Department of Electrical Engineering PDF

Secondo
POWER
ELECTRONICS
Converters,
Applications,
and Design
MOHAN I UNDELAND I ROBBINS
POWER ELECTRONICS
ABOUT THE AUTHORS

Ned Mohan is a professor in the Department of Electrical Engineering at the University of Minnesota,
where he holds the Oscar A. Schott Chair in Power Electronics. He has worked on several power
electronics projects sponsored by the industry and the electric power utilities, including the Electric
Power Research Institute. He has numerous pub lications and patents in this field.
Tore M. Undeland is a Professor in Power Electronics in the Faculty of Electrical
Engineering and Computer Science at the Norwegian Institute of Technology. He is also Scientific
Advisor to the Norwegian Electric Power Research Institute of Electricity Supply. He has been a visiting
scientific worker in the Power Electronics Converter Department of ASEA in Vaasteras, Sweden,
and at Siemens in Trondheim, Norway, and a visiting professor in the Department of Electrical
Engineering at the University of Minnesota. He has worked on many industrial research and
development projects in the power electronics field and has numerous publications.
William P. Robbins is a professor in the Department of Electrical Engineering at the
University of Minnesota. Prior to joining the University of Minnesota, he was a research engineer at the
Boeing Company. He has taught numerous courses in electronics and semiconductor device
fabrication. His research interests are in ultrasonics, pest insect detection via ultrasonics, and
micromechanical devices, and he has numerous publications in this field.
POWER ELECTRONICS Converters, Applications,
and Design SECOND EDITION
NED MOHAN Department of Electrical Engineering
University of Minnesota Minneapolis, Minnesota
TORE M. UNDELAND Faculty of Electrical Engineering and
Computer Science Norwegian Institute of Technology Trondheim, Norway
WILLIAM P. ROBBINS Department of Electrical
Engineering University of Minnesota Minneapolis, Minnesota

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Copyright © 1989, 1995 by John Wiley &
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Library of Congress Cataloging in
Publication Data: Mohan, Ned.
Power electronics : converters, applications, and design /
Ned Mohan, Tore M. Undeland, William P. Robbins.- 2nd ed.
p. cm. Includes bibliographical references and
indexes.
ISBN 0-471-58408-8 (cloth) 1. Power electronics. 2. Electric
current converters. 3. Power semiconductors. 1. Undeland,
Tore M. II. Robbins, William P. III. Title. TK7881.15.M64 1995
621.317--dc20
94-21158
CIP
Printed in the United States of
America.
10 9 8 7 6 5 4 3 2 1

To Our Families ... Mary, Michael, and Tara
Mona, Hilde, and Arne
Joanne and Jon
PREFACE
SECOND EDITION
The first edition of this book was published in 1989. The basic intent of this edition remains the
same; that is, as a cohesive presentation of power electronics fundamentals for
applications and design in the power range of 500 kW or less, where a huge market
exists and where the demand for power electronics engineers is likely to be. Based on the
comments collected over a five-year period, we have made a number of substantial
changes to the text. The key features are as follows:
• An introductory chapter has been added to provide a review of basic electrical and
magnetic circuit concepts, making it easier to use this book in introductory power
electronics courses. A chapter on computer simulation has been added that describes
the role of com puter simulations in power electronics. Examples and problems based
on PSpice® and MATLAB® are included. However, we have organized the material in such a
way that any other simulation package can be used instead or the simulations can
be skipped altogether.
• Unlike the first edition, the diode rectifiers and the phase-controlled thyristor con
verters are covered in a complete and easy-to-follow manner. These two chapters now contain
56 problems.
• A new chapter on the design of inductors and transformers has been added that
describes easy-to-understand concepts for step-by-step design procedures. This
material will be extremely useful in introducing the design of magnetics into the
curriculum.
• A new chapter on heat sinks has been added.

