Professional Education Seminars

APEC 2005 features 18 professional education seminars with a broad range of topics. The conference committee has worked hard to make sure there is something of interest to all APEC attendees during each of the seminar time periods. As always, APEC seminars offer a practical mix of theory and application for the professional working in power electronics. Unlike other conferences that charge by the seminar, at APEC one low fee gains you access to any and all of the seminars, along with the notes for every seminar. Whether you want to review an important topic area, broaden your understanding of a neighboring discipline, or take advantage of the practical experience of experts in the field, the APEC 2005 seminars are a must for every conference attendee.

Please note that the room assignments are tentative and subject to change. Please check with the registration desk at the conference for the latest information.

PROFESSIONAL EDUCATION SEMINARS

Chuck Mullett, ON Semiconductor

Governor's Ballroom, Salon A

This presentation is designed for those who deal with power supplies, rather than those who are highly experienced designers. It is appropriate for entry-level engineers in power supply design as well as those associated with them, such as sellers, buyers, evaluators and specifiers. Using the desktop computer power supply as an example, it conducts a tour through the entire ac-to-dc power supply, beginning at the input and ending at the several outputs used in today's personal computers. It also includes an overview of the electrical specifications and the relevant safety and EMI standards.

Included in the course is a short discussion of each of the key components used in modern power supplies---resistors, capacitors, inductors, transformers, FETs, diodes and optocouplers. This is followed by an overview of the most popular circuit topologies and a very short course on magnetics to aid in the understanding of the tradeoffs in magnetic components, a major cost driver in switched-mode power supplies. The course also addresses the use of power factor correction (PFC) circuits to reduce the input current harmonics in compliance with standards for the worldwide markets.
Each of the major power supply circuits is explained, including the input filters, power converter and output regulator circuits. Photos of the inside of the power supply are included, with identification of all of the key components. Actual voltage and current waveforms enhance the understanding of today's modern power supplies.

Jian Sun, Rensselaer Polytechnic Institute

Governor's Ballroom, Salon B

This seminar introduces advanced modeling, analysis, control, and design techniques for single phase power-factor-correction (PFC) converters. It is designed to bring advanced theories and the latest development in these areas to practicing engineers who have some basic knowledge of PFC technologies. It will help the attendees to develop an in-depth understanding of the fundamentals, and provide them with advanced analytical tools and methods for practical development.

The seminar will first review the basics of single-phase power factor correction using boost and boost-derived topologies. Double averaging is then introduced as a systematic reduced-order modeling method for single-phase PFC converters, and design of both the input current loop and the output voltage loop using appropriate models is discussed.

The seminar then provides an in-depth treatment of the input current crossover distortion issue, identifying all major sources of such distortion and quantifying their effects using analytical methods. Advanced circuits and control techniques for reducing current crossover distortion will be introduced. Recently developed input current feedforward control and digital control techniques will also be covered. Additionally, the tutorial will present input impedance models of boost PFC converters and discuss their applications in input filter design as well as in analysis and mitigation of undesirable converter-source interactions.

John Donlon, Eric Motto and William Kephart, Powerex

Governor's Ballroom, Salon E

Information provided on IGBT module data sheets varies considerably between manufacturers and leaves the designer with some questions regarding the selection of devices. 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 product and generally towards an application. The seminar's goal is 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.

James Kokernak, Advanced Energy Conversion

Governor's Ballroom, Salon D

Power electronics is an enabling technology that is fundamental to the deployment of distributed generation systems. As such, distributed generation represents a significant market opportunity for power electronics professionals. This seminar provides an introduction to distributed generation and its reliance on power electronics. A pragmatic approach is offered that considers the various types of resources that are considered to fall within distributed generation, followed by consideration of the regulatory requirements on the power converters. With this as background, system design features and architectures are discussed to give attendees with a solid introduction into the field.

Richard Redl, ELFI and Gabor Reizik, Analog Devices

Room 406

The buck converter is the most widely used dc-dc converter topology in power management and microprocessor voltage-regulator (VRM) applications. Those applications require fast load and line transient responses and high efficiency over a wide load current range. This seminar reviews advanced control techniques aimed at speeding up the transient responses and increasing the light-load efficiencies without adversely affecting the efficiency at full load. Three topics are covered:

1. Fast regulation of the output voltage using either a fast feedback loop (i.e. without a voltage-error amplifier), the combination of fast and slow feedback loops, or some type of power-equalizing control,
2. Voltage positioning solutions for VRM applications, and
3. Control techniques which ensure high efficiency over a wide load current range.

