Junction Temperature Model and Degradation Effect in IGBT Multichip Power Modules

This paper presents a junction temperature model for multichip IGBT power modules based on the on-state voltage measured at high current. In order to reduce the error during the calibration of the model, the characterization is carried out in DC-Current tests while acting on the cooling system to modify its thermal resistance. This way, different junction temperatures are reached when similar power losses are been generated. Based on the obtained results, a model for the online estimation of the junction temperature is obtained, which could be implemented in operating converters. Moreover, the effect of the degradation of the emitter bond wires in the estimation is analyzed.