Resonant Power Converters E-Book

Marian K. Kazimierczuk

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 647

Veröffentlichungsjahr: 2012

Beschreibung

This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them with a number of easy-to-use tools for the analysis and design of resonant power circuits. Resonant power conversion technology is now a very hot area and in the center of the renewable energy and energy harvesting technologies.

Leseprobe

Contents

Cover

Half Title page

Title page

Copyright page

Dedication

Preface

About the Authors

List of Symbols

Chapter 1: Introduction

1.1 References

Part I: Rectifiers

Chapter 2: Class D Current-Driven Rectifiers

2.1 Introduction

2.2 Assumptions

2.3 Class D Half-Wave Rectifier

2.4 Class D Transformer Center-Tapped Rectifier

2.5 Class D Bridge Rectifier

2.6 Effects of Equivalent Series Resistance and Equivalent Series Inductance

2.7 Synchronous Rectifiers

2.8 Summary

2.9 References

2.10 Review Questions

2.11 Problems

Chapter 3: Class D Voltage-Driven Rectifiers

3.1 Introduction

3.2 Assumptions

3.3 Class D Half-Wave Rectifier

3.4 Class D Transformer Center-Tapped Rectifier

3.5 Class D Bridge Rectifier

3.6 Synchronous Rectifiers

3.7 Summary

3.8 References

3.9 Review Questions

3.10 Problems

Chapter 4: Class E Low dv/dt Rectifiers

4.1 Introduction

4.2 Low dv/dt Rectifier with a Parallel Capacitor

4.3 Resonant Low dv/dt Rectifier

4.4 Summary

4.5 References

4.6 Review Questions

4.7 Problems

Chapter 5: Class E Low di/dt Rectifiers

5.1 Introduction

5.2 Low di/dt Rectifier With A Parallel Inductor

5.3 Low di/dt Rectifier With A Series Inductor

5.4 Summary

5.5 References

5.6 Review Questions

5.7 Problems

Part II: Inverters

Chapter 6: Class D Series-Resonant Inverter

6.1 Introduction

6.2 Circuit Description

6.3 Principle of Operation

6.4 Topologies of Class D Voltage-Source Inverters

6.5 Analysis

6.6 Voltage Transfer Function

6.7 Efficiency

6.8 Design Example

6.9 Class D Full-Bridge Series-Resonant Inverter

6.10 Relationships Among Inverters and Rectifiers

6.11 Summary

6.12 References

6.13 Review Questions

6.14 Problems

Chapter 7: Class D Parallel-Resonant Inverter

7.1 Introduction

7.2 Principle of Operation

7.3 Analysis

7.4 Short-Circuit and Open-Circuit Operation

7.5 Electronic Ballast for Fluorescent Lamps

7.6 Design Example

7.7 Full-Bridge Parallel-Resonant Inverter

7.8 Summary

7.9 References

7.10 Review Questions

7.11 Problems

Chapter 8: Class D Series-Parallel-Resonant Inverter

8.1 Introduction

8.2 Principle of Operation

8.3 Analysis

8.4 Design Example

8.5 Full-Bridge Series-Parallel-Resonant Inverter

8.6 Summary

8.7 References

8.8 Review Questions

8.9 Problems

Chapter 9: Class D CLL Resonant Inverter

9.1 Introduction

9.2 Principle of Operation

9.3 Analysis

9.4 Design Example

9.5 Full-Bridge CLL Resonant Inverter

9.6 Summary

9.7 References

9.8 Review Questions

9.9 Problems

Chapter 10: Class D Current-Source-Resonant Inverter

10.1 Introduction

10.2 Principle of Operation

10.3 Analysis of The Parallel-Resonant Circuit

10.4 Analysis of The Inverter

10.5 Design Example

10.6 Summary

10.7 References

10.8 Review Questions

10.9 Problems

Chapter 11: Phase-Controlled Resonant Inverters

11.1 Introduction

11.2 Phase-Controlled Current-Source Inverters

11.3 Phase-Controlled Voltage-Source Inverters

11.4 Single-Capacitor Phase-Controlled Series-Resonant Inverter

11.5 Design Example

11.6 Summary

11.7 References

11.8 Review Questions

11.9 Problems

Chapter 12: Class E Zero-Voltage-Switching Resonant Inverter

12.1 Introduction

12.2 Principle of Operation

12.3 Analysis

12.5 Efficiency

12.6 Matching Resonant Circuits

12.7 Design Example

12.8 Push-Pull Class E ZVS Inverter

12.9 Summary

12.10 References

12.11 Review Questions

12.12 Problems

Chapter 13: Class E Zero-Current-Switching Resonant Inverter

13.1 Introduction

13.2 Circuit Description

13.3 Principle of Operation

13.4 Analysis

13.5 Power Relationships

13.6 Element Values of Load Network

