Optimization Design of High-Speed Permanent Magnet Synchronous Motor Rotor for New Energy Vehicles

The development of permanent magnet synchronous motor(PMSM) for new energy vehicle presents a trend of high voltage, high speed, high efficiency, high power density, and low vibration and noise which has set a higher demands on the design of motors. Taking the design of the surface-mounted rotor structure of PMSM for new energy vehicles with a rated power of 45 kW and a rated speed of 12000r/min as an example, this paper optimizes the rotor structure by adopting “segmented rotor pole structure + combination of different permanent magnet materials at different angles” and other approaches. The study aims to ameliorate the sinusoidality of the magnetic field in air gap, while ensuring that the output torque is not reduced, thereby reducing the THD of the air-gap magnetic density and winding back-emf. The simulation results show that when the permanent magnet is split into 5 segments, the harmonic distortion of the magnetic density in air gap is reduced by more than 31%, and the harmonic distortion rate of the back-emf is reduced by 3%. This study has certain theoretical guidance for the design of high-speed PMSM for new energy vehicles.