An Electro-Thermal Coupling Model of Trench Gate SiC MOSFETs

An electro-thermal coupling model is proposed for trench gate SiC MOSFETs. Firstly, focusing on the nonlinear differences of trench gate devices, the C-V characteristics are analyzed, and a nonlinear model of terminal capacitance is reconstructed. Then, after the model is built, double pulse experiments are conducted on trench gate SiC MOSFET devices to verify the accuracy of the model for trench gate devices. Next, the temperature-dependent electrical parameters in the high-temperature circuit model are supplemented and corrected on the basis of the completed trench gate SiC MOSFET circuit model, with a modeling temperature range of 25-200°C. Finally, a thermal network model is built, and the existing electrical model is coupled with the thermal model in real time to form an electro-thermal coupling model and applied to DC-DC converters. Experimental and simulation comparisons are made to predict the junction temperature under different operating conditions. The average error of the steady-state junction temperature of the trench gate device is 3.6%, verifying the accuracy of the electro-thermal coupling model.