Electro-thermal simulation of current sharing in silicon and silicon carbide power modules under short circuit condition of types I and II

Abstract

Current sharing during short circuit events of types I and II has been investigated by electro-thermal compact simulation of semiconductor devices paralleled in a 650V power module. The response of silicon IGBTs has been compared to that of silicon carbide MOSFETs. The study of current unbalance due to symmetrical and asymmetrical interconnect topologies has been followed by isothermal and full electro-thermal simulation of the power modules. It has been shown that replacing in the simulation the active devices within the module by resistors leads to misleading results, because the current unbalance under short circuit conditions is mainly due to the difference in the gate-source/gate-emitter voltage among the individual paralleled devices. Finally, it has been demonstrated that in the investigated power modules, self-heating contributes to the mitigation of current unbalance.