A section of the seminar is devoted to a novel switched noise filter concept that overcomes one of the disadvantages of the fast feedback loop, namely unwanted response to noise picked up from nearby converters and other sources of electromagnetic interference.

The seminar is targeted toward an audience with intermediate background in the topic.

Babak Fahimi, University of Texas at Arlington and Steve Pekarek, Purdue University

Room 408

Adjustable speed motor drives play a crucial role in technology advancement for a variety of industries. This has motivated researchers around the world to pay special attention to engineer a quieter, more efficient, and more productive adjustable speed motor drive. Although significant advances have been made towards this goal, lack of an in-depth understanding of the electromechanical energy conversion at a microscopic level has impeded the quest for a quantum leap in enhancement of the performance. The proposed seminar offers a new perspective to the above problem by offering a microscopic point of view under which new excitation schemes for adjustable speed motor drives are extracted. The topics include control solutions for elimination of torque pulsation, mitigation of radial forces/pulsation of the radial forces, and optimization of torque density. Experimental results from a low cost torque ripple minimization for PMSM drives will be demonstrated. Furthermore, special attention has been given to magnetic interpretation of field orientation in adjustable speed ac drives from a microscopic point of view. The proposed seminar provides an insightful and in-depth understanding of advanced energy conversion for practicing engineers in industry and graduate students who conduct research in the area of adjustable speed motor drives.

Conor Quinn, Artesyn Technologies; Collon Lee, Emerson/Astec Power; Richard Garvey, Texas Instruments and Greg Miller, Intersil

Governor's Ballroom, Salon A

This seminar presents the basic issues in choosing, applying, and designing POL converters for on-board power systems. A unique feature of this seminar is that there are four speakers, two from power supply companies, and two from semiconductor companies. This will expose the audience to a much wider range of experience, knowledge and opinion than normally available in a seminar.

The first portion of the seminar introduces the modern POL converter, its components and basic operation and finishes with a discussion of the key decision points of the "make versus buy" decision. The second portion of the seminar covers the basic issues of using POL converters: layout and voltage regulation, EMI, thermal management and protection against fault conditions.

The second half of the seminar gives an introduction to designing a POL converter. The basics of component selection and converter stability are presented. Three different design examples of increasing complexity are presented to introduce the audience to the basic choices and tradeoffs.

The seminar concludes with a brief wrap-up and question and answer period for the audience. This seminar is intended for board or system designers charged with implementing POL converters but who are not necessarily experienced power supply designers. The level of the material is application focused and at an introductory to intermediate level.

Michael Schutten, GE Global Research Center

Governor's Ballroom, Salon B

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. Several videotaped experiments demonstrate fundamental EMI coupling techniques and electrical fixes.

Dan Jitaru, Delta Energy Systems

Governor's Ballroom, Salon E

The seminar will present a comprehensive overview of the integrated and quasi-integrated magnetic concepts and implementations. In the quest for higher power densities and higher efficiency integrated magnetic structures have become more popular. There will be presented many forms of integrated magnetic in close correlation with converter topologies. Included are several structures wherein the transformer and the storage elements are placed on the same magnetic core, forming the traditional integrated magnetic with emphasis on the latest trends. Also presented will be structures wherein two independent power trains are placed on the same standard magnetic core and structures wherein the main transformer and a signal transformer are sharing the same magnetic core without interference. The focus for the integrated magnetic will be for low profile or planar magnetic structures. Ripple steering in new applications will be also presented. There will be presented the advantages of different forms of magnetic integration in very high current and low voltage application.

The seminar will also show some present and future trends in magnetic integration and new forms of planar magnetics. The presentation will be highlighted with design guidance, design example and experimental results.

Laszlo Balogh and David Figoli, Texas Instruments

Governor's Ballroom, Salon D

The quest for increased integration, more features and added flexibility is under constant cost pressure, and continually motivates the exploration for new avenues in power management. One area gaining significant attention is the application of digital technology to power supply control techniques. Several topics will be discussed, including defining digital power design, interface between digital and analog components, determining key metrics for choosing an appropriate microcontroller or DSP to meet required performance when working with a sampled data system and realizing the importance of the development environment and software. Special focus will be on similarities and differences between analog and digital implementations of basic power supply control functions.

