Impact of Flux Barriers Shape on the Performance of Reduced Rare-Earth Multilayer Interior Permanent Magnet Synchronous Motor

Multilayer interior permanent magnet synchronous motor has more flexibility when choosing different magnet materials for rotor structures. It also has high power density and high efficiency during high-speed operation. However, due to the limited availability of rare earth materials, high cost, and environmental issues, there is a need to replace with non-rare-earth or reduce rare earth magnet material in the interior permanent magnet synchronous motors. To improve motor performance, different shapes of flux barriers inserted in double U-shaped rotor topology still require detailed analysis, which is yet to be explored in the literature from a design perspective. So, this work proposes a reduced rare earth double-layer U-shaped rotor topology with a hybrid magnet structure to reduce rare earth magnets. The design process includes fractional slot windings, the impact of different flux barrier shapes in the rotor topology, and the manufacturing of the stampings. This study examines the reduction of cogging torque and core losses and improves the efficiency of low-voltage level, especially two-wheeler applications for high CPSR. Cost estimation, comparative analysis of proposed topology, and simulation results as obtained from the 2D FEM simulation software have been presented.