switching features. Four-phase buck/boost converters with bi-directional operation and in discontinuous conduction mode (DCM) are designed and implemented. The optimal negative current is determined and controlled to reduce reactive power loss, while achieves ZVS and ZCS turn-on for the active switches in the bi-directional converters. Variable frequency and PWM control are also introduced to fit load requirements and insure the DCM operation. Simulation and experimental results obtained from a four-phase interleaved prototype have verified its performance and feasibility.
Presenters:
Tsai-Fu Wu, National Tsing Hua University
Jeng-Gung Yang, National Chung Cheng University
Chia-Ling Kuo, National Chung Cheng University
Ming-Chang Kuo, National Chung Cheng University

Title: Optimized Switching Control Strategy for Current-Fed Half-Bridge Converter
Abstract: A switching control strategy is proposed for current-fed half-bridge converters. An active switch based voltage doubler circuit at the secondary side of the isolation transformer is used to obtain zero-current-switching at turn-off and zero-voltage-switching at turn-on in the primary side switches of the current-fed half-bridge converter. The operation of the current-fed half-bridge converter with the proposed switching control strategy is explained using the equivalent circuit during each sub-interval of operation. The operation of the current-fed half-bridge converter is simulated using MATLAB/Simpower and PSIM to verify the feasibility of the switching control strategy. Experimental results are provided to validate the converter’s operation.
Presenters:
Dulika Nayanasiri, Nanyang Technological University
Mahinda Vilathgamuwa, Nanyang Technological University
Douglas Maskell, Nanyang Technological University

Title: Self-Oscillating Resonant Gate Drive for Resonant Inverters and Rectifiers Composed Solely of Passive Components
Abstract: This paper presents a new self-oscillating resonant gate drive composed solely of passive components. The gate drive can be used in various resonant converters and inverters and can be used for both low and high side gate drive. The paper presents examples of how higher order harmonics can be used to improve the performance of the gate drive and how the gate drive can be implemented in a class E inverter, a class DE inverter and in class E inverter with a synchronous class E rectifier. The paper shows practical implementations of all the proposed inverters and converters operating in the Very High Frequency (VHF) range, all showing good results with peak efficiency up to 82% and output regulation from 70% to full load without bursting.
Presenters:
Mickey Madsen, Technical University of Denmark
Jeppe Pedersen, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: LLC Performance Enhancements with Frequency and Phase Shift Modulation Control
Abstract: This paper will present an algorithm that uses a combination of frequency modulation (FM) and phase shift modulation (PSM) to enhance both the controllability and efficiency of an LLC dc-dc converter. It will be shown that, the proper “marriage” of FM and PSM will result in the ability to support a wider range of operating conditions without comprising efficiency or control monotonicity. These operating points include but are not limited to: monotonic start up, light load regulation, high input voltage, constant-current and constant-power.
Presenters:
Brent McDonald, Texas Instruments
Fan Wang, Texas Instruments

Title: Zero Voltage Switching Forward-Flyback Converter with Efficient Active LC Snubber Circuit
Abstract: This paper describes a Boundary Mode Forward-Flyback Converter (BMFFC) with zero-voltage switching that is able to process power efficiently. The theoretical analysis and operating principle of the BMFFC are presented in detail. A non-dissipative LC snubber that recycles energy to the input source is employed in order to suppress the voltage spike caused by the leakage inductance of the transformer. The relatively large snubber capacitor also significantly reduces turn-off loss. Following a detailed design procedure, a 200W prototype with a 25-50VDC input and 230VDC output was constructed and tested in order to evaluate the performance of the BMFFC.
Presenters:
Frank Chen, University of Central Florida
Ahmadreza Amirahmadi, University of Central Florida
Issa Batarseh, University of Central Florida

Title: Design and Optimization of Parallel DC-DC System Based on Current-Driven Phase Shift Full Bridge Converter
Abstract: This paper proposes the design and optimization of a high power DC-DC parallel system. Three levels of optimizations have been considered in this paper. Firstly, the current-driven phase-shift-full-bridge (PSFB) converter with fewer components, lower voltage stress and no snubber is chosen as the power module, and several attractive features which are suitable for parallel operation are analyzed. Secondly, in the control level, the natural current-limited feature of the current-driven PSFB converter is fully utilized to improve the parallel-current-shared and current-limited control loops design. Finally, in the system level, a parallel controller is configured. Based on the fast full-power-transfer feature of the current-driven PSFB converter, the load-depended control strategy is further designed to improve the system efficiency and compromise the good output dynamic response. A prototype with 2kW, 24V/83A output is also built in this paper, and the experimental results show the validity of the analysis.
Presenters:
Lei Sun, Huazhong University of Science and Technology
Yu Chen, Huazhong University of Science and Technology
Xiangbo Xia, Huazhong University of Science and Technology
Li Peng, Huazhong University of Science and Technology
Yong Kang, Huazhong University of Science and Technology

Title: Combination of DCM and CCM DC/DC Converters for Input-Series Output-Series Connection
Abstract: This work presents the analysis of the behavior of a modular system of DC/DC converters with input-series output-series connections. The goal is to explore a simple solution that provides a stable operation by connecting totally independent converters working in DCM, except one of them (working in CCM) that determines the input-output voltage ratio. This approach has been experimentally validated. The paper deals with an improved version of this solution, achieving a better performance when including an additional control of the input voltages of the DCM modules.
Presenters:
Cristina Fernández, Universidad Carlos III de Madrid
Pablo Zumel, Universidad Carlos III de Madrid
Marina Sanz, Universidad Carlos III de Madrid
Antonio Lazaro, Universidad Carlos III de Madrid
Andrés Barrado, Universidad Carlos III de Madrid

Title: Current Adaptive Resonant Loop Soft Switching PWM Converters
Abstract: In light loading mode, most of the existing soft switching techniques have higher switching loss than their hard switching counterparts as the amplitude of the current in the resonant loop is greater than the load current of the switching instant point. To solve this problem, in the paper, a class of Current Adaptive Resonant Loop (CARL) soft switching PWM converters are proposed, in which, not only all power switches and diodes operate with zero current switching (ZCS), the resonant current amplitude also self adaptively tracks the value of the switching instant point of load current value, at both turn-on and turn-off durations. Compared to their hard switching counterparts, the CARL soft switching PWM converters add only three auxiliary components including one auxiliary switch device, one resonant capacitor and one resonant inductor. The advantages of the proposed CARL soft switching PWM converters are verified by the experimental results of a buck converter.
Presenters:
Trillion Q. Zheng, Beijing Jiaotong University
Tiancong Shao, Beijing Jiaotong University
Na Han, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University
Jianqiang Liu, Beijing Jiaotong University

Title: Dynamical Modeling of the Non-Isolated Single-Inductor Three-Port Converter
Abstract: The non-isolated single-inductor three-port converters (SI-TPCs) are the cost-effective way to connect the renewable source, energy-stored component and load in those applications without isolation requirements. However, the dynamic features of SI-TPCs are complicated due to the multi-port, bidirectional energy flowing and a variety of energy management modes. To facilitate the control-loop design, this paper first deduces the general average equations for the SI-TPCs, and then proposes the available small-signal models for different energy management modes. According to the analysis results, the smoothing switching among different modes is also presented. The experimental results are also given to verify the validity of the analysis.
Presenters:
Yu Chen, Huazhong University of Science and Technology
Pengcheng Zhang, Huazhong University of Science and Technology
Xudong Zou, Huazhong University of Science and Technology
Yong Kang, Huazhong University of Science and Technology

Title: Digital Implementation and Performance Evaluation of a Time-Shift-Controlled LLC Resonant Half-Bridge Converter
Abstract: Time-shift control (TSC) is a novel control technique for resonant converters that outperforms the traditional direct frequency control (DFC) method implemented in all of the currently available control ICs. In fact, TSC makes the dynamic behavior of resonant converters closely resembling that of a first-order system. Thus, closing the control loop to meet stability and even demanding dynamic performance specifications becomes a much easier task. This paper, after briefly reviewing the concepts related to TSC, describes its implementation with a digital controller specific for power conversion applications. An LLC resonant half-bridge converter is operated with both TSC and DFC and the dynamic performance achievable with both control methods is compared. This benchmark highlights the advantages of TSC, confirming its superior performance in terms of dynamic response and showing additional benefits such as its inherent ability to prevent hard switching of the half-bridge switches and its tendency to reduce the effects of the asymmetries in the power circuit.
Presenters:
Claudio Adragna, STMicroelectronics
Dino Ciambellotti, STMicroelectronics
Marco Dell’Oro, STMicroelectronics
Fulvio Gallenda, STmicroelectoincs

Title: A Novel Push-Pull Forward Converter with a Passive Resonant Network Introduced in the Secondary Winding
Abstract: This paper proposes a novel push-pull forward converter (PPFC) of which a passive resonant network is introduced in the secondary winding. The proposed converter can effectively overcome the drawbacks of the conventional PPFC, such as the high turn-off voltage overshoots of rectifier diodes and switches, without increasing the complexity or cost of the system. Furthermore, efficiency of the converter can be improved. Operating principles of the converter is analyzed in general, and selecting reference of the resonant capacitor is given. Finally, a 400W prototype is built to verify the effectiveness of the converter. The experimental results show that the novel PPFC can significantly improve efficiency of the converter, enhance stability of the system and is very suitable to low voltage and high current input applications.
Presenters:
Deshang Sha, Beijing Institute of Technology
Tianmei Luo, Beijing Institute of Technology

Title: High Frequency Resonant Bidirectional SEPIC Converter Suitable for Battery Equalization and Charger Applications
Abstract: This digest proposes a DC-DC converter that can be used in battery equalization and charging/discharging applications. The proposed topology is a high frequency (? 5 MHz) resonant bidirectional SEPIC DC-DC converter. The resonant technology and high frequency operation will allow the size and cost of a battery equalizer to be reduced because of the ability to reduce the size of the magnetic components. In this digest, the topology of the DC-DC converter is proposed, analyzed, and realized, and then verified by simulation and experimental results. It is shown that this converter can obtain an efficiency that is greater than 81%.
Presenters:
Timothy Florencki, University of Wisconsin-Madison
Yehui Han, University of Wisconsin-Madison

Title: A 10-MHz Resonant Gate Driver Design for LLC Resonant DC-DC Converters Using GaN Devices
Abstract: A new high frequency resonant gate driver for commercail GaN devices with off-chip inductor is derived. Simulation shows as much as 40% gate driving loss saving. A LLC DC-DC converter using a conventional gate driver is designed and tested. The designed high frequency gate driver design is in progress. The complete testing and comparison will be carried after the fabrication of the designed gate driver.
Presenters:
Yu Long, University of Tennessee
Weimin Zhang, University of Tennessee
Benjamin J. Blalock, University of Tennessee
Leon M. Tolbert, University of Tennessee
Fred Wang, University of Tennessee

Title: Optimization of a 96% Efficient 12-1 V Gallium Nitride Based Point of Load Converter
Abstract: A 12-1 V Gallium Nitride based POL converter demonstrates over 96% efficiency and under 4 ns switching time. This is accomplished through a layout technique that does not require costly microvias but still minimizes parasitic inductance to support fast switching. Part selection and layout techniques are explored among three POL versions with incremental improvements. Expansion to multiple phases is explored, and experimental data illustrates that switching losses are remarkably low. This work shows how to properly employ modern wide bandgap semiconductor technology in power supply design for highly efficient DC-DC conversion.
Presenters:
Luke Jenkins, Auburn University
Christopher Wilson, Auburn University
Justin Moses, Auburn University
Jeffrey Aggas, Auburn University
Benjamin Rhea, Auburn University
Robert Dean, Auburn University

Title: Quasi-Parallel Switched-Capacitor and Regulating PWM DC-DC Converter
Abstract: Switched capacitor converters allow high conversion ratios, lightweight, magnetic-less power converters, but they suffer from poor load and line regulation. Not to mention discontinuous conversion ratios. Utilizing the quazi parallel configuration, an isolated multilevel modular capacitor clamped converter (MMCCC) can be regulated with a lesser power rated H-Bridge converter. This allows the MMCCC to handle the majority of the power even over the wide input range of 36V to 72V while the H-Bridge regulates the output voltage.
Presenters:
Kenton Yeates, University of Wisconsin-Madison
Yehui Han, University of Wisconsin-Madison

Title: Soft-Charging Operation of Switched-Capacitor DC-DC Converters with an Inductive Load
Abstract: Switched-capacitor (SC) converters are becoming a strong candidate for high power density integrated converters. Traditionally, these SC converters have suffered from two main problems: capacitor charge transfer loss and lossy output voltage regulation. This paper proposes a hybrid SC converter topology that addresses both problems simultaneously. The proposed topology compares favorably in terms of efficiency and power density to both SC converters and buck converters. Unlike SC converters, it can maintain its efficiency for output voltages that are lower than the nominal value determined by the topology. A discrete prototype with a large step-down ratio of 8-to-1 and a power rating of 100 W has been designed and built to demonstrate the potential of the hybrid converter.
Presenters:
Yutian Lei, University of Illinois at Urbana-Champaign
Robert Pilawa-Podgurski, University of Illinois at Urbana-Champaign

Title: Control and Performance of a Single-Phase Dual Active Half Bridge Converter Based on 15kV SiC IGBT and 1200V SiC MOSFET
Abstract: A single-phase Dual Active Half Bridge (DAHB) DC-DC converter topology is evaluated for medium voltage (MV) application. A 15kV SiC-IGBT based three-level half-bridge is connected to the high voltage (HV) primary side of a high frequency (HF) transformer operating at 10kHz link-frequency. A 1200V SiC-MOSFET based two-level H-bridge is connected on the low voltage (LV) secondary side. This topology requires fewer switches and is suitable for MV application particularly with high step-down ratio where HF transformer may have considerable parasitics. It offers advantage of half blocking voltage requirement per device on the HV side and a simpler transformer saturation protection implementation. This paper also presents a robust D-Q based inner current control technique for the single phase DAB. The converters on both HV and LV side of the DAHB, can also be switched in 60 degree zero quasi-square mode to eliminate third harmonic voltage. The square and 60 degree modes of operation are compared. The DAHB converter topology and controls are validated with simulation results followed by experimental results.
Presenters:
Awneesh Tripathi, North Carolina State University
Krishna Mainali, North Carolina State University
Dhaval Patel, North Carolina State University
Subhashish Bhattacharya, North Carolina State University
Kamalesh Hatua, Indian Institute of Technology Madras

Session: D04-Power Converter Control in Grid Application
Track: Power Electronics for Utility Interface

Title: Autonomous Active and Reactive Power Distribution Strategy in Islanded Microgrids
Abstract: This paper presented a wireless reactive power control for CCM converter based on reverse droop method. The proposed control strategy was applied in a microgrid system to RES units in order to coordinate with ESS unit based on an adaptive reactive power droop method. The principle of the adaptive Q ” V droop method control and its coordination with the proposed V – Q was presented and illustrated. Real-time hardware-in-the-loop results were carried out to in order to verify the overall primary control concept in an islanded microgrid within different scenarios.
Presenters:
Dan Wu, Aalborg university
Fen Tang, Beijing Jiaotong University
Josep Maria Guerrero, Aalborg university
Juan Carlos Vasquez, Aalborg university
Guoliang Chen, ShangHai Solar Energy & Technology, Co.Ltd.
Libing Sun, ShangHai Solar Energy & Technology, Co.Ltd.

Title: A Novel Harmonic Control Approach of Distributed Generation Converters in a Weak Microgrid
Abstract: This paper proposes a novel approach to compensate the voltage at the point of common coupling (PCC) and the grid line current harmonics through a distributed generation (DG) interfacing converter in a weak microgrid. In the proposed approach,the PCC voltage was indirectly derived from the measured converter output voltage,DG line current and line impedance. A voltage closed-loop controller and a current closed-loop controller are designed to achieve both functions of DG real power generation and PCC harmonics compensation. Therefore, the traditional harmonic measurement devices installed at the PCC as well as the long distance communication between the PCC and the converter are fully eliminated. Matlab simulations and some preliminary experimental results are presented to show the effectiveness of the proposed approach.
Presenters:
Guangqian Ding, Shandong University
Feng Gao, Shandong University
Yi Tang, Aalborg University
Lei Zhang, Shandong University
Song Zhang, State Grid of China Technology College

Title: Electric Spring for Power Quality Improvement
Abstract: The concept of electric springs (ES) was originally introduced to provide voltage support in power grid with intermittent renewable energy sources. Further research works show that ES can be extended to include advanced applications in future power system to concurrently perform line voltage support and active or/and reactive power compensations with a minimal energy storage requirement. In this paper, a comprehensive discussion on the application of ES for voltage stabilization and power quality improvement is presented. To achieve this, an input voltage control and an input current control are introduced to respectively regulate the bus voltage and current. Detailed mathematical derivations of the proposed control paradigm are provided. Results validate the effectiveness of adopting this control methodology in the ES for a practical power system with a fluctuating AC power source and reactive loads.
Presenters:
Yan Shuo, University of Hong Kong
Siew-Chong Tan, University of Hong Kong
Chi Kwan Lee, University of Hong Kong
Shu Yuen Ron Hui, University of Hong Kong

Title: Decoupled Closed-Loop Power Flow Control for the Controllable Network Transformers (CNT)
Abstract: Rising system load, increases in penetration of renewable energy, and limited investment in transmission infrastructure are fostering the need for a smarter and more dynamically controllable grid. FACTs devices can be used to control power flow and mitigate these stresses. But such devices are either too complicated and expensive for implementation or incapable of independently controlling active and reactive power. A Controllable Network Transformer (CNT), has a fractionally-rated, direct ac/ac converter, and was introduced as a simpler and more cost-effective solution to realize dynamic power control between two areas. This paper presents a fully decoupled closed-loop controller for a CNT to achieve independent active and reactive power control.
Presenters:
Hao Chen, Georgia Institute of Technology
Amrit Iyer, Georgia Institute of Technology
Ronald Harley, Georgia Institute of Technology
Deepak Divan, Georgia Institute of Technology

Title: Investigating the Influence of Semiconductor Device Voltage Drops on Harmonic and Reactive Current Compensation with Cascaded Multilevel Inverters
Abstract: The influence of on-state voltage drop of semiconductor devices on the harmonic current and reactive power compensation effect using cascaded multilevel inverter is studied in this paper. It has been found that the device voltage drop may cause severe distortion in the compensator voltage and greatly deteriorate the compensation performance. Analysis, simulation and experiment were conducted to study the influence of the device voltage drop so as to get insight into semiconductor device selection and design for cascaded multilevel inverter based harmonic current and reactive power compensators.
Presenters:
Deliang Wu, Huazhong University of Science and Technology
Shuo Wang, University of Texas at San Antonio
Li Peng, Huazhong University of Science and Technology

Title: Versatile Unidirectional AC-DC Converter with Harmonic Current and Reactive Power Compensation for Smart Grid Applications
Abstract: This paper introduces a versatile unidirectional ac-dc converter with harmonic current and reactive power compensation. Since numerous unidirectional ac-dc converters can be connected with ac power systems, existing commercial converters possess the ability to improve substantially the stability of ac power systems by compensating harmonic current and reactive power. In this paper, the feasibility and limitations of the unidirectional ac-dc converter are explained when it is employed for harmonic current and reactive power compensation, and a control strategy for such functionalities is proposed. A MATLAB/Simulink model and a 1 kW dual boost PFC prototype board controlled by a digital signal processor are implemented to demonstrate the effectiveness of the proposed control method for improving power quality of the grid.
Presenters:
Sung Min Park, University of Connecticut
Sung-Yeul Park, University of Connecticut

Title: Fuzzy-Logic-Based Gain-Scheduling Control for State-of-Charge Balance of Distributed Energy Storage Systems for DC Microgrids
Abstract: This paper proposes a modular and decentralized gain-scheduling control strategy based on fuzzy logic that ensures stored energy balance among distributed energy storage units as well as low voltage deviation in a DC microgrid. The proposed gain-scheduling control, assures good stored energy balance and small voltage deviation. Additionally, this strategy does not require a centralized control. Hardware in the loop simulations show the advantages of the proposed strategy.
Presenters:
Nelson Diaz, Aalborg University
Tomislav Dragicevic, Aalborg University
Juan Carlos Vasquez, Aalborg University
Josep Maria Guerrero, Aalborg University

Title: Control Loop Design of a Two-Stage Bidirectional AC/DC Converter for Renewable Energy Systems
Abstract: It is known that single-phase ac/dc converter requires big output capacitor to filter the power ripple. To interface a dc nanogrid to single-phase utility, bidirectional power flow and small dc output voltage ripple are necessary. By cascading a full-bridge ac/dc converter with a bidirectional buck converter, a two-stage ac/dc topology is adopted to reduce the dc-link capacitor. A bidirectional control system is designed to minimize the output voltage ripple. The designed controller can work for both rectifier and regeneration. A 10 kW prototype is used for verification. The dc side output voltage ripple is small and mode transition is smooth.
Presenters:
Fang Chen, Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Dong Dong, Virginia Polytechnic Institute and State University

Title: An Active Damper to Suppress Multiple Resonances with Unknown Frequencies
Abstract: The increasing use of power electronics devices tends to aggravate high-frequency harmonics and trigger resonances across a wide frequency range into power systems. This paper presents an active damper to suppress multiple resonances with unknown frequencies. The active damper is realized by a high-bandwidth power converter that can selectively dampen out the wideband resonances. A cascaded adaptive notch filter structure is proposed to detect the frequencies of resonances, which makes the active damper different from the resistive-active power filter for harmonic resonance suppression. The performance of the active damper is validated by implementing it to suppress the resonances in a grid-connected inverter with a long power cable. The results show that the active damper can become a promising approach to stabilizing the future power electronics based power systems.
Presenters:
Xiongfei Wang, Aalborg University
Frede Blaabjerg, Aalborg University
Marco Liserre, Aalborg University

Title: Single-Phase Soft-Switching AC-Link Buck-Boost Inverter
Abstract: The soft-switching ac-link universal power converters have received noticeable attention during the last few years. These converters, which can appear as dc-dc, dc-ac, ac-dc, or ac-ac, are compact and reliable. They are an extension of the dc-dc buck-boost converters, in which the current of the link inductor is alternating. By adding a small capacitor to the link and by modifying the control scheme the switches can all be turned on at zero voltage, and they can also have a soft turn-off. The application of this converter in the three-phase dc to ac and the three-phase ac-ac conversion has been successfully evaluated. The three-phase soft-switching ac-link buck-boost inverter is currently available in the market and has recently been listed in the California Energy Commission list of approved photovoltaic inverters. In this paper the application of this converter in the dc to single-phase ac conversion will be studied in detail and two single-phase inverter configurations will be proposed and evaluated.
Presenters:
Mahshid Amirabadi, University of Illinois at Chicago
Hamid A. Toliyat, Texas A&M University
William Alexander, Ideal Power Converters

Title: Single-Phase Current Source Converter with New Modulation Approach and Power Decoupling
Abstract: In this work it is presented a Current Source Converter (CSC) topology that helps to mitigate double line frequency power ripple (low frequency) effect. Low frequency power ripple presented in single-phase systems propagates through DC-bus converter. This low frequency ripple reduction allows to increase the power converter density by reducing the volume of the DC inductor, without lack of stiffness at the DC-bus. The low frequency mitigation is achieved by using a different single-phase CSC topology that uses three series-connected switches per leg. Thus, it allows independent control for two merged CSCs which share the same DC-bus and the middle switches of the leg. This solution is adequate to connect photovoltaic panels to the electrical grid, among others applications. Evaluation of such a solution by assuming grid modeling is useful and may require powerful simulation tools such as real-time simulator. In order to comply with power processing restrictions, a low frequency model is derived. Control strategies and modulation are presented. Simulation results are provided to validate the theoretical approach, and real-time simulation results, as well.
Presenters:
Montiê Vitorino, Universidade Federal de Campina Grande
Lucas Hartmann, Universidade Federal da Paraíba
Darlan Fernandes, Universidade Federal da Paraíba
Emanoel Silva, Universidade Federal de Campina Grande
Maurício Corrêa, Universidade Federal de Campina Grande

Title: A Review of Passive Filters for Grid-Connected Voltage Source Converters
Abstract: This paper investigates the most promising passive damping methods for the LCL topology but also propose an overview of high order filters capable to offer even more attenuation than the LCL filter at a reduced size. However, it is found that by decreasing the size of the passive elements, the filter becomes more sensitive to grid impedance variations. Hence, a comparison of the filter features including the robustness to impedance variations and harmonic attenuation capability is important from a practical implementation point of view. The design and analysis of the proposed methods is validated through simulation and experimental results.
Presenters:
Remus Narcis Beres, Aalborg University
Xiongfei Wang, Aalborg University
Frede Blaabjerg, Aalborg University
Claus Leth Bak, Aalborg University
Marco Liserre, Christian-Albrechts-Universität zu Kiel

Title: Research of the Voltage and Current Sharing Issue of an H-Bridge Based Power Electronic Transformer
Abstract: Power Electronic Transformer (PET) is one of the key components for the future power electronics based power distribution systems. In this paper, the input-voltage and output-current sharing issue of a three-stage H-bridge based PET based on the total control strategy is discussed. It finds that the output-current sharing control serves to automatically achieve input-voltage sharing control. In order to simplifying the control strategy, the output-current sharing control can be removed if the tolerance of the output filter inductors is under the range presented in this paper. Simulation results verify the analysis.
Presenters:
Xinyu Wang, Xi’an Jiaotong University
Shaodi Ouyang, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Fei Meng, Xi’an Jiaotong University
Riffat Javed, Xi’an Jiaotong University

