Research On Noise Reduction Methods Of Motors Based On The Characteristics Of Negative Magnetostrictive Materials

In large motors,the vibration noise caused by magnetostrictive effect of silicon steel sheets on stator core is larger.In order to study the effect of magnetostrictive effect on stator core,the magnetostrictive characteristics of non-oriented silicon steel sheets were measured.Based on the measured data,a magneto-mechanical coupling numerical model was established,the vibration of the stator of the motor under magnetostrictive action is studied,and the main vibration frequency of the stator core of the motor is single and double supply power frequency,The measured vibration results were consistent with the numerical analysis,which verifies the correctness of the model.A simulation model was designed to simulate the direction of the magnetic field in the motor.The coil is not in contact with the non-oriented silicon steel sheet,so there is only magnetostrictive force caused by the changing magnetic field on the non-oriented silicon steel sheet.The position coordination of the silicon steel sheet is changeable,and the influence of the magnetostrictive effect on the stress characteristics of the non-oriented silicon steel sheet in different directions of the magnetic field is analyzed.it is found that the main frequency of the vibration is affected by the silicon steel sheet at different positions.In the direction of magnetic path turning,the non-oriented silicon steel sheet vibrate obviously at the power supply frequency.At the same time,an experiment was designed to measure the vibration signals on the non-oriented silicon steel sheet under the changing magnetic field,which was consistent with the experimental results.Aiming at the problem of motor vibration and noise caused by the magnetostrictive effect of silicon steel sheet.A new method was proposed that punching holes in a motor stator core and filling a material with negative magnetostrictive properties to suppress motor vibration and noise.The negative magnetostrictive deformation offset the positive magnetostrictive deformation so as to achieve the purpose of noise reduction.In this thesis,Sm0.88Nd0.12Fe2 was selected as the negative magnetostrictive material for punching and filling the stator core of motor.Sm0.88Nd0.12Fe2 alloy was prepared by vacuum arc furnace.The microstructure?crystal structure and magnetostrictive properties of as-cast and annealed Sm0.88Nd0.12Fe2 were measured and observed.It was found that the magnetostrictive properties of the alloys were significantly improved under annealing conditions.According to the constitutive equation of magnetostrictive material.The negative magnetostrictive material Sm0.88Nd0.12Fe2 was filled in the stator hole of the motor.Compared with the stress and vibration of the unfilled material,the stress and vibration of the motor stator core obviously decrease after the filling of Sm0.88Nd0.12Fe2.At the same time,the vibration noise of the perforated filling material Sm0.88Nd0.12Fe2 on the silicon steel sheet was designed and measured,and the vibration peak was significantly reduced compared with the unfilled material.This thesis presents a method of filling negative magnetostrictive material with holes in motor stator core,which is beneficial to further suppress the vibration and noise caused by magnetostrictive effect of silicon steel sheet,and provided a new idea for reducing the electromagnetic vibration and noise of motor.It has certain academic significance and application prospects.