Design and thermal performance analysis of a new water-cooled structure for permanent magnet synchronous motors for electric vehicles

Abstract

In order to solve the problem of severe stator winding heating due to the single cooling structure of a permanent magnet synchronous motor (PMSM) for electric vehicles (EVs), and to further improve the heat transfer capability of the PMSM, a new water-cooled structure is proposed in which cooling pipes are placed at the stator yoke to increase the heat transfer area. In order to evaluate the heat transfer effect of this new water-cooled structure, this paper takes a 50kW PMSM for EVs as the research object. By establishing a three-dimensional full-domain fluid-solid coupled heat transfer model, setting boundary conditions and reasonable assumptions, the full-domain fluid-heat coupled field of the PMSM is calculated numerically, and the fluid flow characteristics and heat transfer variation laws of the new water-cooled structure are analyzed. The results show that compared with the original cooling structure, the maximum temperature drop of stator winding and permanent magnet can reach 5.23% and 11.17% respectively. The results obtained can provide a reference for future research on the thermal performance and water-cooled structure optimization of PMSMs for EVs.