13.7 Design Example

13.8 Summary

13.9 References

13.10 Review Questions

13.11 Problems

Chapter 14: Class DE Power Inverter

14.1 Introduction

14.2 Principle of Operation of Class DE Power Inverter

14.3 Analysis of Class De Power Inverter

14.4 Components

14.5 Device Stresses

14.6 Design Equations

14.7 Maximum Operating Frequency

14.8 Class De Inverter With Single Shunt Capacitor

14.9 Output Power

14.10 Cancellation of Nonlinearities of Transistor Output Capacitances

14.11 Summary

14.12 References

14.13 Review Questions

14.14 Problems

Part III: Converters

Chapter 15: Class D Series-Resonant Converter

15.1 Introduction

15.2 Half-Bridge Series-Resonant Converter

15.3 Full-Bridge Series-Resonant Converter

15.4 Design of Half-Bridge SRC

15.5 Summary

15.6 References

15.7 Review Questions

15.8 Problems

Chapter 16: Class D Parallel-Resonant Converter

16.1 Introduction

16.2 Half-Bridge Parallel-Resonant Converter

16.3 Design of The Half-Bridge PRC

16.4 Full-Bridge Parallel-Resonant Converter

16.5 Summary

16.6 References

16.7 Review Questions

16.8 Problems

Chapter 17: Class D Series-Parallel-Resonant Converter

17.1 Introduction

17.2 Circuit Description

17.3 Half-Bridge Series-Parallel-Resonant Converter

17.4 Design of Half-Bridge SPRC

17.5 Full-Bridge Series-Parallel-Resonant Converter

17.6 Summary

17.7 References

17.8 Review Questions

17.9 Problems

Chapter 18: Class D CLL Resonant Converter

18.1 Introduction

18.2 Circuit Description

18.3 Half-Bridge CLL Resonant Converter

18.4 Design of Half-Bridge CLL Resonant Converter

18.5 Full-Bridge CLL Resonant Converter

18.6 Llc Resonant Converter

18.7 Summary

18.8 References

18.9 Review Questions

18.10 Problems

Chapter 19: Class D Current-Source-Resonant Converter

19.1 Introduction

19.2 Circuit Description

19.3 Design of Csrc

19.4 Summary

19.5 References

19.6 Review Questions

19.7 Problems

Chapter 20: Class D Inverter/Class E Rectifier Resonant Converter

20.1 Introduction

20.2 Circuit Description

20.3 Principle of Operation

20.5 Design of Class D Inverter/Class E Resonant Converter

20.6 Class E ZVS Inverter/Class D Rectifier Resonant DC-DC Converter

20.7 Class E ZVS Inverter/Class E ZVS Rectifier Resonant DC-DC Converter

20.8 Summary

20.9 References

20.10 Review Questions

20.11 Problems

Chapter 21: Phase-Controlled Resonant Converters

21.1 Introduction

21.2 Circuit Description of SC PC SRC

21.3 Design Example

21.4 Summary

21.5 References

21.6 Review Questions

21.7 Problems

Chapter 22: Quasiresonant and Multiresonant DC-DC Power Converters

22.1 Introduction

22.2 Zero-Voltage-Switching Quasiresonant DC-DC Converters

22.3 Buck Zvs Quasiresonant DC-DC Converter

22.4 Boost Zvs Quasiresonant DC-DC Converter

22.5 Buck-Boost Zvs Quasiresonant DC-DC Converter

22.6 Zero-Current-switching Quasiresonant DC-DC Converters

22.7 Buck Zcs Quasiresonant DC-DC Converter

22.8 Boost Zcs Quasiresonant DC-DC Converter

22.9 Buck-Boost Zcs Quasiresonant DC-DC Converter

22.10 Zero-Voltage Switching Multiresonant DC-DC Converters

22.11 Zero-Current Switching Multiresonant DC-DC Converters

22.12 Zero-Voltage Transition Pwm Converters

22.13 Zero-Currenttransition Converters

22.14 Summary

22.15 References

22.16 Review Questions

22.17 Problems

Chapter 23: Modeling and Control

23.1 Introduction

23.2 Modeling

23.3 Model Reduction and Control

23.4 Summary

23.5 References

23.6 Review Questions

23.7 Problems

Appendices

Appendix A: Spice Model of Power Mosfets

Appendix B: Introduction to Spice

Appendix C: Introduction to MATLAB

Appendix D: Introduction to Saber

Answers to Problems

Index

RESONANT POWER CONVERTERS

Copyright © 2011 by John Wiley & Sons, Inc., All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data

Kazimierczuk, Marian.Resonant power conveners / Marian K. Kazimierczuk, Dariusz Czarkowski. — 2nd ed.p. cm.Includes bibliographical references and index.ISBN 978-0-470-90538-8 (cloth)1. Electric current converters. 2. Electric resonators. 3. Power electronics. I. Czarkowski,Dariusz. II. Title.TK7872.C8K39 2010621.3815’322—dc222010031082

