A Real-Time Thermal Model for Monitoring of Power Semiconductor Devices

A resistance-capacitance (RC) thermal network with temperature-dependent thermal conductivities and heat capacitances is used to calculate the junction temperature of insulated-gate bipolar-transistor modules using a device model realized in Simulink. The collector current I_C, collector-emitter voltage V_CE, and the case temperature T_C measured during the cycling are used as input parameters of the proposed model. The proposed model is easier to implement compared with the thermosensitive electrical parameter (TSEP) method, and it is compared with an R_C network with constant thermal conductivity and heat capacitance model and experimentally verified by using a TSEP method. The results of the proposed model show an improvement of the accuracy for determining the junction temperature compared with the model with constant thermal conductivity and heat capacitance.