S.1    Power Electronics for Alternative Energy

Jih-Sheng Lai, Virginia Tech

Raymond Hudson, Xantrex

Philip Krein, University of Illinois

This seminar is intended as a technical overview of power electronics challenges in the context of alternative energy resources. Many such resources have fundamental characteristics in common. Fuel cells and photovoltaic (PV) cells deliver low-voltage dc that requires careful control of power draw. This must be processed and delivered to a grid-interactive inverter. Many wind and microturbine devices deliver variable frequency ac that is rectified for delivery to a grid-interactive inverter, although a few larger wind systems use wound-rotor induction machines to reduce inverter ratings. This seminar covers fundamental source characteristics, circuit topologies, control techniques, and overall architecture of the power electronics for the most widely discussed sources. Interconnection standards, regulatory compliance, and essential grid-tie control techniques are discussed. Grid-tie control issues, particularly synchronization, proportional-resonant control, admittance compensation, and reactive power aspects will be discussed. The intended audience includes power electronics engineers interested in the architecture and operation of alternative energy systems. Participants should have a general understanding of typical inverter circuits.

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S.2     Ripple Regulator Review

Richard Redl, ELFI S.A.

The hysteretic ripple regulator has been around for a long time, but its inherent limitations (poorly defined switching frequency, imperfect dc regulation) relegated it to low-cost fringe applications. Recently developed variations are free from those limitations, and have become widely popular in portable power and computer VRM applications, due to their simplicity, fast transient response, and, for some types, a switching frequency that is proportional to the load current in DCM (important in applications where high efficiency should be maintained over a wide load range). This seminar presents a comprehensive review of the ripple regulators. The first part discusses the basic types (hysteretic, constant-off-time, constant-on-time, and constant-frequency versions), including the schematic and waveforms, switching frequency, dc regulation, and stability. The second part discusses how to increase the PWM ramp, reduce the noise sensitivity, and stabilize the switching frequency. The third part is devoted to the topic of improving the dc regulation by introducing a high-dc-gain amplifier in the feedback loop. Four different approaches will be covered. The fourth part addresses modeling and stability issues. The seminar concludes with a short discussion of miscellaneous topics (voltage positioning, multiphase operation, application of the ripple-regulator concept in topologies other than the buck converter). The seminar is targeted toward an audience with intermediate background in the topic.

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S.3.     Practical Soft Switching Power Converter Design

Ernest H. Wittenbreder, Jr., Technical Witts, Inc.

Transistor switching losses create an effective upper limit to both conversion efficiency and power density, particularly for off line power supplies. Soft switching offers a solution, but the practical reality is that these circuits are more complex and come with a whole new set of design issues specific to soft switching circuits. Achievement of the full benefits of soft switching circuits requires an understanding of the critical timing issues of these circuits and practical methods for designing auxiliary circuits that are necessary to accomplish soft switching. This seminar concentrates on circuits that have primarily square wave voltages and currents, rather than circuits with sinusoidal wave forms. Mostly these circuits are similar to well known hard switching circuits, but with circuit mechanisms in place to accomplish lossless switching over a broad range of line and load. A variety of practical soft switching circuits and the problems and practical solutions associated with these circuits are described. The differences in the design optimization processes for hard switching and soft switching converters are described. Well known and proven soft switching topologies are described as well as some new topologies which offer significant improvements over the more commonly known topologies. This seminar is significant now as energy efficiency legal mandates have been recently established, since soft switching is one of the most effective methods for achieving higher efficiency in off line power supplies. This seminar is intended for intermediate and advanced level power supply engineers who want a better understanding of the practical tradeoffs and design issues associated with soft switching circuits.

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S.4.     Digital Control of Power Converters

Mohammed Arefeen, Texas Instruments Inc.

