Turn-off modes of silicon carbide MOSFETs for short-circuit fault protection

Abstract

With the rapid development of semiconductor technology, the applications of silicon carbide (SiC) MOSFETs have been booming in recent years, where short-circuit fault protection plays an important role. In this paper, voltage and current waveforms under different short-circuit faults are analyzed. Then, two types of turn-off modes, namely a soft turn-off mode and a two-stage turn-off mode are introduced. The peak voltage, short-circuit energy and anti-interference performances of SiC MOSFETs under the different turn-off modes are analyzed and compared at various DC bus voltages. The obtained experimental results show that the soft turn-off mode can reduce voltage spikes. However, it needs a blanking time to improve the anti-interference performance of the system, which increases the short-circuit energy. For the two-stage turn-off mode, the anti-interference performance of the system is improved and the short-circuit energy is obviously decreased. However, the peak voltage generated by the two-stage turn-off mode is slightly larger than that of the soft turn-off mode. On the whole, the two-stage turn-off mode is more competitive than the soft turn-off mode for the short-circuit fault protection of SiC MOSFETs.