Topology Optimization of Liquid-Cooled Heat Sinks for High-Power-Density IGBT Modules

High-power-density insulated gate bipolar transistor (IGBT) modules in new energy vehicles require efficient heat dissipation and good temperature uniformity. This study proposes a tri-objective topology optimization method for a liquid-cooled heat sink using average temperature, temperature variance, and flow dissipation as the objective functions. A two-dimensional model was established in COMSOL to investigate the effects of the fluid volume fraction, inlet pressure, and optimization-weight distribution on the optimized topology and thermo-hydraulic performance. The results show that a fluid volume fraction of 0.4 and an inlet pressure of 15 Pa provide the best overall performance. Compared with the bi-objective design, introducing temperature variance as a third objective reduces temperature variance by 50.23%, with only a 1.08% increase in average temperature. Three-dimensional simulations further verify the optimized design. Compared with a conventional pin-fin heat sink, the topology-optimized structure reduces the average temperature by 10.43% and the temperature variance by 44.37%, while increasing the flow dissipation by 49.57%. These results show that tri-objective topology optimization is an effective method for improving the thermal management of high-power-density IGBT modules.