Study Of Affection From Magnetostriction In Laminated Core On Vibration Noise Of Transformer And AC Motor

In order to find an effective method of decreasing vibration and noise in laminated cores ofpower transformer and AC motor, the vibrations are analyzed based upon the coupling betweenthe magnetic field and the mechanical deformation including the magnetostriciton (MS) effect ofthe core iron. The MS characteristics of silicon sheets is firstly measured; then amagneto-mechanical strong coupled model of laminated cores including MS effect is founded;and using the proposed model, the magnetic field, deformation and noise level of the cores arestudied by analysis and experiment. It provides an analysis and experimental methods for designlower vibration and noise cores. Main points of this paper are as follows:(1) The magnetic and magnetostrictive properties of silicon steel core of oriented siliconsteel sheet and no orientation silicon steel sheet are measured based on the cores of EpsteinFrame.(2) MS force is given by finite element method and the magneto-elastic coupled modelincluding MS is calculated by compiled program. The magnetic field, MS forces and vibrationdeformation of transformer cores are all calculated. Then the results are compared withmeasurement results. They are agreement which proved the correctness of the numerical modeland calculation method.(3) Considering the anisotropic MS and magnetization characteristic of laminated core, anumerical model of three-dimensional magneto-mechanical strong coupled is established. Basedon the model, the magnetic field, vibration and acoustic field of a dry power transformer coresare analyzed and measured.(4) Based on the research of MS, vibration and noise of transformer laminated core, theflexible high permeability soft magnetic composites is provided to filled the overlapping gaps toreduce the electromagnetic vibration and noise, which uses the relieving method of reducingvibration and noise caused by MS. The reduction effect is verified through theoretical analysisand experimental measurement.(5) The vibration of permanent magnet synchronous motor with MS is analyzed. Theinteraction of electromagnetic force vibration of core under different frequencies of single effectand iron core deformation, vibration acceleration, strain energy density distribution is thencalculated. Finally, experimental study is carried out of the permanent magnet synchronousmotor and the influence of the MS to the core vibration is achieved.It is the first time that using flexible high permeability soft magnetic composites to filloverlapping gaps of transformer laminated core to reduce electromagnetic noise is concerned inthis paper. It offers a new method to reduce the electromagnetic noise of transformer laminated cores with a feasible solution. The achievement of this paper provides theoretical basis to designand verify new noise-reduction measures.