Analysis And Optimization Of Vibration And Noise Of Modular Permanent Magnet Synchronous Motor For New Energy Vehicles

With the increasingly serious problems of energy shortages and environmental degradation,more and more attention has been paid to energy-saving and environmentallyfriendly transportation,and new energy vehicles have developed rapidly.Because permanent magnet synchronous motors have the advantages of small size,simple structure,and good speed regulation performance,they are widely used as drive motors in the field of new energy vehicles.Modular stator permanent magnet synchronous motors are gradually being favored by new energy automobile motor manufacturers due to their advantages of high material utilization,high slot full rate and fast winding speed.In the performance requirements of new energy vehicles,vibration and noise are important indicators,and they have a decisive influence on the comfort of the car.Modular stator permanent magnet synchronous motor has a certain influence on its electromagnetic performance and structural strength due to its block assembly structure,so the research on the vibration and noise of this type of motor is of great significance.This thesis takes the modular permanent magnet synchronous motor of new energy vehicle as the research object,and conducts research on it from four aspects: radial electromagnetic force wave,stator mode,vibration and noise and noise optimization.1.Analytical calculation and analysis of the armature winding magnetomotive force,radial air gap magnetic density and radial electromagnetic force wave of the non-modular permanent magnet synchronous motor are first carried out;then,based on the electromagnetic field calculation theory,a set of the two-dimensional electromagnetic model of a modular permanent magnet synchronous motor with 54 slots and 12 poles formed by the splicing of 6 stator modules.The constant permeance,tooth permeance,and radial gas permeance of the modular permanent magnet synchronous motor are corrected by introducing correction coefficients.The gap flux density and radial electromagnetic force waves are analyzed;finally,the validity of the above analytical calculations is verified by the finite element calculation method.2.Analyze the structural modal of the modular permanent magnet synchronous motor,and use the finite element method and electromechanical analogy method to calculate the inherent modal of the stator core single-ring mode and the stator casing double-ring mode;the double-loop model Experiments were carried out on the influence of different connection modes on the motor mode,which verified the validity of the finite element calculation and analytical calculation of the modular permanent magnet synchronous motor.3.Through the analysis of the mechanical modulation of the stator teeth of the motor,the mechanism of the effect of the modulation of the stator teeth on the vibration and noise of the motor is analyzed;based on the two-dimensional electromagnetic model of the modular permanent magnet motor,the electromagnetic force of the stator teeth,the vibration of the motor and the noise of the motor are analyzed.On the one hand,the finite element method was used to conduct a multi-physics coupling analysis of the motor’s vibration and noise;the simulation results found that the modularity of the motor’s stator intensified the motor’s vibration and noise.4.Based on the simulation method of multi-physics coupling of motor vibration and noise,the optimization of motor vibration and noise is explored.The laws of motor vibration and noise under different pole arc coefficients,slot opening widths and magnetic steel shapes are studied,and the laws of noise variation are analyzed in detail using the theory of mechanical modulation of electromagnetic force waves by stator teeth.The results showed that: the change of pole arc coefficient,slot opening width and magnet shape can adjust the magnitude of the modulation force wave of the stator teeth and reduce the vibration and noise of the motor.