Optimal design of five-phase permanent magnet assisted synchronous reluctance motor for low output torque ripple

This paper presents the optimal design of five-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM) for low torque ripple. PMa-SynRMs are similar to interior permanent magnet (IPM) motors in structure but with reduced permanent magnets, PMa-SynRMs are more economical. In this study, lumped parameter model (LPM) is used in the approach to initially design the five-phase PMa-SynRM. Thousands of models are designed by LPM, which are then converged to optimized model using differential evolution strategy (DES). Optimization is done with maximum efficiency and minimum torque ripple as objective. The optimized 3 kW five-phase PMa-SynRM is then analyzed by finite element method (FEM) for fine tuning. Simulation results for back electromotive force (EMF), developed torque, torque ripple, cogging torque, and other necessary motor parameters such as d and q-axis inductances variation over respective axis currents are verified by fabricated prototype.