Design of High-speed Wet-type Permanent Magnet Synchronous Motor Considering Oil Frictional Loss

This paper proposes a wet-type permanent magnet synchronous motor (WTPMSM) for the Electro-Hydrostatic Actuator (EHA), in which the stator and the rotor are all immersed in the special aviation hydraulic oil. Although the oilimmersed structure can enhance the heat dissipation performance, the fluid frictional loss will also significantly increase due to the hydraulic oil in the air-gap. In this paper, a 8-pole/ 10-slot five-phase WTPMSM is first proposed with the concentrated single-layer winding, which has strong fault tolerant capacity. The accurate calculation method of oil frictional loss for the WTPMSM is then proposed based on CFD, while the influence of the air-gap on oil frictional loss is analyzed, which can provide a guideline for the air-gap choice. Finally, the WTPMSM performance is analyzed by considering the oil frictional loss. The simulation result shows that the WTPMSM has excellent fault tolerant performance and high power density, very suitable for the aerospace EHA application.