A Study on Optimal Pole Design of Spoke-Type IPMSM With Concentrated Winding for Reducing the Torque Ripple by Experiment Design Method

An optimal design procedure is proposed to effectively reduce the torque ripple by optimizing the rotor pole shape of the spoke-type IPMSM with concentrated winding. The procedure is composed of two steps. In step 1, the steepest descent method (SDM) is used with only two design variables to rapidly approach the optimal shape. From the near optimal rotor shape as a result of the step 1, the design variables are reselected, and the drawing spline curves are utilized to explain more complex shape with the Kriging model in step 2. By using an optimal design procedure, we show that the optimized rotor pole shape of the spoke-type IPMSM effectively reduces the torque ripple while still maintaining the average torque.