Optimum Design of Line-Start Permanent-Magnet Synchronous Motor Using Mathematical Method

This paper presents an analytical method to design an optimum Line-Start Permanent-Magnet Synchronous Motor (LSPMSM). An initial LSPMSM (L0) is designed by combining an induction motor (IM0) and an interior permanent magnet (IPM0) motor. The IM0 and IPM0 are designed analytically from sizing equations. The optimum LSPMSM is developed from IM cage optimization for starting torque and permanent magnet (PM) optimization of the IPM for efficiency. By combining the rotors of the optimised IM and IPM, an optimum hybrid rotor is obtained for the LSPMSM. The optimized motor has better performance in the transient and steady state compared to L0. The proposed optimisation method based on a mathematical model is implemented using a genetic algorithm (GA). An optimization case study is implemented using both the proposed mathematical method and FEM. The optimization results indicate that the optimum design found using the proposed mathematical method is obtained more rapidly and has comparable performance to that found using FEM optimization.