Session: D05-Power Converter Modeling and Design in Grid Application
Track: Power Electronics for Utility Interface

Title: WattsWorth: Monitor Electric Power Anywhere
Abstract: Energy monitoring and control strategies can be asymmetrical, chasing pennies of hoped-for savings with dollars of installation and monitoring expense. Modern sensors can be used to accurately measure voltage and current without the requirement for a permeable magnetic core or the need to surround the conductor, e.g., with a Rogowski coil. These sensors can be used to find currents and voltages without the need to invasively separate existing conductors. These sensors could greatly lower installation and monitoring expense, and provide quickly installed access for acquiring actionable energy consumption information and power quality assessment.
Presenters:
John Donnal, Massachusetts Institute of Technology
Steven B. Leeb, Massachusetts Institute of Technology

Title: Bidirectinal Switched Boost Converter for AC-DC Hybrid Microgrid
Abstract: In this paper a bidirectional switched boost converter is proposed. Conventional Z-source converter (ZSC) requires two inductors and two capacitors of equal inductance and capacitance which is difficult to realize in practice. Switched boost converter (SBC) is an improved derivative of ZSC comprising of one inductor and one capacitor which overcomes the stability issues associated with it. But power flow is limited to one direction in case of SBC. In AC-DC hybrid micro grid and in some energy storage applications bidirectional power flow is the most essential requirement. Proposed bidirectional switched boost converter (BSBC) retains the advantage of SBC and provides additional advantage of bidirectional power flow which makes it more suitable for AC-DC hybrid micro grid. Unaltered voltage gain is achieved at the AC bus and DC bus in both the directions of power flow. The Matlab simulation results are shown to verify the operation and theoretical analysis of proposed BSBC converter.
Presenters:
Manoranjan Sahoo, Indian Institute of Technology, Hyderabad
Siva Kumar K, Indian Institute of Technology, Hyderabad

Title: Solid-State Transformer Stability and Control Considerations
Abstract: This paper discusses the stability issues in a solid-state transformer (SST) and presents the necessary tools and procedures to analyze stability of a special type of SST. The SST discussed in this paper is comprised of three cascaded power electronic stages including a rectifier, a dual active bridge (DAB) converter, and an inverter. In this paper, first the topology of the SST under study is introduced and some information about the controller systems used with this type of converter is provided. Next, the Middlebrook criterion is reviewed as the main means for analyzing the stability of interconnected power electronic topologies. Then, the small-signal model of each stage of the SST is presented and the input and output impedances of each stage are derived. These impedances are necessary to analyze the stability of the system using the Middlebrook criterion. Using the Middlebrook criterion and the derived impedances stability of an SST in different operating points is predicted. Finally, the results from simulation of the SST being studied are used to confirm the theoretical predictions.
Presenters:
Mostafa Khazraei, Missouri University of Science and Technology
Anand Prabhala, Missouri University of Science and Technology
Reza Ahmadi, Missouri University of Science and Technology
Mehdi Ferdowsi, Missouri University of Science and Technology

Title: A Rapid Prototyping Tool for Load and Source Emulation in a Microgrid Test Laboratory
Abstract: This paper details the development of a microgrid laboratory test rig to emulate linear and non-linear loads, unbalanced three and four wire loads and electric power sources such as wind turbines, flywheel energy storage systems, photovoltaic arrays, etc. The test rig developed in this paper is composed of two 15 kW DC/AC converters connected in a back to back configuration, a rapid prototyping tool based on an FPGA, a Linux PC and the real time communication protocol Ethercat allowing the ability to utilize real-time Simulink to develop inverter control. Current control strategies were investigated to control harmonic currents and results were verified through experimental tests.
Presenters:
Diarmaid Hogan, University College Cork
Michael Egan, University College Cork
John Hayes, University College Cork
Gordon Lightbody, University College Cork
Francisco Gonzalez-Espin, United Technologies Research Centre

Title: Grid Current Shaping of Single Phase Diode Rectifier with Small DC-Link Capacitor for Three Phase Motor Drive
Abstract: In this paper, motor drive system fed by single phase diode rectifier without power factor correction (PFC) circuit is proposed. The system considered in this paper consists of single phase diode rectifier, three-phase inverter, and small DC-link capacitor. Where DC-link capacitance is very low, grid current can be directly affected by electrical output power of the inverter. Using this aspect, the proposed method in this paper can drive the motor and shape the grid current with low harmonics simultaneously. This paper proposes the motor current reference generation method and the direct regulation method of the inverter output power by modifying the output voltage reference. Comparative analysis of IPMSM and SynRM with proposed drive system is also included. With the proposed regulator, the harmonic components of the grid current can be suppressed exactly and immediately. Also, cost and size of the inverter system can be reduced by removing large capacitor and PFC circuit from the system. The improved performance of the proposed method was verified by the experimental results using the inverter system with a 5?F DC-link capacitor.
Presenters:
Yeongrack Son, Seoul National University
Jung-Ik Ha, Seoul National University

Title: Filter-Capacitor Current Compensation for Division-Summation Digital Controlled Single-Phase Bi-Directional Inverter with LCL Filter to Reduce Grid-Current Distortion
Abstract: This paper presents filter-capacitor current compensation for Division-Summation (D-?) digital controlled single-phase bi-directional inverter with LCL filter to reduce grid-current distortion. The single-phase bi-directional inverter allows wide filter-inductance variation and it can operate in grid-connection mode and rectification mode with power factor correction. With the D-? digital control, the inverter can cover wide inductance variation and can track sinusoidal inductor current reference precisely. However since there typically exists, the injected grid current will contain harmonic components. With estimated filter”capacitor current compensation, the grid-current distortion can be improved significantly. Experimental and simulated results from a 5 kW single-phase bi-directional inverter have verified the feasibility of the proposed compensation approach.
Presenters:
Tsai-Fu Wu, National Tsing Hua University
Li-Chun Lin, National Chung Cheng University
C.-H. Chang, Nation Chung Cheng University
P.-H. Lee, Nation Tsing Hua University

Title: A High Power Density Grid Connected Soft Switched Inverter
Abstract: The paper proposes a new ZVS technique for full-bridge single-phase inverter that has several application such as: PV ac module. The technique eliminates the LCL filter between inverter and grid which results in a simple control, simpler design, more compact and more efficient ac module. The proposed topology uses a passive LC small auxiliary circuit which operates under fixed frequency and leads to a simpler EMI filter design. Using the proposed topology, the switching frequency can be increased to achieve a more compact and higher efficiency circuit. A controller to minimize conduction loss in the auxiliary circuit is designed and analysis, simulation and experimental results are also provided to verify the theory.
Presenters:
Behnam Koushki, Queen’s University
Sayed Ali Khajehoddin, University of Alberta
Alireza Safaee, Queen’s University
Praveen Jain, Queen’s University
Alireza Bakhshai, Queen’s University

Title: Dyna-C: Experimental Results for a 50 kVA 3-Phase to 3-Phase Solid State Transformer
Abstract: A compact, isolated, current-source based bidirectional solid state transformer (SST) with configurability for supporting low- or medium-voltage DC and AC application is discussed in this paper. More specifically, design considerations and practical implementation techniques for realizing a 50 kVA 3-phase to 3-phase SST are presented. Results from experimental measurements are shown and discussed.
Presenters:
Anish Prasai, Varentec, Inc.
Hao Chen, Georgia Institute of Technology
Rohit Moghe, Varentec, Inc.
Zbigniew Wolanski, Varentec, Inc.
Kireeti Chintakrinda, Varentec, Inc.
Aaron Zhou, Varentec, Inc.
Juan Carlos Llambes, Varentec, Inc.
Deepak Divan, Varentec, Inc.

Title: Stacked Modular Isolated Dynamic Current Source Converters for Medium Voltage Applications
Abstract: Medium voltage, high power applications of power converters using lower rating semiconductor devices are gaining more favor in industries. Current solutions include stacking converters and stacking devices to reach that goal. This paper presents the stacking of modular current source converters that are introduced in a companion paper and proposes a control strategy to stabilize the converter operation. Simulation results are provided to verify the control strategy.
Presenters:
Hao Chen, Georgia Institute of Technology
Anish Prasai, Varentec, Inc.
Deepak Divan, Varentec, Inc.

Title: Instantaneous Fault Current Limiter for PWM-Controlled Voltage Source Converters
Abstract: The PWM-controlled VSCs are commonly used in industrial and utility applications. In spite of superior features of fast voltage regulation and stable DC-link voltage, PWM-controlled VSCs have the major drawback of being sensitive to the grid disturbances, especially the unbalanced conditions and system faults. This paper presents an alternative solution to improve the PWM-controlled VSC performance under unbalanced conditions and system faults and also under distorted input voltage condition caused by other harmonics rather than the negative sequence voltage. This solution is based on direct calculation of the negative sequence (or other harmonics) reference voltage without using any current regulator.
Presenters:
Saman Babaei, North Carolina State University
Mahsa Ghapandar Kashani, North Carolina State University
Subhashish Bhattacharya, North Carolina State University

Title: Rainflow Algorithm Based Lifetime Estimation of Power Semiconductors in Utility Applications
Abstract: Rainflow algorithms are one of the best counting methods used in fatigue and failure analysis in semiconductor lifetime estimation models. The conventional rainflow algorithm used in power semiconductor reliability does not consider the time dependent mean temperature calculation. The equivalent temperature calculation proposed by Nagode et al is applied to semiconductor lifetime estimation for the first time. A month long load profile to include the various cases in cycle counting of the stress-strain hysteresis loop is used as a test profile. The algorithm is applied to reactive compensation data of a STATCOM to predict lifetime of the IGBT.
Presenters:
Lakshmi Reddy GopiReddy, University of Tennessee
Leon M. Tolbert, University of Tennessee
Burak Ozpineci, Oak Ridge Natinal Laboratory
Joao Pinto, Universidade Federal de Mato Grosso do Sul

Title: Development of Solid State Arc-Free Socket for DC Distribution System
Abstract: The DC distribution system is becoming an appealing spot due to its higher energy efficiency in recent years. However, the arcing and related potential for fire and human touch is the main safety problem in DC application. In this paper, a totally arc-free socket is proposed and developed by embedding solid state device. Besides, over temperature and over current protection features has been also embedded for realizing trip function for each single outlet. Simulation and experimental results based on 380V DC, which is a common medium voltage applied in data center and DC micro grid, has been discussed.
Presenters:
Kai Tan, North Carolina State University
Alex Huang, North Carolina State University
Adam Martin, North Carolina State University

Title: Modular and Compact Design for an Isolated High-Frequency-Link Inverter Using Hybrid-Modulation Scheme
Abstract: High frequency link (HFL) power converters, due to advancements in magnetics and semiconductor devices, are gaining considerable attention. The overall power density and reliability of the HFL inverter are increased by eliminating the bulky dc-link capacitor. The resulting pulsating-dc link (PDCL) waveform can be used to reduce the switching requirement of the HFL inverter. This paper presents a modular and compact design for a high-frequency link (HFL) inverter using insulated-gate bipolar transistor (IGBT) power modules. Hybrid modulation (HM) scheme uses the pulsating-dc link feature of the dc-link capacitor-less HFL inverter to reduce the switching requirement of the inverter.
Presenters:
Arash Rahnamaee, University of Illinois at Chicago
Sudip Mazumder, University of Illinois at Chicago

Title: Grid-Connected Single-Phase Multi-Level Inverter
Abstract: This digest proposes a single-phase five level pulse width modulation (PWM) inverter for grid connection. Two different control techniques for generating PWM have been used. Both of these control techniques have some switches operate at line frequency and the other operate at switching frequency. The proposed inverter has advantages of less number of components and low Total Harmonic Distortion (THD) compared with the conventional multi-level inverter. The simulation and experimental results prove the powerful merits of the proposed inverter.
Presenters:
Mahmoud A. Sayed, South Valley University
Maha G. Elsheikh, Aswan University
Mohamed Orabi, Aswan university
Emad M. Ahmed, Aswan University
Takaharu Takeshita, Nagoya Institute of Technology

Session: D06-Inverters
Track: Motor Drives and Inverters

Title: Feedforward Control of Output Current for Three-Phase Voltage Source Inverter (VSI) with Transformer
Abstract: This paper concentrates on the load disturbance in three-phase voltage source inverter (VSI) with an output transformer. The transformer could be smaller when placed behind the LC filter. But the voltage drop on the leakage impedance may reduce the quality of output voltage. Output current feedforward control is proposed to eliminate the influence of load disturbance. The distinct features of the proposed feedforward control scheme are error-free steady-state and fast dynamic response. Finally, experiment results are given to verify the feasibility and validity of the proposed control strategy.
Presenters:
Yu Qi, Huazhong University of Science and Technology
Li Peng, Huazhong University of Science and Technology
Zeyi Huang, Huazhong University of Science and Technology
Manlin Chen, Huazhong University of Science and Technology
Lei Sun, Huazhong University of Science and Technology

Title: Model Predictive Current Control of a Three-Level Five-Phase NPC VSI Using Simplified Computational Approach
Abstract: The paper proposes a computationally efficient finite state model based current control of a three-level neutral point clamped (NPC) five-phase voltage source inverter. The space vector model of a five-phase voltage source inverter (VSI) yields 243 space vectors, with 240 active and three zero vectors. The presented technique utilizes a modified switching algorithm to reduce the computation time while incorporating all the 243 switching state vectors. Search is made by the algorithm to find the vector which minimizes the chosen cost function. Capacitor voltage balancing is also done by incorporating an additional cost function. The performance of the current control heavily depends upon the choice of the cost function, the number of vectors used and the sampling time. The developed technique is tested for an RL load using simulation and an experimental approach.
Presenters:
Atif Iqbal, Qatar University
Haitham Abu-Rub, Texas A&M University at Qatar
Sk. M Ahmed, Texas A&M University at Qatar
Patercio Cortes, Santa Maria University
Jose Rodriguez, Universidad Tecnica Federico Santa Maria

Title: A High-Performance Z-Source Inverter with Low Capacitor Voltage Stress and Small Inductance
Abstract: The proposed novel Z-source inverter is well settled the limitations and drawbacks of the traditional Z-source inverter. It does not exist inrush current at startup and can operate with low Z-source network capacitor voltage stress and can operate in light-load or low power factor with small inductance normally, largely enhanced the load capacity of the inverter.That is, it has smaller volume and weight but still matintaining the high performance at the same time. Simulation and experimental results are presented in the paper to verified the validity of the proposed novel Z-source inverter.
Presenters:
Liqiang Yang, South China University of Technology
Dongyuan Qiu, South China University of Technology
Bo Zhang, South China University of Technology
Guidong Zhang, South China University of Technology

Title: Comprehensive Analysis on Carrier-Based PWM Modulations for Advanced Composited Clamping Five-Level Converter
Abstract: An advanced five-level Modular Multilevel-clamped Composited Multilevel Converter (5L-M-MC2) is introduced and the comprehensive understanding on its carrier-based PWM modulation is analyzed in detail in this paper. The line-to-line voltage levels degrade when the modulation index decreases from 1 to 0 with a certain style. The differences of the degradation in the three classic Carriers Disposition PWM modulation methods are pointed out and their level degradation points are explored to give a better understanding on this advanced 5L-M-MC2. Finally, the experimental results of three Carriers Disposition PWM modulations are exhibited to verify the validity of the main contributions of this paper.
Presenters:
Heya Yang, Zhejiang University
Haoze Luo, Zhejiang University
Pengfei Sun, Zhejiang University
Chushan Li, Zhejiang University
Wuhua Li, Zhejiang University
Xiangning He, Zhejiang University

Title: Efficiency Characterization and Thermal Study of GaN Based 1 kW Inverter
Abstract: Rapid advancement of gallium nitride (GaN) based device technologies enables the possibility to design inverters that have superior performance capabilities compared to Si based inverters. It is prevalently acknowledged that GaN-based switching devices outperformed the Si-based counterparts in many aspects such as lower power consumption, faster switching frequencies, and higher operating temperatures. GaN devices will benefit many applications such as hybrid and plug-in electric vehicles, solar power inverters, industrial motor drives. Nevertheless, the superiorities of GaN devices in inverter design have not been fully explored by researchers, and the purpose of this paper is to evaluate the high efficiency capabilities that can be achieved using these new devices and the resulting benefits on the thermal side. As a case study, 1 kW GaN FETs inverter is considered. Loss and efficiency analysis is performed under various load conditions, and the requirements on heat sink for various ambient temperatures are specified according to the loss values obtained. Analysis results are compared with conventional Si-based inverters.
Presenters:
Di Han, University of Wisconsin-Madison
Anuradha Ogale, University of Wisconsin-Madison
Silong Li, University of Wisconsin-Madison
Yingjie Li, University of Wisconsin-Madison
Bulent Sarlioglu, University of Wisconsin-Madison

Title: A Low Frequency Input Current Reduction Scheme of a Two-Stage Single-Phase Inverter with DC-DC Boost Converter
Abstract: A two-stage single-phase grid-connected inverter has 120Hz component in input current as influence of pulsating output power at double of the grid frequency. The 120Hz component of input current has to be reduced or eliminated because low frequency current can damage a source or reduce efficiency in the photovoltaic, fuel cell and battery systems. Prior studies which deal with reduction of the 120Hz component have their own limits. Thus, it is unavoidable to use a bulky dc link capacitor or a high gain controller. This paper proposes the feed-forward compensation for current control of the boost converter in a two-stage single-phase grid-connected inverter. The feed-forward compensation substantially removes 120Hz component from the input current without a bulky dc link capacitor or a high gain current controller as removes the disturbance of dc link voltage from the current control. Removal of the disturbance is analyzed with a small-signal model and bode plot. Simulation and experimental results are provided for validation.
Presenters:
Jun-Ho Kim, Hanyang University
Ki-Young Choi, Hanyang University
Rae-Young Kim, Hanyang University

Title: Soft-Switching Z-Source Inverters with Coupled Inductor
Abstract: This paper presents a new resonant soft-switching quasi-Z- source inverter. On the basis of the quasi-Z-source inverter, the proposed inverter inherits the features of high voltage boost ability, circuit simplicity and high reliability. A resonant network with coupled inductor is employed to achieve the soft-switching scheme. All active devices (switches and diodes) in the inverter are turned on and off under zero voltage or zero current switching condition. The principle of the proposed converter and analysis of operation are proposed. Simulation and experimental results are given to illustrate the soft-switching characteristics. The theoretical analysis and simulation agrees well with experimental results.
Presenters:
Xinping Ding, Qingdao Technological University
Hong Yuan, Qingdao Technological University
Chenghui Zhang, Shandong University
Junming Zhang, Zhejiang University

Title: Two-Layer Distributed Cooperative Control of Multi-Inverter Microgrids
Abstract: Renewable-intensive microgrids are mainly actualized using voltage-source inverters (VSI). Voltage-controlled and current-controlled VSIs can manage voltage/frequency and active/reactive power flow in microgrids, respectively. A two-layer cooperative strategy is proposed that simultaneously controls both the voltage/frequency as well as the active/reactive power flow. The proposed strategy is fully distributed; each inverter only requires its own information and those of neighbors on the communication graph. The sparse communication structure requires one-way communication links and is more reliable than centralized control structure. The simulation of a 7-inverter microgrid system verifies the proposed control methodology.
Presenters:
Ali Bidram, University of Texas at Arlignton
Ali Davoudi, University of Texas at Arlignton
Frank L. Lewis, University of Texas at Arlignton

Title: A New Nested Neutral Point Clamped (NNPC) Converter for Medium-Voltage (MV) Power Conversion
Abstract: In this paper, a new Voltage Source Converter (VSC) for Medium Voltage (MV) applications is presented which can operate over a wide range of voltages (2.4kV-7.2KV) without the need for connecting power semiconductor in series. The operation of the proposed converter is studied and analysed. In order to control of the proposed converter, a Space Vector Modulation (SVM) strategy which benefits from the switching state redundancy has been used. This strategy helps to control the output voltage and stabilize voltages of the flying capacitors in the proposed converter. Performance of the converter under different operating conditions is investigated in the MATLAB/Simulink environment. The feasibility of the proposed converter is evaluated experimentally.
Presenters:
Mehdi Narimani, Ryerson University
Bin Wu, Ryerson University
George Cheng, Rockwell Automation
Navid Zargari, Rockwell Automation

Title: Direct Parallel Operation of Cascaded H-Bridge Multilevel Inverters
Abstract: This paper proposes a method to parallel m digital controlled cascaded H-bridges (CHB) multilevel inverters directly with high bandwidth current sharing capabilities. The proposed method utilizes switch signal synchronization with dead time control to eliminate circulating current and adopts “piecewise” master-slave strategy to achieve equal current distribution in less than one cycle. A prototype is designed, built, and tested.
Presenters:
Su Sheng, Northeastern University
Brad Lehman, Northeastern University

Title: Interleaved Carrier-Based Modulations for Reducing Low-Frequency Neutral Point Voltage Ripple in the Three-Phase Neutral Point Clamped Inverter
Abstract: In this paper, a novel modulation technique based on the combination of the standard sinusoidal and double signal pulse width modulations is proposed, obtaining a mitigation of both losses and low frequency NP voltage ripple. Comparison with hybrid PWM approach will be reported, as far as losses and oscillation of NP voltage. Simulation and experimental results based on a TMS320F28035 DSP controller and a NPC three level inverter are presented to confirm the effectiveness of the proposal.
Presenters:
Roberto Petrella, Università di Udine
Alessandro Pevere, Università di Udine

Title: A Capacitor Voltage Balancing Method with Zero-Voltage Switching for Split Phase Inverter
Abstract: This paper presents a new method of current control that employs burst mode in order to balance the dc-side capacitor voltages of split phase inverters. By alternating the inductor current in every switching period, zero-voltage switching (ZVS) can be achieved, which avoids the reverse recovery issue of power MOSFETs. As a result, super-junction MOSFETs instead of IGBTs can be employed to achieve higher efficiency. Combining the hysteresis current control with traditional pulse-width modulation (PWM), a new burst mode control method is proposed in this paper. The minimum operation time during a set modulation period is limited then the efficiency at the light load can be increased. A buck-and-boost converter is employed as the auxiliary circuit for the capacitor voltage balancing circuit. Due to the proposed ZVS method, inductor volume can be reduced. A prototype with 25 A current capacity is built to verify all the performance of the presented control method. The efficiency over the whole load range is over 98% with a peak efficiency of 98.4%.
Presenters:
Lanhua Zhang, Virginia Polytechnic Institute and State University
Bin Gu, Virginia Polytechnic Institute and State University
Jason Dominic, Virginia Polytechnic Institute and State University
Baifeng Chen, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University

Title: Effective Dithering Technique for EMI Reduction in Three Phase DC/AC Inverters
Abstract: Dithering the switching frequency is one of the effective tools to reduce EMI. To maximize the dithering usefulness, the effect of its parameters on the EMI reduction needs to be understood. In this paper, the parameters of triangular dithering are investigated to find their values that yield the minimum EMI. By increasing the amplitude of the dithering signal and selecting its frequency to be equal to the inverter frequency, the EMI is reduced. By selecting a phase shift of ?/12 between the dithering signal and any of the inverter currents, the EMI is minimized compared to other phase shifts
Presenters:
Ali Elrayyah, University of Akron
Yilmaz Sozer, University of Akron

Title: Charging Method for the Second Battery in Dual Inverter Drive Systems for Electric Vehicles
Abstract: In this work, we focus on the electric vehicle (EV) application of the dual source inverter, and consider using one charger for the dual source inverters: In this proposed scheme, only Battery~1 is charged by an external charger. Battery~2 is charged via Inverter~1 and 2 from Battery~1. The charging algorithms differ based on the motor operation status: The motor is at stand-still, running under a base speed, and over a base speed in the field weakening region.
Presenters:
Jinseok Hong, Pohang University of Science and Technology
Heekwang Lee, Pohang University of Science and Technology
Kwanghee Nam, Pohang University of Science and Technology

Title: Control and Analysis of the High Efficiency Split Phase PWM Inverter
Abstract: This paper proposes a new split phase PWM inverter which could split the bridge arms by coupled inductor and prevent the short through. By using the traditional bipolar or unipolar PWM control schemes, the circulating current which is caused by the feature of inductors will exist in the circuit and will increase the current ripple and power loss. To improve the efficiency of the inverter, an advanced unipolar PWM control strategy is proposed in this paper to reduce the current ripple in the inverter. Simulation is done to verify the better performance of split phase PWM inverter and the proposed advanced unipolar PWM control strategy.
Presenters:
Suxuan Guo, North Carolina State University
Alex Huang, North Carolina State University

Session: D07-Motor Drives
Track: Motor Drives and Inverters

Title: An Improved Direct Torque Control Method for PMSM
Abstract: This paper presents an improved direct torque control (DTC) method for permanent magnet synchronous motors. The proposed DTC method generates the diver signal with SVPWM for the fixed switching frequency and low torque ripple relative to conventional hysteresis controllers. Different with the popular SVM-DTC, the proposed method obtains amplitude and angle of reference voltage vector directly by the torque and flux linkage loop respectively without complicated calculations that reproduces the simplicity and robustness of conventional DTC. Furthermore, the observation and control of torque angle in the proposed method ensures the PMSM operating stably. The validity of the control method is verified by experimental tests.
Presenters:
Xin Qiu, Nanjing Aeronautics and Astronautics University
Wenxin Huang, Nanjing Aeronautics and Astronautics University
Feifei Bu, Nanjing Aeronautics and Astronautics University