As power converters evolve with advanced features, system designers are relying more and more on advanced digital controllers and the extensive suite of power electronics 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 is 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 power converter design engineers. In addition, for many, the transition from closing various control loops in analog fashion to a completely digital manner is not as straight forward as the hoped for. In order to close loops digitally, one needs to understand the implications of PWM resolution, the accuracy of analog to digital conversion, sampling requirements and finally how to implement digital PID and/or similar blocks. The goal of this seminar is to go through every step necessary to build a digital power converter. The seminar will provide general examples which can be applied to wide range digital controllers. The seminar will highlight the major topics of a digital implementation by discussing implementation of a DC/DC converter. The attendants of this seminar will gain in depth knowledge about the following topics:

1. What is a digital power converter? – Comparing with an analog implementation.
2. What to look for while selecting a digital controller.
3. How to obtain maximum accuracy from a fixed point controller instead of using floating point device.
4. How to relate PWM operation and digital sampling to avoid limit cycling.
5. Resolution is not everything - How to measure the true performance of an analog to digital converter.
6. The tricks to obtain maximum benefit from “C” code without device cycle penalties.
7. Complete system examples showing PID implementations, and DC/DC converter implementation.

This seminar is targeted for system software and hardware engineers with intermediate to advanced experience.

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S.5.     Advanced Packaging Techniques for Power Electronics Circuits

Douglas C. Hopkins, University at Buffalo

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 derivatives. Advanced electro-physical design integrates several traditional packaging techniques, such as directbond-copper, FR-4 and IMS into a single system. Recently, advanced materials, such as conductive epoxies and adhesives, allow unique positioning of components to increase density and improve thermal management. New organic systems are being introduced for flexible, thin circuits. Finally, the use of SiC has fostered significant development in approaches that offer high temperature operation, or extended reliability at traditional temperatures. An update is given on lead-free soldering issues. Recent results in electro- and thermo-migration testing will show the impact on reliability, and how new design rules are needed. Finally, significant time will be given to Aluminum-based circuit design, such as with direct-bonded-aluminum, aluminum PWBs and composites (AlSiC), to show advantages of using “ near mono-material” metallurgical hierarchies to greatly increase reliability and provide higher temperature packaging of devices, e.g. SiC diodes and transistors. The material is presented from electrical, thermal and physical perspectives. Attendance at previous APEC Packaging Seminars, or similar, is assumed.

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S.6.     Understanding and Using the PMBus™ Protocol

Robert V. White, Artesyn Technologies

The open-standard PMBus™ digital power management protocol has become very popular with more than 30 adopters including large OEMs like Dell and Intel. By providing a consistent way for host systems to communicate with power converters of all types, both suppliers and OEMs benefit. Suppliers can now develop one power management interface solution and be confident that it will be accepted by most of their customers. For the OEMs, a standard power management interface means that they need only develop their system power management firmware once for use with any number of supplier offerings. And with a standard interface available and in use, the IC companies can now invest in developing integrated solutions that can be used by many customers. These benefits to suppliers, OEMs and IC companies are the drivers for the widespread acceptance of PMBus. This seminar will provide an overview of the PMBus protocol somewhere between the introductory and intermediate level. The seminar starts with the basic of PMBus – what it is, what it is not, PMBus signals, and how those signals are connected in a typical system. The next part of the seminar examines the PMBus transport layer – how the bytes and bytes are moved from a sending device to a specified receiving device. This includes a look at the SMBus, used for the basic transport, packet structure, the protocol for reading and writing commands and data over the bus, and the ALERT interrupt protocol. Before looking at the PMBus command set, the seminar will look at two fundamental topics. The first is the canonical model of memory in a PMBus device and how it is managed at startup to assure consistent and proper operation. The other topic is the data formats used in the PMBus protocol. The PMBus offers two data formats – one that puts the conversion burden on the host device and one that puts the conversion burden on the PMBus device. It is important to understand these two formats and how to choose the one best for a given system. The seminar then starts working its way through the PMBus command set. The commands for on/off control, setting and adjusting the output voltage, monitoring status and fault management will be treated with some depth. Additional commands, such as those related to fan management, will be presented briefly.