To Alicja, Anna, Katarzyna, and Andrzej To Hanna, Barbara, and Bartosz

PREFACE

Energy is considered number one of 10 challenges facing humanity today. Energy processing is a large portion of energy technology. Power electronics is a branch of electrical and electronic engineering concerned with the analysis, simulation, design, manufacture, and application of switching-mode DC-DC power converters. Resonant power conversion is in the center of the renewable energy and energy harvesting technologies. This book is focused on the analysis and design of DC-AC resonant inverters, high-frequency rectifiers, and DC-DC resonant converters that are basic building blocks of various high-frequency, high-efficiency low-noise energy processors. The past two decades have initiated a revolution in and unprecedented growth of power electronics. Continuing advances in this area have resulted in DC and AC energy sources that are smaller, more efficient, lighter, less expensive, and more reliable than ever before. Power processors are widely used in the computer, telecommunication, instrumentation, automotive, aerospace, defense, and consumer industries. DC-DC converters are being used in power supplies to power practically all electronic circuits that contain active devices. The growing escalation in complexity of modern electronic systems is imposing challenging demands on the capabilities of circuit designers.

Many design problems encountered in a great diversity of products can be solved using the unique capabilities of resonant technology. Information on resonant power processors is scattered throughout many different technical journals, conference proceedings, and application notes. This volume brings the principles of resonant technology to students, scientists, and practicing design engineers. The state-of-the-art technology of high-frequency resonant power processors is covered in a systematic manner for the first time. The reader will be introduced to the topologies, characteristics, terminology, and mathematics of resonant converters. The fundamental-frequency component approach is used in the analyses of DC-DC resonant converters. The book provides students and engineers with a sound understanding of existing high-frequency inverters, rectifiers, and DC-DC resonant converters and presents a general and easy-to-use tool of analysis and design of resonant power circuits. It is written in a clear, concise, and unambiguous style.

The text provides rigorous in-depth analysis to help the reader understand how and why the power converters are built as they are. The fundamental-frequency component method is used throughout the entire book. This approach leads to relatively simple closed-form analytic expressions for converter characteristics, which provides good insight into circuit operation and greatly simplifies the design process. Graphic representations of various characteristics are emphasized throughout the text because they provide a visual picture of circuit operation and often yield insights not readily obtained from purely algebraic treatments.

This book is intended as a textbook for senior-level and graduate students in electrical engineering and as a reference for practicing design engineers, researchers, and consultants in industry. The objective of the book is to develop in the reader the ability to analyze and design high-frequency power electronic circuits. A knowledge of network analysis, electronic circuits and devices, complex algebra, Fourier series, and Laplace transforms is required to handle the mathematics in this book. Numerous analysis and design examples are included throughout the textbook. An extensive list of references is provided in each chapter. Problems are placed at the end of each chapter. Answers to selected problems are given at the end of the book. Complete solutions for all problems are included in the Solutions Manual, which is available from the publisher for those instructors who adopt the book for their courses.

