A Study on Switching Surge Voltage Suppression of SiC MOSFET by Digital Active Gate Drive

High voltage SiC power MOSFETs are a suitable replacement for the conventional Si IGBTs in power conversion systems due to its high speed switching capability. High speed switching operation of SiC MOSFETs induces switching surge voltage interconnected to the parasitic inductance in the wiring of power conversion systems or power modules. Active gate drive of SiC MOSFETs enables to suppress the switching surge voltage by optimizing the gate driving waveform. This paper proposes a digital active gate driver as the advanced active gate drive for SiC MOSFETs for suppressing the switching surge voltage. The results are compared to the conventional snubber capacitor. The proposed digital active gate driver suppresses the peak surge voltage at least 18% without the undesired additional current oscillation by the snubber circuit.