Mission-Profile-Based Lifetime Study for a SiC/IGBT Module in a Propulsion Inverter

This work studies the lifetime of two silicon carbide (SiC) and one silicon insulated gate bipolar transistor (Si-IGBT) power modules in a three-phase propulsion inverter for two different driving cycles. The ECE-City manual and the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) are used as the mission profiles for the lifetime comparisons. For the WLTC, the urban and highway phases are included. The effect of blanking time and the MOSFET’s reverse conduction is considered on the power loss analysis. The lifetime versus different fluid rates of the heatsink are also compared for the three modules over the two mission profiles. The analysis shows that, the WLTC drive cycle causes considerably larger accumulated damage on the three compared modules’ devices, in comparison to ECECity manual. Moreover, its impact on the SiC-based devices is higher compared to that of the Si-IGBTs. However, the SiC modules present substantially higher lifetime, (>80%) for WLTC and (>90%) for ECE-City manual, compared to Si-IGBTs. In addition, it is observed that, a reasonable range of fluid flow rate in the heatsink can play a considerable role in improving or reducing the lifetime of the power devices in a reliability-wise optimization.