Cooling System Design for High-Power-Density Permanent Magnet Synchronous Motor Based on Micro Heat Pipe Array

High power-to-weight ratio and reliability are key priorities in the advanced design of permanent magnet synchronous motors (PMSMs). This article develops and characterizes an efficient cooling structure for PMSMs to achieve these goals by applying a novel micro heat pipe array (MHPA). The cooling structure with MHPA is arranged in motor slots with concentrated winding, creating an efficient cooling path directly contacting the winding and iron core. Stator modules are manufactured and tested to verify the effectiveness of the developed structure at the first stage. The impact of MHPA placement on electromagnetic and thermal performance is investigated. The superiority of the design with horizontally slot-bottom placed MHPA is demonstrated. Two prototypes of PMSMs with identical specifications and dimensions were built for testing: one equipped with the described cooling system and the other with conventional air cooling. Simulation and test results prove the effectiveness of the developed cooling structure on over 14 °C hotspot temperature reduction and 10% power density improvement.