Investigation of Permanent Magnet Segmentations and Gaps in 2-Pole High-Speed Permanent Magnet Motor with Toroidal winding

This paper investigates the influence of different permanent magnet (PM) segmentations on electromagnetic performances of 2-pole high-speed PM motors, considering parallel and perpendicular PM segmentations referring to diametric magnetization direction. Meanwhile, taking into account the manufacturing process, the influence of the gap between two PM segmentations on parasitic effects, i.e. cogging torque and rotor loss, is also investigated, together with the influence of different motor topologies. In addition, different shaft materials are compared for high-speed applications. Compared with unsegmented ring PM, parallel segmentation can achieve a 25% reduction of rotor loss, while perpendicular segmentation has a negligible effect. Furthermore, the gap in the parallel PM segmentation has more significant impact on parasitic effects.