Optimization design of low-speed surface-mounted PMSM for pumping unit

Efficiency and torque ripple are usually especially concerned during the working process of permanent magnet synchronous motor (PMSM). The loss and cogging torque generated during the working process of PMSM are analyzed. A low-speed surface-mounted PMSM used for direct-drive pumping unit is optimized. For increasing efficiency and reducing cogging torque, Taguchi's method is employed and height of stator yoke, width of stator tooth, thickness of permanent magnet, and air-gap length are selected as the variables. The orthogonal experiment is conducted with FEM. The mean of the results and the two-order interaction effects between the selected variables are analyzed, then the best optimization combination is determined by the analysis of variance. The results show that Taguchi's method is an efficient and effective approach, which is finally proved by the prototype test.