Efficient thermal management of GaN power devices using electric-field-regulated nanoparticle-enhanced phase change materials

Compact, high-efficiency power electronic systems require effective thermal management under localized, spatially non-uniform heat loads, as exemplified by gallium nitride (GaN) power devices. Although phase change material (PCM) and nanoparticle-enhanced phase change material (NePCM) systems can provide compact latent-heat buffering for such loads, conventional approaches are generally passive during operation, and faster melting does not necessarily translate into lower local device temperatures. In this study, a non-uniform DC electric field was applied to regulate the melting behavior and particle redistribution of an n-octadecane-Al 2 O 3 NePCM in a transparent visualization chamber coupled with a GaN heat-source array. The evolution of the melting front and the infrared surface temperature field were monitored as the applied voltage was varied from −15 to ＋15 kV at a fixed heat input of 2.4 W. Without an electric field, the NePCM formulation containing 0.02 vol.% Al 2 O 3 nanoparticles and an oleic acid dispersant shortened the recorded complete-melting time by 32.8%, from 9.67 to 6.50 h, while the estimated peak junction temperature showed no measurable reduction. Under applied electric fields, the near-electrode melting front was reshaped, the complete melting time was shortened, and post-melting particle redistribution depended on voltage magnitude and polarity. During the heated melting experiments, the maximum estimated electrode-side electrical power was 3.01 mW. For the selected diagonal dual-source layout, applying −10 kV reduced the peak junction temperature from 109.7 to 77.1 ° C and decreased the maximum difference between peak and mean infrared surface temperatures by nearly 10 ° C. These results show that non-uniform DC fields can provide active regulation of NePCM thermal response, offering an experimental basis for localized hotspot control in compact high-power-density power modules under spatially non-uniform loading. • A GaN heat-source array links field-regulated NePCM melting with device temperature. • The tested NePCM formulation shortens complete melting time by 32.8% at 0 kV. • Non-uniform DC fields reshape the melting pathway and particle distribution. • Voltage magnitude and polarity regulate post-melting Al 2 O 3 redistribution. • Applying −10 kV reduces peak junction temperature by 32.6 ° C.