Website Comments
Correction or comment
on apec-conf.org?
|
|
|
Home  Conference at a Glance Rap Sessions
|
Professional Education Seminars |
|
|
|
|
S.1 Feedforward Control of Switching Regulators
Richard Redl, ELFI, S.A.
Feedforward control is a conceptually simple, highly effective and extremely robust, but not very well known or appreciated, technique for improving the transient responses of switching regulators to both input-voltage and load-current perturbations and for stabilizing the loop gain or the switching frequency.
This seminar presents a comprehensive overview of feedforward control. The first part discusses small signal input-voltage feedforward in the basic dc-dc converters, both with voltage-mode and current mode control. The second part discusses small-signal load-current feed forward for the same converters. The third part discusses the extension of the feedforward concept to large perturbations in the input voltage and/or load current and introduces several power-equalizing control techniques. The fourth part discusses feedforward pulse-width modulators (both constant-frequency and variable-frequency). The fifth part is devoted to miscellaneous practical topics (feedforward stabilization of the switching frequency, implementing input voltage feed forward in isolated converters with secondary-side control, feedforward to the input of the error amplifier). The seminar is targeted toward an audience with intermediate background in the topic.
Back to Top
S.2 Microcontrollers for Power Supply Engineers
Robert V. White, Artesyn Technologies
Microcontrollers and other programmable digital devices are becoming common in power supply design. Although not often used for the real time PWM loop, they are very useful for housekeeping, protection, data logging and communication. In server power supplies, using a microcontroller for functions like startup sequencing, over temperature protection, and fan speed control can save 100 discrete parts. Aside from the material cost, this is a significant savings in manufacturing cost and a significant reduction in calculated failure rate. For many power supplies engineers the world of microcontrollers is an unknown. Just finding the starting point can be difficult. This seminar provides just such an introduction – a roadmap to the world of microcontrollers and programmable devices. The overall goal is provide the attendee with the basic knowledge of the tools and processes needed for developing microcontroller based circuits and systems. The first part of the seminar acquaints the attendee with the various types of devices and their principal characteristics. Microcontrollers, microprocessors, digital signal processors (DSPs), digital signal controllers (DSCs), programmable logic devices (PLDs), and field programmable gate arrays (FPGAs) will be compared and contrasted. Some of the more popular microcontroller families such as the 8051, Atmel AVR and Microchip PIC will be given a closer look. The goal is for the attendee to be able to choose the appropriate device for their project. The goal of the second part is to enable the attendee to choose the appropriate software and is for their project. The discussion starts with a look at programming in assembly takes to write, test, and debug the code and to move the code into the microcontroller. This includes an introduction to the key programming tools – assemblers, linkers, compilers, Make programs, and integrated development environments (IDEs). Once the program is written, it must be debugged. Tools like simulators, debuggers, and emulators will be presented. In addition, the program must be loaded into the microcontroller. Both external and in-circuit programmers will be described. The third part of the seminar looks at common functional blocks in microcontrollers and how they can be used in power supply design. First, oscillators, without which no microcontroller can work, are reviewed. Next, timers and interrupts are discussed. Then functions like PWM outputs, A/D and D/A converters, comparators and other linear devices are presented. The last part of this section is a discussion of communication interfaces such as UARTS, I²C, and SPI. This seminar is introductory in nature and no previous experience with microcontrollers or programming is needed.
Back to Top
S.3. EMI Causes, Measurements, and Reduction Techniques for Switch-Mode Power Converters
Michael Schutten, GE Global Research
This seminar is intended as a comprehensive introduction for engineers wishing to obtain a fundamental understanding of EMI issues associated with switch-mode power converters, and experienced engineers desiring a detailed understanding of electromagnetic interference (EMI) causes and fixes for power converters. The seminar begins with an introduction to noise coupling mechanisms and their properties. The concept of impedance mismatch is presented as a basis for understanding filtering concepts. Differential-mode (DM) and common-mode (CM) separation and filtering approaches are derived, and measurement and separation techniques presented. DM & CM measurement and EMI reduction techniques are presented for an experimental flyback converter. Converter layout techniques and principles are derived, and experimentally verified. The seminar provides an emphasis on how DM and CM currents are created in power converters, and layout and construction techniques to minimize the need for costly filtering. Several practical EMI reduction techniques and construction methods are provided throughout the presentation.
