Thermal Analysis and Experimental Validation of a 30 kW 60000 r/min High-Speed Permanent Magnet Motor With Magnetic Bearings

Thermal analysis calculation is an indispensable checking process in the design of the high-speed permanent magnet synchronous machine (HSPMSM) with the active magnetic bearings, due to its high loss density and non-contact support mode. The finite element method (FEM) is applied for visual global temperature distribution. Because the thermal analysis is a complex problem reflected the interaction among the electromagnetic field, temperature field, and fluid field, so it cannot be solved independently, and a multi-physical field simulation based on magneto-thermal-fluid coupled iterative solution is proposed. An electromagnetism (EM) model is established to solve electromagnetic loss and the computational fluid dynamics (CFD) software is used to simulate convective condition, both the results are applied to the thermal analysis of motor. The data interaction is bidirectional and transfers in the form of a field, and the interaction during the EM model, the CFD model, and thermal analysis is fully considered to guarantee high accuracy. Finally, two prototypes of 30-kW 60000 r/min magnetically suspended HSPMSMs have been developed. The experimental results of back-to-back towing test validate the accuracy of the proposed multi-physical field simulation.