control in power electronic

Control in Power Electronics

Selected Problems

ACADEMIC PRESS SERIES IN ENGINEERING

Series Editor

J. David Irwin

Auburn University

This is a series that will include handbooks, textbooks, and professional reference books on cutting-edge

areas of engineering. Also included in this series will be single-authored professional books on state-of-the￾art techniques and methods in engineering. Its objective is to meet the needs of academic, industrial, and

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and graduate level.

This series editor, J. David Irwin, is one of the best-known engineering educators in the world. Irwin has

been chairman of the electrical engineering department at Auburn University for 27 years.

Published books in the series:

Supply Chain Design and Management, 2002, M. Govil and J. M. Proth

Power Electronics Handbook, 2001, M. H. Rashid, editor

Control of Induction Motors, 2001, A. Trzynadlowski

Embedded Microcontroller Interfacing for McoR Systems, 2000, G. J. Lipovski

Soft Computing & Intelligent Systems, 2000, N. K. Sinha, M. M. Gupta

Introduction to Microcontrollers, 1999, G. J. Lipovski

Industrial Controls and Manufacturing, 1999, E. Kamen

DSP Integrated Circuits, 1999, L. Wanhammar

Time Domain Electromagnetics, 1999, S. M. Rao

Single- and Multi-Chip Microcontroller Interfacing, 1999, G. J. Lipovski

Control in Robotics and Automation, 1999, B. K. Ghosh, N. Xi, and T. J. Tarn

CONTROL IN POWER

ELECTRONICS

Selected Problems

Editors

MARIAN P. KAZMIERKOWSKI

Warsaw University of Technology, Warsaw, Poland

R. KRISHNAN

Virginia Tech, Blacksburg, Virginia, USA

FREDE BLAABJERG

Aalborg University, Aalborg, Denmark

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San Francisco Singapore Sydney Tokyo

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Copyright 2002, Elsevier Science (USA).

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Contents

Preface vii

List of Contributors xi

Part I: PWM Converters: Topologies and Control

1. Power Electronic Converters

Andrzej M. Trzynadlowski 1

2. Resonant dc Link Converters

Stig Munk-Nielsen 45

3. Fundamentals of the Matrix Converter Technology

C. Klumpner and F. Blaabjerg 61

4. Pulse Width Modulation Techniques for Three-Phase Voltage Source Converters

Marian P. Kazmierkowski, Mariusz Malinowski, and Michael Bech 89

Part II: Motor Control

5. Control of PWM Inverter-Fed Induction Motors

Marian P. Kazmierkowski 161

6. Energy Optimal Control of Induction Motor Drives

F. Abrahamsen 209

7. Comparison of Torque Control Strategies Based on the Constant Power Loss

Control System for PMSM

Ramin Monajemy and R. Krishnan 225

8. Modeling and Control of Synchronous Reluctance Machines

Robert E. Betz 251

9. Direct Torque and Flux Control (DTFC) of ac Drives

Ion Boldea 301

10. Neural Networks and Fuzzy Logic Control in Power Electronics

Marian P. Kazmierkowski 351

v

Part III: Utilities Interface and Wind Turbine Systems

11. Control of Three-Phase PWM Rectifiers

Mariusz Malinowski and Marian P. Kazmierkowski 419

12. Power Quality and Adjustable Speed Drives

Steffan Hansen and Peter Nielsen 461

13. Wind Turbine Systems

Lars Helle and Frede Blaabjerg 483

Index 511

vi CONTENTS

Preface

This book is the result of cooperation initiated in 1997 between Danfoss Drives A=S

(www.danfoss.com.drives) and the Institute of Energy Technology at Aalborg University in

Denmark. A four-year effort known as The International Danfoss Professor Program* was

started. The main goal of the program was to attract more students to the multidisciplinary area

of power electronics and drives by offering a world-class curriculum taught by renowned

professors. During the four years of the program distinguished professors visited Aalborg

University, giving advanced courses in their specialty areas and interacting with postgraduate

students. Another goal of the program was to strengthen the research team at the university by

fostering new contacts and research areas. Four Ph.D. studies have been carried out in power

electronics and drives. Finally, the training and education of engineers were also offered in the

program. The program attracted the following professors and researchers (listed in the order in

which they visited Aalborg University):

