Analytical Stator Design for Reducing the Cogging Torque in Surface-Mounted PM Motors

We present an analytical method for the calculation of cogging torque in surface permanent-magnet (PM) motors. The cogging torque is calculated by integrating the Maxwell stress tensor inside the air gap. The stator design techniques are applied to reduce the cogging torque in SPM motors. The used techniques are stator dummy slots, teeth pairing and stator slot skewing. The direct search method is used to find the optimum geometry in the mentioned methods. Finally, the validity of the proposed model and the obtained results are verified with Finite Element Analysis.