Rotor Design of Permanent Magnet Synchronous Reluctance Motors in Rail Traffic Vehicle

Permanent Magnet Synchronous Motor (PMSM) has been widely used in rail vehicle due to its remarkable advantage of high torque density, high efficiency and wide range of speed regulation. Optimizing the rotor design of PMSM, has become the main methods to achieve good sinusoidal wave form of air-gap flux density and to reduce the vibration noise. This paper mainly presents the principal of reducing air-gap flux harmonic by using double-layer rotor design. The finite element method is used in this paper to verify the air-gap magnetic density harmonic, the modal stiffness and the NVH performance of PMSM. By optimizing the wave shape of air-gap magnetic density, the peak efficiency of PMSM is up to 97% and the vibration noise reduce to 75dB, which is significantly lower than the induction motors among the same efficiency range. With this optimal rotor design, the PMSM can highly improve the competitiveness and performance compared to conventional induction motor.