Robust Design Optimization of SPMSM based on Manufacturing Uncertainty Analysis of Prototype

This study presents a robust design optimization (RDO) method for surface-mounted permanent magnet synchronous motors (SPMSMs) used in servo applications. Manufacturing uncertainties such as variations in stator and rotor geometry were measured from a prototype and shown to cause additional harmonic components (AHCs) in cogging torque. Sensitivity analysis identified rotor eccentricity and slot opening width as the most influential design variables. A kriging-based surrogate model was constructed, and optimization was performed to minimize the mean and variance of cogging torque while satisfying a voltage constraint. The optimized design was validated through simulation and experiments on four prototypes, showing reductions of 52 % and 59 % in the 16th and 18th harmonic components, respectively. These results confirm the effectiveness of the proposed RDO method in improving torque consistency under actual manufacturing variation.