Page 7 - Power Electronics Handbook

viii Preface

to include rectification, so taht the a.c. is controlled to give a variable d.c.
voltage.
Although similar in concept to ax. line control and rectification, the next
chapter describes a completely different application, the use of power
electronics to vary the frequency of an a.c. supply without first going through
d.c. These are also referred to as cycloconverters.
Chapters 11, 12 and 13 are related, since in these the power semi-
conductors switches operate from a d.c. supply and need to be forced
commutated. Chapter 11 classifies the various commutation systems which
are popularly used, and Chapters 12 and 13 describe two prime application
areas, those of voltage control and of frequency changing.
Finally Chapter 14 describes some of the most common applications of
power semiconductor components and circuits, introduced in earlier chapters
of the book. This includes power supplies, electrical machine control, heating
and lighting, and automobile control applications.
I started my career as a power electronic engineer at just about the time
that the first thyristors were becoming commercially available. From then on
I have continued to learn daily, as new developments have been made and
new material published. I am grateful to the many authors who have enriched
the technical press with their writings and so made this possible. To them,
and to the many other power electronic engineers, who have worked to
extend our knowledge in this valuable area, this book is gratefully
dedicated.

Fraidmn Mazda
Bishop’s Stortford
September 1997