Effect of Multilayer Windings on Five-Phase Interior PM Machines

Thanks to their higher power density and efficiency, the interior permanent magnet (IPM) machines equipped with a fractional slot concentrated winding (FSCW) layout have shown potentials in electric vehicle applications. Literature has shown that the application of multilayer winding layout to three-phase machines is effective in reducing the effect of low order space harmonics and the induced eddy current loss components in the rotor core and magnets. Besides, the machine saliency and the reluctance torque component are improved. This paper attempts to extend the same concept to five-phase windings. The effect of multilayer design with different stator winding connections is also investigated using some favorable slot/pole combinations of the five-phase case. The comparison between different winding layouts for different slot/ pole combinations is carried out using 2-D finite element analysis. The study mainly focuses on the effect of the multilayer winding design on the induced eddy current losses in both machine core and magnets and the machine torque density.