Thermal and Electrical Modeling and Optimization of SiC Power Modules for Traction Inverters

White Paper Overview 

This paper discusses the modeling and validation of silicon carbide (SiC) power modules for electric vehicle (EV) traction inverters. SiC MOSFETs offer high efficiency but present design challenges due to their sensitivity to parasitic inductances and fabrication inconsistencies. 

We explore in-depth the impact of package parasitic mismatch and die−level mismatch on the robustness of SiC power modules. The case study focuses on onsemi’s Single Side Direct Cooling (SSDC) power module that integrates 900 V SiC MOSFETs in a 6−pack configuration.

An equivalent circuit model is built using ANSYS simulation tools and extracted RLC parasitic values. The model’s electrical and thermal performance is compared with experimental test data. 

Key findings highlight the impact of package layout constraints and process variations on module performance. Electro-thermal simulations assess Joule heating effects, while electrical simulations analyze switching behavior. Finally, mitigation strategies such as optimizing internal gate resistance are proposed to enhance module ruggedness.