Journal: IEEE Transactions on Industry Applications
Authors: Yun-Jae Won, Jae-Hyun Kim, Soo-Min An, Myung-Seop Lim
DOI: 10.1109/TIA.2026.3691640
This article proposes a robust optimal design process for surface-mounted permanent magnet synchronous motors (SPMSMs) with step-skew to minimize the mean and deviation of cogging torque considering manufacturing tolerances. The manufacturing tolerance items of the stator and rotor are presented, including those associated with the segmented stator structure. Samples are fabricated to measure the variation of each item. The additional harmonic components (AHCs) of the cogging torque induced by the tolerances are analytically derived. A statistical impact analysis based on finite element analysis (FEA) is performed to determine the permanent magnet (PM) magnetization angle, PM left–right thickness difference, and stator inner radius as the most influential factors for the cogging torque deviation. Then, sensitivity analysis is conducted to determine the design variables that significantly affect the mean and deviation of the cogging torque. Optimization based on a kriging surrogate model is performed to obtain optimum models that minimize the mean and deviation of the cogging torque while satisfying the constraints. The two optimum models improve not only the cogging torque characteristics with step-skew but also those without step-skew compared with the base model. Experimental verification is performed using fabricated prototypes corresponding to the optimum models. The verification confirms that the measured cogging torque values fall within the statistical distributions of each optimum model, and that the native harmonic component (NHC) of cogging torque is significantly reduced compared with the base model.