TABLE OF CONTENTS The first transistor was discovered in 1948 by a team of physicists at the Bell Telephone Laboratories and soon became a semiconductor device of major importance. Before the transistor, amplification was achieved only with vacuum tubes. Even though there are now integrated circuits with millions of transistors, the flow and control of all the electrical energy still require single transistors. Therefore, power semiconductors switches constitute the heart of modern power electronics. Such devices should have larger voltage and current ratings, instant turn-on and turn-off characteristics, very low voltage drop when fully on, zero leakage current in blocking condition, ruggedness to switch highly inductive loads which are measured in terms of safe operating area (SOA) and reverse-biased second breakdown (ES/b), high temperature and radiation withstand capabilities, and high reliability. The right combination of such features restrict the devices suitability to certain applications. Figure 3.1 depicts voltage and current ranges, in terms of frequency, where the most common power semiconductors devices can operate.
The plot gives actually an overall picture where power semiconductors are typically applied in industries: high voltage and current ratings permit applications in large motor drives, induction heating, renewable energy inverters, high voltage DC (HVDC) converters, static VAR compensators, and active filters, while low voltage and high-frequency applications concern switching mode power supplies, resonant converters, and motion control...
