Thermal Analysis of High-Speed SMC Motor Based on Thermal Network and 3-D FEA With Rotational Core Loss Included

This paper presents the thermal analysis of a high-speed motor with soft magnetic composite (SMC). Due to the high operation frequency, the core loss is much greater than the other losses and, hence, is the major heat source in the high-speed motor. Therefore, it is of crucial importance to be able to calculate the core loss accurately. In this paper, the rotational core-loss model is employed and implemented by using 3-D magnetic-field analysis (FEA). Two methods to model the thermal behavior are presented. The first method uses a combination of lumped and distributed thermal parameters, which are obtained from motor dimensions and thermal constants. The second method employs 3-D FEA to accurately calculate the temperature distribution. Core losses are directly coupled into the thermal calculation by keeping the same hexahedral meshing for magnetic-field analysis and thermal analysis. A testing bench for the high-speed SMC motor prototype has been set up to measure the core loss. The temperature rises were measured by thermal probes. The calculation and measurement results are compared and discussed.