Improved Thermal Management and Analysis for High-Power Heat Pipe Cooled FSCW PMSM for HEV Auxiliary Power Unit Application

Fractional-slot concentrated-winding (FSCW) permanent magnet synchronous machines (PMSMs) offer attractive performance advantages such as compact structure and high torque density. To achieve high performance and high reliability of high-power FSCW PMSMs, efficient thermal management remains a significant challenge. This paper presents and analyzes a mixed heat pipe cooling method, where heat pipes are integrally designed into both the stator core and windings of high-power FSCW PMSMs, enabling them to be placed as close to the heat source as possible. Furthermore, a simplified iterative optimization design method based on a lumped parameter thermal network is performed to optimize the heat pipe cooled FSCW PMSMs. The effectiveness of the mixed heat pipe cooling system in high-power FSCW PMSMs is demonstrated through the analysis, construction, and testing of a 110kW prototype. The simulated and experimental results indicate that the peak winding temperature of the prototype with the mixed heat pipe cooling system can be reduced by 29°C compared to that of the machine with the water jacket cooling method under rated conditions.