SiC MOSFETs based split output half bridge inverter: Current commutation mechanism and efficiency analysis

Abstract

Body diode of SiC MOSFETs has a relatively high forward voltage drop and still experiences reverse recovery phenomenon. Half bridge with split output aims to decouple both the body diode and junction capacitance of SiC MOSFETs, therefore achieving a reduced switching loss in a bridge configuration. This paper makes the current commutation mechanism and efficiency analysis of half bridge with split output based on SiC MOSFETs. Current commutation process analysis is illustrated together with LTspice simulation and afterwards, verified by the experimental results of a double pulse test circuit with split output. The double pulse test shows the devices' current during commutation process and the reduced switching losses of SiC MOSFETs compared to that of the traditional half bridge. The efficiency comparison is presented with experimental results of half bridge power inverter with split output and traditional half bridge inverter, from switching frequency 10 kHz to 100 kHz. The experimental results comparison shows that the half bridge with split output has an efficiency improvement of more than 0.5% at 100 kHz switching frequency.