Increase of Output Power from IGBTs in High Power High Frequency Resonant Load Inverters

The primary goal of this work is to replace MOSFETs with IGBTs in high frequency (~300kHz) high power (0.1-1MW) inverters with series resonant load, a topology commonly used for induction heating. In this application, the IGBT losses are totally dominated by turn-off losses, and the turn-off losses decay less than linearly with the current. This is an invitation to develop a new control strategy which makes the necessary derating of the IGBTs less severe. For the conditions in this work, the new strategy can give 3 times more output power compared to a simple current reduction destressing for the same number of paralleled IGBTs.