Research On Magnetic Strain Of Laminated Structures Of Electrical Steel Sheets And Its Stress Influence

With the rapid development of power grid system,the noise generated by power equipment due to vibration has an increasingly prominent impact on the life of the equipment itself and the health of the surrounding residents.The main source of vibration and noise of the body of power equipment is caused by the magnetostrictive effect of electrical steel materials and the electromagnetic effect among its laminations.At present,scholars at home and abroad are mainly committed to the measurement and simulation of magnetostrictive strain caused by the magnetic field in a single electrical steel material.However,in the actual operation,due to the clamping force,overlapping forms,overlapping width of laminations and other factors,the magnetic strain characteristics of electrical steel laminated core are different from those of single electrical steel sheet.Therefore,it is necessary to carry out in-depth and detailed research on the strain characteristics caused by magnetism of electrical steel laminated structure directly.In order to find out the law of the influence of clamping force,overlapping form and overlapping width of laminations on the characteristics caused by magnetism of electrical steel laminated structure,this thesis studied the establishment of electrical steel lamination structure simulation model,multi-physical field simulation calculation and experimental test system from the perspective of the combination of simulation calculation and experimental research.The research results lay a foundation for the optimization design of core structure and the proposal of vibration and noise reduction measures.The main research contents of this thesis are as follows:Firstly,the magnetic strain measuring device and experimental scheme of electrical steel laminated structure were determined.The single-phase double-column and three-phase three-column electrical steel laminated core structures were designed,and several lamination cores with different lapping methods and lapping widths were made.The experimental scheme of the effects of clamping force,lapping form and lapping width on the magnetic strain characteristics of electrical steel laminated structure was put forward,and the stress application method was determined.Secondly,the magnetic strain performance of electrical steel laminated structure under the influence of stress was simulated.The magnetic field simulation physical model of electrical steel laminated structure was established.The magnetic field performance of laminated core under different lap forms and lap widths was simulated and calculated based on the finite element method,and the optimal lap mode and lap width were determined.On this basis,the structural force field simulation model of electrical steel sheet laminated structure was established,the effects of different stresses on the magnetic strain performance of electrical steel sheet laminated structure were discussed,and the multi physical field coupling calculation of the electrical steel sheet laminated structure simulation model was completed.Finally,the experimental study and result verification of magnetic strain performance of electrical steel laminated structure under the influence of stress were investigated.A magnetic strain performance test system of single-phase double-column laminated core was developed,and the test points were set at the core column,yoke and joint of the laminated core.The effects of lap form,lap width and stress on the magneto strain properties of laminated core were measured and analyzed.A magnetic strain performance test system of three-phase three-column laminated core was built,the experimental tests on the T-joint and corner area of three-phase three-column laminated core were conducted,and the influence rule of stress on the magnetic-strain performance of laminated core under different magnetic field intensity was measured and analyzed.Meanwhile,the validity of the experimental scheme and simulation calculation is verified.