The Thermal Simulation Study of DC-DC Converters Based on Phase Change Cooling

DC-DC converters typically rely on liquid cooling for heat dissipation. However, these methods suffer from slow heat dissipation and large temperature fluctuations. Under short-term high-power conditions, these methods struggle to effectively limit the temperature rise of power devices, compromising the reliable operation of DC-DC converters. Phase-change heat dissipation is more promising but lacks theoretical analysis at the converter level. To this end, the flow-solid-thermal coupling model of the phase change heat sink is established by studying phase change materials (PCMs) such as paraffin wax and low-melting-point alloy (LMPA), and using numerical simulations. The heat dissipation performance of different PCMs is analyzed and compared with that of traditional cooling methods. The results show that under power losses of 45.2 W, the temperature rise of the SiC MOSFET using an LMPA is reduced by more than 50% compared to paraffin-based cooling. With power losses of 73.2 W, the phase change heat sink reduces the SiC MOSFET temperature by 23.6 °C compared to a conventional heat sink.