Permanent magnet material and pulsating torque minimization in spoke type interior PM machines

摘要

This paper proposes an alternative spoke type interior permanent magnet machine (STIPMM) design to minimize the pulsating torque and decrease the use of permanent magnet materials. The proposed rotor design consists of a number of rotor lamination stacks with notches made on the surface and packed in the axial direction. Within each stack, the width of the permanent magnets (PMs) and the span of the notches are different from those in the other lamination stacks. By varying the magnet width and the span of the notches in each lamination stack, the pulsating torque of the machine can be minimized while reducing the amount of PM materials used. A differential evolution (DE) algorithm was used to solve this minimization problem by evaluating a large number of design candidates. Finite element analysis was employed when calculating the cost function of the optimization. The rated performance of the optimum design is benchmarked against a base-line STIPMM in which the rotor was modified based on the 2007 Camry motor model. The results show improvement in the pulsating torque and the PM material utilization of the proposed model.