Thermal Design of Stacked Power Modules for Electric Drive Applications

This paper reports the thermal design of a stacked arrangement inserting four IGBT modules between five heat sinks to achieve good cooling performance while enabling them to be installed into the limited space. Such stacked four IGBT modules can be used for a variable voltage converter (VVC), a three-phase motor inverter (M-INV) and a three-phase generator inverter (G-INV) of one electric control system in one electric vehicle or hybrid electric vehicle. Work presented in this paper are the thermally related structure design and thermal-electric and computational fluid dynamics coupled simulation, while the prototyping and thermal test of the stacked arrangement are still ongoing. The simulation results indicate that the stacked arrangement can be designed into a compact 121 mm × 94.7 mm × 90.8 mm structure while achieving the maximum virtual junction temperature below 150 °C under the coolant feed temperature of 70 °C, flow rate of 10 L/min and pressure drop of 0.16 bar for the VVC delivering 150 kW, the M-INV delivering 100 kW and the G-INV delivering 50 kW. If validated with the ongoing work, the stacked arrangement can be employed to increase power density and improve electrical and thermal performance of the power modules in the electric control systems with multiple converters/inverters.