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S.7.    Fuel Cell Systems for Transportation and Stationary Power Generation

Kaushik Rajashekara, Rolls-Royce Corporation

With the requirements for reducing emissions and improving fuel economy, the automotive companies are developing electric, hybrid, and fuel cell vehicles. Fuel cell based vehicles are already in the demonstration phase. Fuel cells are also being considered for on-board power generation in automobiles, trucks, airplanes, and ships. The use of high temperature fuel cells for stationary power generation is getting increasing importance for distributed power generation and for stand-alone power systems. Power electronics and control systems are enabling technologies for the advancement of fuel cell based systems. In this seminar, the different fuel cell technologies are examined for transportation and power generation applications. The operating strategies of fuel cell vehicles with the associated power electronics and control architectures will be explained. The power conversion strategies and the functions of the power electronics sub-systems and their requirements will also be discussed. The hybrid fuel cell system consisting of SOFC and Gas turbine systems with the associated power conversion and control strategies will be discussed. The FeedomCar and SECA programs and the targets for the fuel cell based systems will be presented. The status of fuel cell systems and the future strategies will be presented.

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S.8.    Application Characteristics of High Power IGBT Modules

John F. Donlon, Eric R. Motto, Nicholas Clark, Powerex, Inc.

Information provided on IGBT module data sheets varies considerably between manufacturers and can leave the designer with many questions regarding device selection. Issues the designer must deal with include interpretation of device ratings, gate drive requirements, and providing device and system protection. The intent of this seminar is to aid the designer in applying an IGBT to a new product. Questions and concerns a designer might have will be addressed by the various techniques and circuit examples that will be presented. IGBT chip technology and device packaging options will also be discussed. The attendee should leave the course with a better understanding of the IGBT, both specifically as a device and how it functions in an application. The goal will be to impart an understanding of the desirable features, characteristics, and limitations of the IGBT. This will include the application of IGBTs in power circuits, protecting the IGBT from internal and external disturbances, and an understanding of thermal design and handling considerations. The seminar is intended for design engineers new to IGBTs as the main switch in power conversion equipment as well as refresher for the experienced designer with questions about confusing or conflicting information on the data sheets from various manufacturers. It should also be of interest to those who use, apply, procure, or specify power electronic products based on the IGBT as the power switch.

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S.9.    Application-Driven Design and Control of Brushless Permanent Magnet Motors

Mehdi Abolhassani, Black and Decker Corp.

The increasing rate of depletion of fossil energy resources on one hand and growing energy cost and demand on the other hand has initiated considerable research activities worldwide to explore means for tapping into high efficiency motor/drive technologies. Replacing DC machines and induction machines with permanent magnet (PM) machines has recently gained great interest in appliance, automotive, medical, aerospace and military industries. The advent of high quality, high coercivity, high energy product (40 MGO), and high temperature grade (1800 C) NdFeB permanent magnet material is the driving force behind the wide-spread use of PM motors in one industrial sector after another. Permanent magnet excitation is current-free and lossless, enabling PM motors to rank as the motor with highest efficiency and power density (kW/kg) as compared to other electric motors. Despite crystal advantages, some large industries, while being rather conservative and inclined to cling to technologies that seem to have worked in the past, have had rather slow gain in wide acceptance of PM motors. One of the major contributing factors is the fact that adopting PM motors in industrial driven applications that demand their own unique requirements, needs its special design rules and control methods that are far less well developed and limited in their availability compared to those for DC and induction motors. Recognizing this situation, this tutorial has been organized to address the state-of-the-art of application-oriented practical key issues in the areas of design, analysis, and drive control methods of PM machines. In this tutorial, design requirements and analysis approaches of combined motor and drive systems in a wide variety of applications in home appliances, automotive, aerospace, and industry use have been carefully developed, and practical and manufacturing issues are discussed. Also, practical implementation of digital control methods of sensored and sensoreless variable speed PM motor drives are offered. It is believed that this represents a special opportunity for engineers in industry and academia to receive a comprehensive review of the application oriented design rules and control methods of these intriguing PM brushless motors and drive systems.

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S.10.  Rapid Prototyping of Digital Controls for Power Electronic Equipment:  Methodologies and Tools

Antonello Monti, Roger Dougal, University of South Carolina

The use of rapid prototyping and auto-coding is becoming a standard practice in design of digital controls for power electronics. A variety of commercial tools support the process. This seminar will first present a methodological overview of rapid prototyping and its implications in the design of digital control systems, and then it will provide an unbiased review of some available tools and compare the pros and cons of them. Finally, the seminar will introduce a set of simple rules for adopting an auto-coding process at very low cost. The seminar is designed for people with industrial experience in the design of digital control systems at the intermediate level.

