Comparison of MOS devices for high frequency inverters

The switching performances of power MOSFETs, insulated gate bipolar transistors (IGBTs), and two types of MOS-controlled thyristors (MCT) are evaluated and compared. The devices all have a similar forward blocking voltage rating of near 1 kV and current ratings that were matched as closely as possible. All the devices were operated up to their maximum possible frequency. It is shown that, below several hundred kilohertz switching frequency, a power MOSFET is undesirable because of the extremely large forward voltage drop and the need for parallel operation during high current switching applications and that, above 500 kHz, the MOSFETs are the only devices that can operate effectively. Also, it is shown that the IGBTs operate effectively up to about 200 or 300 kHz, the fairly long turn-off limits their ability to function at higher frequencies, and the MCTs are limited to switching below about 50 to 100 kHz.<>