Prediction And Analysis Of Vibration And Noise Of Permanent Magnet Synchronous Motor

When PMSM is running,motor vibration and motor noise are often accompanied by each other.The main purpose of this research is to study the causes of the electromagnetic noise of permanent magnet motor,the relationship between the design parameters of the motor and the electromagnetic noise and the calculation method of the electromagnetic noise.The work of this paper includes the following aspects:Firstly,in order to reduce the distortion rate of air gap flux density waveform of PMSM,an accurate and rapid analytical method for optimizing the shape of magnetic poles is proposed.The magneto MFs,inter-polar MFs and permeability functions in the air gap are optimized.Based on the analytical model,the electromagnetic parameters such as no-load air gap flux density and line-no-load back electromotive force of an 8-pole 36-slot PMSM are calculated and analyzed.The results show that the analytical calculation is in good agreement with the finite element calculation,indicating that the method has certain practical value.On the basis of determining the length of the narrowest gap,through the parametric design of the end thickness of the permanent magnet,the ideal performance parameters of air-gap magnetic density,linear no-load back electromotive force and tooth groove torque are obtained.It provides a reference for the optimal design of magnetic pole shape of PMSM.Secondly,the mode of the motor is the basis for analyzing the vibration of the motor.If the calculation of stator mode of the permanent magnet synchronous motor is not accurate,it will be impossible to avoid the main force wave frequency of the radial electromagnetic force from being designed near the anti-resonance point in the design stage.Therefore,this article respectively to the permanent magnet motor stator core and stator assembly(including the stator core,winding and chassis)modal simulation analysis,get the three-dimensional vibration of the stator natural frequency and modal vibration mode,analyzes the structure influences the natural frequency and vibration mode of motor parts,avoid permanent magnet motor work runtime resonance.The modal experiment of the prototype is carried out by the exciter excitation method,and the obtained low order natural frequency is compared with the simulation results,the error is within a reasonable range,and the reliability of the finite element simulation analysis method is verified.Finally,in the density of radial electromagnetic force of permanent magnet synchronous motor in spatial distribution,the density of radial electromagnetic force based on the analysis of the distribution of the time,this article will use the finite element analysis software ANSYS Workbench Harmonic Response module electromagnetic vibration and noise of permanent magnet synchronous motor coupling simulation analysis,get the motor vibration displacement,vibration velocity and vibration acceleration curve,and the results of vibration velocity is used to calculate the noise sound pressure level(SPL).The noise SPL of the motor is obtained by vibration noise experiment,and the accuracy of the coupling analysis is verified.The design scheme of the permanent magnet motor with different thickness of magnetic extremes is optimized and analyzed.By comparing the results before and after optimization,it can be seen that the optimized motor can effectively reduce the vibration noise of the motor on the premise of ensuring the electromagnetic performance.