Double-Side Cooled 3.3 kV, 100 A SiC MOSFET Phase-Leg Modules for Traction Applications

This thesis presents the development of a double-side cooled 3.3 kV, 100 A SiC MOSFET phase-leg power module for heavy-duty traction applications. Parasitic extraction and thermal simulations of the module showed a parasitic inductance of 2.89 nH and junction temperature of 108.3 °C at a heat flux of 156 W/cm² under a typical water-cooling condition. Electric field simulations identified high electric field stress at the module's outer surface edges exposed to air, posing a risk for partial discharge. To mitigate this risk, a solution that involves covering the critical point in an epoxy was proposed, analyzed, and validated through partial discharge inception voltage tests. Steps for fabricating the module are presented. Static electrical characterization of the fabricated module showed an average on-resistance of 31 mΩ and an average leakage current of 356 nA at VDS of 3 kV, which are similar to those of the unpackaged devices. The module with a double-side cooling design achieved an exceptional power density of 116.6 kW/cm³, more than twice that of any single-side cooled 3.3 kV SiC module. This makes it highly suitable for next-generation electric transportation systems that require high power density and efficient thermal management, such as electric trucks, railways, and eVTOL aircraft.