Measurement And Simulation Of Magnetic Characteristics Of New Magnetic Materials Under Multi-Physical Factors

As the hub of electromechanical energy conversion in electric power system and industrial field,high efficiency and low loss are its eternal development propositions.In recent years,with the rapid development of grid technology,electrical equipment is required to gradually develop in high frequency and miniaturization.Compared with traditional silicon steel materials,new amorphous and nanocrystalline magnetic materials have high permeability,low coercivity and low specific loss,and have excellent energy saving performance under high frequency conditions.However,due to the structure and physical characteristics of the materials themselves,amorphous and nanocrystalline magnetic materials are very sensitive to the changes of physical factors such as temperature and stress,while the motors and transformers using amorphous and nanocrystalline materials cannot avoid the introduction of stress in the process of assembly,punching and winding.Due to the presence of loss during operation,the temperature will rise,which in turn affects the magnetic properties.Therefore,the complex magnetic characteristic measurement method of such magnetic materials is studied,and the hysteresis model considering temperature and stress factors is the premise of improving the design level and performance analysis accuracy of electrical equipment design.Therefore,this thesis is advocating high-power high-frequency transformer and high-frequency high-speed motor today has high theoretical value and practical application prospects.This thesis first is based on the surface-fit measurement method described in IEC60404-6,and the experimental device is improved in combination with the laboratory.Air flux compensation system is added to offset the influence of air flux on the measurement results,which effectively improves the accuracy of the measurement results.Quantitative loading of stress is realized by mechanical fixture and force sensor with designed clamp,and the high frequency magnetic properties of nanocrystalline materials were measured considering temperature and stress respectively.Combined with the self-developed high frequency magnetic properties measurement system,the measurement frequency is up to 20 k Hz.By comparing magnetic hysteresis and experimental measurement data,as the temperature increases,the coercive force will increase,the magnitude of the saturation point magnetic field is increased,and the iron loss of the material is significantly increased;However,the compressive stress has no significant impact on the intensity of saturation point magnetic field,but the remaining magnetization strength and coercive force are significantly increased,and the effect is significant when there is a variation in the ring sample.According to the experimental data of the nanocrystalline material obtained above,a dynamic hysteresis model capable of respectively considering temperature and compressive stress is established.Due to the high measurement frequency,the eddy current loss is relatively large,therefore,this thesis first is based on the traditional JA hysteresis model,combined with the iron loss separation theory,introduces the eddy current correction coefficient,and finally obtains a dynamic JA hysteresis model.Then,the particle swarm optimization algorithm is applied to the parameter identification of the JA model,and the change trend of the model parameters calculated under the action of temperature and compressive stress is fitted,and finally the dynamic JA hysteresis model dependent on temperature and compressive stress is obtained.The proposed hysteresis model has higher simulation accuracy by comparing the experimental measurement results.