Marian P. Kazmierkowski, Warsaw University of Technology, Poland

Andrzej M. Trzynadlowski, University of Nevada, Reno, USA

Robert E. Betz, University of Newcastle, Australia

Prasad Enjeti, Texas A&M, USA

R. Krishnan, Virginia Tech, Blacksburg, USA

Ion Boldea, Politehnica University of Timisoara, Romania

Peter O. Lauritzen, University of Washington, USA

Kazoo Terada, Hiroshima City University, Japan

Jacobus D. Van Wyk, Virginia Tech, Blacksburg, USA

Giorgio Spiazzi, University of Padova, Italy

Bimal K. Bose, University of Tennessee, Knoxville, USA

Jaeho Choi, Chungbuk National University, South Korea

Peter Vas, University of Aberdeen, UK

* F. Blaabjerg, M. P. Kazmierkowski, J. K. Pedersen, P. Thogersen, and M. Toennes, An industry-university collaboration

in power electronics and drives, IEEE Trans. on Education, 43, No. 1, Feb. 2000, pp. 52–57.

vii

Among the Ph.D. students visiting the program were:

Pawel Grabowski, Warsaw University of Technology, Poland

Dariusz L. Sobczuk, Warsaw University of Technology, Poland

Christian Lascu, Politehnica University of Timisoara, Romania

Lucian Tutelea, Politehnica University of Timisoara, Romania

Christian Klumpner, Politehnica University of Timisoara, Romania

Mariusz Malinowski, Warsaw University of Technology, Poland

Niculina Patriciu, University of Cluj-Napoca, Romania

Florin Lungeanu, Galati University, Romania

Marco Matteini, University of Bologna, Italy

Marco Liserre, University of Bari, Italy

The research carried out in cooperation with the Danfoss Professor Program resulted in many

publications. The high level of the research activities has been recognized worldwide and four

international awards have been given to team members of the program.

Most of the research results are included in this book, which consists of the following three parts:

Part I: PWM Converters: Topologies and Control (four chapters)

Part II: Motor Control (six chapters)

Part III: Utilities Interface and Wind Turbine Systems (three chapters)

The book has strong monograph attributes, however, some chapters can also be used for

undergraduate education (e.g., Chapters 4, 5, and 9–11) as they contain a number of illustrative

examples and simulation case studies.

We would like to express thanks to the following people for their visionary support of this

program:

Michael Toennes, Manager of Low Power Drives, Danfoss Drives A=S

Paul B. Thoegersen, Manager of Control Engineering, Danfoss Drives A=S

John K. Pedersen, Institute Leader, Institute of Energy Technology, Aalborg University

Kjeld Kuckelhahn, Vice President of Product Development, Danfoss Drives A=S

Finn R. Pedersen, President of Fluid Division, Danfoss A=S, former President of Danfoss

Drives A=S

Joergen M. Clausen, President and CEO of Danfoss A=S

We would also like to thank the Ministry of Education in Denmark and Aalborg University for

their support of the program.

We would like to express our sincere thanks to the chapter contributors for their cooperation

and patience in various stages of the book preparation. Special thanks are directed to Ph.D.

students Mariusz Cichowlas, Marek Jasinski, Mateusz Sikorski, and Marcin Zelechowski from

the Warsaw University of Technology for their help in preparing the entire manuscript. We are

grateful to our editor at Academic Press, Joel Claypool, for his patience and continuous support.

viii PREFACE

Thanks also to Peggy Flanagan, project editor, who interfaced pleasantly during copyediting and

proofreading. Finally, we are very thankful to our families for their cooperation.

