Vector Inverse Jiles-Atherton Hysteresis Model And Its Finite Element Calculation

Electrical steel sheets(or silicon steel sheets)are widely used as core materials for various electrical products such as rotating motors and transformers due to their good magnetic permeability and low loss characteristics.In the design stage of electrical products,the electromagnetic performance simulation calculation is required,and the modeling accuracy of the magnetic properties and loss characteristics of the electrical steel sheet directly affects the reliability of the simulation calculation results.In the actual operation of the transformer,there will be a rotating magnetic field in the T-joint junction part.When the electrical steel sheets are in the actual working condition of rotating magnetization,the rotating loss is greater than the alternating loss.It is necessary to accurately analyze and model the rotating magnetic characteristics.At present,the domestic study for modeling the rotating magnetic characteristics of electrical steel sheets is still in its infancy due to limited experimental conditions.With the help of the existing rotating magnetic characteristic measurement system in the laboratory,this thesis,on the basis of fully analyzing the measurement data of the rotating magnetic characteristic of electrical steel sheets,proposed a two-term vector inverse Jiles-Atherton hysteresis model with variable parameters and a three-term vector inverse Jiles-Atherton hysteresis model.By using the experimental data from the two-dimensional rotating magnetic characteristics,the model parameters were identified and compared with the experimental measurement data,and the modeling accuracy of the model was discussed.Finally,the proposed three-term vector inverse Jiles-Atherton hysteresis model was applied to the finite element calculation of the magnetic field characteristics of the transformer core.The main research contents are as follows:First of all,by comparing and analyzing the several existing mathematical models describing the hysteresis characteristics of electrical steel sheets and considering the parameters characteristics of the Jiles-Atherton hysteresis model with clear physical meanings and fewer model parameters,this model was determined to be used for modeling the rotating magnetic properties of electrical steel sheets.Secondly,based on the existing measurement data in the laboratory,the rotating magnetic characteristics of the electrical steel sheet were analyzed and a two-term vector inverse Jiles-Atherton hysteresis model with variable parameters was proposed.The calculation formula of the hysteresis model parameters were derived,and the parameter identifications were carried out and its modeling accuracy was verified using measured data.The results show that the simulation accuracy of the model for the rotating magnetic characteristics near the saturation region still needs to be improved.Thirdly,in order to further improve the accuracy of the two-term vector inverse Jiles-Atherton model,the parameters related to magnetic domain rotation were introduced,and a three-term vector inverse Jiles-Atherton hysteresis model was developed.Similarly,the variable parameter method was used for parameter identification,the calculation results of the model were compared with the experimental data,and the improvement effect of the model was verified.Finally,the three-term vector inverse Jiles-Atherton hysteresis model was applied to the simulation calculation of the magnetic performance of the transformer core,the finite element calculation method was given,and the magnetic characteristic distribution of the transformer core was obtained.The results show that the proposed vector inverse Jiles-Atherton hysteresis model can effectively analyze the rotating magnetic performance of the transformer core.