The book is divided into three parts: Part I, “Rectifiers,” Part II, “Inverters,” and Part III, “Converters.”

High-frequency rectifiers are covered in Chapters 2 through 5. Chapter 2 deals with Class D current-driven rectifiers, and Chapter 3 is devoted to the study of Class D voltage-driven rectifiers. Each of these chapters contains analyses of three types of rectifiers, namely, the half-wave, transformer center-tapped, and bridge rectifiers. Chapter 4 presents two Class E low dv/dt rectifiers, whereas Chapter 5 deals with two Class E low di/dt rectifiers.

High-frequency resonant inverters are discussed in Chapters 6 through 14. The Class D series-resonant converter is thoroughly covered in Chapter 6. Many topics discussed in this chapter apply also to other resonant inverters presented in the following chapters. The Class D parallel-resonant inverter is the topic of Chapter 7. Chapters 8 and 9 discuss dual Class D series-parallel and Class D CLL resonant inverters, respectively. The Class D current-source inverter is covered in Chapter 10. Chapter 10 also discusses zero-voltage-switching techniques in resonant inverters. The Class D current-source inverter is covered in Chapter 11. An example of a constant-frequency phase-controlled Class D resonant inverter, namely, the single-capacitor phase-controlled resonant inverter is given in Chapter 12. The Class E resonant inverters are analyzed in Chapters 13 and 14. Chapter 13 deals with a zero-voltage-switching Class E inverter, and Chapter 14 presents a Class DE power inverter, which is a zero-current-switching Class E inverter.

Converters are studied in Part III, which ties together the material of Parts I and II. Resonant DC-DC converters that are a result of cascading resonant inverters with high-frequency rectifiers are presented in Chapters 15 through 22. Chapters 15 through 19 discuss converters with inverters presented in Chapters 6 through 10. Hence, Chapter 15 covers a Class D series-resonant converter, Chapter 16 presents a Class D parallel-resonant converter, Chapter 17 deals with a Class D series-parallel-resonant inverter. Chapter 18 gives an analysis of a Class D CLL resonant converter, and Chapter 19 discusses a Class D current-source converter. An example of matching a Class D inverter with a Class E rectifier that leads to a Class D inverter/Class E rectifier resonant converter is presented in Chapter 20. Chapter 21 gives an analysis of a single-capacitor phase-controlled resonant converter that belongs to a broad family of phase-controlled converters. Chapter 22 presents zero-voltage switching (ZVS) and zero-current switching (ZCS) quasi-resonant DC-DC power converters (QRCs), multiresonant DC-DC converters (MRCs), and zero-voltage-transition converters (ZVTs) and zero-current transition DC-DC converters (ZCTs). Chapter 23 contains modeling and control of resonant power converters.

We are pleased to express our gratitude to many individuals for their help during the preparation of this book. The first author had the privilege to teach numerous superb students at the Technical University of Warsaw, Warsaw, Poland, and at Wright State University, Dayton, Ohio. He would like to express his deepest appreciation to them for their research contributions, ideas, suggestions, and critical evaluations of the original manuscript. He also wishes to express his gratitude to Rafal Wojda for the MATLAB figures.

Throughout the entire course of this project, the support provided by John Wiley & Sons, Wiley Interscience Division, was excellent. We wish to express our sincere thanks to George J. Telecki, Senior Editor, and Lucy Hitz, Editorial Assistant, Dean Gonzalez, Illustration Manager, and Kristen Parrish, Production Editor. It has been a real pleasure working with them. Last but not least, we wish to thank our families for their support.

The authors invite the readers to contact them directly or through the publisher with comments and suggestions about this book.

