Compact electro-thermal modeling of a SiC MOSFET power module under short-circuit conditions

A novel physics-based, electro-thermal model which is capable of estimating accurately the short-circuit behavior and thermal instabilities of silicon carbide MOSFET multi-chip power modules is proposed in this paper. The model has been implemented in PSpice and describes the internal structure of the module, including stray elements in the multi-chip layout, self-heating effect, drain leakage current and threshold voltage mismatch. A lumped-parameter thermal network is extracted in order to estimate the internal temperature of the chips. The case study is a half-bridge power module from CREE with 1.2 kV breakdown voltage and about 300 A rated current. The short-circuit behavior of the module is investigated experimentally through a non-destructive test setup and the model is validated. The estimation of overcurrent and temperature distribution among the chips can provide useful information for the reliability assessment and fault-mode analysis of a new-generation SiC high-power modules.