Research On Harmonic Reduction And Lightweight Design Of No Load Back EMF For Disc Permanent Magnet Motor

Compared with the traditional cylinder permanent magnet motor,the disc permanent magnet motor has the advantages of short axial size,simple structure and high power density.The motor is widely used in wind power generation,flywheel storage,electric vehicles,aerospace and other narrow space applications.But in some strict working environment,the sine degree and weight of back EMF waveform of disc permanent magnet motor are required to be higher.This paper is mainly based on the single rotor cored disc permanent magnet motor,including the electromagnetic design and simulation modeling,reducing the harmonic of back EMF waveform and proposing a lightweight design which can reduce the weight of the motor.(1)The basic topological structure of the disc permanent magnet motor is introduced in this paper.Combined with the basic dimension equation of the disc permanent magnet motor and the equivalent magnetic circuit method,the main design parameters of the single rotor disc permanent magnet motor with iron core are obtained,and the finite element simulation model is built according to the design parameters.(2)Based on 2D equivalent linear model,the formula of no-load air gap flux density of single rotor cored disc permanent magnet motor is deduced,and the expression of no-load back EMF is obtained.Combined with the expression,aiming at the problem of high harmonic content of no-load back EMF waveform of 24 slot 20 pole disc permanent magnet generator,a multi parameter combination method based on pole slot matching,pole arc coefficient and inclined pole mode is proposed to solve the problem Through the finite element simulation calculation and comparison of the results of various combination parameters,and the FFT analysis of the back EMF waveform in MATLAB,the influence of the proposed method based on multi parameter combination on the harmonic of the back EMF waveform is explored.(3)On the premise that the motor still has good performance,the stator yoke flux density of 12 slot 10 pole disc permanent magnet motor is analyzed,and a lightweight design method by weakening the stator yoke core is proposed.The stator magnetic density cloud diagram,stator current,back EMF waveform and stator mass before and after lightweight are compared and analyzed,and the rationality of the proposed lightweight structure is analyzed.(4)The prototype of the proposed lightweight stator structure is developed and the experimental platform is built.The experimental results are compared with the simulation results,and the influence of the proposed lightweight structure on the motor performance is further analyzed.