A Rotor Structure Designed for Low Noise Emission

A permanent magnet synchronous motor model combining a U-shaped structure and a V-shaped structure (U+V-type) is proposed to decrease the noise of electromagnetic field and improve the output torque, and the influence on noise is studied by comparing with a V+V-shaped structure (V+V-type). The core length, magnet size, outside diameter and some other parameters are the same for both models. After the simulation and comparison of back EMF, torque ripple, cogging torque, and air gap magnetic density between the two models, it is concluded that the electromagnetic characteristics of the U+V-type motor are better than those of the V+V-type model. Finally, noise optimization is carried out based on the U+V-type motor, and theoretical analysis was carried out from the perspective of decreasing electromagnetic force and optimized torque ripple. After comparing torque ripple and the noise of electromagnetic field, it can be seen that the decibel value of electromagnetic noise was decreased by 4.5% on the original basis. The research proves the proposed topological structure's effectiveness and the theoretical analysis's correctness, and it offers a better optimization design for reducing electromagnetic noise and increasing the output torque.