Short Circuit Behavior of Series-Connected 10 kV SiC MOSFETs

Proper voltage sharing among series-connected power MOSFETs is important for reliable operation and particularly crucial under short circuit stress. An uneven voltage sharing may result in an early failure of the more stressed MOSFET. In this paper, for the first time, the short circuit behavior of the series-connected 10 kV SiC MOSFETs is investigated and analyzed using the experimental results. An active clamping circuit is demonstrated at 5.7 kV dc link voltage to improve the voltage sharing during the short circuit. Analytical expressions and the experimental data have been used to estimate the short circuit (SC) robustness of the series-connected 10 kV SiC MOSFETs. The estimated short circuit withstand time of the two series-connected 10 kV SiC MOSFETs is superior to the 15 kV SiC IGBTs.