Initial discussions will include benefits, limitations, cost and performance of a digital power design. A second area of focus will be on interface techniques that simplify the task of control feedback. Finally, the presenters will suggest guidelines for selecting the microcontroller or DSP that provide the resources to implement a digitally controlled power supply with considerations to CPU utilization, interrupt overhead and MIPS flexibility. Presentation will also include examples that demonstrate configuration, supervision and full digital loop control.

Prabjit Singh, IBM Corporation

Room 406

Converters with resonant elements are, in general, complex and difficult to understand and analyze. Solving them using the conventional approach involving differential equations is tedious. Even if successful, the conventional mathematical approach often lacks the physical insight essential for converter design. State-plane analysis allows the graphical representation of the behavior of converters containing resonant elements. It provides both the physical insight and the ability to quantitatively analyze converters, without resorting to complex mathematical operations.

The basis of state-plane analysis will be introduced. It will be shown how the technique handles the resonant sub-intervals, during which a converter can be reduced to a simple circuit containing at most a resonant network inductor and capacitor, a constant voltage and a constant current source. The theoretical basis for the representation of a resonant sub-interval time-domain behavior as a circular trajectory on a normalized current versus normalized voltage plot will be explained. Output characteristics will be shown to be quite readily derived from trigonometric manipulations of the state-plane trajectory.

Three simple examples of the application of state-plane analysis to converter design will be presented. In the first example, the peak voltage across a flyback MOSFET will be derived; the second example will deal with the qualitative understanding of the behavior of a single switch forward converter with active clamp, and the third example will deal with the quantitative derivation of the output characteristics of a zero-voltage switching quasi-square-wave converter.

Ned Mohan, University of Minnesota

Room 408

The objective of this seminar is two-fold. The first-half will begin with basics and analyze induction and permanent-magnet ac machines in a way that clearly explains how these machines operate on a physical basis, and hence how they ought to be controlled for optimum performance. The second-half of this seminar will examine the basis of vector control and encoder-less operation of ac machines in order to design speed and position controllers for such machines.

This approach is very simple such that entry-level practicing engineers can easily comprehend it. It provides a new way to look at electric drives and their control, thus it should be beneficial to intermediate and advance-level audience.

Bob White, Artesyn Technologies

Governor's Ballroom, Salon A

Digital control, today's hot topic, actually has two aspects. One is the real-time, cycle-by-cycle control of the switching in a power converter. The other aspect is non-real-time system management. The system management of digital control has been around for many years and is growing in popularity. This seminar, containing all new material, reviews the fundamentals of digital power system management for the entry-level to intermediate power system user or designer.

The first part of the seminar addresses the basics of the "what" of digital power system management. The discussion starts with understanding what one wants to manage in a power system and proceeds to understanding the flow of information in the power system.

The second part of the seminar talks about the "how." The elements of a protocol are introduced along with an overview of existing protocols for power system management.

The third part of the seminar examines the details of the "what," taking a more in-depth look at issues like addressing, data integrity, and transport. It also looks at the various possible controls, configuration and status information in some detail.

Ernest Wittenbreder, Technical Witts

Governor's Ballroom, Salon B

The purpose of this course is to provide the power supply design engineer with a better understanding of the scientific and engineering principles of EMI generation, coupling mechanisms, EMI avoidance, and EMI reduction techniques and to provide the engineer with very specific information that he can use to accomplish low noise power supply designs. Circuit synthesis methods that can be used to form new power supply topologies with much improved EMC from standard well known topologies will be presented. An exhaustive review of the many typical EMI problem areas is provided and proven methods are described to avoid those problem areas. PWB layout techniques and techniques applicable to construction, component design, circuit and component placement, shielding, and snubbing will be presented. The attendee will learn about EMI filter design and EMI filter component and interface issues. This course will be a benefit to all power supply design engineers regardless of their level of experience and ability.

