A gate driver based soft-switching SiC bipolar junction transistor

This paper presented a new soft-switching concept that the soft transition is achieved based on gate driver control. A new soft-switched IGBT and MOSFET Gated Transistor (SS-IMGT) base drive structure is proposed for high power SiC BJT. The proposed base scheme can proportionally drive SiC BJT into near-saturate region. In addition, the zero voltage turn-on for BJT can be adaptively achieved at all load current range with very simple control. The whole SS-IGMT structure could be regarded as an "improved" voltage driven device. The new structure has inherent soft transition property with reduced stress and switching loss. The proposed gate driver based soft switching method is verified by experimental test with both Si and SiC BJT. SiC BJT demonstrate superior turn-off behavior compared to Si BJT. Further effort will be on utilizing the excess energy of resonant inductor to further reduce the conduction voltage drop across SiC BJT.