Slot/pole combinations choice for concentrated multiphase machines dedicated to mild-hybrid applications

This paper presents multiphase permanent magnet machines with concentrated non-overlapped winding as a good candidate for automotive low voltage mild-hybrid applications. These machines often require a trade-off between low speed performances such as high torque density and high speed performances like flux weakening capabilities. This paper describes how to choose a key design parameter to ease this compromise, the slots/poles combination, according to three parameters: winding factor including harmonics factor, rotor losses amount thanks to a comparison factor, and radial forces balancing. The comparison criterions are based on both analytical formula and Finite Element Analysis.