Research On Vibration Analysis And Vibration Reduction Method Of Permanent Magnet Motor

The main sources of motor noise are mechanical noise,air noise,and electromagnetic noise.In many large motors,the motor vibration noise caused by the magnetostrictive effect accounts for a relatively large amount.This article mainly introduces the contribution of magnetostrictive effect to the vibration and noise of permanent magnet synchronous motors and the solutions.Firstly,the magnetostrictive effect of non oriented silicon steel sheet under alternating magnetic field is analyzed in finite element method,and the variation law of surface stress of non oriented silicon steel sheet with different placement angle and different number of laminated sheets is studied.According to the simulation results in the finite element method,an experimental platform was built and the experimental scheme was made.The vibration and strain of non oriented silicon steel sheets with different number of laminated sheets and different placement angles in alternating magnetic field were measured.Through time-domain and frequency-domain analysis,it was found that with the increase of the number of non oriented silicon steel sheets,the strain value and vibration amplitude on the surface of silicon steel sheets would gradually decrease.It is also found that the low frequency vibration noise of the motor is mainly concentrated in the power frequency of one and two times of the power frequency.The results are consistent with the simulation.Secondly,the magnetic mechanical coupling numerical model of the motor stator is established.The experiment of filling negative magnetostrictive material on the motor stator is carried out in the finite element method,and the surface stress changes at different times after filling the material are compared.Then,the position and size of the negative magnetostrictive material filled in the stator of the motor is determined by parametric scanning and nested cycle method,and the filling scheme of the actual motor is formulated.The actual motor stator is drilled and filled with nickel rod.The surface strain and vibration of the motor stator are measured,and the results are consistent with the simulation In order to reduce the vibration and noise of the motor to a certain extent.The maximum strain value can be reduced by 16%.Finally,based on BP neural network and finite element calculation data modeling analysis.Firstly,two methods of determining the best hole position and hole size by finite element calculation are introduced,namely,the parametric scanning method in Comsol Multiphysics and the combined simulation method with COMSOL Multiphysics with Matlab,the joint simulation method can write all the data to txt document directly after the calculation,and give the parameter combination of the optimal filling scheme.Then,the BP neural network algorithm is used as the substitute model of the finite element calculation,and the data generated by the joint simulation method is regressed and analyzed,the stress values of other 100 groups of parameters are predicted with the accuracy of 1.9011×10^-10.which further reduces the time of finite element calculation and improves the calculation efficiency.