Back to Top
S.4. Understanding Derating-Reliability-Risk Connection
Sabin Lupan, International Rectifier
With stress on product quality and longer life cycle, reliability concepts and practices are gaining momentum. And engineers and designers are realizing that failure rates are no longer related to electrical or thermal stress alone, but to an interplay of hardware, software/logic and transmission media. And derating is no longer a panacea to reliability improvement but only one element in a systemic approach to product quality in a broad sense. The decisions we make span a continuum of risk tacking that can result in anywhere from annoyance to monetary and time loss to loss of lives and civilizations (remember Trinity). This seminar is crafted to help engineers understand and apply reliability concepts during the product life cycle. And identify the stakeholders with their contributions and interaction across boundaries. It is developed at conceptual level around issues (what?) motives (why?) methods (how?) responsibilities/stakeholders (who?) and time frames ( when?). Aimed at practicing engineers with some experience, the seminar is divided into 3 parts with each for over an hour. The first part starts with a review of terms and definitions to establish a common ground of understanding. And presents a brief historical review on the development of various reliability and related concepts. It sheds light on the famous “bath tub” diagram and illustrates the three time zones, each with its specific distribution, issues and stakeholders. The second part focuses on the product’s life cycle stages, each with its issues and stakeholders. Various stages discussed here include design Design/Prototype/Test, Procurement/Incoming inspection, Production, Useful life and Disposal. It will explore derating and its impact on reliability. And show how the designer can balance the reliability allocation among the various parts of the system and use tools to minimize components variance (stronger average part) and minimize stress. As each stakeholder contributes to product reliability in the new ecosystem, the last section will examine the stakeholders Risk-Benefit equation, including perceived risk versus perceived benefit. Also, as the trend is toward soft world, most products favor a mix of hardware and software. This section will investigate the pros and cons of hardware/software allocation.
Back to Top
S.5. Permanent Magnet Machines: Design, Modeling, and Control
David Torrey, Advanced Energy Conversion
Permanent magnet (PM) machines are the machine of choice in an ever‐expanding list of applications. This seminar will examine the issues associated with the design, modeling, and control of PM machines. Both surface magnet and embedded magnet machines will be discussed. Both axial and radial machine topologies will be discussed. The seminar is broken down into two sections. The first section focuses on the internal details of PM machines. This begins with a review of electromechanical energy conversion principles, leading into a description of machine geometry, topologies, winding design, and general design objectives. The second section focuses on achieving the desired performance from PM machines when excited through an inverter. Elements from the first section are reinforced as terminal descriptions are connected with the underlying electromechanics, leading to PM machine models from which control laws can be derived.
Back to Top
S.6. Hybrid Power Converters
Christian Klumpner, University of Nottingham
Nowadays, most of the power electronic equipment is based on well established power converter topologies, which are classified based on their operating mode (voltage source, current source, Z-source, resonant etc), on the way they are controlled (phase shift control, Pulse width modulation, Pulse amplitude modulation, Hysteresis control etc), number of levels in the output voltage/current waveform etc. The term “hybrid power converters” which emerged lately in research, normally refers to a power converter structure based on a combination/arrangement of two (or more) different types of power converters that operate/behave differently but overall provide additional advantages or cancel each other drawbacks within the hybrid arrangement. As the power level processed by the component converters is different, the one that would process the bulk of the power would be referred as the “main” power converter, while the other one(s), as “auxiliary”. The objectives of this tutorial are to introduce the hybrid concept, to explore how a few relevant hybrid arrangements are implemented and controlled and what potential benefits may be achieved. The pool of hybrid power electronic converters will consist of seven hybrid arrangements, as detailed in the following proposed structure section.
