Core Loss and Thermal Behavior of High-Speed SMC Motor Based on 3-D FEA

Abstract

In a high-speed motor, core loss is much greater than other losses and is the main source of heat due to the high operating frequency. Therefore it is of crucial importance to be able to calculate the core loss accurately. The rotational core loss model is employed in this paper. Practical methods considering the alternating magnetic filed only are also presented, which are useful to designers who do not have rotational core loss data. The three-dimensional (3-D) finite element analysis (FEA) is used to calculate the accurate temperature distribution. Core losses are coupled directly into thermal calculation by keeping the same hexahedral mesh structure between magnetic field analysis and thermal analysis. These methods are applied to a 2 kW, 20 krpm high-speed claw pole motor with soft magnetic composite (SMC) core, and the results are compared and discussed finally.