This study proposes an unequal air-gap model for PMSMs with the objective of reducing the torque ripple and improving the demagnetization characteristics. Shape optimization is performed to optimize the design variables of the unequal air-gap model, which are the shape of the unequal air-gap and the angle between the Vshaped permanent magnets. An optimization process was performed by the Kriging model based on Latin
Hypercube Sampling (LHS), and Genetic Algorithm (GA). Finite element analysis (FEA) was also utilized to analyze the torque and demagnetization characteristics. As optimal design results, the torque ripple of the optimal model was reduced by 7.7 % and the demagnetization temperature was improved by 2.2 %.