Back to Top
S.7. Stability Analysis and Loop Control in Switching Power Supplies
Christophe Basso, ON Semiconductor
Switch Mode Power Supplies are widely used in nowadays equipments, ranging from a few tens of watts in consumer applications to several hundred of watts and above in industrial applications. Despite the various architectures found in this field, they all share the need for a control circuit that maintains one or several delivered variables within a defined range. Because of extreme time pressure on their shoulders, engineers do not often take the necessary time to understand and analyze the constraints brought by the design of a robust control loop. Targeting practicing engineers and graduating students, this seminar describes how to efficiently compensate a power converter whether it is operated from a dc or an ac source. The seminar starts by teaching how to optimally select the cross over frequency and the phase margin in relationship with your design specifications. Then, the presentation shows how poles and zeros must be placed depending on the kind of transient response you expect. Using Mathcad® and SPICE, the author maintains a permanent link between what theory dictates and what the market reality is. In particular, the compensation schemes are first described with an operational amplifier and then further modified to cope with a TL431. The seminar balances analytical aspects and real case examples to show how to design a stable power supply. It targets an audience with an intermediate background in the presented subject.
Back to Top
S.8. Maximizing the Effect of Modern Low Voltage Power MOSFETs
Lutz Gorgens, Infineon
This seminar presents strategies for optimizing switched mode power converters in general with a focus on AC/DC SMPS and DC/DC converters. The seminar gives a in depth analysis on the causes for losses and how they can be optimized. The trade-of between loss-generation and ringing in the system is analyzed and strategies for optimization are presented. Simple models for calculating power losses in converters are derived, that allow the estimation of power losses based on datasheet values. These models are based on the concepts of inductively limited switching and MOSFET controlled switching, which present the two extreme versions of the switching process and are explained in detail in the seminar. Comparisons between simulation and measurements are used to highlight typical application conditions. The simple models allow immediate practical use for designing power converters. The optimization strategies target devicerelated effects, i.e. impact of package on electrical and thermal performance, as well as concept and layout related effects, i.e. parasitic inductance and resistance, placing of passive and active components. The seminar provides the basic information for entry level designers, as well as the details that help experts optimizing the efficiency with the latest generations of power MOSFETs.
Back to Top
S.9. Advanced Thermal Management Materials for Power Electronics
Carl Zweben, Consultant
This course provides an in-depth discussion of the increasing number of ultrahighthermal-conductivity materials that address key packaging problems: heat dissipation and thermal stresses, warping, which arise from differences in coefficient of thermal expansion (CTE). Topics include material properties, manufacturing processes, applications, cost, lessons learned, and future directions, including carbon nanotubes.Traditional materials are included for reference. There are now many low-CTE, low-density materials with thermal conductivities ranging between that of copper (400 W/m-K) and 1700 W/m-K. Thermally conductive carbon fibers allow heat removal from the bottom, as well as the top of a chip, expanding the range of convection cooling. The fibers also can tailor substrate and printed circuit board (PCB) CTE, potentially eliminating the need for underfill. Carbon nanotubes and fibers can greatly increase thermal interface material thermal conductivity. Low-CTEsolders under development will provide additional advantages. Advanced materials are being used in an increasing number of commercial and aerospace microelectronic and optoelectronic applications, including servers, laptops,phased array antennas, telecommunication equipment, laser diodes, solid state lighting, plasma displays, liquid crystal displays, etc. For example, low-CTE diamond particle reinforced SiC heat spreaders having a thermal conductivity of over 600 W/m-K were used in IBM servers.
