Heat-Pipe-Based Thermal Management System Design for a 250-kW GaN-Based Integrated Modular Motor Drive

Integrated modular motor drive (IMMD) is an effective approach for realizing high-efficiency, high-power-density, and fault-tolerant electric machines. However, designing an efficient thermal management system (TMS) for the motor drive becomes a challenge, particularly due to space constraints. This paper presents the design of a TMS based on 3 mm heat pipes for a 250 kW IMMD intended for aviation applications. The power electronics module is simulated using PLECS software where an electrothermal analysis is conducted. A simplified thermal resistance model of the system is developed to estimate the die junction temperature of GaN semiconductors. The performance of the proposed TMS is evaluated through experimental tests and compared to an off-the-shelf heat sink. The results demonstrate that, at a fluid temperature of 24 °C, the designed TMS outperforms the off-the-shelf heat sink. Additionally, the designed TMS was tested with a fluid temperature of 41 °C, matching the temperature of the coolant fluid in the final application. The results indicated that the maximum estimated die junction temperature of the GaN semiconductors is 95.16 °C while generating the rated power loss in the converter.