Title: Design of a Novel Filter Topology with Active Impedance Regulator for Three-Phase Motor Drive System
Abstract: This paper presents a novel hybrid output filter topology for inverter-motor system. It is composed of a conventional LC filter cascaded with an active motor CM impedance regulator. The active circuit, utilizing an integrated high-voltage op-amp, is very efficient in decreasing the motor CM equivalent capacitance as well as damping the high common voltage on the motor terminal. Therefore, the motor impedance is also used as part of the filter and the common voltage can be eliminated dynamically in the active impedance regulator by feedback control. Experimental verification of the filter topology is provided with a laboratory system consisting of a 380 V inverter and a 1kW permanent magnet synchronous motor.
Presenters:
Wenjie Chen, Xi’an Jiaotong University
Xu Yang, Xi’an Jiaotong University

Title: Initial Rotor Position Estimation of Permanent Magnet Synchronous Machines Using Square-Wave Voltage Injection with a Single Current Sensor
Abstract: This paper presents a saliency-based position sensorless drive of permanent magnet (PM) machines using a single current sensor for cost-effective applications. For the single current sensor system, the dc-link current is measured for the reconstruction of three-phase currents. The phase current reconstruction can only be realized when active voltages are applied. This limitation results in six immeasurable areas for the current reconstruction using the pulse width modulation (PWM) technology. In order to implement the saliency-based sensorless control, a square-wave voltage is injected to minimize the harmonics of reconstructed saliency current for the rotor position estimation. By injecting a square-wave voltage on the direction of rotor d-axis, the injection voltage vector is nearly perpendicular to the fundamental voltage vector. By using the proposed signal injection technique on a single current sensor system, the saliency-based sensorless drive can work on an interior PM machine at the speed of 60-rpm under full torque load based on the experimental evaluation.
Presenters:
Shih-Chin Yang, Texas Instruments

Title: Comparative Evaluation of Direct Torque Control Strategies for Permanent Magnet Synchronous Machines
Abstract: This paper presents a detailed comparative evaluation of several DTC strategies for permanent magnet synchronous machines, namely basic DTC, model predictive DTC, DTC with duty ratio modulation. Field orient control is also included in this study. The aforementioned control strategies are reviewed and their performance are analyzed and compared. The comparison is carried out through simulation of a 60 kW PMSM. With the intent to fully reveal advantages and disadvantages of each control strategy, critical evaluation has been conducted on the basis of several criteria. The choice of control scheme can be determined based on specific requirements of particular application.
Presenters:
Feng Niu, Hebei University of Technology
Kui Li, Hebei University of Technology
Bingsen Wang, Michigan State University
Elias G. Strangas, Michigan State University

Title: Fast Control of PWAM Boost-Converter-Inverter System for HEV/EV Motor Drives
Abstract: This paper introduces a fast closed-loop control strategy for a pulse width and amplitude modulation (PWAM) boost-converter-inverter system for HEV/EV motor drives. The PWAM method, in which the dc-link voltage is controlled to have a 6?fluctuation following the output peak voltage envelop, provides several advantages over the traditional PWM method, such as less switching loss, less dc-link capacitor, higher power density and lighter weight. The boost converter is responsible for generating the fluctuating dc-link voltage, thus needs fast control especially when the output fundamental frequency of the inverter is high. However, the boost converter suffers from low bandwidth due to the existence of a right-half-plane (RHP) zero. In light of this, a multiloop feedback linearized control strategy is adopted to realize the fast dynamic control requirement.
Presenters:
Yang Liu, Michigan State University
Fang Zheng Peng, Michigan State University

Title: A Simplified Method to Estimate the Rotor Position Using the High Frequency Voltage Signal Injection
Abstract: This paper presents a simple algorithm for estimation of the rotor position. The injected high frequency voltage is a sinusoidal voltage and is injected into the stator of a motor. An interior permanent magnet synchronous motor (IPMSM) has spatial saliency because d-axis inductance and q-axis inductance are different from each other. The injected high frequency voltage is influenced by saliency. Therefore, the rotor position is included in the stator current of the motor. The rotor position is estimated using filters but the estimated rotor position has error due to the time delay. Therefore, the proposed method decreases the number of filters and uses different synchronous reference frame transformation (SFT) to extract the rotor position error between the estimated value and actual value. The simulation results present the effectiveness of the proposed method by showing waveforms of the rotor speed and position with load conditions.
Presenters:
Tae-Min Yoon, Ajou University
Hyun-Woo Sim, Ajou University
June-Seok Lee, Ajou University
Kyo-Beum Lee, Ajou University

Title: Adaptive PWM Algorithm Using Digital-Signal Processing Based THD Measurement for Electric Vehicle Application
Abstract: This paper presents an advanced pulse width modulation (PWM) method with cross-correlation-based digital signal processing for electric vehicle (EV) application. The algorithm is designed to adaptively apply PWM techniques depending on motor operating conditions: space vector PWM (SVPWM) method in the high total harmonic distortion (THD) condition and the discontinuous PWM (DPWM) method in the low harmonics operating condition of an EV motor. The phase current of EV motor changes by the torque command and the THD requirements to be calculated in real time to select PWM method. Proposed simple cross-correlation-based THD calculation presents minimal computation load and short convergence time to apply a real-time adaptive PWM algorithm for EV traction inverter. Experimental verification of proposed algorithm is performed by using 80kW Permanent Magnet (IPM) Motor setup.
Presenters:
Jeihoon Baek, Samsung Advanced Institute of Technology
Seungdeog Choi, Akron University
Sangshin Kwak, Chungang University

Title: Sensorless Control of Non-Salient PMSM Using Simultaneous Injection of Two HF Signals
Abstract: In recent years, sensorless techniques based on HF carrier injection have become very popular as they are capable to estimate rotor position in a wide speed range. They can provide precise control over interior PMSMs without accompanying need for a position sensor. However, in surface-mounted PMSMs, estimation of rotor position is only reliable at light loads due to the very small saliency arising from main flux saturation. The anisotropy caused by stator flux saturation is not necessarily in alignment with rotor position especially at heavy loads. In this paper a novel solution is proposed to make use of sensorless scheme in surface-mounted PMSM even at heavy loads. Validity of proposed scheme is approved by simulation and experimental result and will be included in final version.
Presenters:
Mohammad Ali Ghazi Moghadam, Queen’s University
Mokhtar Yaghoubi, Sharif University of Technology
Farzad Tahami, Sharif University of Technology
Alireza Bakhshai, Queen’s University
Praveen Jain, Queen’s University

Title: The Excitation Control Strategy of the Three-Stage Synchronous Machine in the Start Mode
Abstract: In order to overcome the excitation problem of three-stage synchronous machine(TSM) used as starter for the engine cranking, this paper presented a novel three-phase open-winding structure of the exciter for the proposed machine with the dual-inverter for supplying the integrated ac and dc excitation power. The operation principle of the dual-inverter and the control method of the three-phase ac excitation and dc excitation were analyzed in detail and the selection basis of the dc excitation frequency and the switching point were derived by the characteristics of the main exciter. Then, the simulation and experiment results verify that the integrated ac and dc excitation control strategies could supply steady excitation current and the smooth switching process from ac to dc excitation for the proposed machine in the start process.
Presenters:
Jiadan Wei, Nanjing Aeronautics and Astronautics University
Qingqing Zheng, Nanjing Aeronautics and Astronautics University
Mingming Shi, Jiangsu Electric Power Research Institute
Bo Zhou, Nanjing Aeronautics and Astronautics University
Jie Li, Nanjing Aeronautics and Astronautics University

Title: A 2-D Fuzzy Logic Based MRAS Scheme for Sensorless Control of Interior Permanent Magnet Synchronous Motor Drives with Cyclic Fluctuating Loads
Abstract: Model reference adaptive system (MRAS) is usually employed for the rotor position/speed estimation in sensorless interior permanent magnet motor (IPMSM) drives, and the adjustment of control parameters in MRAS is a key issue for the IPMSM drive system with the cyclic fluctuating load. In order to avoid the complicated manual tuning of the control parameters, a new MRAS scheme based on fuzzy logic is proposed in this paper, in which a fuzzy controller replaces the conventional PI regulator. To implement this new MRAS scheme, a two-dimensional (2-D) fuzzy rule is designed. The proposed control scheme is employed in the IPMSM drives with the cyclic fluctuating load, such as compressors. In order to lower the motor speed ripple caused by the cyclic fluctuating load, a feed-forward compensation strategy with the load-matching motor output torque pattern is developed. Experimental results demonstrate the feasibility and effectiveness of the proposed fuzzy logic based MRAS scheme, which shows that the rotor position estimation error is limited within a very low level.
Presenters:
Kai Sun, Tsinghua University
Yuchao Shi, Tsinghua University
Lipei Huang, Tsinghua University
Yongdong Li, Tsinghua University
Xi Xiao, Tsinghua University

Title: Asymmetrical Multi-Lane Multi-Phase Motor Drives
Abstract: Asymmetrical multi-lane multi-phase motor drives are introduced in this paper. There are two conventional symmetrical drive systems for multi-phase motors. First one is modular phase multi-lane drive with single-phase inverters and second one is single-lane multi-leg inverter. While first one has high level of fault-tolerance, second one is a cost-effective solution. New class of drive systems, asymmetrical multi-lane drive systems, is proposed that provide a complete spectrum of solution for different application. Five-phase motors will be used as an example to explain and clarify the new class of drive systems. Pros and cons of possible asymmetrical designs are discussed and compared with symmetrical drives. Experimental test results are presented for a two-lane asymmetrical drive.
Presenters:
Ali Mohammadpour, Rensselaer Polytechnic Institute
Leila Parsa, Rensselaer Polytechnic Institute

Title: Control of Independent Multi-Phase Transverse Flux Linear Synchronous Motor Based on Magnetic Levitation
Abstract: This paper proposes the control system for the independent multi-phase transverse flux linear synchronous motor (TFLSM) based on magnetic levitation. Especially, the stator winding structures of the TFLSM are composed of the independent multi-phase unlike the conventional three-phase linear motors. Therefore, this paper presents the control algorithms for the magnetic levitation and thrust force of the TFLSM including an initial startup to maintain air gap and current control of the independent 3-phase. In addition, the principle of operation and its special structures are briefly described. The validity and effectiveness of the control algorithm is verified through the several experimental results.
Presenters:
Seon-Hwan Hwang, Kyungnam University
Jang-Mok Kim, Pusan National University
Deok-Je Bang, Korea Electrotechnology Research Institute
Ji-Won Kim, Korea Electrotechnology Research Institute
Dae-Hyun Koo, Korea Electrotechnology Research Institute
Do-Hyun Kang, Korea Electrotechnology Research Institute

Title: A Low Cost Sensorless Drive for Hybrid Stepper Motors Based on Back-EMF Observer and d-Axis Current Injection for Industrial Labelling Machines
Abstract: A sensorless speed control for a two-phase hybrid stepper motor is proposed for an actual industrial application, i.e. a high speed labeller. Sensorless operation is achieved by means of a simple yet reliable stationary reference frame back EMF observer, that can be analytically tuned. The adoption of a standard three phase inverter contributes to the reduction of the system costs, while the injection of a small constant direct axis current leads to a strong reduction of the estimation noise effect, especially at low speed. Theoretical analysis, as well as full simulation and experimental characterization is reported, demonstrating the importance and effectiveness of the proposal.
Presenters:
Andrea Antonioli, Elta Elettronica
Michele Antonioli, Elta Elettronica
Sandro Calligaro, Università di Udine
Roberto Petrella, Università di Udine

Title: Torque Control for IPMSM in the High Speed Range Based on Voltage Angle
Abstract: The six-step operation based on the voltage angle control is proposed. Specifically, the voltage angle adjusts the motor torque with six-step PWM, and d-axis current feedback loop is added for stability. The proposed method was verified through various simulations.
Presenters:
Heekwang Lee, Pohang University of Science and Technology
Junwoo Kim, Pohang University of Science and Technology
Jinseok Hong, Pohang University of Science and Technology
Kwanghee Nam, Pohang University of Science and Technology

Session: D08-Higher Power Device Switching
Track: Devices and Components

Title: 1000V Wide Input Auxiliary Power Supply Design with 1700V Silicon Carbide (SiC) MOSFET for Three-Phase Applications
Abstract: The paper proposes a single end Flyback design with 1700V Silicon Carbide (SiC) MOSFET to replace conventional two-switch Flyback converter. An active start-up circuit with 1700V SiC MOSFET is implemented to optimize the converter design with wide input voltage to 1000Vdc and lower power losses. A 60W auxiliary power supply is developed to demonstrate higher performance and lower component count to support wide input voltage range with this new 1700V SiC MOSFET device.
Presenters:
Jimmy Liu, Cree, Inc.
Kin Lap Wong, Cree, Inc.
John Mookken, Cree, Inc.

Title: Comparison of High Power Semiconductor Devices Losses in 5MW PMSG MV Wind Turbines
Abstract: This paper provides a comparison of high power semiconductor devices in 5MW-class Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) wind turbines. High power semiconductor devices of IGCT, module type IGBT, press-pack type IGBT, and press-pack type IEGT of both 4.5kV and 6.5kV are considered in this paper. Benchmarking is performed based on neutral point clamped 3-level back-to-back type voltage source converter supplied from grid voltage of 4160V. The feasible number of semiconductor devices in parallel is designed through the loss analysis considering both conduction and switching losses under the given operating conditions of 5MW-class PMSG wind turbines, particularly for the application in offshore wind farms. The loss analysis is confirmed through PLECS simulations. The comparison result shows that press-pack type IGBT and IGCT semiconductor device have the highest efficiency considering the snubber loss of IGCT.
Presenters:
Kihyun Lee, Chonbuk National University
Kyungsub Jung, Chonbuk National University
Yongsug Suh, Chonbuk National University
Changwoo Kim, Dawonsys Co.
Hyoyol Yoo, Dawonsys Co.
Sunsoon Park, Dawonsys Co.

Title: A High-Speed Protection Circuit for IGBTs Subjected to Hard-Switching Faults
Abstract: This paper describes a high-speed protection circuit for IGBTs subjected to hard-switching faults. Under hard-switching fault conditions, the constant gate voltage (Miller plateau) is not found in the gate voltage and an amount of gate charge is smaller than that under normal turn-on conditions.A hard switching fault can be detected by monitoring both a gate voltage and an amount of gate charge during the turn-on transient period. IGBTs can be rapidly protected from destruction because a blanking time is unnecessary in this method. It is confirmed by simulation that the protected circuit detects the fault within only 1 us.
Presenters:
Takeshi Horiguchi, Mitsubishi Electric Corporation
Shin-Ichi Kinouchi, Mitsubishi Electric Corporation
Yasushi Nakayama, Mitsubishi Electric Corporation
Takeshi Oi, Mitsubishi Electric Corporation
Hiroaki Urushibata, Kanazawa Institute of Technology
Shoji Okamoto, Tokyo Institute of Technology
Shinji Tominaga, Tokyo Institute of Technology
Hirofumi Akagi, Tokyo Institute of Technology

Title: Thermal Stress and High Temperature Effects on Power Devices in a Fault-Resilient NPC IGCT-Based Converter
Abstract: Given the vital importance of medium voltage NPC converters for the electric drive systems, a significant investment is made in their protection schemes; however, when the protection scheme does not work as expected in the design stage, the converters suffer major damage. This work presents a fault-resilient design for NPC converter aiming to limit the damage pattern in the converter upon protection scheme malfunction conditions. As the success of the fault-resilient design depends on the thermal management of the power semiconductors, an investigation about the effects of high temperatures on the power devices behavior in short-circuit condition is addressed.
Presenters:
Anderson Rocha, Centro Federal de Educação Tecnológica de Minas Gerais
Braz de Jesus Cardoso Filho, Universidade Federal de Minas Gerais
Giti Karimi Moghaddam, North Carolina State University
Richard D. Gould, North Carolina State University
Subhashish Bhattacharya, North Carolina State University

Title: Methodology for Switching Characterization Evaluation of Wide Band-Gap Devices in a Phase-Leg Configuration
Abstract: Double pulse tester (DPT) is a typical method to evaluate the switching behavior of power devices. This paper summarizes the key issues of DPT, including layout design, measurement considerations, and data processing. Also, a practical method is proposed for switching losses evaluation by calculating the difference between the input energy supplied by dc capacitor and the output energy stored in load inductor. Based on 1200 V SiC MOSFETs, the test results show that regardless of V?I timing alignment, this method can accurately indicate the switching losses of both the upper and lower switches by detecting only one switching current.
Presenters:
Zheyu Zhang, University of Tennessee
Ben Guo, University of Tennessee
Fred Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee
Benjamin J. Blalock, University of Tennessee
Zhenxian Liang, Oak Ridge National Laboratory
Puqi Ning, Oak Ridge National Laboratory

Title: Impact of Ringing on Switching Losses of Wide Band-Gap Devices in a Phase-Leg Configuration
Abstract: This paper investigates the effects of ringing on the switching losses of wide band-gap devices in a phase-leg configuration. An analytical switching loss model is derived to identify the switching energy dissipation induced by oscillation damping. This part of energy is found to be at most the reverse recovery energy and the energy stored in the parasitics. But the parasitic ringing will cause interference between two devices in a phase-leg (i.e., cross talk), leading to large shoot-through current and excessive switching losses. The analysis results have been verified by double pulse test with 1200 V SiC MOSFETs.
Presenters:
Zheyu Zhang, University of Tennessee
Ben Guo, University of Tennessee
Fred Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee
Benjamin J. Blalock, University of Tennessee
Zhenxian Liang, Oak Ridge National Laboratory
Puqi Ning, Oak Ridge National Laboratory

Title: Monitoring IGBT’s Health Condition via Junction Temperature Variations
Abstract: Insulated gate bipolar transistor (IGBT) failures are a major issue in modern power electronics applications. Two most dominated failure mechanisms of IGBTs are solder fatigue and bond wire wear-out. This paper proposes a new method to online monitor an IGBT’s health condition by using the instantaneous junction temperature variation between present and the first operating cycles of the IGBT with the same operating current. In this work, the instantaneous junction temperature of an IGBT is estimated from a thermal network model. The proposed method is validated by experimental results obtained from accelerated aging tests for IGBTs.
Presenters:
Bo Tian, University of Nebraska-Lincoln
Wei Qiao, University of Nebraska-Lincoln
Ze Wang, University of Nebraska-Lincoln
Tanya Gachovska, University of Nebraska-Lincoln
Jerry Hudgins, University of Nebraska-Lincoln

Title: Optimization of Bi-Directional Flyback Converter for a High Voltage Capacitor Charging Application
Abstract: This paper presents an optimization technique for a flyback converter with a bi-directional energy transfer. The main goal is to optimize the converter for driving an incremental dielectric electro active polymer (IDEAP) actuator, which must be charged and discharged from 0 V to 2500 V DC, supplied from a 24 V battery. The optimization routine sweeps through a database of switching devices, and transformer core types and sizes. For each core, important winding parameters such as, the space allocation for primary and secondary windings, and the spacing between the secondary windings are also swept. This enables the optimization routine to calculate and optimize the losses caused by transformer parasitics such as leakage inductance, self-capacitance and AC resistance which is crucial in achieving a high energy efficiency and high power density required for this application. The efficiency and loss distribution results provided by the optimization routine give a deep insight into transformer design and its impact on total converter efficiency. Finally, experimental work on a prototype of the bi-directional flyback converter is presented.
Presenters:
Prasanth Thummala, Technical University of Denmark
Henrik Schneider, Technical University of Denmark
Zhe Zhang, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: Study on Case Temperature Distribution for Condition Monitoring of Multidie IGBT Modules
Abstract: This paper reports a comprehensive study on the distribution of TC and its influence on TJ estimation using a thermal network model for a multidie IGBT module before and after aging. Specifically, experimental studies using accelerated aging tests are conducted for a 9-die IGBT module. Results demonstrate that the TC at the position close to the package side and terminal lead should be used to estimate TJ for condition monitoring of the multidie IGBT module. Moreover, the variation of TC and nonuniformity of the TC distribution can be used as indicators for health condition monitoring of the multidie IGBT module.
Presenters:
Bo Tian, University of Nebraska-Lincoln
Ze Wang, University of Nebraska-Lincoln
Wei Qiao, University of Nebraska-Lincoln

Session: D09-Lower Power Device Switching
Track: Devices and Components

Title: Three-Level Driving Method for GaN Transistor with Improved Efficiency and Reliability Within Whole Load Range
Abstract: Compared with Si MOSFET, gallium nitride(GaN) power transistor has higher reverse conduction voltage drop due to the absence of body-diode, which will result in higher reverse conduction loss. Furthermore, the oscillation on the driving voltage is quite severe when the GaN transistor operates in high frequency condition, which is critical for GaN transistor because of its relatively narrow driving voltage range. To guarantee GaN transistor operating reliably, driving voltage can’t be set high enough to have lower conduction resistance, thus reducing the forward conduction loss. The existed three-level driving method for GaN transistor solves the issue of high reverse conduction voltage drop in some extent, but not completely, and the problem of driving voltage ringing still exists. This paper proposes an improved three-level driving method for GaN transistor in synchronous Buck converter. The method can reduce the reverse conduction loss in the whole load range and effectively decrease the ringing of the driving voltage.The mechanism for the reduction of the driving voltage ringring is presented and simulation results are given finally.
Presenters:
Tong Sun, Nanjing Aeronautics and Astronautics University
Xiaoyong Ren, Nanjing Aeronautics and Astronautics University
Hao Dang, Nanjing Aeronautics and Astronautics University
Zhiliang Zhang, Nanjing Aeronautics and Astronautics University
Xinbo Ruan, Nanjing Aeronautics and Astronautics University

Title: Advantage of the Use of an Added Driver Source Lead in Discrete Power MOSFETs
Abstract: In the modern power supply designs, more and more attention is given to the electrical efficiency of the overall system. Among all the semiconductor devices, the transistors are by far the most important ones; almost all of them are three pin devices (MOSFET, BJT, IGBT) and on the contrary of the diodes they have a driving section which makes them more sensitive to issues related to the interaction between power to handle and input signal. Aim of the article is to illustrate the limitation that is related to a 3 pin device and depict the advantage of using a fourth driving source pin also known as Kelvin source besides the traditional power source. In a 3 pin device during every switching cycle, the stray inductance of the source wire bonding coupled together with the slope of the current being interrupted is generating a voltage signal always opposed to the driving signal Vgs. The effect of such opposing signal is to slow down the switching cycle and in turn to increase the cycle by cycle switching losses. The effect of such fourth driving source pin solution is the reduction of the overall power losses in the transistor which turns into a lower operation temperature.
Presenters:
Cristiano Gianluca Stella, STMicroelectronics
Marc Laudani, STMicroelectronics
Antonino Gaito, STMicroelectronics
Massimo Nania, STMicroelectronics

Title: Effects on Power Transistors of Terrestrial Cosmic Rays: Study, Experimental Results and Analysis
Abstract: This paper discusses the reliability of power transistors subjected to terrestrial neutrons when they are normally biased between drain-source terminals. The typical failures phenomenon that can occur in a power MOSFET (SEB and SEGR) will be introduced. Experimental tests on different power MOSFETs and IGBTs technologies are shown. Finally, the complete analysis of the results and the discussions in terms of FITs, MTTFs and Normal-Incident Cross Sections were performed to highlight major of minor impact of the phenomenon on reliability of different devices.
Presenters:
Giuseppe Consentino, STMicroelectronics
Marc Laudani, STMicroelectronics
Giovanni Privitera, STMicroelectroincs
Calogero Pace, Università della Calabria
Carlo Giordano, Università della Calabria
Ambato Jorge Luis Hernandez, Università della Calabria
Massimiliano Mazzeo, Università della Calabria

Title: Study of SiC Vertical JFET Behavior During Unclamped Inductive Switching
Abstract: The unclamped inductive switching (UIS) testing and simulations are performed to investigate the SiC JFET behavior and failure mode during UIS. A record high UIS energy density dissipated in the SiC JFET has been measured. Uniform channel openings and gate bias of the cells are critical for JFET ruggedness because the major portion of the UIS current flow through the vertical channels.
Presenters:
Xueqing Li, United Silicon Carbide, Inc.
Anup Bhalla, United Silicon Carbide, Inc.
Petre Alexandrov, United Silicon Carbide, Inc.
Leonid Fursin, United Silicon Carbide, Inc.