Marian P. Kazmierkowski, Warsaw University of Technology, Poland

R. Krishnan, Virginia Tech, Blacksburg, USA

Frede Blaabjerg, Aalborg University, Denmark

Preface ix

List of Contributors

F. Abrahamsen Aalborg, Denmark

Michael Bech Aalborg University, Aalborg, Denmark

Robert E. Betz School of Electrical Engineering and Computer Science, University of

Newcastle, Callaghan, Australia

Frede Blaabjerg Institute of Energy Technology, Aalborg University, Aalborg, Denmark

Ion Boldea University Politehnica, Timisoara, Romania

Steffan Hansen Danfoss Drives A=S, Grasten, Denmark

Lars Helle Institute of Energy Technology, Aalborg University, Aalborg, Denmark

Marian P. Kazmierkowski Warsaw University of Technology, Warsaw, Poland

C. Klumpner Institute of Energy Technology, Aalborg University, Aalborg, Denmark

R. Krishnan The Bradley Department of Electrical and Computer Engineering, Virginia Tech,

Blacksburg, Virginia

Mariusz Malinowski Warsaw University of Technology, Warsaw, Poland

Ramin Monajemy Samsung Information Systems America, San Jose, California

Stig Munk-Nielsen Institute of Energy Technology, Aalborg University, Aalborg, Denmark

Peter Nielsen Danfoss Drives A=S, Grasten, Denmark

Andrzej M. Trzynadlowski University of Nevada, Reno, Nevada

x

CHAPTER 1

Power Electronic Converters

ANDRZEJ M. TRZYNADLOWSKI

University of Nevada, Reno, Nevada

This introductory chapter provides a background to the subject of the book. Fundamental

principles of electric power conditioning are explained using a hypothetical generic power

converter. Ac to dc, ac to ac, dc to dc, and dc to ac power electronic converters are described,

including select operating characteristics and equations of their most common representatives.

1.1 PRINCIPLES OF ELECTRIC POWER CONDITIONING

Electric power is supplied in a ‘‘raw,’’ fixed-frequency, fixed-voltage form. For small consumers,

such as homes or small stores, usually only the single-phase ac voltage is available, whereas

large energy users, typically industrial facilities, draw most of their electrical energy via three￾phase lines. The demand for conditioned power is growing rapidly, mostly because of the

progressing sophistication and automation of industrial processes. Power conditioning involves

both power conversion, ac to dc or dc to ac, and control. Power electronic converters performing

the conditioning are highly efficient and reliable.

Power electronic converters can be thought of as networks of semiconductor power switches.

Depending on the type, the switches can be uncontrolled, semicontrolled, or fully controlled. The

state of uncontrolled switches, the power diodes, depends on the operating conditions only. A

diode turns on (closes) when positively biased and it turns off (opens) when the conducted

current changes its polarity to negative. Semicontrolled switches, the SCRs (silicon controlled

rectifiers), can be turned on by a gate current signal, but they turn off just like the diodes. Most of

the existing power switches are fully controlled, that is, they can both be turned on and off by

appropriate voltage or current signals.

Principles of electric power conversion can easily be explained using a hypothetical ‘‘generic

power converter’’ shown in Fig. 1.1. It is a simple network of five switches, S0 through S4, of

which S1 opens and closes simultaneously with S2, and S3 opens and closes simultaneously

with S4. These four switches can all be open (OFF), but they may not be all closed (ON) because

they would short the supply source. Switch S0 is only closed when all the other switches are

open. It is assumed that the switches open and close instantly, so that currents flowing through

them can be redirected without interruption.

1

The generic converter can assume three states only: (1) State 0, with switches S1 through S4

open and switch S0 closed, (2) State 1, with switches S1 and S2 closed and the other three

switches open, and (3) State 2, with switches S3 and S4 closed and the other three switches open.

Relations between the output voltage, vo

, and the input voltage, vi

, and between the input current,

i

i

, and output current, io

, are

vo ¼

0 in State 0

vi

in State 1

vi

in State 2

8

<

:

ð1:1Þ

and

i

i ¼

0 in State 0

io

in State 1

io

in State 2:

8

<

:

ð1:2Þ

Thus, depending on the state of generic converter, its switches connect, cross-connect, or

disconnect the output terminals from the input terminals. In the last case (State 0), switch S0

provides a path for the output current (load current) when the load includes some inductance, L.

In absence of that switch, interrupting the current would cause a dangerous impulse overvoltage,

Ldio=dt ! 1.

