control of electric machine drive systems pdf

It has been eight years since my book, Control Theory of Electric Machinery, was
published in Korean. In the past six years, more than 2500 copies of the book have
been sold in Korea. Some of them are used as a textbook for a graduate course at
several universities in Korea. But most of them are used as a reference book in the
industry. After publishing the book in Korean, I received a lot of encouragement and
inquiry to translate the book into English.

But my tight schedule has delayed the translation. However, four years ago, several foreign students and visitors attended my graduate course class and they need some study materials so I was forced to translate the book into English. After two years of hard work, the English-version manuscript is
now ready for publication. During the translation, the contents of this book was revised and upgraded. I hope that this book will be a good reference for the students and engineers in the field.

Modern technology, which today is called information technology, is based on
the stable supply of energy, especially electric energy which is the most widely used.
Many people in modern society think that electric energy can be produced for as
long as we want. However, because clean water and air are growing scarce, electric
energy comes to us as a very limited resource.

As modern society develops, more and more electric energy is needed. But mass production, transportation, and use of environmentally friendly electric energy have become a very difficult problem. Electric energy goes through various steps of transformation from production to
final use. Mechanical energy acquired from a primary energy source such as oil, gas, nuclear, and hydraulic power can be converted to electric energy through electromechanical energy conversion. More precisely, after mechanical energy from various sources is transformed to electric energy through a generator, voltage and frequency are controlled for proper purpose, and in developed countries, more than 60% of energy is transformed into mechanical energy again for later use.

Hence, in the whole process of production and consumption of electric energy, the most
critical fields of engineering are efficient control of voltage/current and frequency
and appropriate control of electric machines. For 30 years my academic interest has
been the control of electric machinery and I have dedicated myself to research and
development of this field. This book has been written to share these experiences
with my colleagues.

Even small research results cannot be achieved alone and I owe this book to the efforts of many others. First of all, I mention my academic advisor for Master’s and Ph.D. courses taken at Seoul National University, Professor Minho Park, who opened my path in the field of power electronics and control of electric machines. Second, I recognize my honored professor and at the same time my father-in-law, JongsooWon. He taught electric machine subjects and I inherited many good, everyday
reference books related to that area from him.

Third, I thank Professor Thomas Lipo, who accepted me as a visiting researcher at the University of Wisconsin in Madison. During my two years at the University of Wisconsin, my understanding of electric machine control jumped at quantum speed. I am also very grateful to the faculty and colleagues at the University of Wisconsin and the many other professors and students of Seoul National University and other universities I have visited for the many discussions that lead to this book. Through conversations and arguments, I can now more solidly understand the problems and solutions of electric machine control.

Also, this book would not have been possible without the extremely hard work of my former Master’s and Ph.D. students. Their invaluable effort and time are merged together in this book, which summarizes and reorganizes our academic research results for the past 20 years. In particular, many Ph.D. and Master’s dissertations are foundations of this book. Problems in Chapters 1, 4, 5, 6, and 7, and Appendix A come from the research results of my collaboration and work with many in industry and I thank the many companies and people there.