Title: Contour Mode Piezoelectric Ring Micro-Resonators on Si for Series Resonant Converters
Abstract: Microelectromechanical systems (MEMS) resonators on Si have the potential to replace the discrete L-C components in a series resonant converter. With acoustic coupling rather than inductive coupling, these MEMS resonator can achieve better EMI performance besides reducing size, weight and volume of the power converter. In this paper, ring shaped piezoelectric micro-resonators have been presented. These resonators vibrate in contour mode achieving low resonant frequency. COMSOL Multiphysics simulation results have been provided showing mode of vibration at resonant frequency. A CMOS compatible fabrication process has been proposed and implemented. In addition, the fabricated devices have been characterized and experimental results are included in the paper. Finally, PSIM simulation of a series resonant inverter incorporating the equivalent electrical model of the resonator has been performed.
Presenters:
Abusaleh Imtiaz, University of Utah
Faisal Khan, University of Utah
Jeffrey Walling, University of Utah

Title: Design and Analysis of a Buck-Type Class-D Gate Driver IC
Abstract: This paper describes a design approach to minimize the gate-switching loss of a buck-type class-D gate driver. This recently-proposed gate driver works as a mini bidirectional buck converter itself, which charges and discharges the gate node of a power device (e.g. IGBT) by feeding a chain of short pulses into an LC filter, of which widths gradually increase or decrease. The presented analysis discusses the optimal design parameter values such as the inductance, pulse-switching frequency, internal switch sizes, and transition time. The theoretical findings are confirmed by the measurement results, which demonstrated a 62% energy-recycling while switching a 120-nC IGBT at 40-kHz and 15-V.
Presenters:
Taewook Kang, Seoul National University
Jaeha Kim, Seoul National University

Session: D10-Magnetics & Component Aplications
Track: Devices and Components

Title: Power Losses Calculations in Windings of Gapped Magnetic Components
Abstract: Winding loss is a very relevant topic in the design of magnetic components. Although this kind of losses have been subject of investigation for years their analytical calculation in gapped components is still limited and the use of numerical tools are commonly needed for winding characterization. A general 2-D equivalent analytical model for windings losses calculation in gapped magnetic components is presented that shows very good results compared with FEA calculation. The model can be integrated on design and optimization tools in order to evaluate the influence of the gap over windings since early stages of the design process.
Presenters:
Fermín Antonio Holguín, Universidad Politécnica de Madrid
Roberto Prieto, Universidad Politécnica de Madrid
Rafael Asensi, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Simple Analytical Approach for the Calculation of Winding Resistance in Gapped Magnetic Components
Abstract: The Dowell expression is one of the most commonly used methods for calculating the winding losses in magnetic components. Although this method represents a useful tool for calculate the equivalent resistance in windings of magnetic components it cannot be properly applied to components whose structure do not match with classical 1D arrangement or simply where an air gap is present. Modifying the Dowell´s equation, and taking advantage of the orthogonality between skin and proximity effects, a new simple solution is proposed in this work which results, compared with experimental measurements, shows a very good accuracy.
Presenters:
Fermín Antonio Holguín, Universidad Politécnica de Madrid
Rafael Asensi, Universidad Politécnica de Madrid
Roberto Prieto, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Prediction and Experimental Verification of Core Loss and Temperature Distribution for Geometrically Scaled FINEMET Toroids Using Finite Element Analysis
Abstract: Nanocomposites are becoming a proven class of materials that possess the capability to operate at high switching frequencies and handle high power levels. Understanding how their loss characteristics scale and thermal behaviors change as core geometries are altered is vital when designing for grid applications. This article utilizes ANSYS Maxwell finite element analysis (FEA) software to predict the Steinmetz coefficients associated with the core loss for FINEMET based toroids that geometrically vary. Results of the simulation are supported with experimental verification. Secondly, this article experimentally shows temperature contour variation with changes in toroid geometry pulsed with a 20 kHz switching square wave to be predicted using FEA.
Presenters:
Brandon Grainger, University of Pittsburgh
Oreste Scioscia, University of Pittsburgh
Thomas McDermott, University of Pittsburgh
Gregory Reed, University of Pittsburgh
Eric Lin, ANSYS, Inc

Title: An Axial Magnetic Gearbox with an Electric Power Output Port
Abstract: Recently, magnetic gearboxes (MGBs) are attracting more followers as they offer great benefits over conventional mechanical gearboxes including contactless operation, lower noise, lower vibration, and they are maintenance-free. Improving MGBs performance is one of the popular topics under research. Axial MGB is one of the magnetic gear topologies that is suitable for applications which require a physical isolation between the input and output shafts. Unlike radial MGB, axial MGB is relatively simple, has an excellent reliability, and has a relatively low axial force magnitude exerted on the high and low speed rotors. In this paper, an axial MGB with an additional electric power output port is proposed. A conventional 14/4 axial MGB is equipped with Q-phase coils fitted around the ferromagnetic pole-pieces which represent a third output electric port used to sink extra power transmitted from one rotor side to the other side. This extracted output electric power can be used to feed an electrical load while transmitting a mechanical power without using an extra electrical generator. The proposed system is investigated using 3D finite element method analysis.
Presenters:
Hassan Zaytoon, Alexandria University
Ayman Abdel-Khalik, Alexandria University
Ahmed Massoud, Qatar University
Shehab Ahmed, Texas A&M University at Qatar

Title: Analysis of High-Speed PCB with SiC Devices by Investigating Turn-Off Overvoltage and Interconnection Inductance Influence
Abstract: The purpose of this paper is to analyze the interconnection inductances’ contribution to overvoltage during device turn-off transient of silicon carbide (SiC) devices. To prevent the SiC devices from exceeding its maximum voltage rating, the ringing and overshoots of the voltage and current caused by the device capacitance and interconnection inductance have to be considered. Analytical studies are conducted to compare the influences of printed circuit board (PCB) and packaging inductances on the peak turn-off voltage overshoot under various operating conditions. Experimental results are shown to validate the simulation model.
Presenters:
Jukkrit Noppakunkajorn, University of Wisconsin-Madison
Di Han, University of Wisconsin-Madison
Bulent Sarlioglu, University of Wisconsin-Madison

Title: A New Coupled Inductors Used in Interleaving Bidirectional DC/DC Converter
Abstract: In order to overcome the disadvantages in traditional “EE” shape coupled inductors that the distributions of the air gaps are too concentrated, the distributions of the magnetic pressure and flux are not uniform, the air gaps are too nearly to the windings, this paper proposes a structure of “E ? E” shape coupled inductors. It is proved with simulation and experiment that in the “E ? E” structure, a parallel connection air gap magnetic circuit is increased to make the distributions of the magnetic pressure and flux more uniform, the inductance and strength of coupling larger, the air gaps are far away from the windings to reduce the air gaps’ diffusion flux and bypass flux, the windings are wound around the central poles which has smaller length-width ratio to reduce the wingding’s length. When the “E ? E” shape coupled inductors are used to interleaving magnetic integration bidirectional DC/DC converter, the ripple wave of the output voltage is smaller, the wave form of the inductor current is smoother, and the peak current is smaller.
Presenters:
Yugang Yang, Liaoning Technical University
Jie Ma, Liaoning Technical University
Jingyuan Ye, Liaoning Technical University
Zhanling Han, Liaoning Technical University

Title: High Current Planar Magnetics for High Efficiency Bidirectional DC-DC Converters for Fuel Cell Applications
Abstract: The paper presents an analysis of different planar windings configurations focusing on dc and ac resistance in order to achieve highly efficiency in dc-dc converters. The analysis considers different winding arrangements taking into account the manufacturing complexity and challenges. The analysis of the different configurations is based on FEM analysis and it is focused on high current magnetics for dc-dc converters for fuel cell applications. Theoretical and FEM analysis are verified on an experimental 6 kW dc-dc isolated full bridge boost converter prototype based on fully planar magnetics.
Presenters:
Riccardo Pittini, Technical University of Denmark
Zhe Zhang, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: Data Driven Modeling and Verification for Silicon Carbide JFET with Thermal Effects
Abstract: A data driven model with thermal effects is proposed for normally-off SiC JFET in this paper. The novel feature of the model is that it saves the trouble of obtaining the physical parameters. Besides, the effect of temperature on SiC JFET performance is taken into account. It is important because the physical parameters on materials and dimensions of a particular SiC JFET device are difficult to be obtained for device users. The model is implemented based directly upon the characteristics of device datasheet and data from experimental tests. Simulation and experiments are carried out for the research of steady state characteristics, switching characteristics and short-circuit characteristics, which verify the accuracy of the model. Method of data driven modeling can be applied to the other power semiconductor switches.
Presenters:
Li-Gang Ruan, Nanjing Aeronautics and Astronautics University
Ping Zhu, Nanjing Aeronautics and Astronautics University
Li Wang, Nanjing Aeronautics and Astronautics University

Title: Performance Evaluation of Graphite Thin Slabs for Induction Heating Domestic Applications
Abstract: The inductive characteristics of graphite thin slabs are investigated with the objective of designing convenient loads for domestic induction heating uses. For this purposes it is defined a figure of merit consisting of the increment of the resistance of a loaded planar coil with respect to the resistance of the coil in the air. The equivalent resistance of the coupled coil-slab system is obtained by means of analytical calculations which are compared to resistance measurements. Performance of graphite slabs of different thicknesses and a ferromagnetic conventional material are compared.
Presenters:
Jesus Acero, Universidad de Zaragoza
Ignacio Lope, Universidad de Zaragoza
José Miguel Burdío, Universidad de Zaragoza
Claudio Carretero, Universidad de Zaragoza
Rafael Alonso, Universidad de Zaragoza

Title: Genetic Algorithm Based High Density Inductor Optimization
Abstract: In order to reduce the inductor size and achieve a more compact integrated converter, genetic algorithm based inductor optimization is presented. This optimization can effectively search the design space and also keeps a short design time. Some practical considerations and detailed implementations are introduced.
Presenters:
Tao Fan, Institute of Electrical Engineering, Chinese Academy of Sciences
Puqi Ning, Institute of Electrical Engineering, Chinese Academy of Sciences
Xuhui Wen, Institute of Electrical Engineering, Chinese Academy of Sciences
Yaohua Li, Institute of Electrical Engineering, Chinese Academy of Sciences
Qiongxuan Ge, Institute of Electrical Engineering, Chinese Academy of Sciences

Title: Simplified Design Method for Litz Wire
Abstract: A simplified approach to choosing number and diameter of strands in litz wire is presented. Compared to previous analyses, the method is easier to use. The parameters needed are only the skin depth at the frequency of operation, the number of turns, the breadth of the core window, and a constant from a table provided in the paper. In addition, guidance is provided on litz wire construction”how many strands or sub-bundles to combine at each twisting operation. The maximum number of strands to combine in the first twisting operation is given by a simple formula requiring only the skin depth and strand diameter. Different constructions are compared experimentally.
Presenters:
Charles Sullivan, Dartmouth College
Richard Zhang, Massachusetts Institute of Technology

Session: D11-System Integration II
Track: System Integration

Title: Thermal Analysis of a Submodule for Modular Multilevel Converters
Abstract: This paper presents a loss calculation method based on the selection of IGBTs and Diodes, and on an analysis of conduction and switching losses in multilevel pulse width modulation (PWM) systems. A comparison between the Modular Multilevel Converter (MMC) and other multilevel topologies, adapted to medium voltage applications, will thus be presented in order to highlight issues such as thermal disparity within the power modules. The proposed method is applied to the MMC topology to show the impact of the variation of different operation parameters on the thermal behaviors, especially with that of AC and DC currents.
Presenters:
Martin Wu Cong, Université de Grenoble / Schneider Electric – PRIMES
Yvan Avenas, Université de Grenoble / G2Elab
Marc Miscevic, Université de Toulouse
Miao-Xin Wang, Schneider Electric
Radoslava Mitova, Schneider Electric
Jean-Paul Lavieville, Schneider Electric
Philippe Lasserre, PRIMES Platform

Title: Analysis of the Stability of Power Electronics Systems: a Practical Approach
Abstract: Current trends in power distribution systems, such as telecommunications, computers, transportation and utility grid applications, are focused on distributed architectures instead of centralized approach. Distributed architectures are more complex since a network of power electronics converters is required to distribute power with appropriate performance. Hence, new challenges regarding integration of a power distribution systems made up by multiple converters must be addressed since the active nature of power electronic converters results in complex dynamic behavior when they are interconnected to each other. In addition, these power distribution systems are typically comprised of subsystems made up by a variety of manufacturers, which do not provide the data required to parameterize a model due to reasons of confidentiality. In this paper, a practical approach to analyze the stability of power distribution systems is proposed in order to provide an easy method to develop the integration of power distribution systems.
Presenters:
Marina Sanz, Universidad Carlos III de Madrid
Virgilio Valdivia, Universidad Carlos III de Madrid
Pablo Zumel, Universidad Carlos III de Madrid
David López Del Moral, Universidad Carlos III de Madrid
Cristina Fernández, Universidad Carlos III de Madrid
Antonio Lázaro, Universidad Carlos III de Madrid
Andrés Barrado, Universidad Carlos III de Madrid

Title: Designing and Testing Battery Charger Systems for California’s New Efficiency Regulations
Abstract: The State of California has adopted tough new energy efficiency standards for battery charger systems. These regulations promise to save cost, energy, and greenhouse gas emissions, but they also present new challenges to engineers and managers involved in the planning, design, and system integration of battery charger systems. This paper aims to provide guidance by explaining the requirements of the standard, demonstrating proper test methods, analyzing real-world test results, and discussing significant factors affecting compliance. Experimental results and lessons-learned are presented for modern industrial lead acid battery charge systems. Although charger hardware conversion efficiency is important, the software algorithm is at least as important, as is the efficiency of the battery itself, and the system interconnections and cabling.
Presenters:
Chris Botting, Delta-Q Technologies Corp.
Roger Stockton, Delta-Q Technologies Corp.
Deepak Gautam, Delta-Q Technologies Corp.
Murray Edington, Delta-Q Technologies Corp.
Fariborz Musavi, Delta-Q Technologies Corp.

Session: D12-Modeling and Control I
Track: Modeling, Simulation, and Control

Title: Research on DC Capacitor Voltage Self-Balancing Space Vector Modulation Strategy of Five-Level NPC Converter
Abstract: DC capacitor voltage balance is one of the key issues in the control of three-level NPC (neutral point clamped) converter. In this paper, it analyses the influence of space vectors to the DC voltage balance in five-level NPC converter SVM (space vector modulation) strategy and present a novel DC capacitor voltage self-balancing SVM strategy. The novel strategy divides the whole five-level space vector diagram into low modulation region (mSV?0.5) and high modulation region (mSV>0.5). In low modulation region, DC capacitor voltage balance is achieved by combining objective function method with reference voltage decomposition method. In high modulation area, DC capacitor voltage balance is realized by applying an optimal balancing vector selection (OBVS) method. The characteristics of the novel strategy are smaller amount of calculation, much simpler realization and better control effect. Simulation and experimental results verify the correctness of the proposed method.
Presenters:
Yue Wang, Xi’an Jiaotong University
Ning Li, Xi’an Jiaotong University
Su Li, Xi’an Jiaotong University
Wulong Cong, Xi’an Jiaotong University
Wanjun Lei, Xi’an Jiaotong University
Zhao’an Wang, Xi’an Jiaotong University

Title: Fast DC Component Suppression Method for Phase Locked Loop
Abstract: When the grid voltage has dc component, low frequency oscillation appears in phase locked loop (PLL) and will influence its performance. This paper proposes a fast dc component suppressing method for the phase locked loop. This method can filter out the DC component appeared in the sampled grid voltage according to the calculation of different sampling points. The calculation time of this method is much short than existing methods. Moreover, with delayed signal cancellation modules, the proposed PLL can keep the fast and accurate calculation of fundamental voltage amplitude and phase angle when harmonic distortion occurs.
Presenters:
Cong Ma, Shandong University
Feng Gao, Shandong University
Guo-Qing He, China Electric Power Research Institute
Guang-Hui Li, China Electric Power Research Institute

Title: Ride-Through Capability Enhancement of VSC-HVDC Based Wind Farms Using Low Speed Flywheel Energy Storage System
Abstract: This paper presents a backup power balancing technique for the energy-fed voltage source converter high voltage DC transmission systems during different AC side faults based on flywheel energy storage systems. The proposed technique aims to prevent the rise of DC link voltage during fault as well as reduce the voltage and current stresses on the switching devices. An induction machine based flywheel energy storage system is connected in parallel with the onshore side converter; therefore the trapped energy in the DC link during AC faults can be stored in the flywheel. A simulation case study for the proposed system is presented and an experimental setup is implemented to investigate system performance.
Presenters:
Mohamed Daoud, Qatar University
A. Massoud, Qatar University
Shehab Ahmed, Texas A&M University at Qatar
Ayman Abdel-Khalik, Alexandria University
A. Elserougi, Alexandria University

Title: Design of Energy Control Method for Three-Phase Buck-Type Rectifier with Very Demanding Load Steps
Abstract: In this paper,a three-phase buck-type rectifier is adopted in the aircraft application and the load of the system is behaving with a very demanding power profile.In order to protect the generator from suffering high load steps, an energy control method with low bandwidth for the rectifier is brought forward.Benefiting from the low bandwidth control loop,the rectifier demands smooth power from the generator while the load exhibits high power steps.Consequently the power imbalance during the transition will result into the voltage rising over the output capacitor of the rectifier,and accordingly makes sufficient output capacitance a key of this application.
Presenters:
Sisi Zhao, Universidad Politécnica de Madrid
José María Molina, Universidad Politécnica de Madrid
Marcelo Silva, Universidad Politécnica de Madrid
Jesús Angel Oliver, Universidad Politécnica de Madrid
Pedro Alou, Universidad Politécnica de Madrid
Javier Torres, INDRA
Fernando Arévalo, INDRA
Oscar Garcia, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Dynamic Model and Control of Wound-Rotor Machine in Single-Phase Grid System
Abstract: This paper proposes a dynamic model and control of Single-Phase Induction Machine (SPIM) which has three-phase rotor windings. In this model, the SPIM is reconstructed from the d-q model of three-phase induction machine. The currents, torque, and power factor are analyzed as a function of rotor currents and stator fluxes and compared to the conventional models. The proposed model has the same steady-state characteristics as double-revolving-field model and unlike the conventional models, it also includes dynamic characteristics of general SPIM. Based on the model, the vector control of speed and power factor is considered by applying a rotor-side inverter. Experimental results validates the proposed model and control.
Presenters:
Kahyun Lee, Seoul National University
Yongsu Han, Seoul National University
Jung-Ik Ha, Seoul National University

Title: A Building-Block Approach to Efficiency and Cost Models of Power Electronic Systems
Abstract: This digest presents efficiency and cost models of power electronic converters based on converter ratings and datasheet information for rapid prototyping.It is useful for component selection process and estimates accurate efficiency and cost for design decisions. Generalized eqautions represents power losses of each building block and then customized to reach converter-specific models.Cost models are derived based on an extensive market survey.To illustarte this approach 3 topologies are used boost,buck in CCM and flyback in DCM.Achieved cost and loss estimates produce less than 8% error.The final paper will demonstrate literature review,derivations for loss models and cost models eqations and demonstration of the developed GUI.
Presenters:
Amruta Kulkarni, University of Connecticut
Ali Bazzi, University Of Connecticut

Title: One-Step Ahead Model Predictive Controller of Three-Phase Inverter for Uninterruptible Power Supply Applications
Abstract: This paper proposes a dual-loop inverter voltage control strategy for uninterruptible power supply (UPS) utilizing an one-step ahead model predictive control in the inner-loop. The proposed MPC optimizes the cost function of the tracking error without any use of numerical methods. Moreover, any off-line optimization is not necessary and the online membership test is very simple. It is shown that the proposed MPC makes the closed-loop system globally asymptotically stable in the presence of input constraints. Following the conventional dual-loop strategy, the PI controller is used in the outer-loop to regulate the output voltage. The experimental results illustrate that the capacitor voltage rapidly goes to its reference in a satisfactory manner while keeping other state variables bounded under an unexpected load changes.
Presenters:
Seok-Kyoon Kim, Korea University
Chang Reung Park, Seoul National University of Science and Technology
Young Il Lee, Seoul National University of Science and Technology

Title: Improved Modulation Techniques to Eliminate Leakage Ground Currents in Three-Phase Photovoltaic Systems
Abstract: Nowadays transformerless PV converters are widely used in the energy conversion stage of a PV plant, because their good characteristics regarding efficiency, size, cost and weight. The main problem in transformerless PV systems is the common mode voltage variations that can generate leakage ground currents through the parasitic capacitance formed between the PV panels and ground. This paper comparisons the performance characteristic of conventional space vector PWM (SVPWM), AZSPWM, NSPWM and RSPWM. Based upon that, an improved AZSPWM scheme is proposed. Theoretical analysis is verified via simulation by means of MATLAB/SIMULINK. Experimental results will be upgrade soon.
Presenters:
Hao Huang, Xi’an Jiaotong University
Wenjie Chen, Xi’an Jiaotong University
Xiaomei Song, Xi’an Jiaotong University

Title: Small-Signal Impedance Identification of Three-Phase Diode Rectifier with Multi-Tone Injection
Abstract: AC and DC impedances of power converters are used for stability analysis of modern power systems at AC and DC interfaces. Multi-tone approach is implemented for d-q impedance identification to improve measurement time of the traditional single-tone approach. In linear loads, the multi-tone approach could give the same results with single-tone approach because superposition holds for linear system. For three-phase nonlinear loads, different results are observed from multi-tone and single-tone approach. In this paper, 6-pulse Diode Bridge Rectifier is studied to analyze the reason of result difference. An algorithm is proposed to improve the multi-tone approach and avoid result differences.
Presenters:
Bo Zhou, Virginia Polytechnic Institute and State University
Marko Jaksic, Virginia Polytechnic Institute and State University
Zhiyu Shen, Virginia Polytechnic Institute and State University
Bo Wen, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University

Title: A Time-Efficient Modeling and Simulation Strategy for Aggregated Multiple Microinverters in Large-Scale PV Systems
Abstract: This paper presents a time-efficient modeling and simulation strategy for aggregated microinverters in large-scale simulations, with a 20-panel system used as an example. As the microinverter configuration emerges to overcome reliability and loss mismatch issues in centralized PV inverters, a model that can be used for rapid prototyping is required. This model is also helpful in predicting behaviors of individual microinverters in a large-scale system. Dynamic microinverter models that include switching action may not be suitable for simulating multiple microinverters as they yield a significant computational burden and long simulation time compared to simplified but accurate average models. This paper introduces the average model of a basic microinverter composed of a boost stage and an H-bridge represented by a single matrix form aggregation of multiple microinverters in a larger system to achieve faster simulation times with accurate transient and steady-state results. A 200W prototype microinverter board is tested to verify the proposed average and dynamic models.
Presenters:
Sung Min Park, University of Connecticut
Ali Bazzi, University of Connecticut
Sung-Yeul Park, University of Connecticut
Weiqiang Chen, University of Connecticut

Title: A Carrier Based PWM Technique for Capacitor Voltage Balancing of Single-Phase Three-Level Neutral-Point-Clamped Converters
Abstract: In this paper is presented a PWM technique for single-phase neutral-point-clamped converters for capacitors voltage balancing. The technique is based on the injection of a common mode voltage signal into the sinusoidal modulating signals of the conventional carrier-based pulse width modulation. Although several strategies have been reported for such a problem by using the voltage signal injection, the proposed method is very simple with easy implementation. It is presented a set of equations to demonstrate how the injected voltage signal introduces a dc component on the neutral-point current, which can be controlled in order to allow the capacitors voltages balancing. Selected results have been used demonstrate the effectiveness of the proposed strategy.
Presenters:
Isaac Freitas, Universidade Federal da Paraíba
Marcos Bandeira, Universidade Federal da Paraíba
Fabiano Salvadori, Universidade Federal da Paraíba
Simplicio da Silva, Universidade Federal da Paraíba
Luciano Barros, Universidade Federal da Paraíba
Cursino Jacobina, Universidade Federal de Campina Grande
Euzeli dos Santos Jr., Purdue School of Engineering and Technology

Title: Inverter Device Nonlinearity Characterization Technique for Use in a Motor Drive System
Abstract: This paper introduces a detailed nonlinearity characterization technique for insulated-gate bipolar transistor inverters in a drive system which is able to measure device nonlinearities. Methods are derived from measurements of the voltage on the inverter phases. These measurements are obtained while applying a set of direct currents to an electrical machine. These methods are then applied to tests using alternating current. The study of inverter nonlinearities is useful in order to improve controller accuracy, implement sensorless controllers, and conduct condition monitoring. These methods fulfill the need to characterize each device in an inverter. In addition to characterizing every device using either AC or DC current, the method is resistant to noise; for these reasons the method is applicable in the field. Simulations and experimental work demonstrate the benefits and applicability of the methods.
Presenters:
Andrew Babel, Michigan State University
Annette Muetze, Technische Universität Graz
Roland Seebacher, Technische Universität Graz
Klaus Krischan, Technische Universität Graz
Elias G. Strangas, Michigan State University

Title: Multi-Level Single-Phase Shunt Current Injection Converter Used in Small-Signal DQ Impedance Identification
Abstract: This paper describes the detailed design of a single-phase multi-level cascaded H-bridge shunt current injection converter. A special attention is given toward the proper selection of inductors and capacitors, trying to optimize the selected component values. The proposed control is extensively treated and inner current and outer voltage loops are completely analyzed. Furthermore, voltage balancing is included into the control to assure dc voltage control for each H-bridge module. Analytical expressions, which describe the design procedure, are derived, making the presented analysis complete. The designed converter is simulated using detailed switching simulation model and excellent agreement between theory and simulation results are obtained. Initial hardware results are obtained and complete results will be included into a final paper. The proposed converter presents a new solution for the single-phase shunt current injection for small-signal dq impedance measurements, which has several important advantages over the classical solutions.
Presenters:
Marko Jaksic, Virginia Polytechnic Institute and State University
Zhiyu Shen, Virginia Polytechnic Institute and State University
Igor Cvetkovic, Virginia Polytechnic Institute and State University
Dushan Boroyevich, Virginia Polytechnic Institute and State University
Rolando Burgos, Virginia Polytechnic Institute and State University
Paolo Mattavelli, Università degli Studi di Padova / Virginia Polytechnic Institute and State University

