Short-circuit ruggedness assessment of a 1.2 kV/180 A SiC MOSFET power module

While investigations on short-circuit ruggedness of discrete SiC MOSFET are widely encountered in the scientific literature, there is not so much research dealing with the operational robustness of high power SiC MOSFET modules. In this paper, the short-circuit (SC) ruggedness under hard switching fault (HSF) of a commercial 1.2 kV/180 A SiC MOSFET power module in half-bridge configuration will be presented. The test conditions, such as DC-link voltage (V_DC), gate resistance (R_g) and gate-source supply voltage (V_GS) are varied systematically to investigate the effect of these parameters on the peak current and short-circuit energy. The peak current of the investigated module can be as high as 2.5 kA for V_GS=20 V and does not depend significantly on the gate resistors used in this research. A safe operating area (SOA) is mapped at different VGS and pulse durations and for VDS=800 V, which is typically encountered in applications for devices of these ratings. Five modules were failed in total, with a critical short-circuit energy, E_cr ranging from 7.3 J to 9.7 J. The failure mechanism is generally the thermal runaway. Prior to failure, a decrease in V_GS can be observed which is an indication of an increased gate-source leakage current. The results obtained in this experimental work show a good withstand capability of the modules to SC events. The experimental data obtained during this work gives an insight into the device behavior and limitations during SC events and can be used by gate driver designers to develop protection circuits.