Back to Top
S.10. Energy Efficiency Specifications and Standards Activity for Power Supplies
Arnold Alderman, Anagenesis
Back to Top
S.11. EMI: Design Path for a Typical Digital Motor Control Project
Arefeen Mohammed, Texas Instruments
As motor drives evolve with advanced features like advanced algorithms, position sensorless operations, multiple axis control using a single controller etc, motor drive designers are relying more and more on advanced digital controllers and the extensive suite of motor-control focused hardware and software solutions to help them get their designs to market faster with more customized features, and better performance. A hurdle often faced by system developers working with a digital controller knowing how and where to get started both from software and hardware point of view. A good example system that illustrates the software and hardware configurations can be invaluable for any motor drive design engineer. The goal of this seminar is to go through every design step necessary for a successful project implementing a digital controller based motor drive. The discussion topics will also address how to integrate test routines for various standards like IEC-60730 compliance. The seminar will provide general examples which can be applied to wide range digital controllers. The attendants of this seminar will gain in depth knowledge about the following topics 1. The benefits of a digital controller in a motor drive system. 2. How to create modular software strategy for the ease of system implementation. 3. How to obtain maximum accuracy from a fixed point controller instead of using floating point device. 4. The tricks to obtain maximum benefit from “C” code without device cycle penalties 5. How to use incremental system build process to minimize system “bugs”. 6. Integrating test routines for regulatory standard compliance. 7. Complete drive system example. This seminar is targeted for system software and hardware engineers with intermediate to advanced experience.
Back to Top
S.12. Analysis and Comparison of Voltage-Mode PWM, Current-Mode PWM, Hysteretic, Constant-On Time, and Constant-Off Time DC-DC Converters
Chunping Song, National Semiconductor
In power electronics field, there are mainly 5 different kinds of DC-DC converters, which are voltage-mode PWM, current-mode PWM, hysteretic, constant-on time, and constant-off time DC-DC converters. With so many options, have you ever been in confusion about which one to choose for your end applications? To clarify this confusion, in this seminar, the performances of these five kinds of DC-DC converters are thoroughly analyzed and compared. With the performance analysis, you will understand the topology, operation, small signal model, stability requirement, load and line transient response, and DC regulation accuracy of each kind of these converters. With the performance comparison, you will understand the pros and cons of each kind of these converters, and will be in better position to choose the right kind of DC-DC converter for your end applications. The topic will be treated in-depth. And the levels of the intended audience includes intermediate and advanced.
Back to Top
S.13. Multiphase Voltage Regulator Control and Design Considerations
Wenkai Wu, Texas Instruments
Multiphase voltage regulators have been widely used to power modern electronics. The presentation provides the designer with the knowledge necessary to effectively design multiphase regulator for the latest generation CPU and DDR applications, which are facing increasingly stringent design requirements. The seminar will discuss the tradeoffs of selecting efficiency, density and cost. It will describe control architecture selection, system tolerance specification, PWM modulators and techniques for improving transient performance. It will introduce the designers to the output impedance oriented designer procedure, techniques for dynamic phase shedding, coupled inductor implementation, selection of discrete solution or integrated solution. The seminar is intended for engineers with entry to intermediate level knowledge of multiphase converter control and design, although specialists will benefit from some insights.
Back to Top
S.14. Control and Modeling of DC-DC Converters
Ray Ridley, Ridley Engineering
This seminar will present an in-depth discussion of the many issues involved in controlling converters. Many aspects of the design of control systems will be covered, including topologies, modes of operation, passive components, compensation, optocouplers and filters. Live demonstrations will be presented of loop gain and impedance measurements on working converters and power stage components. The course is recommended to all levels of engineers who work with switching power supplies at power levels from less than 1 W to 100 kW.
