Influence of Anti-parallel Diode on UIS of IGBT

Some literature works have been reported to investigate the unclamped inductive switch (UIS) robustness of the IGBTs, but the influence of anti-parallel diode on UIS of IGBT has not been extensively investigated. In this paper, the UIS characteristics of IGBT with and without two types of anti-parallel diodes are experimentally studied and analyzed. It is found that the parallel combination of SiC Schottky diode and IGBT has better UIS capability than the single IGBT, while the parallel combination of FRD and IGBT has worse UIS capability than the single IGBT. The leakage current characteristics indicates that the current commutation to the parallel diode is the major reason of the influence of parallel diode on UIS failure of IGBT.