May 2010

MARIAN K. KAZIMIERCZUKDARIUSZ CZARKOWSKI

ABOUT THE AUTHORS

Marian K. Kazimierczuk is Robert J. Kegerreis Distinguished Professor of Electrical Engineering at Wright State University, Dayton, Ohio, USA. He has received M.S., Ph.D., and D. Sci. degrees from the Department of Electronics, Technical University of Warsaw, Warsaw, Poland. He is the author of six books, 145 archival refereed journal papers, 175 conference papers, and seven patents. He is a Fellow of the IEEE. He received the Outstanding Teaching Award from the American Society for Engineering Education (ASEE) in 2008, National Professorship of Technical Sciencies of Poland in 2009, and Southwestern Ohio Council for Higher Education (SOCHE) Award in 2010. His honors also include the Board of Trustees’ Award, Brage Golding Distinguished Professor of Research Award, Outstanding Faculty Member Award, Excellence in Professional Service Award, and several college Excellence in Teaching Awards. His research interests are in the areas of power electronics, including resonant DC-DC power converters, PWM DC-DC power converters, modeling and controls, RF power amplifiers and oscillators, semiconductor power devices, high-frequency magnetic devices, renewable energy sources, and evanescent microwave microscopy. He has served as an Associate Editor of the IEEE Transactions on Circuits and Systems, IEEE Transactions on Industrial Electronics, Journal of Circuits, Systems and Computers, and International Journal of Circuit Theory and Applications.

Dariusz Czarkowski is an Associate Professor at the Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, NY, USA. He received an M.S. degree in electrical engineering from AGH University of Science and Technology, Cracow, Poland, an M.S. degree in electrical engeneering from Wright State University, Dayton, OH, and a Ph.D. degree in electrical engineering from the University of Florida, Gainesville, FL. His research interests are in the areas of power electronics and power systems. He has served as an Associate Editor of the IEEE Transactions on Circuits and Systems and International Journal of Power and Energy Systems.

LIST OF SYMBOLS

CHAPTER 1

INTRODUCTION

A block diagram of a general energy converter is shown in Fig. 1.1. It converts one form of energy into another form of energy. Modern electronic systems demand high-quality, small, lightweight, reliable, and efficient power processors [1]–[11]. Linear power regulators [8] can handle only low power levels (typically below 20 W), have a very low efficiency, and have a low power density because they require low-frequency (50 or 60 Hz) line transformers and filters. The higher the operating frequency, the smaller and lighter the transformers, filter inductors, and capacitors. In addition, dynamic characteristics of converters improve with increasing operating frequencies. The bandwidth of a control loop is usually determined by the corner frequency of the output filter. Therefore, high operating frequencies allow for achieving a faster dynamic response to rapid changes in the load current and/or the input voltage. As a result, high-frequency power technology, which employs semiconductor power switches, has developed rapidly in recent years.

FIGURE 1.1 Block diagram of energy converter.

High-frequency power processors can be classified into three categories:

Inverters (DC-AC converters)

Rectifiers (AC-DC converters)

DC-DC converters

DC-AC inverters, whose block diagram is depicted in Fig. 1.2(a), convert DC energy into AC energy. The input power source is either a DC voltage source or a DC current source. Inverters deliver AC power to a load impedance. In many applications, a sinusoidal output voltage or current is required. To generate a sinusoidal voltage and/or current waveforms, DC-AC inverters contain a resonant circuit; therefore, they are called resonant DC-AC inverters. Power MOSFETs are usually used as switching devices in resonant inverters at high frequencies and in isolated-gate bipolar transistors (IGBTs) and MOS-controlled thyristors (MCTs) at low frequencies.

FIGURE 1.2 Block diagrams of high-frequency power processors. (a) Inverters (DC-AC converters). (b) Rectifiers (AC-DC converters). (c) DC-DC converters.

A block diagram of an AC-DC rectifier is depicted in Fig. 1.2(b). Rectifiers convert an AC voltage or current into a DC voltage. At low frequencies of 50, 60, and 400 Hz, peak rectifiers are widely used; however, the ratio of the diode peak current to the diode average current is very high in these rectifiers, and the diode current waveforms contain a large amount of harmonics. Therefore, peak rectifiers are not used at high frequencies. In this book, rectifiers suitable for high-frequency applications are given and analyzed.

