Design of Five-Phase Permanent Magnet Assisted Synchronous Reluctance Motor for Low Output Torque Ripple Applications

Beak, J., Bonthu, S., & Choi, S. (2016). Design of Five-Phase Permanent Magnet Assisted Synchronous Reluctance Motor for Low Output Torque Ripple Applications. IET Electric Power Applications. 10(5), 339-346.

Abstract

his paper presents the design of five-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM) for integrated starter and generator (ISG) of hybrid electric vehicle with low torque ripple. When ISG works as starter in order to operate engine, PMa-SynRM produces 3 kW power at the rated speed of 1800 rpm with reduced vibration by multi-phase structure. PMa-SynRMs are similar to interior permanent magnet motors in structure but are more economical due to reduced permanent magnets. In this study, lumped parameter model (LPM) using magnetic circuit design is used in the approach to initially design the five-phase PMa-SynRM. Numerical equations are integrated with the LPM to design the machine with its given range of design parameter values. Thousands of designs are generated by LPM, which are then converged to optimised model using differential evolution strategy. In this study, optimisation is done with maximum efficiency and minimum torque ripple as objective. The optimised 3 kW five-phase PMa-SynRM is then analysed by finite element method for fine tuning. Simulation results for back electromotive force, flux linkage, developed torque, torque ripple, cogging torque, torque speed characteristics and d and q-axis inductances variation over respective axis currents are verified by fabricated prototype.