| A key issue in the field of electromagnetics research today is the simulation of the magnetic properties of magnetic materials.Specifically involves three directions,including how to describe the magnetic properties of materials with a suitable mathematical model;and devices and methods for measuring magnetic properties that can correspond to this mathematical model,in order to achieve the purpose of reasonably extracting the magnetic property data of materials Finally,it involves combining the numerical calculation method of electromagnetic field with the material characteristic model,so as to solve practical problems in engineering.The study of these three aspects can achieve the purpose of accurately simulating and calculating the magnetic field and loss distribution in the core of electrical equipment using the magnetic characteristics of soft magnetic materials in actual operation,and can be used as a theoretical basis for optimizing equipment design,so that core loss and local overheating can be reduced.Electrical equipment has higher reliability.The main work and results of this paper are as follows.Based on the inadequacy of the original J-A model that cannot accurately simulate small hysteresis loops,a new and improved dynamic J-A model is proposed in this paper.Introduce a scaling factor R that can change the slope of the small hysteresis loop into the main differential equation of the original JA model,construct a new improved static JA model,and combine it with loss statistics theory to form a new dynamic JA model.By comparing the calculation results with the measurement results,it is shown that the improved dynamic J-A model proposed in this paper improves the accuracy of the original model by simulating the hysteresis loop with small hysteresis loops.Mechanical stress will affect the microscopic magnetic domain structure of ferromagnetic materials.Macroscopically,the hysteresis characteristics of magnetic materials will change and cause changes in the material's magnetic loss,making the heating phenomenon in the operation of power equipment more obvious.This article first conducts relevant experiments to measure the magnetic properties of magnetic materials under stress,analyzes the effect of stress on magnetic properties,and then adds a non-linear loss component to the loss separation method to simulate the magnetic loss results at high frequencies under stress,and corrects the losses The coefficient of each loss component in the separation method is used to represent the effect of stress.Based on the above analysis,an analytical method for simulating the total loss of magnetic materials under stress is proposed.By comparing the simulation results with the measurement results,it is shown that the analytical method proposed in this paper is effective for simulating the total loss of magnetic materials under stress.A 25cm Epstein square ring designed to measure the magnetic characteristics of ultra-thin silicon steel sheets was designed and manufactured.The test frequency range was 45Hz-1kHz.The thickness of the ultra-thin silicon steel samples was 0.08mm.Hysteresis loops of ultra-thin silicon steel samples under different experimental conditions were measured with custom Epstein square rings and compared with laboratory BROCKHAUS-MPG200 electrical steel measurement system test results to prove the accuracy of the custom Epstein square rings.Combining the hysteresis model with the finite element analysis,the numerical analysis formula of the magnetic field finite element was deduced,and the corresponding computer program was compiled.The finite element analysis was carried out for the non-oriented electrical steel sheet using the proposed magnetic characteristics simulation method.The results show the accuracy of the proposed method. |
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