Design optimisation of high performance fractional-slot distributed winding PM Synchronous machines for In-wheel application in Electric Vehicles

Abstract

In general, PM machines with conventional integer slot distributed winding (ISDW) schemes exhibit significant cogging torque resulting in high torque ripple which makes them unsuitable for EV applications which require low torque pulsations. This paper presents detailed analysis of the performance of PM Synchronous motor (PMSM) with fractional slot distributed winding (FSDW) scheme which shows significant reduction in torque ripple compared ISDW PM machines. Effect of the fractional slot winding distribution on electromagnetic torque pulsations has been analysed using Finite element (FE) computation technique. For a fair quantitative comparison between the above machine types, a flexible optimisation approach is proposed in this paper which generates Pareto fronts of the individual machine types.