The advances in power electronics since this book was first published in 1987 have chiefly been in the development of more effective semiconductor switching devices. In particular, the future of high power switching applications will involve reduced use of the silicon controlled rectifier (SCR) and gate turn-off thyristor (GTO) and increased use of the metal–oxide–semiconductor (MOS) controlled thyristor (MCT). The most influential development, however, is likely to be due to increased ratings of metal–oxide–semiconductor fieldeffect transistor (MOSFET) devices and, in particular, widespread use of the insulated gate bipolar transistor (IGBT). Design data of these switching devices is widely available from manufacturers. Increases in the range of semiconductor switches and their nonlinear nature has influenced practitioners to move towards computer based design rather than analytical studies. Simulation techniques are widespread and expert systems are under development.

Chapters 1–3 have been extensively revised, compared with the original text, to incorporate much new material, especially concerned with modern semiconductor power switches. With regard to the switching properties of semiconductor devices the authors have adopted an analytically fundamental approach rather than the current industrial standard. This is educationally easier to understand and more conservative in solution than accepted industrial practice.

Some re-organisation of the original text has permitted expansion of the section on Adjustable Speed Drives, now in Chapter 4, to include a brief treatment of various types of synchronous motor.

The previous work on step-wave inverters has been concentrated into the new Chapter 11 and an additional chapter has been included on pulse-width modulation (PWM) control.