Ed Bloom, e/j Bloom Associates

Governor's Ballroom, Salon E

Power magnetics continue to be the major contributors to the cost and packaging difficulties of modern power conversion systems. Because of this situation, power supply designers are now turning to three new construction techniques for power magnetics. These techniques are planar, integrated (IM) and planar integrated (PIM) designs for both power transformer and power inductor components. Planar, or flat, construction methods for magnetics are those employing low-height ferrite core structures with windings often implemented in various printed-circuit formats. Planar construction approaches have many electrical advantages over conventional "hard-wired" techniques. In addition to improved performance, the simplicity of their construction allows them to be built and assembled in a cost-and-time-effective manner without the need for highly skilled labor or special winding equipment. Integrated (IM) designs are those that blend power transformer and power inductive functions together on a single magnetic core. PIM designs are simply IM constructions employing planar approaches for windings and low-profile magnetic cores. This seminar is intended to provide basic design information for the practicing power electronics engineer on the developmental aspects of planar and integrated power magnetic components. Topics to be covered include general guidelines for core selection and winding designs. Advances in PIM constructions will also be presented.

Art Brockschmidt, Boeing Phantom Works

Room 406

Anyone can search the net and assemble a thousand pages of 'failure analysis' literature in a few minutes -- finding straightforward practical examples and direct experience for power electronics is difficult. Failures range from development test failures to long-term reliability concerns. Power electronic hardware failures can be spectacular, are often costly, or cascade to other hardware. This seminar provides both the novice and the experienced designer with analytical techniques, case histories, and check lists to prevent and resolve failures. An overview of troubleshooting techniques and a checklist of what can zap your power electronics is provided. The seminar structure allows any particular issue to be discussed in detail. The designer controls internally generated transients, but not the external environment. This seminar summarizes external threats. Component drift requires a worst-case analysis to assure long-term reliability, and worst-case analysis techniques are included. The presentation of case histories is the author's preferred tool for transferring knowledge. In addition to presenting 15 specific case histories, sharing of "horror stories" by attendees will be encouraged. An extensive reference list is included. Using analytical tools such as PSpice is covered, while the use of mathematics is held to a minimum.

R. David Middlebrook, California Institute of Technology

Governor's Ballroom, Salon D

Feedback systems are usually designed with the familiar single-loop block diagram in mind. Various non-idealities, such as unavoidable minor loops and direct forward transmission, make the single-loop block diagram progressively less useful, especially at higher frequencies.

The general feedback theorem (GFT) defines a "natural" block diagram model that is identical in format to the single-loop model that is conventionally assumed, thus providing a desirable link between general feedback theory and a detailed circuit diagram analyzed in terms of factored pole-zero transfer functions.

The GFT is illustrated on a potentially unstable Darlington emitter/source follower stage, and leads to design criteria that limit the maximum peaking regardless of the value of the load capacitance.

Another example is a two-stage feedback amplifier having various non-idealities, including loading interactions at all points, direct forward transmission, and two minor loops.

The GFT is computer friendly, and emphasis is on the numerical and graphical results obtained by use of an Intusoft ICAP/4 circuit simulator.

John M. Miller, J-N-J Miller

Room 408

This seminar takes an in-depth look at the most widely applied hybrid electric vehicle powertrain - the power split electronic CVT. CVT, or continuously variable transmissions in their purely mechanical implementations have been applied for many years in automotive products owing to their seamless matching of vehicle speed to engine characteristics without need for clutches or gear shifting. However, the main disadvantage of the mechanical CVT is that is not capable of high torque transmission nor of efficient torque transfer at ratio coverage of six to one or higher. The electronic CVT, e-CVT for short, circumvents this major disadvantage by doing away with mechanical belts and sheaves and of toroids and rollers. To realize electronic CVT functionality the e-CVT relies on a pair of electronically controlled electric machines and a power split device to achieve seamless, clutch free and no step ratio gear shifting to match vehicle speed with engine speed characteristics. This course presents the essentials of power split technology as it is currently being applied in the Toyota PRIUS gasoline-electric hybrid as well as the GM-Allison compound split. Sizing the electric machines and their attendant power inverters for use as engine starter-generator (input side) and main motor-generator (output side) are discussed along with system dynamics and state equations for each mode of operation. Power split, e-CVT, transmissions have five or more modes of operation, each of which will be discussed in depth including derivation of the modeling equations and application to simulation using Ansoft Simplorer. The participants will gain fundamental knowledge of how mechanical power flows through the device while electric power circulates between the pair of electric machines and electrical energy storage, ESS, system via dedicated power inverters. State-of-charge of the ESS is modeled and simulated as the vehicle executes a standard drive cycle to illustrate the complex electrical and mechanical interactions of power split. Participants will have acquired the knowledge to more fully appreciate the methodology of designing, modeling and simulation of hybrid electric propulsion systems at the drive train and vehicle level. Practical examples will be presented.