Electromagnetic Analysis and Vibration Reducing of Segmented Skew Rotor for Built-in U-shaped Permanent Magnet Motor

This paper presents a detailed analysis of the electromagnetic force and vibration behavior of segmented skew rotor for built-in U-shaped permanent magnet motor. First, the configuration of U-shape permanent magnet motor is introduced and designed. Subsequently, the effect of segmented skew rotor on output torque and torque ripple is investigated. By comparing the results, the optimum angle between different rotor sections is determined. Furthermore, this paper compares the electromagnetic performances of the motor with segmented skew rotor and the normal rotor. It proves that the motor with the segmented skew rotor can reduce the torque pulsation, make the back-EMF more sinusoidal, improve the magnetic weakening ability and reduce vibration. Comparing with the motor with normal rotor, the output torque fluctuation of the motor with segmented skew rotor is reduced from 42 N•m to 7 N m. Meanwhile, the fluctuation of cogging torque is reduced from 55 N m to 3 N m and the noise is reduced by 18dB. Finally, the test is carried out to validate the theoretical analysis, and the experimental results agree with the simulation results. This paper proves optimizing the number of rotor segments and angle between rotor segments have an important effect on electromagnetic characteristics of built-in permanent magnet motor. It can reduce torque ripple, vibration and noise of motor. It provides an idea to optimize the electromagnetic characteristics of the motor and reduce the vibration and noise of the motor.