Comparative Analysis of Surface-Attached Cooling Structure for Efficient Thermal Management of SPMM-TW

Efficient thermal management is the essential precondition for electrical machines to achieve high power density and reliable operation. This article presents a surface-attached cooling structure (SACS) for the thermal management of slotless permanent magnet motor with toroidal winding (SPMM-TW). The SACS consists of several channels attached to the surface of the toroidal winding, and the shorter heat path guarantees that the heat generated in the winding can be effectively extracted. Three-dimensional electromagnetic finite-element analysis and the computational fluid dynamics (CFD) are used to evaluate the losses of the SPMM and obtain the accurate convective heat transfer coefficient (CHTC). For predicting the winding temperature accurately, the layered winding model is proposed to simulate the actual winding conditions. In addition, the influence of different channel materials on the temperature rise is experimentally evaluated on the same prototype. The experimental results show that the layered winding model can well simulate and predict the actual temperature distribution of the winding, and the SACS can effectively reduce the temperature rise of the winding compared with the housing water jacket cooling, where the SPMM with the SACS can withstand a continuous current density of 17.2 A/mm 2 and a peak current density of 28 A/mm 2 .