Thermal Simulation of Air-Cooled PMSM with Novel Winding Structure and Specialized Cooling Design for eVTOL Applications

For high-power-density permanent-magnet synchronous machine (PMSM) used in electric vertical takeoff and landing (eVTOL) aircraft, heat dissipation is challenging due to potential temperature rise, which may cause irreversible demagnetization of permanent magnets and winding insulation damage. This paper presents a thermal simulation analysis of an air-cooled PMSM with a novel winding structure and specialized cooling design for eVTOL applications. The motor's power losses are calculated by electromagnetic simulation. Then the novel winding structure composed of stacked 26 thin copper sheets is subjected to equivalence, and its equivalent thermal conductivities in the radial, circumferential, and axial directions are calculated. The multiple reference frame (MRF) method was employed to model the cooling airflow generated by the propeller. Finally, a computational fluid dynamics (CFD) analysis was conducted on the PMSM featuring open end caps and a hollow rotor design for cooling, with results showing that temperatures are maintained within a reasonable range and validating the effectiveness of the cooling design for air-cooled motors.