Heat Transfer Enhancement in Liquid-Cooled Minichannel Heat Sinks of Silicon Carbide MOSFET Power Inverters

Abstract

Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) power inverters are widely used in electric vehicles (EVs) due to their high efficiency. However, under high power loss conditions, conventional cooling methods become inadequate, necessitating effective thermal management. This study numerically investigates heat transfer enhancement in a three-dimensional serpentine minichannel heat sink (SMHS) with embedded vortex generators (VGs) for cooling two SiC MOSFETs, each dissipating 60 W. Two VG configurations with equal projection areas are considered: rectangular winglet pair and delta winglet pair (DWP), along with common flow up (CFLU) and common flow down flow orientations. The MOSFET thermal stack-up is mathematically modeled, and uniform volumetric heat generation is applied at the SiC junction to resemble realistic power loss conditions. Simulations are performed using the finite-volume solver ANSYS Fluent for Reynolds numbers ranging from 388 to 1812. SMHS maintains the junction temperature below the specified threshold, while the addition of VGs further reduces it by 3.77 °C. Although addition of VGs results in similar junction temperature reductions, SMHS with DWP under CFLU flow orientation exhibits a higher heat transfer coefficient, lower thermal resistance, and reduced pressure drop. Consequently, improved thermal performance is achieved, ensuring effective thermal management for EV power inverters.