High temperature silicon carbide (SiC) die are the most critical and expensive component in electric vehicle (EV) power electronic packages and require both active and passive methods to dissipate heat during transient operation. The use of phase change materials (PCMs) to control the peak junction temperature of the SiC die and to buffer the temperature fluctuations in the package during simulated operation is modeled here. The latent heat storage potential of multiple PCM and PCM composites are explored in both single-sided and dual-sided package configurations. The results of this study show that the addition of phase change material (PCM) into two different styles of power electronics (PE) packages is an effective method for controlling the transient junction temperatures experienced during two different drive cycles. The addition of PCM in a single-sided package also serves to decrease temperature fluctuations experienced and may be used to reduce the necessary number of SiC die required for EVs, lowering the overall material cost and volume of the package by over 50%. PCM in a single-sided package may be nearly as effective as the double-sided cooling approach of a dual-sided package in the reduction of both peak junction temperature of SiC as well as controlling temperature variations between package layers.