Session: D13-Modeling and Control II
Track: Modeling, Simulation, and Control

Title: Control Strategy for a Single-Input Dual-Output Converter with One Idling Output Port
Abstract: This paper studies that one output port of a single input dual output converter is idling. One control strategy to block power flowing into the idling output port, is proposed. Noteworthily, the phase analysis taking into consideration the dead-time is the key to realize the idling output port. This control strategy adopts negative phase compensation to eliminate the negative feedback effect of the dead-time.
Presenters:
Mei Liang, Beijing Jiaotong University
Trillion Q Zheng, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University
Jing Miao, Beijing Jiaotong University

Title: Unified Control of a Buck Converter for Wide Load Range Applications
Abstract: A new discrete time state feedback controller is presented, which allows the high bandwidth voltage control of a buck converter for any load condition whether it operates in discontinuous conduction mode (DCM), continuous conduction mode (CCM) or in the boundary of these regions. This makes the buck converter applicable for wide load range applications.
Presenters:
Christoph van der Broeck, Rheinisch-Westfaelische Technische Hochschule Aachen
Rik W. De Doncker, Rheinisch-Westfaelische Technische Hochschule Aachen
Sebastian Richter, AixControl GmbH
Jochen von Bloh, AixControl GmbH

Title: On the Modeling of Switched Capacitor Converters with Multiple Outputs
Abstract: The internal nodes of switched capacitor converters can be used to provide multiple pulsed width modulated voltages that, in combination with filter inductors, can extend the available dc outputs. Such converter architecture requires models that accurately predict the behaviour of switched capacitor converters operated in current output mode. Based on the well-known output impedance model, a new circuit representation is proposed for converters with multiple current-loaded outputs. A characterization methodology is developed to determine the parameters of said model. Predictions of the new model compare favorably to circuit simulations and experimental measurements.
Presenters:
Julià Delos, Philips Research
Toni Lopez, Philips Research
Eduard Alarcón, Technical University of Catalonia
Marcel M.A. Hendrix, Eindhoven University of Technology

Title: Time-Optimal Control in DC-DC Converters: a Maximum Principle Perspective
Abstract: In this paper, we present an analytical framework to investigate time-optimal trajectories in dc-dc buck, boost, and buck-boost converters using Pontryagin’s maximum principle. Particularly, we evaluate cases where a time-optimal transfer of converter states can be achieved with a single switching action, and furthermore, determine if such a control can be uniquely synthesized.
Presenters:
Sairaj Dhople, University of Minnesota
Katherine Kim, University of Illinois at Urbana-Champaign
Alejandro Domínguez-García, University of Illinois at Urbana-Champaign

Title: Small Signal Analysis and Design of Active Droop Control Using Current Mode Equivalent Circuit Model
Abstract: This paper proposes a small signal model for active droop control in equivalent circuit form. Active droop control is an average current mode control with proportional output voltage feedback. The proposed model takes the switching ripple of the voltage and current feedback into account, and the model is valid up to half of switching frequency. The features of the active droop controlled converters with ESR dominant capacitor and ceramic capacitor are identified. Design guidelines of the compensator and external ramp are proposed to simplify the compensator, maximize the control bandwidth and reduce the output capacitor numbers. The over designed external ramp complicates the loop design and degrades the performance. The model is applicable to different modulations.
Presenters:
Yingyi Yan, Virginia Polytechnic Institute and State University
Pei-Hsin Liu, Virginia Polytechnic Institute and State University
Fred C. Lee, Virginia Polytechnic Institute and State University

Title: Research on Stability of Buck Converter with Output-Current-Feedforward Control
Abstract: The method of using output-current-feedforward (OCFF) control to realize zero output impedance is analyzed in this paper. It is found that the converter may have stability problems in this method. The expression of OCFF controller is calculated when different current sampling points (inductor current, load current) are selected. When OCFF is applied, there is a negative feedback loop existing in this model and this loop may cause instability. The system stability with different current sampling points is analyzed . The conclusions are verified by simulation and experiment results.
Presenters:
Beibei Wang, Beijing Jiaotong University
Pengyu Jia, Beijing Jiaotong University
Trillion Q. Zheng, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University

Title: Stability Analysis and Control of Nonlinear Phenomena in Bidirectional Boost Converter Based on the Monodromy Matrix
Abstract: In this paper we investigate the nonlinear dynamics of a bidirectional boost converter by employing a nonlinear analysis method based on the Monodromy matrix. This approach can be used to study the influence of system parameters for the stability of power electronics systems. Moreover, the adopted approach is design-oriented which operates in a more straightforward way compared to other nonlinear analysis methods. Based on the derived matrices, a supervising controller is designed to control the nonlinear behavior of the system, which improves the system performance significantly. Simulation results show the effectiveness of this method.
Presenters:
Haimeng Wu, Newcastle University
Volker Pickert, Newcastle University

Title: Novel Small Signal Modeling and Control of an LLC Resonant Converter
Abstract: In this paper, a novel approach to determine the small signal model of an LLC resonant converter is presented. The proposed model uses analysis techniques from communications theory to determine the control-to-output transfer function required for the design of a digital compensation network. The model considers the effects of higher order harmonics and sideband frequencies generated by the variable switching frequency control method, as well as the effects of the LLC resonant tank and the output voltage rectifier. Experimental data from a prototype LLC resonant converter was obtained to verify the analytical results, and revealed that the proposed model is an accurate representation of the prototype converter dynamics. Simulation results demonstrated that a digital compensator design based on the proposed model was able to achieve output voltage regulation.
Presenters:
Brian Cheng, University of British Columbia
Fariborz Musavi, CUI Inc.
William G. Dunford, University of British Columbia

Title: Damping Impact on Dynamic Analysis of LLC Resonant Converter
Abstract: In this paper, the small-signal model of LLC resonant converter is derived from extended describing function (EDF) methodology and the dynamic of the LLC converter are studied based on the small signal model taking into account the circuit parasitic resistance. In designing controller, this damping effect induced by the parasitic resistance is commonly neglected. While it will be shown in this paper that for large transformer ratio, the secondary side parasitic resistance introduces significant damping in the resonant tank. A controller is design for an example LLC circuit. It is shown that the control loop phase margin and cross over frequency is highly dependent on the damping factor, which should be well considered in the control loop design to have desired transient performance. The experimental verification is provided as well.
Presenters:
Zaka Ullah Zahid, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University
Kevin Huang, Analog Devices Inc.
Subodh Madiwale, Analog Devices Inc.
Jeff Hou, Analog Devices Inc.

Title: Extended Averaging Method for Power Supply Systems with Multiple Switching Frequencies
Abstract: This paper introduces a new extended averaging method for switching power converters. By extending the conventional averaging techniques, this method is capable of modeling switching power converters with multiple switching frequencies. Using this method, a model for a cascaded dc-dc converter is derived. Comparison between the model and the actual system is performed. Experimental verifications are provided to validate the modeling method.
Presenters:
Pourya Shamsi, Missouri University of Science and Technology

Title: Small-Signal Modeling of Series-Series Compensated Induction Power Transfer System
Abstract: Based on Extended Describing Functions technique, small-signal modeling technique is applied to Series-Series compensated Induction Power Transfer (IPT) system. The derived model includes both frequency control and phase shift control. The derived model is in good agreement with the results obtained from Simplis software.
Presenters:
Zaka Ullah Zahid, Virginia Polytechnic Institute and State University
Zakariya Dalala, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University

Session: D14-Modeling and Control III
Track: Modeling, Simulation, and Control

Title: On-Chip Coupled Power Inductor for Switching Power Converters
Abstract: This paper proposes a design of an on-chip coupled power inductor (OCPI) structure which consists of a layer of ferrite core material and another layer of coupled spiral windings on a silicon substrate. The flux cancellation effect of the two inversely coupled windings significantly reduces the net fluxes in the ferrite layer, which helps increasing the saturation current of the power inductor. An ANSYS®/Maxwell® 3-D physical model of a 5.6mm×5.6mm two-phase OCPI is developed and simulation results are obtained. Simulation results show that the saturation current (7A/phase) of the OCPI is twice the saturation current (3.5A) of the non-coupled power inductor with the same inductance density. Based on a 3.3V/1.5V 4MHz two-phase buck converter, the equivalent steady state inductance and transient inductance of the OCPI are calculated to be equal to 78.1nH and 22.2nH, respectively.
Presenters:
Zhigang Dang, University of Alabama
Jaber Abu Qahouq, University of Alabama

Title: Slew Rate Control Strategies for Smart Power ICs Based on Iterative Learning Control
Abstract: Smart Power ICs are Power Switches with integrated control and protection functions for the switching of middle and high current loads in industrial and automotive applications. Due to customer specifications and electromagnetic compatibility requirements it is often desired to limit the current and voltage slew rate at the output terminal of the Smart Power IC by minimizing the switching losses at the same time. In order to reduce the development effort and costs, a reusable control strategy is strived for. Therefore, a power optimal digital slew rate control strategy is developed which allows for a systematic limitation of the current and/or voltage slew rates. The strategy is based on the optimization of a gate current profile using Iterative Learning Control. A rapid prototyping test bench is developed for the verification of the control strategy. The performance and robustness is demonstrated by means of measurement results.
Presenters:
Mathias Blank, Technische Universität Wien
Tobias Glück, Technische Universität Wien
Andreas Kugi, Technische Universität Wien
Hans-Peter Kreuter, Infineon Technology

Title: Toward Consensus-Based Balancing of Smart Batteries
Abstract: Smart reconfigurable battery systems allow access to individual cells for monitoring and control purposes, enabling an efficient and flexible energy management among cells that can also be used for voltage balancing. This paper studies consensus protocols and cooperative control tools to illustrate the use of distributed control strategies for voltage balancing in such reconfigurable battery systems. By considering the individual cell as agents, the voltage balancing problem can be reformulated as a consensus problem. In case of leaderless consensus, the criteria required to obtain average consensus is discussed. Moreover, in case of leader-follower consensus approach, the leader selection and its impact on the time-to-reach consensus is analyzed. Several case studies are presented to show the effectiveness of the proposed approaches.
Presenters:
Shankar Abhinav, University of Texas at Arlignton
Giulio Binetti, University of Texas at Arlington
Ali Davoudi, University of Texas at Arlignton
Frank L. Lewis, University of Texas at Arlignton

Title: Pulsed Iv Characterization of GaN HEMTs for High Frequency, High Efficiency Integrated Power Converters
Abstract: Commercial foundry 0.25m RF GaN MMICs were characterized as power switches using pulsed IV system. The devices exhibited current collapse and ON resistance modulation. These trap effects were highly dependent on off state quiescent drain bias voltages. At higher switch voltages, the output power was reduced due increase in the ON resistance and collapse of drain current. Traps located on the surface between gate and drain caused degradation in the ON resistance while the traps in the bulk beneath the gate plate altered the pinch-off voltage. A power HEMT model incorporating traps was developed and simulations correctly predicted knee walk out due to increase in the ON resistance and current collapse associated with change in pinch-off volatage due to bulk traps.
Presenters:
Aaron Pereira, Macquarie University
Anthony Parker, Macquarie University
Michael Heimlich, Macquarie University
Neil Weste, Macquarie University
Larry Dunleavy, Modelithics, Inc.

Title: A New MPPT Control Strategy for Stand-Alone Solar PV Systems with Enhanced Battery Life
Abstract: Generally battery is connected with all stand-alone systems to make them more reliable. If battery is not present in the stand-alone system them MPPT is not possible for off grid load. However battery is an expensive item and its maintenance is cumbersome. One of the issue is overcharging of the battery when MPPT is performed. This paper presents a modified MPPT, called the Required Power Point Tracking (RPPT), which ensures only the power required by the load and the battery (for charging up to the optimal load) is drawn. A front end dc-dc converter tracks the required maximum power. The tracked power is effectively flush out by the dc-ac stage. A new control strategy maintains the dc link voltage constant. The control strategy also helps to optimize size of the capacitor present in the circuit. The proposed scheme ensures that power quality standards are maintained. The working, analysis and simulations of the proposed scheme are included.
Presenters:
Moumita Das, Indian Institute of Technology, Bombay
Vivek Agarwal, Indian Institute of Technology, Bombay

Title: Comparison of the Behavior of Voltage Mode, V² and V²Ic Control of a Buck Converter for a Very Fast and Robust Dynamic Response
Abstract: This paper proposes an optimization method to design the parameters of controls for power converters in order to achieve a very fast dynamic response while remaining stable and robust over the desired operation region. The proposed optimization algorithm is applied to diff erent analog controls and is used to compare the dynamic response of the VM, V2 and V 2Ic control for di fferent cases in order to evaluate which control presents the best performance in terms of dynamic response and stability robustness to system tolerances.
Presenters:
Jorge Cortés, Universidad Politécnica de Madrid
Vladimir Svikovic, Universidad Politécnica de Madrid
Pedro Alou, Universidad Politécnica de Madrid
Jesús Angel Oliver, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Comparison of Audible Noise Caused by Magnetic Components in Switch-Mode Power Supplies Operating in Burst Mode and Frequency-Foldback Mode
Abstract: In this paper, it is shown that operation in burst mode (BM) results in lower audible noise than operation in frequency-foldback mode (FFM). However, the selection of the switching frequency in a burst package can have a significant impact on the audible noise. In both FFM and BM, audible noise can be reduced by decreasing the peak value of current pulses and proportionally increasing the switching frequency in FFM and the burst frequency in BM. In BM, the audible noise can be further reduced if instead of increasing the burst frequency, the number of burst pulses is increased without changing the burst frequency. The presented BM and FFM audible noise analysis is experimentally verified on a dc-dc boost test circuit.
Presenters:
Laszlo Huber, Delta Products Corporation
Milan Jovanovic, Delta Products Corporation

Title: Effects of Edge Termination Using Dielectric Field Plates with Different Dielectric Constants,Thicknesses and Bevel Angles
Abstract: This paper investigates the effects of dielectric constants, thickness and bevel angles on the breakdown voltage (VBD) improvement of 4H-SiC Schottky Barrier Diode (SBD). Three high permittivity dielectrics (AlN, AlON and HfO2) are studied separately as oxide materials for field plates (FP) edge termination. Besides the variation of dielectric constants, different thicknesses and bevel angles are applied to investigate their effects in enhancing VBD of specific configurations. Simulation results have demonstrated that with proper design of materials, thicknesses and bevel angles, field crowding issue in planar devices can be well addressed and 100% ideal VBD can be obtained.
Presenters:
Yi Huang, Rutgers University
Keerthi Jayaprakash, Intersil Corporation
Chun Cheung, Intersil Corporation

Title: Distributed Cooperative Load Sharing in Parallel DC-DC Converters
Abstract: A distributed cooperative control method for load sharing of parallel converters is proposed. Using consensus voting protocols, the need for a master converter or a central controller is eliminated. The proposed modular structure does not require a priori knowledge of the number of active converters, which makes it a viable option for plug-and-play operational framework. Moreover, additional links in the communication graph offers enhanced reliability. Simulation results verify the effectiveness of the distributed current sharing method for a parallel four-converter system, and show resiliency against the loss of converters or communication links.
Presenters:
Seyedali Moayedi, University of Texas at Arlignton
Ali Davoudi, University of Texas at Arlignton

Title: Modeling and Analysis of Resonant Switched Capacitor Converters with Free-Wheeling ZCS
Abstract: This paper introduces a unified modeling methodology to describe and explore the loss mechanism of resonant Switched Capacitor Converter (SCC) operating in a self-commutation zero current switching. The conventional equivalent resistance concept, which assumes a single conduction path of the resonant current, is generalized to model the losses in cases where the resonant current is divided across several conduction loops. The new modeling concept is compatible to describe the losses resulting from resistive elements as well as P-N junction devices, offering a closed-form solution for the equivalent resistance. Verification of the concept has been carried out by simulations and experiments on 3 ” 30W unity and double gain resonant SCC with free-wheeling ZCS. A very good agreement is obtained between the theoretical calculations, simulations and experimental results, well demonstrating the model capability to identify the loss contributors in each conduction path.
Presenters:
Eli Hamo, Ben-Gurion University of the Negev
Michael Evzelman, Utah State University / Ben-Gurion University of the Negev
Mor Mordechai Peretz, Ben-Gurion University of the Negev

Title: Ensuring Volt-Second Balance in High-Power-Density Phase-Shifted Full-Bridge Converter Design
Abstract: The phase-shifted full-bridge (PSFB) converter topology provides a platform which enables the achievement of high power-density through low-loss operation at high frequency. However, this topology is also subject to the risk of flux imbalance in the main power transformer if precautions are not taken to prevent its occurrence. This paper evaluates the power-density implications of the several known mechanisms described in the literature for ensuring flux balance in the context of this converter topology. Additionally, the details of a high-power PSFB prototype converter design are reported and the performance of this system is used to evaluate the practicality of implementing a novel technique for addressing the volt-second balance issue without compromising the converter bus design required to achieve higher power density.
Presenters:
Andrew Lemmon, University of Alabama
Michael Mazzola, Mississippi State University
James Gafford, Mississippi State University
Christopher Parker, Raytheon Company

Title: Research on Soft-Switching and Peak Current of Dual Active Bridge Converters
Abstract: This paper presented the single phase-shifting control method.Compared to traditional phase-shifting,the new methods can realize ZVS or ZCS in the whole scope and reduce the current stress, so as to improve the working efficiency of the converter.
Presenters:
Jing Miao, Beijing Jiaotong University
Xiaojie You, Beijing Jiaotong University
Yan Li, Beijing Jiaotong University
Mei Liang, Beijing Jiaotong University

Session: D15-Quality & Business Issues
Track: Manufacturing, Quality, and Business Issues

Title: Mathematical Method of Scheduling Lead-Acid Battery for Cycling Use
Abstract: A mathematical method is proposed for optimal scheduling lead-acid batteries for cycling use. Typical battery characteristics are first converted into mathematical expressions and then through the proposed optimization algorithm aiming at minimum capital cost, the battery capacity,installation plan, discharge depth and discharge rate are derived, benefiting the designers and customers. A case study is carried out to verify the design procedure and optimization algorithm
Presenters:
Baoquan Liu, Xi’an Jiaotong University
Fang Zhuo, Xi’an Jiaotong University
Yixin Zhu, Xi’an Jiaotong University
Shaohui Zhong, Xi’an Jiaotong University

Session: D16-Photovoltaics
Track: Renewable Energy Systems

Title: A Novel Five-Level Inverter for Solar System
Abstract: Based on the drawbacks of I-type and T-type 5-level inverter, this paper proposes a novel 5-level inverter for solar system and its strategy, aiming at reducing both the conduction loss and the switching loss at high switching frequency, and solving their common issue of unbalanced devices dissipation.The operation and performance of the proposed inverter have been experimentally verified on the prototype.
Presenters:
Fei Wang, Shanghai Jiao Tong University
Lijun Hang, Shanghai Jiao Tong University
Yong Wang, Shanghai Jiao Tong University

Title: Phase Skipping Control to Improve Light Load Efficiency of Three Phase Micro-Inverters
Abstract: Incident solar power on a PV panel is highly variable due its dependence on weather, time of the day and shading which forces the micro-inverter to operate at light loads for a significant period of its operation time. Poor light load efficiency of power converters further reduces the effective power available. This paper proposes a control technique ” Phase Skipping Control, to improve light load efficiency of DC-AC stage of Grid Tied-Three Phase Micro-Inverters. This control technique is independent of the underlying topology; however, to establish its proof of concept, Phase Skipping Control, is implemented on a 400W Three Phase Half Bridge PWM Inverter. Improvement in light load efficiency with Phase Skipping Control is calculated theoretically using a proposed loss model for Half Bridge PWM Inverter. Furthermore, a prototype for 400W Three Phase Half Bridge PWM Inverter is developed for experimental verification of light load efficiency improvement using Phase Skipping Control. Experimental results shows 5.43% increase in efficiency at 10% load and 0.46% increase in CEC efficiency of the Three Phase Half Bridge PWM Inverter.
Presenters:
Utsav Somani, University of Central Florida
Charles Jourdan, University of Central Florida
Ahmadreza Amirahmadi, University of Central Florida
Anna Grishina, University of Central Florida
Haibing Hu, University of Central Florida
Issa Batarseh, University of Central Florida

Title: A Maximum Power Point Tracking Technique for Single-Phase PV Systems with Reduced DC-Link Capacitor
Abstract: Electrolytic capacitors used in photovoltaic (PV) power conditioning units (PCU) for power decoupling purposes are unreliable. Film capacitors can be adopted instead of electrolytic capacitors if the energy storage requirement of the PCU is reduced, since they offer better reliability and have a longer lifetime. The energy storing capacitor size reduction can be facilitated by allowing DC-link voltage to have a specified amount of ripple. However, a high DC-link voltage ripple imposes a double-line frequency ripple in the PV voltage and current. This leads to oscillations in the extracted panel power and thereby results in power loss. In view of this, this paper develops a locus line based maximum power point tracking (MPPT) control algorithm to mitigate this power loss. The proposed digital control algorithm was simulated in MATLAB Simulink and also implemented in a laboratory prototype using TMS320F28035 processor.
Presenters:
Sindhu Krishna Yarlagadda, Aim Electrical Consultants
Wajiha Shireen, University of Houston

Title: A Novel ZVS Resonant-Type Flyback Microinverter with Regenerative Snubber
Abstract: A novel technique for improving the efficiency of a basic dc-ac flyback microinverter is proposed in the paper. The proposed efficiency improving technique is based on a simple snubber, consisting of just a few passive elements and a variable frequency control zero-voltage switching (ZVS) technique. In the paper, the microinverter with the passive snubber is presented, the modes of operation of the converter are discussed and analyzed, the converter’s ZVS operation is explained and the design of the converter is demonstrated with an example. Experimental results obtained from a lab prototype are presented as well.
Presenters:
Aniruddha Mukherjee, University of Western Ontario
Majid Pahlevaninezhad, Queen’s University
Gerry Moschopoulos, University of Western Ontario

Title: Forward Micro-Inverter with Primary-Parallel Secondary-Series Multicore Transformer
Abstract: This paper presents a primary-parallel secondary-series multicore forward micro-inverter for photovoltaic AC-module application. The proposed solution changes the number of active phases depending on the grid voltage, thus enabling the usage of low-profile unitary turns ratio transformers. Therefore, the transformers are well coupled and the overall performance of the inverter is improved. Due to the multiphase solution the number of devices increases but, the current stress and losses per device are reduced contributing to an easier thermal management. Furthermore, the decoupling capacitor is split between the phases, contributing to a low-profile solution without electrolytic capacitors suitable to be mounted in the frame of a PV module.
Presenters:
David Meneses, Universidad Politécnica de Madrid
Oscar García, Universidad Politécnica de Madrid
Pedro Alou, Universidad Politécnica de Madrid
Jesús Angel Oliver, Universidad Politécnica de Madrid
Roberto Prieto, Universidad Politécnica de Madrid
José Antonio Cobos, Universidad Politécnica de Madrid

Title: Enhanced Differential Power Processor for PV Systems: Resonant Switched-Capacitor Gyrator Converter with Local MPPT
Abstract: This paper introduces an enhanced differential power processor topology and principle of operation for photovoltaic systems (PV) that is based on switched-capacitor technology, featuring local maximum power point tracking (MPPT) capability, zero current switching (ZCS), high efficiency over wide operation range, and reduced size. The new converter operates as a voltage-dependent current-source and is regulated by dead-time or frequency control. Local MPPT on the individual PV elements is realized and the operation is demonstrated by simulation and experiments. Differential power processing operation is verified on 100W prototypes, demonstrating ultimate improvement in the power harvesting capability of above 90% and up to 99% out of the available power in the string, under different insolation levels.
Presenters:
Alon Blumenfeld, Ben-Gurion University of the Negev
Alon Cervera, Ben-Gurion University of the Negev
Mor Mordechai Peretz, Ben-Gurion University of the Negev

Title: Intelligent Slope-Based Maximum Power Point Searching Algorithm for Fixed-Pitch Horizontal-Axis Wind Energy Systems
Abstract: This paper proposes a novel machine parameter independent control algorithm that enables wind turbines to quickly and effectively extract maximum power from the wind turbine under changing atmospheric conditions. The energy captured by a wind turbine varies due to variations in wind velocity, air density (influenced by temperature and humidity), turbine aerodynamics, and generator dynamics. Without power electronics and power extraction control techniques, wind systems have low power extraction efficiency. Given that the power from the wind turbine is dependent on generator rotor speed, the proposed algorithm indirectly uses the tip speed ratio (TSR) to assist in the maximum power point search (MPPS). The slope (or indirect TSR) assisted MPPS provides historic system state information and preempt misguided control decisions due to deceptive power readings caused by atmospheric changes. In this paper, the wind energy system, algorithm design framework, performance, and real-time wind speed data is presented.
Presenters:
Joanne Hui, Queen’s University
Alireza Bakhshai, Queen’s University
Praveen Jain, Queen’s University