S.15. Integrated Packaging Techniques
Doug Hopkins, University at Buffalo
Advanced electro-physical design integrates several packaging techniques so as to optimally combine electrical design and thermal management into a highly reliable mechanical structure, be it at the board or box levels. In this seminar power-packaging approaches, such as COF, MID, FR-4, LTCC, IMS, DBC, MMC, are characterized in a continuum to help the electrical circuit designer understand how they can be combined with the electrical circuit for optimal thermal management and mechanical reliability. Introduced this year are developing packaging techniques used in microelectronics that can evolve for use in power electronics. Examples include organic materials to augment typical metal-based techniques and the use of flexible systems such as cooper-on-Kapton® and low temperature cofirable ceramics. These give the designer alternatives to densify their circuits. This seminar targets the experienced power electronics designer who must integrate physical design into their circuits to increase reliability and density. The seminar focuses on leading and next-generation advanced packaging techniques applicable to lighting, supplies, drives and their derivatives. Several special topics will be elaborated on including modern design with bus bars and an in-depth view of reliability concerns associated with high electrical current densities and thermal gradients in solders. The material is presented from electrical, thermal and physical perspectives.
Back to Top
S.16. New Trends in Power Conversion Technologies
Dan Jitaru, Delta Corporate Services
The seminar will present a comprehensive overview of the latest techniques aimed at maximizing the efficiency. The first part will focus on the topology selection, wherein new topology structures will be presented. The latest topologies are developed as a result of the latest changes in the system architecture and the availability of digital control. A special section will be dedicated to the rectification techniques and “intelligent” rectification for low and high voltage application. Another section it is dedicated to the new magnetic structures for efficiency optimization. The magnetic section will be presented together with the latest packaging technologies which play a critical role in efficiency optimization through the minimization of the parasitic elements in the circuit and heat management. The last section it is dedicated to the digital control and digital assisted power conversion for efficiency optimization. This new section underlines the future of power conversion using “intelligent” power processing for efficiency optimization. The presentation will be highlighted with design guidance, design example and experimental results.
Back to Top
S.17. Hybrid Electric and Plug-In Hybrid Electric Vehicles
Alireza Khaligh, Illinois Institute of Technology
As world continues to rely more and more upon vehicular transportation, the looming problems of fuel supply and air pollution become more imminent. The internal combustion engine (ICE) has long been the mechanism that propels our vehicles, and gasoline has been its major source of energy. This fuel supply is dwindling and researchers are looking for new sources of energy. Demands for higher fuel economy, performance, reliability, and reduced emissions push the automotive industry to seek advanced technologies such as electrification of ancillaries and engine augmentations. An immediate solution to this problem is essential, and the most promising answer lies in hybrid electric and plug-in hybrid electric vehicle (HEV and PHEV) technologies. The proposed long-term sustainable solution includes (1) integrating the transportation industry with the electric power industry, (2) using electricity as the carrier, and (3) generating electricity from renewable energy sources. In this presentation, different HEV and PHEV configurations will be presented with a focus on engineering fundamentals as well as state-of-the-art research and development in the components and system integration. In addition, it is focused on drive train configurations and presents a review of conversion strategies to hybridize different vehicles. The level of the intended audience: Intermediate
S.18. Switched Capacitors Converters
Sam Ben-Yaakov, Ben-Gurion University of the Negev
Switched-Capacitor Converters (SCC) are preferred over inductor based switch-mode regulators in low power applications that call for small size, or if the electromagnetic field radiated from the switched inductor may pose a problem. However, SCC suffer from a fundamental power loss deficiency that makes their use in some applications prohibitive. Losses can be reduced by applying soft switched SCC topologies that include an inductor. Another approach that has been recently investigated is SSC topologies with binary resolution that produce many "target voltages" of close proximity. This new SCC class is based on the properties of a novel Extended Binary (EXB) number representation. This seminar includes a comprehensive overview of present switched capacitor converters technology, covering both "hard switched" and "soft switched" configurations followed by in-depth analysis and modeling of the causes of power losses. The review addresses step up, step down and inverting topologies as well as regulation methods. Finally, the concept and features of the new EXB sequences will be presented, backed by simulation and experimental results, and the rules for translating these sequences into SCC topologies will be detailed. The seminar is of intermediate level, intended for users and designers of switched capacitor converters.
|
|
|
|
|
|