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S.11.  EMI:  Theory, Coupling Mechanisms, Equivalent Circuits, and Solutions

Michael J. Schutten, GE Global Research Center

This seminar is intended as a comprehensive introduction for engineers wishing to obtain a fundamental understanding of EMI issues, and experienced engineers with a desire for a thorough understanding of electromagnetic interference (EMI) issues. This seminar introduces the concept of electromagnetic energy coupling between electronic circuits. The fundamentals of EMI are presented including terminology, energy transfer mechanisms, equivalent circuits, and EMI circuit fixes. The seminar provides several examples of how one electronic circuit has the ability to corrupt or damage a different circuit. The characteristics and electrical symptoms of the four methods of EMI energy transfer are presented: Common impedance coupling, magnetic field coupling, electric field coupling, and radiation coupling. Simple methods for approximating the equivalent circuit and low cost solutions at the board or component level are provided. PWB layout and IC decoupling procedures are derived from fundamental EMI concepts. Videotaped experiments demonstrate fundamental EMI coupling techniques and electrical fixes.

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S.12.  Higher Efficiency Power Conversion Through Intelligent Power Processing

Ionel Dan Jitaru, Delta Energy Systems

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.

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S.13.  Power Electronics in Battery Applications:  Safety, Monitoring, and Extending Battery Runtime

Jinrong Qian, Yevgen Barsukov, Dave Heacock, Texas Instruments

Power Electronics has played a very important role in battery applications. Battery management continues to be a significant issue for a wide range of portable devices. “How can I make the system run longer and safer with the battery?” has plagued designers and users. This seminar addresses the issues surrounding battery power management and how power electronics improves battery safety and extends the battery runtime. The first part of the presentation provides the battery electrical behavior, charging and discharging characteristics, cycle life, and all kinds of safety protections including over-charging, over temperature, over-current and short circuit in battery packs. It also includes the battery UL testing, battery failure mechanisms, and IEEE standards. The second part of the presentation is focused on how to achieve fast charging from USB, reviews relationships between the charge voltage, charge current and cycle life, battery charging system architecture, interaction between system and charger for Li-Ion batteries. Dynamic Path Management (DPM) technology is going to be presented to maximize use of the AC adapter power while charging the battery and supplying the system simultaneously. Practical switching mode chargers and their control integrated circuits (ICs) are going to be presented for portable devices. The third part is focused on how to monitor the battery remaining capacity for extending battery run time. We are going to review the most commonly used monitoring approaches: coulomb counting, voltage measurement based and impedance track based fuel gauges. System side fuel gauge along with the design challenges will be discussed in detail. The fourth part of the seminar will talk about how to select topology for achieving 3.3V from a Li-Ion battery and compare the battery runtime for different solutions. Then we will present a high efficiency 6 MHz integrated DC-DC buck converter for smallest size solution and lowest input voltage (down to 0.5V) boost converter for fully using the energy from the battery. High integration power management ICs (PMICs) are also discussed for further minimizing the total solution size and improving system efficiency for extending the battery runtime. The last session is to talk about the battery chemistry development trends for meeting the challenge in power hungry portable power equipment applications. Different chemistry Li-Ion batteries and their characteristics are going to be discussed. This seminar is structured to provide in-depth coverage of the topics of the power electronics in battery powered applications, and is intended for the audience from entry level to intermediate experience level.

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S.14.  Modeling and Analysis of Pulse-Width Modulation

Jian Sun, Rensselaer Polytechnic Institute

Pulse-width modulation (PWM) is at the center of every control method in power electronics. Its design affects almost all aspects of converter operation, from steady-state and dynamic control performance to EMI and thermal. The basic principles of commonly used PWM methods have been well established and easy to understand. Yet achieving optimal performance in terms of control, power quality, and EMI requires in-depth understanding of the modulation process and its spectral and dynamic characteristics, which is mathematically much more involved due to the highly nonlinear nature of the PWM process. This seminar provides a systematic and in-depth treatment of various PWM methods. It targets practicing engineers and researchers who want to develop an in-depth understanding of different modulation processes and to master the necessary modeling and analysis tools. To that end, a double Fourier series method will be introduced first as a general analytical tool for analyzing PWM signals. The method is then used to characterize different PWM methods and provide insights for several commonly observed phenomena such as harmonic cancellation under double-edge modulation and time-variant behavior beyond half the switching frequency. Additional topics that will be treated in detail include 1) small-signal modeling of both constant- and variable-frequency modulators and the limitation of the models as well as the effects of interleaving; 2) harmonic injected and space vector modulation for three-phase converters, and 3) interleaving of three-phase PWM converters and their relationship to multilevel converters.