Instead of listing the input–output relations as in Eqs. (1.1) and (1.2), the so-called switching

functions (or switching variables) can be assigned to individual sets of switches. Let a ¼ 0 when

switch S0 is open and a ¼ 1 when it is closed, b ¼ 0 when switches S1 and S2 are open and

b ¼ 1 when they are closed, and c ¼ 0 when switches S3 and S4 are open and c ¼ 1 when they

are closed. Then,

vo ¼ aðb cÞvi

ð1:3Þ

and

i

i ¼ aðb cÞio

: ð1:4Þ

The ac to dc power conversion in the generic converter is performed by setting it to State 2

whenever the input voltage is negative. Vice-versa, the dc to ac conversion is realized by periodic

repetition of the State 1–State 2– ::: sequence (note that the same state sequence appears for the

ac to dc conversion). These two basic types of power conversion are illustrated in Figs. 1.2 and

1.3. Thus, electric power conversion is realized by appropriate operation of switches of the

converter.

Switching is also used for controlling the output voltage. Two basic types of voltage control

are phase control and pulse width modulation. The phase control consists of delaying States 1

FIGURE 1.1

Generic power converter.

2 CHAPTER 1 / POWER ELECTRONIC CONVERTERS

and 2 and setting the converter to State 0. Figure 1.4 shows the generic power converter

operating as an ac voltage controller (ac to ac converter). For 50% of each half-cycle, State 1 is

replaced with State 0, resulting in significant reduction of the rms value of output voltage (in this

case, to 1=

ffiffiffi

2

p

of rms value of the input voltage). The pulse width modulation (PWM) also makes

use of State 0, but much more frequently and for much shorter time intervals. As shown in Fig.

1.5 for the same generic ac voltage controller, instead of removing whole ‘‘chunks’’ of the

waveform, numerous ‘‘slices’’ of this waveform are cut out within each switching cycle of the

converter. The switching frequency, a reciprocal of a single switching period, is at least one order

of magnitude higher than the input or output frequency.

The difference between phase control and PWM is blurred in dc to dc converters, in which

both the input and output frequencies are zero, and the switching cycle is the operating cycle.

The dc to dc conversion performed in the generic power converter working as a chopper (dc to

dc converter) is illustrated in Fig. 1.6. Switches S1 and S2 in this example operate with the duty

ratio of 0.5, reducing the average output voltage by 50% in comparison with the input voltage.

The duty ratio of a switch is defined as the fraction of the switching cycle during which the

switch is ON.

To describe the magnitude control properties of power electronic converters, it is convenient

to introduce the so-called magnitude control ratio, M, defined as the ratio of the actual useful

output voltage to the maximum available value of this voltage. In dc-output converters, the useful

output voltage is the dc component of the total output voltage of the converter, whereas in ac￾output ones, it is the fundamental component of the output voltage. Generally, the magnitude

control ratio can assume values in the 1 to þ1 range.

FIGURE 1.2

Ac to dc conversion in the generic power converter: (a) input voltage, (b) output voltage.

1.1 PRINCIPLES OF ELECTRIC POWER CONDITIONING 3

In practical power electronic converters, the electric power is supplied by voltage sources or

current sources. Each of these can be of the uncontrolled or controlled type, but a parallel

capacitance is a common feature of the voltage sources while a series inductance is typical for

the current sources. The capacitance or inductance is sufficiently large to prevent significant

changes of the input voltage or current within an operating cycle of the converter. Similarly,

loads can also have the voltage-source or current-source characteristics, resulting from a parallel

capacitance or series inductance. To avoid direct connection of two capacitances charged to

different voltages or two inductances conducting different currents, a voltage-source load

requires a current-source converter and, vice versa, a current-source load must be supplied

from a voltage-source converter. These two basic source-converter-load configurations are

illustrated in Fig. 1.7.

1.2 AC TO DC CONVERTERS

Ac to dc converters, the rectifiers, come in many types and can variously be classified as

uncontrolled versus controlled, single-phase versus multiphase (usually, three-phase), half-wave

versus full-wave, or phase-controlled versus pulse width modulated. Uncontrolled rectifiers are

based on power diodes; in phase-controlled rectifiers SCRs are used; and pulse width modulated

FIGURE 1.3

Dc to ac conversion in the generic power converter: (a) input voltage, (b) output voltage.

4 CHAPTER 1 / POWER ELECTRONIC CONVERTERS