Title: Unified Maximum Power Tracking Among Distributed Power Sources
Abstract: Uniform Input Voltage Distribution (UIVD) control for Distributed-Input Series-Output (DISO) converter power systems is utilized to achieve the grouped maximum power throughput from non-identical distributed renewable power sources having similar peak power voltages. Furthermore, this paper introduces a simplified Maximum Power Tracking (MPT) controller developed for DISO configurations that facilitate simultaneous processing of distributed power flows. Without UIVD, the distributed sourcing peak powers are conventionally tracked by independent MPT controllers. For power sources having similar peak power voltages and an achievable over 97% tracking efficiency,such independent MPT controllers are not necessary. Instead, UIVD enables the implementation of a single MPT controller to achieve the near-maximum output of the ideally available power. The resulting system and control architectures offer near-maximum power transfer with a lower parts count. Two DISO power converter bus architectures are validated through computer simulation: one having a battery-dominated output voltage and the other with a regulated output voltage.
Presenters:
Kasemsan Siri, Aerospace Corporation
Frank Chen, University of Central Florida
Majd Batarseh, Princess Sumaya University

Title: An Improved MPPT Technique for High Gain DC-DC Converter Using Model Predictive Control for Photovoltaic Applications
Abstract: This paper presents an enhanced Maximum Power Point Tracking (MPPT) of Photovoltaic (PV) systems by means of Model Predictive Control (MPC) techniques. The PV array can feed power to the load through a DC/DC converter boosting the output voltage. Due to stochastic behavior of solar energy, MPPT control technique of PV arrays is required to operate at maximum power point. Extracting the maximum power from PV systems has been widely investigated within the literature. The main contribution of this paper is enhancement of the Incremental Conductance (INC) method through a fixed step predictive control under measured fast solar radiation variation. The proposed predictive control to achieve Maximum Power Point (MPP) speeds up the control loop since it predicts error before the switching signal is applied to the selected high gain multilevel DC-DC converter. Comparing the developed technique to the conventional INC method shows significant improvement in PV system performance. Experimental validation is presented using the dSpace CP 1103 to implement the MPC on custom built dc-dc converter hardware.
Presenters:
Mohammad Bagher Shadmand, Texas A&M University
Mostafa Mosa, Texas A&M University at Qatar
Robert S Balog, Texas A&M University
Haitham Abu-Rub, Texas A&M University at Qatar

Title: Modeling and Analysis of DC-Link Voltage for Three-Phase Four-Wire Two-Stage Micro-Inverter
Abstract: In double-stage grid-connected photovoltaic (PV) micro-inverters, the dynamic interaction between the dc/dc stage and dc/ac stage may reduce the system performance. DC-link voltage control plays a key role for two-stage micro-inverter application. Modeling &analysis of dc-link voltage has been investigated in this paper. The first-stage circuit employs transient maximum power point tracking method to realize fast MPP tracking without causing output distortion and dc-link variation. In order to keep dc-link voltage constant, injecting current to grid varies with the output of a positive feedback of dc-link voltage regulator at steady situation. Two disturbances to cause dc-link constant are investigated and small signal model of dc-link voltage is also built while considering dynamic response. Followed by the small signal model of dc-link voltage, the dc-link capacitance is also calculated. The performance of dc-link voltage control is verified by experimental results based on a 400 watt two-stage three-phase four-wire prototype with grid-connected, the input voltage from 35V to 60V, dc-link voltage 400Vdc and AC output voltage 110V RMS.
Presenters:
Frank Chen, University of Central Florida
Qian Zhang, University of Central Florida
Ahmadreza Amirahmadi, University of Central Florida
Issa Batarseh, University of Central Florida

Title: Fuzzy Logic Based Control System for Cascaded H-Bridge Converter
Abstract: In this paper a simple and effective CHB capacitor voltage control system is proposed. An FLC based control architecture employed in the voltage balancing loop is completely independent of the cluster voltage PI control loop. The proposed method can be used with simple and modular PWM techniques such as PS-PWM while avoiding increased control system complexity.
Presenters:
Ghias Farivar, University of New South Wales
Vassilios G. Agelidis, University of New South Wales
Branislav Hredzak, University of New South Wales

Title: Voltage Regulation in Single-Stage Boost Inverter for Stand-Alone Applications
Abstract: The voltage regulation for stand-alone three-phase single-stage boost inverter (SSBI) is presented in this paper. In three-phase SSBI, the voltage regulation is achieved by adjusting the boost ratio. The SSBI has been simulated for a wide range of input dc voltages and load levels. Moreover, the performance a 2kW 208/230V laboratory-scale three phase boost inverter is presented for both linear and non-linear loads. The voltage regulation is realized along with implementing the modified PPWM technique in which the charging time stays constant over each sector and staircase pattern is used for discharging states.
Presenters:
Akanksha Singh, Kansas State University
Alireza A. Milani, Kansas State University
Behrooz Mirafzal, Kansas State University

Title: Control and Configuration of Three-Level Dual-Active Bridge DC-DC Converter as a Front-End Interface for Photovoltaic System
Abstract: A novel converter configuration that allows for high frequency transformer integration and high voltage distribution is proposed for large scale grid-connected photovoltaic (PV) system. The proposed configuration has in the front-end of the solar panel, dual-active bridge dc-dc converter with three-level neutral-point clamped secondary and a high-step-up ratio high frequency transformer. The output of the dual-active bridge converter may be connected to a high voltage inverter to achieve high ac voltage to allow for direct interconnection with the utility ac grid at 13.8kV distribution voltage level. The proposed configuration has advantages of high frequency transformer, high efficiency and high voltage operation. Phase-shift modulation technique along with Maximum Power Point Tracking is proposed for the three-level dual-active bridge converter and the overall converter performance is verified in simulation.
Presenters:
M A Moonem, University of Texas at San Antonio
Hariharan Krishnaswami, University of Texas at San Antonio

Title: A Current Control MPPT Method in High Power Solar Energy Conversion System
Abstract: The traditional method of MPPT control for single-stage three/single-phase inverter typically adjusts the voltage reference corresponding to the power variation of PV array. This method usually has two control loops which exhibit slow response speed. This paper proposes a direct current control method to realize MPPT for single-stage three-phase inverter. This method features fast response against disturbance and reduced the DC voltage ripple. The proposed MPPT method is illustrated in detail and a stability analysis method is developed. Simulation results demonstrate the response speed of current control MPPT and validity of stability analysis method. Experimental results are in process.
Presenters:
Bin Wu, University of California, Irvine
Keyue Smedley, University of California, Irvine

Title: Topology Variations and Design Improvements of a Single-Stage Flyback PV Microinverter
Abstract: This paper proposes two novel topological variants of a single-stage flyback PV microinverter, already reported in literature, which is capable of achieving power decoupling without using electrolytic capacitors. Practical design problems related to the original topology are discussed and the beni fits of the modifi ed forms are highlighted, considering a specifi c example. Finally some experimental results on a 110 W prototype are presented.
Presenters:
Shiladri Chakraborty, Indian Institute of Technology Kharagpur
Souvik Chattopadhyay, Indian Institute of Technology Kharagpur

Title: Non-Isolated Individual MPP Trackers for Series PV Strings Through Partial Current Processing Technique
Abstract: Novel individual power extraction topologies through partial current processing (PCP) technique are proposed for series connected photovoltaic panels. In the presented PCP technique only the mismatch currents between the series connected panels are processed. Both of the proposed current fed and voltages fed topologies process the mismatch currents without the need for an isolation transformer. These features increase the system efficiency while decreasing the ratings of the power electronics interface. The simulation and experimental results are presented in this paper to confirm the validity of the proposed configurations, and to verify its effectiveness.
Presenters:
Mohamed Badawy, University of Akron
Ali Elrayyah, University of Akron
Fatih Cingoz, University of Akron
Yilmaz Sozer, University of Akron

Session: D17-Renewable Energy Sources & Systems
Track: Renewable Energy Systems

Title: Emulating Full-Converter Wind Turbine by a Single Converter in a Multiple Converter Based Emulation System
Abstract: A real-time reconfigurable hardware test-bed is being constructed to emulate a transmission network of a power system by modular regenerative converters. This test-bed enables flexible research scenarios without the necessities of using the actual power system equipment. This paper presents the emulation of a full-converter wind turbine using a single converter in order to investigate the impact of renewable energy penetration. By integrating physical models and control strategies into the converter controller, the emulator can imitate the behaviors of the wind turbine accurately. Simulation and experiments performed in the test-bed validate the effectiveness of the emulation, and demonstrate the performance of the emulated wind turbine during different power system scenarios
Presenters:
Yiwei Ma, University of Tennessee
Liu Yang, University of Tennessee
Jingxin Wang, University of Tennessee
Fred Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee

Title: Using Virtual Impedance Network to Improve the Control Performances of LCL-Type Grid-Connected Inverter Under the Weak Grid Condition
Abstract: The grid-connected inverter can be greatly challenged by the weak grid. Particularly, the stability problem may be aroused by the grid impedance and the injected grid current can be greatly distorted by the grid voltage harmonics. The output impedance of the inverter can give an insight into the stable robustness and the harmonic rejection ability. Therefore, the virtual impedance network is proposed to provide additional degrees of freedom for the output impedance optimization, thus to achieve high robustness and strong rejection ability at the same time. Experimental results from a 6kW prototype confirm the effectiveness of the proposed solutions.
Presenters:
Dongsheng Yang, Nanjing Aeronautics and Astronautics University
Xinbo Ruan, Nanjing Aeronautics and Astronautics University
Heng Wu, Nanjing Aeronautics and Astronautics University

Title: Application of a Digital ANF-Based Power Processor for Micro-Grids Power Quality Enhancement
Abstract: This paper proposes a decentralized approach for power quality improvements in smart micro-grids. In this scheme, a modified digital adaptive notch filter (ANF) has been introduced and employed to extract harmonic content and symmetrical components of each harmonic of the voltage and the injected current at the point of common coupling. A universal digital power processor has been developed accordingly to intensify the power quality improvement capabilities of distributed generation systems. The proposed technique allows for compensation of either particular unwanted frequency components or a wide range in the spectral content of the injected current.
Presenters:
Sepide Rafiei, Queen’s University
Ali Moallem, Queen’s University
Alireza Bakhshai, Queen’s University
Davood Yazdani, Fairchild Semiconductor

Title: Second Order Harmonics Reduction Thechnique Using Model Predictive Control for Household Energy Storage Systems
Abstract: This paper proposes an output current ripple reduction algorithm using model-based predictive control (MPC) for an energy storage system (ESS). In single-phase systems, the DC/AC inverter has a second-order harmonic at twice the grid frequency of a DC-link voltage caused by pulsation of the DC-link voltage. The output current of a DC/DC converter has a ripple component because of the ripple of the DC-link voltage. The second-order harmonic adversely affects the battery lifetime. The MPC predicts the output current of next state from a converter model. The optimal duty is determined by minimizing the error between the reference and the predicted current. Due to the calculated optimal duty, the dynamic response is fast. The proposed algorithm has an advantage of reducing the second-order harmonic of the output current in the variable frequency system. The proposed algorithm is verified from the PSIM simulation with the 3 kW ESS model.
Presenters:
Jin-Hyuk Park, Ajou University
Hae-Gwang Jeong, Ajou University
Kyo-Beum Lee, Ajou University

Title: Three-Port ZVS Converter with PWM Plus Secondary-Side Phase-Shifted for Photovoltaic-Storage Hybrid Systems
Abstract: A full-bridge three-port converter (FB-TPC) with PWM plus secondary-side phase shift (PWM+SSPS) control scheme is proposed for photovoltaic-storage hybrid systems. Employing the parasitized control variables along with the potential power transmission paths from the full-bridge converter, the proposed FB-TPC is derived. Moreover, the primary switch’s duty cycle and the phase shift between the leading primary and the corresponding lagging secondary switches are employed as two control freedoms to achieve the voltage regulation between any two of the three ports, namely the PWM+SSPS control scheme. Furthermore, zero-voltage-switching (ZVS) performance is achieved for both the primary and secondary side switches. As a result, high power density and efficiency can be implemented. The operation principle of the proposed converter is analyzed in detail and experimental results of an 800W prototype are provided to verify the feasibility and advantages of the proposed converter along with the control scheme.
Presenters:
Zhe Chen, University of Wisconsin-Madison

Title: A Novel Active Power Control Strategy Based on Droop Control Method for Parallel Inverters
Abstract: The conventional droop control method, which does not require communication lines, is an effective control scheme to dispatch power among inverters in the microgrid. However, this method has inherent tradeoffs: frequency vs. active power accuracy and amplitude regulation vs. reactive power sharing accuracy. To cope with this problem, this paper presents a novel active power control strategy to improve the active power sharing accuracy and eliminate the frequency deviation in steady state. Compared with existing methods, the proposed method do not need any communication line, since this method utilizes the system frequency as signals to coordinates parallel operations. Experimental results are presented to prove the validity of this approach.
Presenters:
Zhiyuan You, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Xuan Zhang, Xi’an Jiaotong University
Teng Wu, Xi’an Jiaotong University
Xinyu Wang, Xi’an Jiaotong University

Title: Thermal Behavior of Doubly-Fed Induction Generator Wind Turbine System During Balanced Grid Fault
Abstract: Ride-through capabilities of the doubly-fed induction generator (DFIG) during grid fault have been studied a lot. However, the thermal performance of the power devices during this transient period is seldom investigated. In this paper, the dynamic model for the DFIG and the influence of the rotor current to the damping time of the stator flux and rotor terminal voltage during the symmetrical grid fault is firstly evaluated. Then, a theoretical analysis for the safety operation area of the power device is given in terms of the various voltage dips and various rotor speeds. Finally, the power loss and the thermal profile are shown at the transient period of the DFIG. It is concluded that the serious voltage dip results in the higher power loss as well as the junction temperature fluctuation, and it may even damage the rotor converter.
Presenters:
Dao Zhou, Aalborg University
Frede Blaabjerg, Aalborg University
Mogens Lau, Danfoss Silicon Power GmbH
Michael Tonnes, Danfoss Silicon Power GmbH

Title: Medium-Voltage (MV) Matrix Converter Topology for Wind Power Conversion Using Medium-Frequency Transformer (MFT) Isolation
Abstract: This paper is focused on a new converter topology with medium frequency transformer isolation for medium voltage (MV) wind turbine generator (WTG) power systems. The approach is a high density power conversion, with simultaneous high performance features suitable for next generation wind power systems for both on-shore and off-shore applications. The proposed topology employs 1-phase multi-level AC-AC converters on the utility side and 3×1 matrix converters (3×1 MCs) on the WTG side; interfaced using a medium frequency transformer (MFT). This avoids DC-Link capacitors and/or resonant L-C components in the power flow path thereby improving the power density and reliability. As the system is lightweight, it can possibly be located at the base of the tower itself. This topology can be used in other renewable energy power converters, motor drives, electric locomotives, etc with slight modifications. The validity of the proposed concept has been verified by simulation results and experiment waveforms from a 6.6kVA scaled down laboratory prototype.
Presenters:
Chunyang Gu, Tsinghua University
Harish Krishnamoorthy, Texas A&M University
Prasad Enjeti, Texas A&M University
Yongdong Li, Tsinghua University

Title: A Distributed Architecture Based on Micro-Bank Modules with Self-Reconfiguration Control Regarding Battery Recovery Effect for DC Microgrids
Abstract: This paper presents a new distributed architecture based on the micro-bank modules for DC microgrids. The benefits include 1) no voltage sharing and overcharge/overdischarge problem; 2) high compatibility and reliability 3) high energy efficiency. Taking advantage of the battery recovery effect, a self-reconfiguration discharge strategy is proposed to further enhance the battery performance and efficiency of the storage system. The analysis and simulation results verified the proposed concept. More detailed analysis and experimental results will be provided in the final paper.
Presenters:
Zhiliang Zhang, Nanjing Aeronautics and Astronautics University
Yong-Yong Cai, Nanjing Aeronautics and Astronautics University
Xiao-Fei He, Nanjing Aeronautics and Astronautics University
Yan-Fei Liu, Queen’s University

Title: Doubly Fed Induction Generator Based Wind Turbine Systems Subject to Recurring Grid Faults
Abstract: New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the Doubly Fed Induction Generator wind turbine system under recurring grid faults is analyzed. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced by the second grid fault, and it may result in large current and voltage transient. The damping of the stator natural flux can be accelerated with a rotor natural current in its opposite direction after voltage recovery, but larger torque fluctuations may be introduced. It may influence the reliability of the mechanical system. An improved control strategy is investigated to accelerate the damping of the stator natural flux in ride-through to prevent the superposing of the stator natural flux. While the torque fluctuations are limited. The performance of DFIG under recurring grid faults is verified by the simulation and experiments.
Presenters:
Wenjie Chen, Zhejiang University
Frede Blaabjerg, Aalborg University
Nan Zhu, Zhejiang University
Min Chen, Zhejiang University
Dehong Xu, Zhejiang University

Title: Biomechanical Energy Harvesting System with Optimal Cost-of-Harvesting Tracking Algorithm
Abstract: The study presents an innovative biomechanical energy harvesting system based on the regenerative braking concept applied to the human natural motion. The harvesting system is equipped with a programmable braking profile and a unique power extraction algorithm, which adaptively changes the braking profile to obtain the optimal ratio of energy to effort. These are facilitated by a BLDC generator that is connected to boost converter. A digital current programmed control of the converter enables an adaptive torque variation according to bio and electrical feedbacks. The concept is demonstrated on the human knee joint as the energy source since it is rich of negative work (muscles are acting as brakes).
Presenters:
Ze’Ev Rubinshtein, Ben-Gurion University of the Negev
Mor Mordechai Peretz, Ben-Gurion University of the Negev
Raziel Riemer, Ben-Gurion University of the Negev

Title: SSR Analysis of a DFIG – Based Wind Farm Interfaced with a Gate-Controlled Series Capacitor
Abstract: In this paper, modal analysis of DFIG-based fixed series compensated wind farm is presented. The 22nd order system is modeled in Matlab/Simulink, and modal analysis is performed on the modeled system. The results obtained show that with a fixed compensation, the wind farm can experience sub-synchronous resonance (SSR). In order to eliminate the SSR instability, the gate-controlled series capacitor (GCSC), which is a series FACTS device, is employed in the wind farm. The modeling of the DFIG is updated by adding the GCSC dynamics to it. It will be shown how the GCSC can provide SSR damping in DFIG.
Presenters:
Hossein Ali Mohammadpour, University of South Carolina
Yong-June Shin, Yonsei University
Enrico Santi, University of South Carolina

Title: A Fully Decoupled Feed-Forward Control for Low-Voltage Ride-Through of DFIG Based Wind Turbines
Abstract: With the stator directly connected to the grid, doubly-fed induction generator is very sensitive to gird disturbance. However, wind turbines are required to stay connected to the grid for a given time duration during grid fault, according to the low voltage ride-through requirement. The key point of the low voltage ride-through solution is to depress high rotor current during grid fault. This paper proposes a fully decoupled feed-forward control for the DFIG, enhancing the low voltage ride-through capability. When grid fault happens, the induced EMF is accurately estimated, resulting in minimum transient rotor current and minimum the occurrence of crowbar interruptions. Simulation results are included, demonstrating the viability of the proposed control.
Presenters:
Linyuan Zhou, Xi’an Jiaotong University
Jinjun Liu, Xi’an Jiaotong University
Sizhan Zhou, Xi’an Jiaotong University
Hongwei She, Xi’an Jiaotong University

Title: A Tapped-Inductor Buck-Boost Converter for a Dielectric ElectroActive Polymer Generator
Abstract: Energy harvesting via Dielectric ElectroActive Polymers (DEAPs) has been constantly gaining momentum over the past few years, due to their profound advantages when compared with competing electromagnetic or field-activated technologies. Yet, the low-frequency, high-amplitude pulsating voltage signal appearing across the DEAP generator imposes a great challenge on the candidate power electronic converter which should convert this voltage into a well-defined DC signal. In this paper, a high-efficient, tapped”inductor buck-boost converter, based on a string of three serialized MOSFETs, is used to harvest energy from a DEAP generator.
Presenters:
Emmanouil Dimopoulos, Aalborg University
Stig Munk-Nielsen, Aalborg University

Title: PV System Modeling and a Global-Planning Design for its Controller Parameters
Abstract: The conventional mathematic model of PV (Photovoltaic) cells contains logarithmic terms, which is not conducive to derivation calculation in small-signal modeling. The parameters of PV system are coupling due to its double-loop control method, and it’s hard to precisely choose controller parameters. To solve these two problems above, this paper is based on PV system connected to an infinite power grid, uses the linear-fitting model of PV cells which is conducive to derivation instead of the original engineering one in small-signal modeling, and analyses the small-signal stability of the entire system. Meanwhile, a global-planning design for controller parameters is proposed to globally provide the optimal controller parameters. Simulation results show that the linear-fitting model of PV cells is very similar to the original engineering one, and the proposed design for controller parameters can provide a solution to calculate the global optimization.
Presenters:
Yifeng Xie, Xi’an Jiaotong University
Jingyu Huang, Xi’an Jiaotong University
Xiaokang Liu, Xi’an Jiaotong University
Fang Zhuo, Xi’an Jiaotong University
Baoquan Liu, Xi’an Jiaotong University
Hailong Zhang, Xuji Group

Title: A Wireless, Decentralized and Nonlinear Energy Management Strategy Using PCC Frequency for Islanded AC Microgrids
Abstract: This paper presents an wireless and decentralized and nonlinear energy management strategy for islanded AC microgrid. The energy management strategy is implemented by utilizing the PCC frequency as an agent for all constituent units in order to avoid physical communication lines. The operation principle and equivalent transfer function of the nonlinear unit employing describing functions are explained. The proposed energy management is effective not only for the situation where the battery is not fully charged but also for the circumstance where the battery is fully charged. The effectiveness of the proposed strategy is verified by simulation and experimental results.
Presenters:
Zhiqiang Guo, Beijing Institute of Technology
Deshang Sha, Beijing Institute of Technology
Xiaozhong Liao, Beijing Institute of Technology

Title: Efficiency Control of Multi-String PV System Considering Switching Losses Analysis
Abstract: Photovoltaic (PV) system with multi-strings can be efficiently operated because individual maximum power point tracking (MPPT) of each separated panel is performed by converters which are connected to each panel. For the MPPT, it causes continuous switching losses of the converters. This paper proposes new control operating method in multi-string PV system using parallel DC-DC converters and single DC-AC inverter. In proposed method, the DC link voltage is regulated to the highest maximum power point (MPP) voltage among the panels when the voltage is high enough to deliver power to grid. The converter for panel of the highest voltage passes the power without any switching and the inverter performs MPPT instead of the converter. Also, more optimized MPP is newly decided by analyzing switching losses according to variation of the DC-link voltage and the method for the MPPT is proposed. Thus, the efficiency of the system can be improved in comparison with the conventional method. Experimental results present the feasibility of the proposed control operation and the improved efficiency.
Presenters:
Kwonyub Hyung, Seoul National University
Hojoon Shin, Seoul National University
Jung-Ik Ha, Seoul National University
Anno Yoo, LSIS Co. Ltd.

