Abstract: In this paper, some problems about IGBT's operation characteristics are discussed. A driving mode called zero voltage commutation and zero current commutation (ZVC/ZCC) technique with high efficiency and safety is introduced. By making use of removing charges and reverse avalanche of IGBT, zero voltage or zero current occurs during the commutation course of IGBT. It is very useful for reducing the effects of tailing and latching and improving the operation efficiency and safety.