Robust Optimal Design Process for Minimizing the Deviation of Cogging Torque in PMSMs Considering Interaction between Manufacturing Tolerances

Uniformity of performance and minimized maintenance requirements are highly demanded in industrial applications. However, tolerances in the manufacturing process are inevitable, and the inherent manufacturing tolerances degrade the cogging torque performance of permanent magnet synchronous motors (PMSMs). Therefore, a robust optimal design process was proposed to ensure that even if manufacturing tolerances occur in the PMSM, the output is similar to the intended performance of the engineer. Through this proposed design process, optimization was performed to minimize the mean and deviation of the cogging torque. First, the tolerance items of the stator and rotor were summarized. Second, noise factors were selected by performing an impact analysis on cogging torque deviations by randomly sampling manufacturing tolerances with normal distribution. Finally, design variables that affect the cogging torque were selected through sensitivity analysis reflecting the noise factors, and optimization was performed to minimize the mean and deviation of cogging torque.