A Novel Time-Sharing Conduction Method for Improving SiC MOSFET Reliability

With the development of wind/solar power and severe working conditions the inverter facing, the reliability of power devices is getting more and more attention. However, most of the existing methods for improving reliability of power devices can only reduce the switching loss, but not the conduction loss. Therefore, this paper proposes a novel time-sharing conduction method for a four-leg inverter to improve the reliability of power devices. This method not only reduces the switching loss of SiC MOSFETs but also lower the conduction loss of SiC MOSFETs and it is implemented on a four-leg inverter with a redundant leg and three TRIACs. The performance of this method is verified and compared with three-leg inverter. The simulation results show that both the junction temperature fluctuation and amplitude are decreased greatly and the calculated lifetime of SiC MOSFET is increased tenfold with the proposed method.