Title: A Novel Low Cost Power Converter Topology for Active Power Injection in Low Voltage Monophasic Power Line from Fuel Cells
Abstract: The present paper shows a novel power converter topology that can be applied to inject active electric power into a low voltage monophasic power line (110V to 220V). As this topology is suitable to step up low voltages present in fuel cells stack, it can be also applied in photovoltaic solar panels. The proposed topology is a modification of the common topology composed by two intermediary converters: a DC/DC step-up converter and a monophasic inverter bridge, which is responsible to control the electric power amount and quality that is delivered to the grid. The proposed topology does not use a capacitor in the inverter bridge bus (which has a relatively high voltage if compared to the fuel cell stack output voltage) and does not uses inductors in low voltage circuit, i. e., the fuel cell stack output, which has a higher current value, if compared to the output current delivery to the power grid. Also, the common topology uses high frequency switching transistors in both converters but the proposed topology, although it uses the same amount of power transistors, it requires only fast transistors in the step-up converter.
Presenters:
José Roberto B. A. Monteiro, Universidade de São Paulo
Manoel Luís Aguiar, Universidade de São Paulo
Geyverson Teixeira Paula, Universidade de São Paulo
Azauri A. Oliveira Jr., Universidade de São Paulo
Luiz Gonçalves Neto, Universidade de São Paulo
Ruy Alberto Correa Altafim, Universidade de São Paulo

Title: Effects of DSSC Configuration on Power Conversion Efficiency
Abstract: This paper outlines how the DSSC configuration affects the performance of low power, step-up DC-DC converters. The DSSC is modelled using equivalent circuit components to replicate actual DSSC operation. DC-DC converters are examined in detail to understand where losses occur and how these losses can be reduced by altering the DSSC configuration.
Presenters:
David Newell, National University of Ireland, Galway / SolarPrint
Maeve Duffy, National University of Ireland, Galway
Richard Twohig, SolarPrint

Title: Micro Grid Based PMSG Feeding Isolated Loads
Abstract: This paper deals with design and control of a connected wind energy generation system employing a Permanent Magnet Synchronous Generator (PMSG) driven by a variable speed wind turbine for single-phase local loads. The proposed energy conversion system is using a five level inverter connected with pulse width modulated (PWM) based voltage source converters (VSCs). The dc terminal of the rectifier is connected to the boost converter for the Maximum Power Point Tracking (MPPT) through its rotor speed control. A battery is used to absorb the excess power generated from the wind turbine, and also is used to keep regulated a dc bus voltage. A pitch angle control is integrated to reduce the power generated from the wind turbine in the case of the charge of the battery reaches 90%. The inverter converts the dc voltage to ac controlled voltage to its reference voltage in order to feed an ac local load at any desired voltage. The proposed system is simulated using real time simulator and Hardware in the Loop (HIL) of RT-Lab. The performance of the proposed system is presented to demonstrate its capability of MPTT, dc and ac voltage regulation.
Presenters:
Abdelhamid Hamadi, École de Technologie Supérieure
Salem Rahmani, École de Technologie Supérieure
Kamal Al-Haddad, École de Technologie Supérieure
Khaled Addoweesh, King Saud University

Title: Reliability and Cost Analysis of Solar Photovoltaic and Fuel Cell Based Microgrids
Abstract: Maintaining a reliable operation in microgrids has significant importance. One factor required for the reliable microgrid operation is to keep certain energy reserve without sacrificing the cost for satisfying any load variation. Reliability and cost optimization of photovoltaic and fuel cell based microgrid system is investigated in this paper. A typical residential load is considered in order to introduce an optimal power sharing approach for cost effective and reliable system operation. A nonlinear frequency droop scheme is then applied to achieve the optimization objectives at the intended operating scenarios. The simulation and experimental results are presented to verify the effectiveness of the proposed technique.
Presenters:
Fatih Cingoz, University of Akron
Ali Elrayyah, University of Akron
Mohamed Badawy, University of Akron
Yilmaz Sozer, University of Akron

Title: Control of Squirrel Cage Induction Generator in an Oscillating Point Absorber Based Wave Energy Conversion System
Abstract: This paper presents operation and control of a Squirrel Cage Induction Generator (SCIG) to generate power from an oscillating point absorber based wave energy converter (WEC) system. The oscillating point absorber buoy is assumed to be connected with the SCIG through a rack and pinion gear arrangement. An equivalent mechanical model of the buoy is presented. The SCIG is controlled with indirect field oriented control (IFOC) method to extract power from the WEC. Air gap flux is kept at its rated value in all operating conditions. The torque component of the current is varied in proportion with the buoy speed to harvest variable power from the WEC.
Presenters:
Samir Hazra, North Carolina State University
Subhashish Bhattacharya, North Carolina State University

Title: Power Flow Analysis Algorithm for Islanded LV Microgrids Including Distributed Generator Units with Droop Control and Virtual Impedance Loop
Abstract: In this paper, an improved power flow analysis algorithm for distributed generation (DG) units controlled with P/Q droop functions and virtual impedances in a low voltage (LV) microgrid is proposed. The proposed analysis provides in contrast to conventional power flow calculation techniques: (i) consideration of virtual impedance parameters and (ii) higher accuracy in reactive power flow calculation. The improved power flow analysis algorithm proposed in this paper is validated by comparing the calculation results with detailed time domain simulation results. Case studies have been carried out by analyzing the effects of control parameter variation in the power flow results obtained by the proposed algorithm.
Presenters:
Chendan Li, Aalborg University
Sanjay Chaudhary, Aalborg University
Juan Carlos Vasquez, Aalborg University
Josep Maria Guerrero, Aalborg University

Title: Online LCL Filter Compensation Using Embedded FRA
Abstract: LCL filter control design is challenging because of presence of a resonant pole in the LCL filter transfer function. This paper presents a guideline for LCL filter design, which are often used in grid connected applications, with compensation based on complex poles and zeros. A Software Frequency Response Analyzer (SFRA) is integrated in the control software of the power converter. This enables periodical collection of frequency response data, which can be used to monitor movement of resonant poles due to aging, drifts and degradation of components. The information obtained from embedded SFRA can then be used to adjust the compensation. A feedback linearization method is illustrated to account for the grid voltage disturbances, which cannot be compensated by traditional PI controller. A solar micro inverter board is designed to prove the proposed scheme. Discussions about the embedded design challenges in integration of multiple power stage control, for a micro inverter using a single processor, are included and solutions presented.
Presenters:
Manish Bhardwaj, Texas Instruments
Shamim Choudhury, Texas Instruments
Vieri Xue, Texas Instruments
Bilal Akin, University of Texas at Dallas

Session: D18-Vehicular Electronics II
Track: Vehicular Electronics

Title: Optimal Design and Control of OBC-LDC Integrated Power Unit for Electric Vehicles
Abstract: This paper proposes an integrated circuit sharing internal parts of a low voltage DC-DC converter (LDC) and an on-board charger (OBC) for electric vehicles (EVs). The proposed circuit structure can be operated as an OBC-mode, a LDC-mode, and a simultaneous operating mode. To improve the practicality, also, a built-in zero voltage switching (ZVS) buck circuit is applied. Prototype rated with 3.3 kW OBC and 1 kW LDC was built and the experimental results are carried out in order to verify the performance and the validity of the proposed power unit.
Presenters:
Yun-Sung Kim, Sungkyunkwan University
Chang-Yeol Oh, Sungkyunkwan University
Won-Yong Sung, Sungkyunkwan University
Byoung-Kuk Lee, Sungkyunkwan University
Gwi-Chul Park, Dongahelecomm Corporation

Title: Asymmetric Control Algorithm for Non-Isolated Type on-Board Battery Charger with Single Controller
Abstract: Non-isolated single-stage on-board charger (OBC) for electric vehicles (EVs) has been proposed in order to satisfy high efficiency and high power density. However, the conventional works could not achieve high efficiency according to the voltage variation of the utility and the battery, especially during the step-down operation. This paper proposes an advanced control algorithm to improve the system efficiency under the step-down mode by controlling each switch of the OBC asynchronously. Moreover, the proposed algorithm consists of only one controller, which eliminates a transient state from variation of the controller. From the decreased the magnitude and the ripple of the inductor current, the charging efficiency is improved about 3.5 % from the conventional algorithm under the step-down mode.
Presenters:
Dong-Hee Kim, Sungkyunkwan University
Min-Jung Kim, Sungkyunkwan University
Seung-Hee Ryu, Sungkyunkwan University
Yun-Sung Kim, Sungkyunkwan University
Byoung-Kuk Lee, Sungkyunkwan University

Title: An Interleaving Scheme to Reduce DC-Link Current Harmonics of Dual Traction Inverters in Hybrid Electric Vehicles
Abstract: This paper presents an interleaving scheme to reduce the DC-link current harmonics of dual traction inverters in Hybrid Electric Vehicles. The DC-link current expression of dual traction inverters is derived, considering the modulation schemes, modulation index, displacement power factor, and interleaving angle. Based on the DC-link current analysis, proper interleaving angles to reduce the DC-link current harmonics can be obtained for different operating modes of dual traction electric motor drives. With the proposed interleaving angles, the DC-link capacitor current harmonics can be reduced. Therefore, the required capacitance can be reduced and the lifetime of capacitor can be improved.
Presenters:
Haizhong Ye, McMaster University
Ali Emadi, McMaster University

Title: Propulsion and Battery Charging Systems of an All-Electric Boat Fully Constructed with Interleaved Converters Employing Interphase Transformers and Gallium Nitride (GaN) Power FET Semiconductors
Abstract: This work presents a Power Electronics solution for an all-electric passenger boat. The proposed system is constructed with building blocks comprising interleaved half-bridge converters employing interphase transformer and Gallium Nitride FET semiconductors. The system employs two multi-level drives and an integrated harbor and onboard PV system. The PV battery charger has two stages. One converter per PV panel and a second based on cascaded buck-boost converters that control the battery current and adapts the voltage levels. The operation, control and design expressions are presented. Finally, experimental results verify the feasibility of the proposed system.
Presenters:
Thiago Soeiro, ABB Switzerland Ltd.
Tiago Jappe, Universidade Federal de Santa Catarina
Walbermark dos Santos, Universidade Federal de Santa Catarina
Denizar Martins, Universidade Federal de Santa Catarina
Marcelo Heldwein, Universidade Federal de Santa Catarina

Title: Study of the Characteristics of Battery Packs in Electric Vehicles with Parallel-Connected Lithium-Ion Battery Cells
Abstract: This paper tries to make two contributions to the existing literature for characteristics of battery packs with parallel-connected lithium ion battery cells. (1) The current, capacity and voltage characteristics of battery packs that have lithium ion battery cells connected in parallel (parallel-connected packs) have been analyzed. (2) The definition of State-of-charge (SoC) of the battery pack has been studied. Experimental results on a battery pack with parallel-connected lithium-ion polymer battery (LiPB) cells indicate that the LiPB cell with a better health state leads to a higher discharge current, which results in accelerated aging. It was also found that the battery pack’s SoC cannot be calculated by the cell which has a lower capacity.
Presenters:
Xianzhi Gong, University of Michigan-Dearborn
Rui Xiong, University of Michigan-Dearborn
Chris Mi, University of Michigan-Dearborn

Title: Genetic Algorithm Based Coil System Design for Wireless Power Charging
Abstract: High efficiency and low cost coil system design is one of the key points for wireless power transfer. In this paper, a optimization method with generic algorithm is presented. The coil track layouts are interpreted with binary strings in the design iterations. Some practical considerations and detailed implementations are introduced in the optimization procedure.
Presenters:
Puqi Ning, Institute of Electrical Engineering, Chinese Academy of Sciences
Xuhui Wen, Institute of Electrical Engineering, Chinese Academy of Sciences

Title: Active Balancing System for Electric Vehicles with Incorporated Low Voltage Bus
Abstract: Electric-drive vehicles, including hybrid (HEV), plug-in hybrid (PHEV) and electric vehicles (EV) include a high-voltage (HV) battery pack for propulsion, and a low-voltage (LV) dc bus for auxiliary loads. This paper presents a battery cell balancing architecture based on low-voltage, low-power bypass dc-dc converters that perform run-time active cell balancing using a shared LV bus. Furthermore, the system LV bus eliminates the need for HV-to-LV high step-down dc-dc conversion. The approach is verified by system simulation results and by experimental results for a prototype 4-to-12 V dual-active bridge (DAB) bypass converter.
Presenters:
Daniel Costinett, University of Tennessee
Kelly Hathaway, Utah State University
Muneeb Ur Rehman, Utah State University
Michael Evzelman, Utah State University / Ben-Gurion University of the Negev
Regan Zane, Utah State University
Yoash Levron, University of Colorado at Boulder
Dragan Maksimovic, University of Colorado at Boulder

Title: A Single-Stage Bridgeless High Efficiency ZVS Hybrid-Resonant Off-Road and Neighborhood EV Battery Charger
Abstract: This paper introduces a single-stage battery charger for neighborhood electric vehicles (NEVs) which has the following characteristics: i. operate in continuous-conduction-mode (CCM), ii. include bridgeless operation, iii. realize zero-voltage switching (ZVS) operation for all MOSFETs, iv. provide controlled di/dt turn-off of the output diodes, v. has symmetric operation. The proposed battery charger exhibited minimum number of semiconductor devices compare with state-of-the-art battery charger. The input-output isolation reduces the possibility of safety hazards. The proposed isolation transformer acts as an AC transformer which is much smaller in size and increase transformer efficiency.
Presenters:
Md Muntasir Ul Alam, University of British Columbia
Wilson Eberle, University of British Columbia
Fariborz Musavi, Delta-Q Technologies Corp.

Title: Effect of PWM Schemes on Integrated Battery Charger for Plug-in Hybrid Electric Vehicles: Performance, Power Factor, and Efficiency
Abstract: The IBC system with the additional boost inductor for plug-in hybrid electric vehicles (PHEVs) is analyzed and system performance according to the pulse-width-modulated (PWM) switching schemes, such as interleaved PWM scheme and synchronous PWM scheme, is discussed in terms of efficiency, power factor, and current distortion factor. Contrary to the general multi-phase boost power factor correction converter, the synchronous PWM scheme results in a higher efficiency than the interleaved PWM scheme. The effects of the PWM switching scheme on the IBC system are experimentally demonstrated on a prototype.
Presenters:
Dong-Gyun Woo, Sungkyunkwan University
Yun-Sung Kim, Sungkyunkwan University
Byoung-Kuk Lee, Sungkyunkwan University

Session: D19-Power Electronics I
Track: Power Electronics Applications

Title: Analysis and Design of Voltage Maintaining Method for Series Resonant Capacitor Charging Power Supply
Abstract: High energy density high-voltage metallized film capacitor is one of the most suitable energy storage elements in pulsed power system, such as Electromagnetic Gun (EMG) system. But the voltage drop at high voltage is an inherent problem of metallized film capacitor, which will affect the launching precision of EMG system. To improve the launching precision, this paper mainly focuses on the voltage maintaining method of capacitor charging power supply (CCPS). Based on the traditional series resonant CCPS, a voltage maintaining method is proposed, which feeds energy to capacitor to compensate voltage drop during launching delay. The scheme is simple and easy to implement. It also can switch smoothly from fast charging stage to micro power charging maintaining stage. Furthermore, for the portable CCPS fed by lithium ion battery, the charging voltage maintaining precision is deteriorated by the common-mode voltage. So a common-mode voltage restraining circuit is proposed and analyzed in detail. A 4kV 1.0kJ/s CCPS prototype was constructed. The experimental results of the prototype show that, the CCPS has approximate maintaining accuracy of 0.1‰.
Presenters:
Lei Lin, Huazhong University of Science and Technology
Heqing Zhong, Huazhong University of Science and Technology
Yu Deng, Huazhong University of Science and Technology
Lin Gao, Huazhong University of Science and Technology
Xiaoshan Luo, Huazhong University of Science and Technology
Ao Li, Huazhong University of Science and Technology
Yongfu Liao, Huazhong University of Science and Technology

Title: Analysis and Design of High Frequency LCC Resonant Converter Applied in Corona Generator for Film Treatment
Abstract: The analysis and design of the high frequency corona generator with LCC resonant topology applied in film treatment operating in a critical mode is presented. The design of the required transformer with integrated leakage inductor is described in detail and the designed transformer is accurate with less than 1% error. A prototype has been built based on the designed transformer and the film treatment experiments have been done. The experimental results verify the feasibility and accuracy of the proposed design method. Better treatment effects result from the designed high frequency corona generator.
Presenters:
Chi Zhang, Zhejiang University
Tangtang Guo, Zhejiang University
Shiqiang Hao, Zhejiang University
Xingliang Liu, Zhejiang University
Yufei Dong, Zhejiang University
Jun Liu, Zhejiang University
Xiangning He, Zhejiang University

Title: Interleaved SWISS Rectifiers for Fast EV/PHEV Battery Chargers
Abstract: The SWISS rectifier (SR) is a potential buck-type AC-DC converter for Level-3 EV/PHEV charging. This paper is focused on the development of a battery charger based on parallel connection of SRs. An interleaved switching strategy is proposed and formulated which enables (i) cancellation of the AC-side current harmonics at switching frequency and (ii) reduction of DC-side current and voltage ripples. Performance of the interleaved paralleled SWISS rectifiers (PSRs) under various operating conditions, based on time-domain simulation studies in the MATLAB/SIMULINK environment is evaluated.
Presenters:
Munadir Ahmed, Purdue University
Jaya Deepti Dasika, Purdue University
Maryam Saeedifard, Purdue University
Oleg Wasynczuk, Purdue University

Title: Input-Series Output-Parallel Multiple Output Converter
Abstract: Efficiency is always placed as a priority when evaluating the quality of server power supply. Based on the present server power supply construction, this paper proposes a novel high efficiency input-series output-parallel (ISOP) multiple output converter. The converter consists of a multiple output DCX and a dc-dc converter. Their inputs are connected in series and they obtain their own input voltage by the input voltage-dividing capacitors which will also help realize the power distribution. One output of the DCX is connected in parallel with the output of the dc-dc converter while the others are directly connected to the loads. From the view of efficiency optimization, LLC resonant converter is selected as the topology for the DCX which occupies 90% of the input power and the two-transistor forward converter is chosen as the topology for the dc-dc converter which takes 10% of the input power. Finally, referring to the parameter of a common used serve power supply HuntKey rock 600,, a 500 W prototype based on the Freescale singlechip MC9S12XS128 is built and tested in the lab to verify the feasibility of the converter.
Presenters:
Xiaoyong Ren, Nanjing Aeronautics and Astronautics University
Qiang Zhang, Nanjing Aeronautics and Astronautics University
Zhenjin Pang, Nanjing Aeronautics and Astronautics University
Qianhong Chen, Nanjing Aeronautics and Astronautics University
Xinbo Ruan, Nanjing Aeronautics and Astronautics University

Title: Cell Balancing Control of Single Switch Flyback Converter Using Generalized Filters
Abstract: This paper presents cell balancing method of single switch flyback converter with multi-winding.Proposed method adds a generalized filter for each cell instead of a switch to control the unbalance. With this filter and the switching frequency selection, the magnitude of voltage applied to a particular cell can be reduced or increased. By applying the proposed method, unbalanced voltages by the effective turn-ratios are corrected and balanced voltage without any additional switch at secondary side.
Presenters:
Jin-Woong Kim, Seoul National University
Jung-Ik Ha, Seoul National University

Title: A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers
Abstract: Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz – 3.5 kHz). THD+N below 0.1 % are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 87 %.
Presenters:
Dennis Nielsen, Technical University of Denmark
Arnold Knott, Technical University of Denmark
Michael A. E. Andersen, Technical University of Denmark

Title: State-of-the-Art Multiple Outputs High Brightness (HB) LED Driving Technology
Abstract: In high power HB LED lighting applications, low output voltage LED drivers are preferred due to its low voltage stress and safety requirement, high reliability and safety requirements. However, most LED modules are packaged in low power module, such as 1W and 3W modules. Therefore, more LED strings are required to reduce the forward voltage drop. Since the currents in different LED strings should be kept in same in order to keep same luminance, current sharing techniques must be introduced in multi-output drivers. This paper reviews and compares the state of the art multi-output driving techniques and classified these solutions according to balancing principles
Presenters:
Chen Hu, Zhejiang University
Yuanjun Zhang, Zhejiang University
Xinke Wu, Zhejiang University

Title: Simple Self Driven Post-Regulator for Space Applications
Abstract: This paper proposes a simple alternative to self drive a synchronous rectifier in a buck and a boost converter to allow building a simple and very efficient post regulator. The intention is to use in a space application. Due to the lack of space qualified PWM ICs, the idea is to build a very simple self driven circuit based on a basic IC. Two prototypes were built to check which topology was the most efficient for this application. Even though it was close, the buck converter was slightly better.
Presenters:
Arturo Fernández, European Space Agency
Hadrien Carbonnier, European Space Agency
Olivier Mourra, European Space Agency
Ferdinando Tonicello, European Space Agency

Title: Modular Design of Cascaded H-Bridge for Community Energy Storage Systems by Using Secondary Traction Batteries
Abstract: This paper proposed a Community Energy Storage System (CES) by using reclaimed tractions batteries. The cascaded H-Bridge topology is selected for this application after reviewing all possible solutions. Control strategies to have independent control of each H-Bridge are reviewed and existing control strategies are all centralized control. To have modular design and independent control of each module, a new control strategy is proposed for cascaded H-Bridge converter. With this control strategy, each H-Bridge module will have its own controller and there is no connection between the controllers. All the control strategies are implemented in the local controllers and no central controller is needed. A small scale CES system is built to verify the proposed control strategy with great success.
Presenters:
Sanzhong Bai, North Carolina State University
Srdjan Lukic, North Carolina State University

Title: A Novel Magnetic Reset Zero-Voltage Soft-Switching Inverter with Improved Magnetic Coupling Method
Abstract: This paper will present an improved Coupled-Magnetic method for Reset Zero-voltage switching inverter. The improved inverter topology can fully use leakage inductance of coupled inductor, simplify the coupled inductor design, and improve the inductor coupled efficiency and inverter efficiency. Besides, this improved soft-switching inverter also inherit same merits, which are: The main device is Power MOSFETs, which have low conduction loss and can achieve zero-voltage switching; the auxiliary devices are low current and low cost IGBTs and Diodes, which could achieve zero-current switching. Working procedure was detailed to present the working principle. Resonant circuit was analyzed to present the advantage of proposed method. Resonant circuit timing was also analyzed for resonant components design and selection. At last, experiment results of a 5kW single phase inverter was presented to demonstrate the merit of proposed method.
Presenters:
Baifeng Chen, Virginia Polytechnic Institute and State University
Bin Gu, Virginia Polytechnic Institute and State University
Lanhua Zhang, Virginia Polytechnic Institute and State University
Nathan Kees, Virginia Polytechnic Institute and State University
Jih-Sheng Lai, Virginia Polytechnic Institute and State University

Title: Linear PFC Regulator for LED Lighting with the Multi-Level Structure and Low Voltage MOSFETs
Abstract: This paper proposes a linear PFC regulator for LED lighting applications. The proposed circuit is small in size because the circuit structure consists of only semiconductors and resistors without any reactors and electrolytic capacitors. The current bypass circuit which is connected in parallel to the LED string consists of single MOSFET, two zener diodes and two resistors. The MOSFET is operated in an active state by a self-bias circuit. Thus, an external controller and high voltage gate drivers are not required. The proposed circuit is experimentally validated by using a 15W prototype. From the experimental results, the THD of input current is 5.05% and the power factor is 0.999. In addition, the simulation loss analysis demonstrates an efficiency of 91.6% for a 15 W prototype.
Presenters:
Yuichi Noge, Nagaoka University of Technology
Jun-Ichi Itoh, Nagaoka University of Technology

Title: Power Electronics Integration on Battery Cells
Abstract: This paper introduces a distributed battery equalization structure for battery strings in which power electronic converters are integrated on battery cells. Because each cell is managed individually, the proposed structure has many advantages over traditional ones. Design issues about power converters are discussed. A two-level control algorithm is proposed to perform global and local functions including battery monitor, protection, sensing, and control. At last, the authors built a prototype, which successfully validated the proposed concept.
Presenters:
Ye Li, University of Wisconsin-Madison
Yehui Han, University of Wisconsin-Madison

Title: Single Stage Primary Side Controlled Offline Flyback LED Driver with Ripple Cancellation
Abstract: In this digest, a primary side controlled flyback LED driver with ripple cancellation technology has been proposed. We can achieve high power factor and much smaller low frequency ripple current than a conventional flyback LED Driver. A prospective integrated solution has also been illustrated in this digest for further reducing component cost.
Presenters:
Peng Fang, Queen’s University
Yan-Fei Liu, Queen’s University

Title: Modulation, Control and Capacitor Voltage Balancing of Alternate Arm Modular Multilevel Converter with DC Fault Blocking Capability
Abstract: This paper provides an overview of dc side fault tolerance issues of VSC based HVDC system and the need of fault tolerant converters. The working and dc fault ride through capability of recently introduced Alternate Arm Modular Multilevel Converter(AAMMC) has been discussed. The capacitor voltage balancing issues of AAMMC is analyzed and a novel scheme for balancing capacitor voltages of the wave shaping circuit is presented in this paper. The voltage balancing of capacitors of wave shaping circuits in the arm is done by introducing an overlap period during zero voltage periods. Using the proposed scheme, the magnitude and direction of the current during the overlap period can be controlled by varying the switching pattern. It helps in charging or discharging of sub module capacitor to bring them to their reference value. At the end of overlap period, the arm current is brought to zero before opening the director switch so as to avoid the spike across the arm inductor. The efficacy of the proposed control scheme has been validated using simulation study done in PSCAD/EMTDC.
Presenters:
Ebin Cherian Mathew, Indian Institute of Technology, Bombay
Anshuman Shukla, Indian Institute of Technology, Bombay

Title: An AC-Powered, Flicker-Free, Multi-Channel LED Driver with Current-Balancing SIMO Buck Topology for Large Area Lighting Applications
Abstract: This paper presents an AC-powered LED driver circuit that can drive multiple strings of LEDs with uniform brightness. The circuit is basically a two-stage topology where the first-stage boost converter performs the power-factor correction (PFC) and the second-stage buck converter distributes equal DC currents to multiple LED channels using only a single inductor. The uniform current level, hence uniform brightness, is maintained in an open-loop fashion without the efficiency-degrading current-regulation elements. The single-inductor multiple-output (SIMO) buck converter connects the current-delivering inductor to each channel at a time for an equal period of time, according to a permutating sequence to avoid systematic imbalances. A prototype LED driver demonstrates current difference of 1.93% while delivering 5.4-W to three channels of high-brightness white LEDs.
Presenters:
Hyun-Chang Kim, Seoul National University
Chang Soo Yoon, Seoul National University
Haram Ju, Seoul National University
Deog-Kyoon Jeong, Seoul National University
Jaeha Kim, Seoul National University

Title: Controlling Harmonics in Electrical Power Systems for Satisfying Total and Individual Harmonic Distortion Constraints
Abstract: The growth of power electronics applications has led to harmonic problems in the power system. The phenomenon of harmonic resonance resulting in severe voltage distortion has been reported. Various suppression techniques have been proposed to solve this problem. This paper proposed a technique to multiple Active Power Line Conditioners (APLCs) installed in the same Electric Power System (EPS) operating cooperatively to minimize the harmonics. The APLC operates as a variable conductance for individual and total harmonic frequency according to the corresponding harmonic-voltage distortion. The proposed control is based on Total Harmonic Distortion (THD) and Individual Harmonic Distortion (IHD) reference values (IEEE Std 519-1992 [3]), like this the damping conductance of each harmonic frequency to be separately and autonomously adjusted in response to EPS variation without communication.
Presenters:
Camila Seibel Gehrke, Universidade Federal de Campina Grande
Antonio Marcus N. Lima, Universidade Federal de Campina Grande
Alexandre Cunha Oliveira, Universidade Federal de Campina Grande