ORGANIZATION OF THE BOOK
This book is divided into seven parts. Part 1 presents an introduction to the field of power
electronics, an overview of power semiconductor switches, a review of pertinent electric
and magnetic circuit concepts, and a generic discussion of the role of computer simula
tions in power electronics.
Part 2 discusses the generic converter topologies that are used in most applications. The
actual semiconductor devices (transistors, diodes, and so on) are assumed to be ideal,
thus allowing us to focus on the converter topologies and their applications.
Part 3 discusses switch-mode dc and uninterruptible power supplies. Power supplies
represent one of the major applications of power electronics.
vii
viji
PREFACE
Part 4 considers motor drives, which constitute another major applications
area.
Part 5 includes several industrial and commercial applications in one chapter. An other
chapter describes various high-power electric utility applications. The last chapter in this
part of the book examines the harmonics and electromagnetic interference concerns and
remedies for interfacing power electronic systems with the electric utilities.
Part 6 discusses the power semiconductor devices used in power electronic converters
including diodes, bipolar junction thyristors, metal-oxide-semiconductor (MOS) field effect
transistors, thyristors, gate turn-off thyristors, insulated gate bipolar transistors, and
MOS-controlled thyristors.
Part 7 discusses the practical aspects of power electronic converter design
including snubber circuits, drive circuits, circuit layout, and heat sinks. An extensive new
chapter on the design of high-frequency inductors and transformers has been
added.
PSPICE SIMULATIONS FOR TEACHING AND DESIGN
As a companion to this book, a large number of computer simulations are available directly from
Minnesota Power Electronics Research and Education, P.O. Box 14503, Minneapolis, MN
55414 (Phone/Fax: [phone]) to aid in teaching and in the design of power electronic
systems. The simulation package comes complete with a diskette with 76 simulations of

power electronic converters and systems using the classroom (evalua tion) version of
PSpice for IBM-PC-compatible computers, a 261-page detailed manual that describes each
simulation and a number of associated exercises for home assignments and self-learning,
a 5-page instruction set to illustrate PSpice usage using these simula tions as examples, and
two high-density diskettes containing a copy of the classroom (evaluation) version of PSpice. This
package (for a cost of $395 plus a postage of $4 within North America and $25 outside) comes
with a site license, which allows it to be copied for use at a single site within a company or at
an educational institution in regular courses given to students for academic credits.
SOLUTIONS MANUAL
As with the first edition of this book, a solutions manual with completely
worked-out solutions to all the problems is available from the publisher,
ACKNOWLEDGMENTS
We wish to thank all the instructors who have allowed us this opportunity to write
the second edition of our book by adopting its first edition. Their comments have
been most useful. We are grateful to Professors Peter Lauritzen of the University of Washington,
Thomas Habetler of the Georgia Institute of Technology, Daniel Chen of the Virginia Institute of
Technology, Alexander Emanuel of the Worcester Polytechnic Institute, F. P. Dawson of the
University of Toronto, and Marian Kazimierczuk of the Wright State University for their helpful
suggestions in the second edition manuscript. We express our sincere appreciation to the Wiley
editorial staff, including Steven Elliot, Sean Culhane, Lucille Buonocore, and Savoula
Amanatidis, for keeping us on schedule and for many spirited discussions,
Ned Mohan
Tore M. Undeland William P. Robbins
CONTENTS
PART 1 INTRODUCTION

9
Chapter 1 Power Electronic Systems 1-1 Introduction 3 1-2 Power
Electronics versus Linear Electronics 4 1-3 Scope and Applications 7 1-4
Classification of Power Processors and Converters 1-5 About the Text
12 1-6 Interdisciplinary Nature of Power Electronics 13 1-7 Convention of
Symbols Used 14
Problems 14 References 15
16
Chapter 2 Overview of Power Semiconductor Switches 2-1 Introduction - 16 2-2
Diodes 16 2-3 Thyristors 18 2-4 Desired Characteristics in Controllable Switches 20
2-5 Bipolar Junction Transistors and Monolithic Darlingtons 24 2-6
Metal-Oxide-Semiconductor Field Effect Transistors 25 2-7 Gate-Turn-Off
Thyristors 26 2-8 Insulated Gate Bipolar Transistors 27 2-9 MOS-Controlled
Thyristors 29 2-10 Comparison of Controllable Switches 29 2-11 Drive and
Snubber Circuits 30 2-12 Justification for Using Idealized Device
Characteristics 31
Summary 32 Problems 32 References
33
Chapter 3 Review of Basic Electrical and Magnetic Circuit Concepts 3-1 Introduction - 33
3-2 Electric Circuits 33 3-3 Magnetic Circuits 46
Summary 57 Problems 58 References 60
X CONTENTS
Chapter 4 Computer Simulation of Power Electronic Converters
and Systems 4-1 Introduction 61 4-2 Challenges in
Computer Simulation 62 4-3 Simulation Process 62 4-4 Mechanics of
Simulation 64 4-5 Solution Techniques for Time-Domain Analysis 65 4-6 Widely
Used, Circuit-Oriented Simulators 69 4-7 Equation Solvers 72
Summary 74 Problems 74 References 75