The aim of this study was to improve the thermal performance of a plate heat sink by decreasing the maximum temperature of the insulated-gate bipolar transistors (IGBTs). We investigated the effect of varying the installation method, location, and configuration of six asymmetric high- and low-power IGBTs and calculated the thermal performance of the heat sink as the IGBTs were moved. The forced convective heat transfer at the heat sink was simulated using a shear stress transport k-w turbulence model. We successfully minimized the maximum IGBT temperature by optimizing the IGBT installation location.