 

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S.15.  Power Electronics System Thermal Design

Roger P. Stout, ON Semiconductor

This three-part, half-day seminar is designed for entry- to mid-level electronics system engineers who are reasonably comfortable with Microsoft® Excel. The first part will introduce the overall approach to semiconductor device thermal characterization. Pitfalls in the use and misuse of typically published semiconductor device thermal data will be discussed. The second part will focus on the principle of linear superposition as applied to thermal system design. The goal is to provide the attendee with sufficient understanding to construct and use relatively simple spreadsheet-based tools in real-life system thermal designs. In the process, the following points will be covered: how to correctly utilize published thermal data in a system level thermal model; how to predict actual operating temperatures of the significant power devices; how to predict the operating temperatures of low power but temperature sensitive devices; how this approach may be used in conjunction with more sophisticated thermal analysis tools. The third section will be an in-depth presentation of a specific and highly non-linear thermal failure mechanism, thermal runaway; whence it arises and how it may be analyzed. The focus will be within the particular context of power semiconductor devices, but it should also become evident how the concept may be applied more generally.

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S.16.  Digital Power Control - Beyond the Acceptance Stage:  Achieving Maximum Benefits

Kris Dehnel, Oleg Volfson, Zilker Labs

Emerging digital power conversion technologies offer numerous advantages through their implementations. However, it has to be understood that certain paradigm changes are required on both sides of the power conversion “divide” between power designers and users of power on the system side to let this technology provide the maximum benefits to users. Among the promises that digital control in power converter design offers are: the reduction in component count, wider acceptable components’ tolerance limits, ability to easily and on-the-fly optimize a standard converter module for operation in a specific socket, reduction in cost, and adding value to the power converter. To fully utilize these advantages of digital technology, changes in attitude towards design procedures are required from both power and system designers. New boundaries on who is the “owner” of various features of a converter have to be drawn (and often redrawn) between the power designer, test engineer and system designer. This seminar is concentrating on the practical aspects and features of a digitally controlled power converter and the design, production test, and logistical support steps that allow system’s cost reduction, maximum flexibility, and the best performance that current technologies can offer. The target audience is power supply and system designers with an intermediate to advanced level of understanding of power conversion.

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S.17.  EMI Reduction for Power Electronics Systems

Shuo Wang, Virgina Tech

The seminar will introduce the theory and practice for the generation and reduction of EMI in power electronics systems. The advances in EMI noise suppression and EMI filter design will be addressed in detail. The seminar material starts from the basics to the advanced techniques in EMI reduction. It is designed for the audience starting from entry to advanced level. The seminar will cover the following topics:

1. Fundamentals of EMI for power electronics systems
2. Effects of parasitic parameters in power electronics systems on EMI
3. Methods of EMI suppressions for power electronics systems
4. High performance EMI filter design with parasitic parameters control
5. EMI cancellation techniques
6. Topics in EMI measurement

The seminar would be very valuable to power electronics engineers, students in Universities as well as the researchers in EMI areas.

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S.18.  Creating Value in the Power Electronics Industry

Marshall Miles, Power Perceptions

The foundation of any business is its ability to create value for its customers. This seminar explores the various strategies and requirements for creating value within the power electronics industry and for doing it in a way that produces a sustainable competitive advantage. An overview of key market dynamics and trends is presented with an eye towards the problems this will create for your potential customers. It is in the anticipation and resolution of these problems that there exists the opportunity to create value. This seminar will also address how to define value-creating products, how to link research and development efforts to the value creation strategy through the use of roadmapping, and strategies for creating non-product value. The seminar is intended for those involved in product definition, R&D, sales or marketing as well as anyone with input into the organization’s strategic planning process.

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