Title: A Robust Commutation Circuit for Reliable Single-Step Commutation of the Matrix Converter
Abstract: The commutation process in a matrix converter (MC) is more complex as compared with that of the traditional AC-DC-AC converter due to the lack of natural free-wheeling paths. Reducing the commutation time and process is a main objective of using MC in aerospace applications where the range of frequency is between 360-800 Hz. This paper presents a robust commutation circuit for reliable single-step commutation of the MC, and demonstrates its feasibility through computer simulations and experimental results obtained from a laboratory scale prototype
Presenters:
Ali Nabavi Niaki, University of Toronto
Reza Iravani, University of Toronto
Hassan Kojori, Honeywell Advanced Technology

Title: High Efficiency Transformerless MOSFET Inverter for Grid-Tied Photovoltaic System
Abstract: This paper proposes a new high efficiency single phase transformer-less grid-tied photovoltaic (PV) inverter by using MOSFETs as main power switches. The proposed inverter generates zero leakage current, thus safety issues are ensured. PWM dead time is not required for the proposed topology which reduces the distortion of output current. The proposed topology shows the European Union (EU) efficiency more than 98.5% which is greater than commercially available PV inverters. As a conclusion, the proposed inverter is an attractive solution for single phase transformer-less grid-tied PV inverter.
Presenters:
Monirul Islam, University of Malaya
Saad Mekhilef, University of Malaya

Title: Y-Source Impedance Network
Abstract: This paper introduces a Y-shaped impedance network for realizing converters that demand a high voltage gain while using a small duty ratio. To achieve that, the proposed network uses a tightly coupled transformer with three windings, whose obtained gain is presently not matched by existing networks operated at the same duty ratio. This capability has been demonstrated by mathematical derivation for the proposed network in comparison with other recently reported networks. To further prove the network performance, a single-switch dc-dc converter has been implemented with the network, before testing it in simulation and experiment.
Presenters:
Yam Siwakoti, Macquarie University
Poh Chiang Loh, Aalborg University
Frede Blaabjerg, Aalborg University
Graham Town, Macquarie University

Title: Optimal Control of SVC-MERS and Application in SCIG Powered Micro-Grid
Abstract: In squirrel-cage induction generator (SCIG) powered micro-grid, continuously variable reactive power (CVRP) should be provided to stabilize the grid voltage when load is constantly changing. This paper proposes a novel CVRP compensator, which name is static VAR compensation magnetic energy recovery switch (SVC-MERS). Comparing with static compensator (STATCOM), the proposed device has some advantages in line frequency switching, small dc-capacitor and robustness. To begin with, operation principle of SVC-MERS has been briefly described in this paper. Secondly, optimal directvoltage control (ODVC), which aims to broaden the reactive power compensating range, is proposed and verified by simulation in PSIM. It also has the advantages of sinusoidal output-current waveforms and restrains dc-capacitors voltage. Thirdly, a three phase SVC-MERS has been designed with delta connection and applied to voltage stabilization in a 15kW SCIG powered micro-grid. Then experiments have been finished under different load conditions. Finally, experimental results confirm the conclusion.
Presenters:
Yewen Wei, South China University of Technology
Longyun Kang, South China University of Technology
Rujun Qi, South China University of Technology
Maoqin Wen, South China University of Technology
Miao-Miao Cheng, Hunan University

Title: LLC Resonant Converter Using a Planar Transformer with New Core Shape
Abstract: In this paper, a low profile LLC resonant converter with two transformers using a planar core is proposed for a slim switching mode power supply (SMPS). Design procedures, magnetic modeling and voltage gain characteristics on the proposed planar transformer and converter are described in detail. LLC resonant converter including two transformers using a planar core is connected in series at primary and in parallel by the center-tap winding at secondary. Based on the theoretical analysis and simulation results of the voltage gain characteristics, a 300W LLC resonant converter is designed and tested.
Presenters:
Eun-Soo Kim, Jeonju University
Cheol-Ha Kang, Jeonju University
In-Gab Hwang, Jeonju University
Young-Soo Lee, LG Innotek
Dong-Young Huh, LG Innotek

Title: Dynamic Operation and Control of a Stand-Alone PEM Fuel Cell System
Abstract: An energy autonomous system is required to supply power to remote areas or islands. This paper presents a control strategy for a large-scale Proton Exchange Membrane Fuel Cell (PEMFC) system used in a stand-alone application. The studied system consists of the dynamic model of a PEMFC that has been validated with experimental data, a dc/dc boost converter, a dc/ac Voltage-Source Converter (VSC) and various controllers. The voltage and frequency control scheme of the VSC is designed based on feed-forward and decoupling compensation techniques to lessen the impact of the load dynamics. Moreover, the control of the boost converter is developed to mitigate current ripple of the FC. The model was implemented in a MATLAB/Simulink software environment. The obtained simulation results demonstrate the performance of the control system when the system is subjected to various load variations.
Presenters:
Hamid Reza Esmaeilian, Graduate University of Advanced Technology
Roohollah Fadaeinedjad, Graduate University of Advanced Technology
Gerry Moschopoulos, University of Western Ontario

Title: Implementation of a 2-in-1 Transformer Combined with a PFC Inductor and an LLC Transformer for PSUs
Abstract: In this paper, an integrated transformer applicable to PSUs for a 120W LED TV is proposed, which is comprised a PFC inductor and an LLC transformer placed and integrated on E”I”E type magnetic core. In order to evaluate its performance, the values of coupling coefficient of the proposed integrated transformer are observed under the various air gap topologies. It is found from the observation that among topologies, an integrated transformer with centered air gap shows stable operational characteristic with a minimized mutual coupling (interference). Furthermore, applicability of the proposed integrated transformer to PSUs for 120W LED TV is found from the viewpoint of integration of different magnetic components into one core, which leads to light weight, low cost, high power density, and so on.
Presenters:
Cheol-Ha Kang, Jeonju University
Youngjae Noh, Jeonju University
Juil Kwon, Jeonju University
Eun-Soo Kim, Jeonju University
Jong-Seob Won, Jeonju University
Dong-Hee Kim, LG Innotek
Young-Soo Lee, LG Innotek

Title: Performance Improvement of CM/DM Noise Separator with Impedance Matching Approach
Abstract: Noise separators have been wildly used in separating the common mode and differential mode signals in conducted EMI measurements. The high frequency performance of a single phase noise separator is improved in this paper. It is realized by a detailed calculation of the impedance characterization of the transmission line transformer. Then an impedance matching capacitance is added at the output terminal of the transmission line transformer. The main advantages of the proposed method are twofold. On one hand, compared to traditional noise separator, it can acquire better high frequency performance. On the other hand, the principle to obtain the impedance matching capacitance is very simple and easy to implement. The presented simulation results and laboratory tests validate the effectiveness of the proposed method.
Presenters:
Xinli Chang, Xi’an Jiaotong University
Wenjie Chen, Xi’an Jiaotong University
Xu Yang, Xi’an Jiaotong University

Session: D20-Power Electronics II
Track: Power Electronics Applications

Title: Low Power and High Receiving Sensitivity Wireless Wake-Up Receiver with 2-Stage Power-Supply Control Scheme for Lithium-Ion Battery Systems
Abstract: A wireless wake-up receiver for lithium-ion battery systems was developed and evaluated. A 2-stage power-supply control scheme is added to the wake-up receiver for supporting low power, high receiving sensitivity, and short wake-up time simultaneously. The wake-up receiver consumes only 0.3 uA of the power-down current for “32 dBm of the receiving sensitivity with 11 ms of the wake-up time.
Presenters:
Takahide Terada, Hitachi Ltd.
Mutsumi Kikuchi, Hitachi Ltd.
Akihiko Kudo, Hitachi Ltd.
Takanori Yamazoe, Hitachi Ltd.
Takashi Takeuchi, Hitachi Ltd.

Title: Design and Control Strategy for a New Hybrid Energy Storage System
Abstract: A hybrid energy storage system (HESS) consisted of batteries, ultracapacitors (UCs) and bi-directional DC/DC converter is proposed for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The working modes of the proposed HESS are discussed in detail in this paper. Compared with the conventional HESS, the power level of bi-directional DC/DC converter in this HESS design is reduced on the premise that the power demand is fulfilled. Control strategy for the proposed HESS is also presented in this paper. Due to the control strategy, the working mode switches smoothly and the power of batteries is limited within bounds. To verify the proposed system and control method, simulations and experiments are implemented. In the view of results, the effects of the HESS and its control strategy are examined.
Presenters:
Yanzi Wang, Beijing Institute of Technology
Changle Xiang, Beijing Institute of Technology
Sideng Hu, University of Michigan-Dearborn

Title: A Clamping Circuit Parameter Design Method for IGCT Used in High Power Applications
Abstract: IGCT converters seem to be much suited for high power applications than traditional IGBT converters for the reason of higher rated voltage and current. However, in IGCT converters, the snubber and clamping circuit need to be designed because of the particularity of the devices which makes the main circuit design special complex. This paper proposes a parameter design method of IGCT clamping circuit basing on switching process analysis and differential equation of clamp capacitor voltage. Finally, simulation and experiment results validate the correctness of the improved method.
Presenters:
Yue Wang, Xi’an Jiaotong University
Ning Li, Xi’an Jiaotong University
Changsong Zhang, Xi’an Jiaotong University
Wulong Cong, Xi’an Jiaotong University
Wanjun Lei, Xi’an Jiaotong University
Zhao’an Wang, Xi’an Jiaotong University

Title: An LLC-Based Planar Wireless Power Transfer System for Multiple Devices
Abstract: Wireless power transfer (WPT) has become a popular idea in battery charging for both low- and high-power applications, such as cellphones and electric vehicles (EV). This paper proposes a universal WPT system for multiple electronic devices. An additional inductance is added on the primary LC circuit to make the system less sensitive to load variations while keeping a stable charging voltage. Multiple parallel-connected primary coils provide free-positioning charging for loads. A simple yet effective variable-frequency control algorithm is used to keep maximum and balanced charging power. Simulation results demonstrate the practicability for the system ” high-efficiency, stable working frequency, simple control, as well as maximum and independent charging of each load. A prototype has been built for further tests.
Presenters:
Nan Liu, Mitsubishi Electric Research Laboratories
Bingnan Wang, Mitsubishi Electric Research Laboratories

Title: Thermal Design Optimization of a High-Efficiency Resonant Converter Based on Multi-MOSFET Cells Using the Pareto Analysis
Abstract: Induction heating technology provides high performance and efficient systems that are being quickly adopted in industrial and domestic applications. This paper is focused on the efficiency and power density optimization of the resonant converters used to generate the required magnetic field. A thermal and electrical model is provided, and a Pareto analysis is proposed to optimize the design. As a conclusion, an optimized converter is obtained, outperforming current state-of-the-art induction heating converters.
Presenters:
Oscar Lucía, Universidad de Zaragoza
Hector Sarnago, Universidad de Zaragoza
Fernando Betés, Universidad de Zaragoza
José Miguel Burdío, Universidad de Zaragoza

Title: A Protection Scheme Against DC Faults VSC Based DC Systems with Bus Capacitors
Abstract: This paper describe a novel protection method to limit the fault currents caused by short circuit in a voltage source converter (VSC) based DC systems with capacitors connected to the DC bus. Analyzing the development of DC fault current in such DC systems shows that capacitor discharge dominates the very rapid fault current rising at the instance of faults. If this high slope fault current surge is not limited, stored energy in the capacitor will cause hazard to personals as well as connected equipment. If the discharging current from the DC bus capacitor is not limited, it will require much higher break capability of the DC breakers. Therefore a novel protection method is proposed to limit the DC fault currents by detecting and interrupting the DC capacitor discharge using a solid state circuit breaker (capacitor SSCB) which is connected in series with the DC bus capacitor. Implementing this new method will effectively reduce peak value of the fault current, alleviate current stress of diodes in VSC bridges, in a way that only local current information is required. It needs no external control signals, and power loss of this capacitor SSCB is relatively low.
Presenters:
Chang Peng, North Carolina State University
Alex Huang, North Carolina State University

Title: Design and Desmonstration of a 3.6kV-120V/10KVA Solid State Transformer for Smart Grid Application
Abstract: This paper presents the system design and performance demonstration of a 3.6KV-120V/10KVA solid state transformer lab prototype, which works as the energy router in the smart grid system. Firstly, the hardware design of the system is detailed in the paper. In addition, the advanced control system is developed to achieve high performance of SST. Lastly, several tests are conducted to verify the following advanced features of the solid state transformer: (1) Var compensation; (2) Voltage regulation; (3) Source voltage sag operation; (4) Microgrid integration.
Presenters:
Xu She, North Carolina State University
Xunwei Yu, North Carolina State University
Fei Wang, North Carolina State University
Alex Huang, North Carolina State University

Title: High Efficiency Data Center Power Supply Using Wide Band Gap Power Devices
Abstract: Energy efficiency of typical data centers is less than 50% where more than half of the power is consumed during power conversion, distribution, cooling, etc. In this paper, a combination of two approaches to improve power supply efficiency is implemented and experimentally verified. One approach uses high voltage DC architecture, designed to reduce distribution loss and remove unnecessary power conversion stages. The other approach employs wide band gap (WBG) power devices, including silicon carbide (SiC) and gallium nitride (GaN), which helps to increase converter efficiency and power density. Scaled down prototypes of all power conversion stages in the data center power supply chain are designed, built, and tested. The advantages of utilizing WBG power devices are illustrated through analysis and experiments.
Presenters:
Yutian Cui, University of Tennessee
Fan Xu, University of Tennessee
Weimin Zhang, University of Tennessee
Ben Guo, University of Tennessee
Leon M. Tolbert, University of Tennessee
Fred Wang, University of Tennessee
Benjamin J. Blalock, University of Tennessee
Luke Jenkins, Auburn University
Christopher Wilson, Auburn University
Jeffrey Aggas, Auburn University
Benjamin Rhea, Auburn University
Justin Moses, Auburn University
Robert Dean, Auburn University

Title: Determining the Physical Size of Inductive Couplers for IPT EV Systems
Abstract: Electric Vehicles (EVs) are fast becoming attractive alternatives to conventional vehicles. Inductive power transfer (IPT) is a method that can transfer power to EVs over an air-gap, without physical contact. They can dramatically increase the range, convenience and safety of EV charging. However, determining the physical sizes of the IPT couplers is difficult due to the variation in vehicle classes and charging locations. This paper seeks to determine if suitably sized couplers can be selected which can realize all these demands. A recently proposed EV charging coupler, known as the Double-D (DD), is selected. A method to select the best design from 8 approximately square DD couplers ranging from 300mm to 1000mm in length is presented. A practical design example is presented and possible primary and secondary coupler sizes to charge an EV sedan at 10kW for realistic horizontal misalignments and air-gaps are presented.
Presenters:
Ganesh Nagendra, University of Auckland
Grant Covic, University of Auckland
John Boys, University of Auckland

Title: Load-Voltage-Based Single-Sensor MPPT Controller for Multi-Channel PV Systems
Abstract: The paper presents a Maximum Power Point Tracking (MPPT) controller for a multi-channel (N-Channel) Photovoltaic (PV) solar system which requires only one voltage sensor and no current sensors. The N-channel Load Voltage Single-Sensor MPPT (LV-SS-MPPT) controller is able to track the MPP of each solar panel using only one output voltage value in the N-channels and is able to provide a very good tradeoff between size, cost, and tracking speed. Compared to a conventional N-channel MPPT system which requires N voltage sensors, N current sensors, 2N ADCs (or an ADC with 2N channels) and N MPPT controllers along with the associated conditioning circuitries, the proposed method only requires one voltage sensor, one ADC and one MPPT controller and is able to converge closer to the maximum lower power point of the load when the channels of the system are subject to non-uniform and/or mismatching conditions.
Presenters:
Jaber Abu Qahouq, University of Alabama
Yuncong Jiang, University of Alabama
Wangxin Huang, University of Alabama

Title: An Enhanced Energy Harvesting Method Based on Resonant Current Transformer for High Voltage AC Cable Monitoring Equipment
Abstract: In this paper, an enhanced energy harvesting method based on current transformer in resonant state is proposed. In this method, a resonant capacitor is adopted to resonate with the equivalent magnetizing inductor of the current transformer. Therefore the reactive power on the inductor is compensated, thus the power harvested from the power cable is dramatically increased. Furthermore, the lower side diodes of the conventional rectifier are superseded by fully controllable switches. With the proposed control scheme and PI compensation, the output voltage can be regulated when the primary side current varies in a wide range.
Presenters:
Zhibo Wang, Zhejiang University
Jin Du, Zhejiang University
Rui Wang, Zhejiang University
Wuhao Huang, Zhejiang Provincial Electric Power Company of State Grid
Wei Hu, Zhejiang Provincial Electric Power Company of State Grid
Jiande Wu, Zhejiang University
Yufei Dong, Zhejiang University
Xiangning He, Zhejiang University

Title: Direct 400 V to 1 V Converter for Data Center Power Supplies Using GaN FETs
Abstract: High voltage DC (400 V) power supply architecture is becoming a standard in today’s data center power supply [1]. To further convert from 400 V to 1 V, usually several power stages are connected in series. Therefore, even if the efficiency of each power stage is high; the overall system efficiency is limited. In this paper, a single power stage system which converts 400 V to 1 V directly and performs as the high voltage point of load (HV POL) is proposed. A multi-phase interleaved full bridge phase shift (FBPS) pulse width modulation (PWM) DC/DC converter with input series and output parallel (ISOP) connection is selected as the power stage topology. Proper devices and passive components are selected in order to achieve high efficiency. An adaptive voltage positioning (AVP) controller is designed and implemented in the circuit. Simulation work shows that the proposed system can meet the steady and dynamic performance requirement.
Presenters:
Yutian Cui, University of Tennessee
Weimin Zhang, University of Tennessee
Leon Tolbert, University of Tennessee
Fred Wang, University of Tennessee
Benjamin J. Blalock, University of Tennessee

Title: A Novel Method for Modeling of DC Micro-Grid Based on Characteristic Parameter
Abstract: The characteristic parameters of micro-grid determine its transient response and stability. Due to uncertain load changes as well as large-scale intermittent energy accesses, the micro-grid systems are always subjected to large number of random disturbances which results in micro-grid structure parameters change. To solve this problem, this paper presents a novel model for characteristic parameters calculation of DC micro-grid. The derived model is based on real-time measurement of the transient current which quickly and accurately calculates the characteristic parameters change. A controller is designed using the derived model and simulation is carried out to verify the derived model.
Presenters:
Minghua Zhu, Xi’an Jiaotong University
Chen Li, Xi’an Jiaotong University
Jingyu Huang, Xi’an Jiaotong University
Fang Zhuo, Xi’an Jiaotong University
Liansong Xiong, Xi’an Jiaotong University
Baoquan Liu, Xi’an Jiaotong University
Hailong Zhang, Xuji Group

Title: Overvoltage Protection Scheme for Three-Phase Current Source Converter Built with SiC MOSFETs
Abstract: The overvoltage caused by dc-link inductor current interruption is a serious problem in the current source converters. It becomes even tougher when the fast-switching SiC MOSFETs are applied as switches. This paper proposes two novel overvoltage protection schemes constituted by a diode bridge and series transient-voltage-suppression (TVS) diodes. It can detect and clamp the overvoltage within less than 50 ns .
Presenters:
Ben Guo, University of Tennessee
Fan Xu, University of Tennessee
Fred Wang, University of Tennessee
Leon M. Tolbert, University of Tennessee
Benjamin J. Blalock, University of Tennessee

Title: Experimental Validation of the Steady State and Transient Behavior of a Transformerless Intelligent Power Substation
Abstract: TIPS is a 3-phase SST to interconnect 13.8 kV, 3-phase distribution grid with 480 V, 3-phase utility grid. The concept of TIPS was proposed as a solid state alternative to the conventional line frequency transformer. Various advantages of TIPS include unity power factor operation, controlled bi-directional power flow capability, reactive power compensation to improve grid voltage profile under necessary conditions, high frequency d.c link based isolation, small size and weight due to Silicon Carbide (SiC) devices, and renewable energy integration. This paper focuses on the integration and hardware demonstration of the functionalities of TIPS.
Presenters:
Sachin Madhusoodhanan, North Carolina State University
Awneesh Tripathi, North Carolina State University
Arun Kadavelugu, North Carolina State University
Samir Hazra, North Carolina State University
Dhaval Patel, North Carolina State University
Krishna Mainali, North Carolina State University
Subhashish Bhattacharya, North Carolina State University
Kamalesh Hatua, Indian Institute of Technology Madras

Title: Medium Voltage Power Distribution Architecture with Medium Frequency Isolation Transformer for Data Centers
Abstract: A medium-voltage (MV) data center power distribution system (DC-PDS) architecture using medium-frequency (MF) link transformer isolation is introduced. First the MV transformed from the utility, is interfaced with a MV switch gear system and a diesel power generator (DPG) system. Then this MV is converted to the low voltages (LVs) required by the loads via MF transformer. The MF transformer primary side windings are connected to stacked AC-AC converters. The LV secondary windings are interfaced with several load systems and battery energy storage system (BESS) using different topologies like boost PFC, PWM inverter, etc. The presence of MV switch gear and MF transformer in the architecture results in higher efficiency and power density. The approach also contributes to a reduction in PVC or copper used in conventional DC-PDS.
Presenters:
Bahaa Hafez, Texas A&M University
Harish Krishnamoorthy, Texas A&M University
Prasad Enjeti, Texas A&M University
Shehab Ahmed, Texas A&M University at Qatar
Ira Pitel, Magna-Power Electronics, Inc.

Title: Minimization of Power Loss and Harmonic Distortion in Grid-Tied Cascaded Multilevel Inverters
Abstract: This paper presents the application of a multi-objective optimization method to minimize two conflicting features, power loss and total harmonic distortion, of grid-tied PWM-based cascaded multilevel inverter. These features are similarly important, thus requiring a compromise because of inherent conflict between them. One major challenge is that these features cannot be expressed simply by mathematical formulas due to nonlinear behaviors of PWM-based inverters. In this paper, a modified normalized boundary intersection (NBI) method is applied as the chosen solution, providing an effective approach in converting a multi-objective optimization problem to one objective. A grid-tied cascaded 11-level inverter has been simulated and results are presented to confirm validity of the suggested technique.
Presenters:
Fariba Fateh, Kansas State University
Don Gruenbacher, Kansas State University

Title: A Solid State Variable Capacitor with Minimum DC Capacitance
Abstract: A new solid state variable capacitor (SSVC) with minimum dc capacitance is proposed. A variable ac capacitor (with capacitance variable from 0 to Cac) is traditionally implemented by an H-bridge inverter and a large electrolytic dc capacitor with capacitance of 20 times the ac capacitance value, Cac to absorb the 2w dc ripple. The proposed SSVC consists of an H-bridge and an additional phase leg connected to an ac capacitor with fixed capacitance, Cac and can reduce the dc capacitance to the minimum just for absorbing switching ripples. The fixed ac capacitor controlled by the additional phase leg absorbs the 2w component and theoretically can eliminate 2w ripples to the dc capacitor completely. Therefore, no electrolytic capacitors would be needed. Theoretical analysis of the SSVC is provided. Simulation and experimental results are shown to prove the effectiveness of the proposed SSVC with minimum dc capacitance.
Presenters:
Sisheng Liang, Michigan State University
Xi Lu, Michigan State University
Runruo Chen, Michigan State University
Yang Liu, Michigan State University
Shao Zhang, Michigan State University
Fang Zheng Peng, Michigan State University

Session: D21-Critical Packaging Topics for Power
Track: Packaging and Material Science

Title: Operating Parameter Based Wirebond Model for a Power Module
Abstract: Most of the lifetime models for semiconductor modules are empirical in nature, and do not take all the operating parameters into account. There is a need to develop a generalized lifetime model specific to failure mechanisms that account for all the operating parameters in an application. This paper proposes an operating parameters (current, temperature, dimensions of the wire) dependent lifetime prediction model based on the electrothermomechanical physics of operation of the IGBT based module. Finite element simulation results to study the dependence of individual parameters on the stress are presented. The overall dependence of the parameters on stress will be presented in the final paper.
Presenters:
Lakshmi Reddy Gopireddy, University of Tennessee
Leon M. Tolbert, University of Tennessee
Burak Ozpineci, Oak Ridge Natinal Laboratory

Title: Performace Comparison of Thermal Interface Materials for Power Electronics Applications
Abstract: One important challenge in power electronics design is removing the heat cost effectively from the power devices mounted on thermal vias on a printed circuited board (PCB). Thermal vias is a cluster of small diameter hole plated with copper and is used to transfer the heat from one side of the PCB where the power device is soldered to the other side which is generally mounted on a heat sink using a thermal interface material (TIM). To minimize the contact resistance and provide electrical insulation between the PCB and heat sink, TIMs are used to fill the air gaps and are an essential part of an assembly when solid surfaces are attached together. This paper presents a detailed comparison of the properties of various off-the-shelf available TIMs to be specifically used between PCB with thermal vias and heat sink. Experimental results will also be presented to determine the thermal performance as well as the dielectric strength of various TIMs being studied.
Presenters:
Deepak Gautam, Delta-Q Technologies Corp.
Dale Wager, Delta-Q Technologies Corp.
Murray Edington, Delta-Q Technologies Corp.
Fariborz Musavi, Delta-Q Technologies Corp.