High-frequency rectifiers can be divided into unregulated diode rectifiers, unregulated synchronous rectifiers, and regulated synchronous rectifiers. Both pn junction diodes and Schottky diodes are used in the first group of circuits. Silicon Schottky diodes are used only in low-output voltage applications because their breakdown voltage is relatively low, typically less than 100 V. They have low forward voltage drops of the order of 0.3 to 0.4 V and do not suffer from reverse recovery, resulting in high rectifier efficiency. The leakage current in Schottky diodes is much higher than that in junction diodes. When the peak value of the diode voltage exceeds 100 V, pn junction diodes or silicon carbide diodes [9] must be used. Power pn junction diodes have a forward voltage drop of about 1 V and a reverse recovery effect that limits the operating frequency of rectifiers. Schottky diodes do not suffer from reverse-recovery effects and are suitable for high-frequency applications.

In both unregulated and regulated synchronous rectifiers, power MOSFETs are used. Unlike diodes, power MOSFETs do not have an offset voltage. If their on-resistance is low, the forward voltage drops are low, yielding high efficiency.

High-frequency power processors are used in DC-DC power conversion. A block diagram of a DC-DC converter is shown in Fig. 1.2(c). The functions of DC-DC converters are as follows:

To convert a DC input voltage

V

I

into a DC output voltage

V

O

;

To regulate the DC output voltage against load and line variations;

To reduce the AC voltage ripple on the DC output voltage below the required level;

To provide isolation between the input source and the load (isolation is not always required);

To protect the supplied system from electromagnetic interference (EMI);

To satisfy various international and national safety standards.

Pulse-width modulated (PWM) converters [1]–[9] are well described in the literature and are still widely used in low- and medium-power applications. However, PWM rectangular voltage and current waveforms cause turn-on and turn-off losses that limit the operating frequency. Rectangular waveforms generate broad-band electromagnetic energy and thus increase the potential for electromagnetic interference (EMI). The inability of PWM converters to operate efficiently at very high frequencies imposes a limit on the size of reactive components of the converter and, thereby, on power density. In search of converters capable of operating at higher frequencies, power electronics engineers started to develop converter topologies that shape either a sinusoidal current or a sinusoidal voltage waveform, significantly reducing switching losses. The key idea is to use a resonant circuit with a sufficiently high quality factor. Such converters are called resonant DC-DC converters. In many resonant DC-DC converters, transistors and diodes operate under soft-switching conditions, either zero-voltage switching (ZVS) or zero-current switching (ZCS). These kind of waveforms reduce switching losses and EMI levels.

A resonant DC-DC converter is obtained by cascading a resonant DC-AC inverter and a high-frequency rectifier, as shown in Fig. 1.2(c). The DC input power is first converted into AC power by the inverter, and then the AC power is converted back to DC power by the rectifier. If isolation is required, a high-frequency transformer, which is much smaller than a low-frequency transformer, can be inserted between the inverter and the rectifier.

The cascaded representation of a resonant DC-DC converter is convenient from an analytical point of view. If the input current or the input voltage of the rectifier is sinusoidal, only the power of the fundamental component is converted from AC to DC power. In this case, the rectifier can be replaced by the input impedance, defined as the ratio of the fundamental components of the input voltage to the input current. In turn, the input impedance of the rectifier can be used as an AC load of the inverter. Thus, the inverter can be analyzed and designed as a separate stage, independently of the rectifier. If the loaded quality factor of a resonant circuit is high enough and the switching frequency is close enough to the resonant frequency, a resonant inverter usually operates in continuous conduction mode and forces either a sinusoidal output current or a sinusoidal output voltage, depending on the resonant circuit topology. Therefore, the entire inverter can be replaced by a sinusoidal current source or a sinusoidal voltage source that drives the rectifier. As a result, the analysis and design of the rectifier can be carried out independent of the inverter. Finally, the two stages—the inverter and the rectifier—can be cascaded, in a manner similar to other cells in electronic systems.

The cascaded inverter and rectifier should be compatible. A rectifier that requires an input voltage source (called a voltage-driven rectifier or a voltage-source rectifier) should be connected to an inverter whose output behaves like a voltage source. This takes place in inverters that contain a parallel-resonant circuit. Similarly, a rectifier that requires an input current source should be connected to an inverter whose output behaves like a current source.

