Design and Analysis of a 120kW High-speed Permanent Magnet Motor with a Novel Evaporative Cooling Configuration for Centrifugal Compressor

High-speed permanent magnet synchronous motor (HSPMSM) is widely used in compressor applications as a result of its superior performance. However, high temperature rise is still a crucial problem for high-power HSPMSM. This paper proposes a 120kW, 17750rpm HSPMSM with a novel evaporative cooling configuration used in centrifugal compressor. Based on 2-D finite element method (FEM), electromagnetic design of the motor is carried out. The result of electromagnetic analysis suggests that the motor presents a good performance. Then, the cooling structure of the motor is elaborately introduced. Refrigerant R134a (1,1,1,2 tetrafluoroethane) flowing and evaporating inside the spiral channel provides an excellent cooling performance due to its huge specific latent heat. Steady state thermal analysis based on 2-D FEM is conducted in order to verify the cooling capacity of the new configuration, which shows the motor has a relatively low temperature rise. Therefore, a high efficiency and high reliability design of the motor is achieved, and it could provide a reference for similar motor design.