Electrothermal Simulation Analysis on Power Loss and Junction Temperature of GaN HEMT in Boost DC-DC Converter

Power loss calculation and junction temperature analysis are of great significance to the thermal design in power electronics. In this paper, an electrothermal simulation analysis on GaN HEMT is performed based on the power loss calculation under actual working conditions including conduction loss and switching loss. By coupling the power loss and heat conduction process, the temperature distribution of the GaN HEMT, as well as the junction temperature, can be obtained by both the FEM thermal simulations and RC thermal model. The results show that the switching loss accounts for about 20% of the total power loss, far less than the conduction loss of 80% under the given working conditions. The RC thermal model based on the thermal resistances obtained by FEM simulations can predict the results of FEM simulations well for cases with different heat source distributions, while the model with original thermal resistances from thermal conductivity and size of layers cannot provide accurate predictions. The maximum junction temperature occurs in the case of concentrated distributed heat sources. This research is promising to provide valuable references for thermal management in GaN electronics.