An online junction temperature monitoring correction method for SiC MOSFETs at different parasitic parameters

Due to the remarkable performance of SiC MOSFET on high temperature, it is promising in the future applications in various of applications. The accurate online junction temperature based on dynamic temperature sensitive electrical parameters (TSEPs) is significant for the protection and condition monitoring, which can prolong or monitor the lifetime of SiC MOSFET devices. In this paper, four different dynamic TSEPs including turn-on delay time, turn-off delay time, maximum current turn-on and turn-off switching rate are theoretical analyzed taking the parasitic parameters into consideration. The experimental analysis of the influence of parasitic parameters dynamic TSEPs are carried on using a buck converter test setup. Based on the theoretical and experiments analysis, a junction temperature correction method is proposed for SiC MOSFET. The online junction temperature monitoring experiments are used to verify the accuracy and effectiveness of the proposed method. The results show that the proposed correction method can largely eliminate the junction temperature monitoring error at different parasitic parameters. The maximum measurement error is reduced from 147 °C to 4.7 °C after correction.