Testing and Assessment on the Short-Circuit Withstand Capability of Press-Pack IGBT Considering the Unbalanced Clamping Forces

Abstract

Press-pack insulated gate bipolar transistors (PP-IGBTs) modules have become the mainstream choice in high-power-density applications such as breakers. Sufficient short-circuit (SC) withstand capacity is the key to the safe operation of power electronic equipment. However, the effect of the unbalanced clamping force, which is experienced frequently in the multichip PP-IGBT, on the SC withstand capacity needs to be studied. First, an SC withstand test platform is established to calibrate the critical energy for different voltage levels. Second, the SC process and the withstand capacity for different clamping forces are investigated experimentally. Combined with the finite-element simulation results, the effect of the clamping force on the SC withstand capability is analyzed, and the weak parts are pointed out. An evaluation method of SC withstand capacity considering the effects of the voltage levels and the clamping force is proposed. Finally, the effect of the unbalanced clamping force is experimentally studied using parallel single-chip modules (PPI), and the SC withstand test of a 3300-V/200-A multichip module with unbalanced clamping force is carried out. The results show that the clamping force has little effect on the critical energy, but the module with greater clamping force has worse SC withstand capacity.