A rectifier that requires an input current source (called a current-driven rectifier or a current-source rectifier) should be connected to an inverter whose output behaves like a current source. Inverters that contain a series-resonant circuit force a sinusoidal output current.

Characteristics of a DC-DC converter, for example, efficiency or voltage transfer function, can be obtained simply as a product of characteristics of an inverter and a rectifier. For example, nine converters can be built by using three types of inverters and three types of rectifiers, assuming that the inverters and rectifiers are compatible. To obtain characteristics of all converters with the state-space approach, a tedious analysis of nine complex circuits is required and the results are given in the form of graphs rather than equations. In addition, the entire analysis must be repeated with every change of the converter topology. In contrast, the cascaded representation allows one to obtain characteristics of nine converters from the analysis of only six simple blocks (three inverters and three rectifiers). Moreover, the results are given as closed-form expressions, which makes it easier to investigate effects of various parameters on the converter performance. Because of its advantages, the fundamental-frequency approach outlined above is used throughout this book. If the loaded quality factor of the resonant circuit is very low and/or the switching frequency is much lower or much higher than the resonant frequency, the current and voltage waveforms may significantly differ from sine waves. The converter may even enter a discontinuous conduction mode. In such cases, the state-space analysis should be used.

1.1 REFERENCES

1. R. P. Severns and G. Bloom, Modern DC-to-DC Switchmode Power Converter Circuits, New York: Van Nostrand Reinhold, 1985.

2. R. G. Hoft, Semiconductor Power Electronics, New York: Van Nostrand Reinhold, 1986.

3. J. G. Kassakian, M. S. Schlecht, and G. C. Verghese, Principles of Power Electronics, Reading, MA: Addison-Wesley, 1991.

4. N. Mohan, T. M. Undeland, and W. P. Robbins, Power Electronics: Converters, Applications and Design, 3rd Ed. Hoboken, NJ: John Wiley & Sons, 2003.

5. M. H. Rashid, Power Electronics, 3rd Ed. Upper Saddle River, NJ: Prentice Hall, 2004.

6. R. W. Erickson and D. Maksimovi, Fundamentals of Power Electronics, 2nd Ed. Norwall, MA: Kluwer Academic, 2001.

7. I. Batarseh, Power Electronic Circuits, Hoboken, NJ: John Wiley & Sons, 2004.

8. M. K. Kazimierczuk, Electronic Devices, A Design Approach, Upper Saddle River, NJ: Prentice Hall, 2004.

9. M. K. Kazimierczuk, Pulse-Width Modulated DC-DC Power Converters, Chichester, UK: John Wiley & Sons, 2008.

10. M. K. Kazimierczuk, High-Frequency Magnetic Components, Chichester, UK: John Wiley & Sons, 2008.

11. M. K. Kazimierczuk, RF Power Amplifiers, Chichester, UK: John Wiley & Sons, 2008.

PART I

RECTIFIERS

CHAPTER 2

CLASS D CURRENT-DRIVEN RECTIFIERS

2.1 INTRODUCTION

A resonant DC-DC converter consists of a high-frequency resonant DC-AC inverter and a high-frequency rectifier. A high-frequency rectifier is an AC-DC converter that is driven by a high-frequency AC energy source. The input source may be either a high-frequency current source or a high-frequency voltage source. Rectifiers that are driven by a current source are called current-driven rectifiers [1]–[3]. Some DC-AC inverters contain a series-resonant circuit at the output, for example. Class D or Class E inverters. A series-resonant circuit with a high loaded quality factor QL (i.e., QL ≥ 3) behaves approximately like a sinusoidal current source. For this reason, the current-driven rectifiers are compatible with the aforementioned resonant inverters. In some of these rectifiers, the diode current and voltage waveforms are similar to the corresponding transistor waveforms in Class D voltage-switching inverters (studied in Part II of this book). Specifically, the diode current waveform is a half-sine wave and the diode voltage waveform is a square wave. The on-duty cycle of each diode is 50%. Therefore, these rectifiers are referred to as [1]–[3].