Research On The Hysteretic Modeling Of Soft Magnetic Materials Based On The Preisach Model

Soft magnetic material is widely applied in the fabrication process of the cores of electric motors and transformers.The research of hysteretic properties of soft magnetic material involves the measurement and simulation of magnetic properties of materials and the application of magnetic materials.It provides the theoretical support and the essential realization means for accurately analyzing the operating state of electrical equipment,optimizing the structure and enhancing the reliability on electromagnetic devices.In recent years,due to the development of DC transmission technology and the wide application of a large number of power electronic devices in power system,soft magnetic material is in a DC biased condition,which makes it difficult to model the hysteresis characteristics.Furthermore,with the emergence and development of electromagnetic devices with complex magnetic circuit structures,the internal magnetic field distribution of materials is no longer along a single direction,but a space vector characteristic.An accurate and effective mathematical model is required to analyze the hysteresis characteristics of soft magnetic materials more accurately and quantitatively under complex working conditions.The research in the paper is sponsored by the National Natural Science Foundation of China(Grand No.51777073,51577066)and National Key Research and Development Program of China(Grand No.2017YFB0902703).The magnetic hysteresis and loss characteristics of oriented silicon steel sheet(B27R095)under DC bias were measured by the single sheet tester(SST)in the BROCKHAUS magnetic performance measurement system.The static hysteresis curves are simulated by the Preisach model.Due to the asymmetry of curves under the DC bias,an algorithm is presented to create corresponding asymmetrical first order reversal curves(FORCs)based on the experimental data of major hysteresis loop measured in DC-bias condition.Finally,the DC-biasing dynamic hysteresis model is constructed considering the influence of DC bias magnetic field and AC magnetic flux peak on excess loss.And the loss characteristics of oriented silicon steel sheet under DC bias condition are simulated.The influence of DC bias on different types of losses is analyzed.Simulated results agree well with the measured ones,which verifies the effectiveness and accuracy of the proposed methods.Based on the basic theory of the vector Preisach model,the vector hysteresis characteristics of soft magnetic materials are further explored.In view of the fact that the classical vector Preisach model can not simulate the anisotropy properties of the materials under rotational excitation,an improved model is proposed in the paper to overcome the limitation.By introducing two parameters,the improved model can consider the anisotropic hysteresis characteristics of materials.And thus the simulated results are more accurate than that by classical model.Since the simulated results obtained by the improved model are basically consistent with the measured ones,which lays the foundation for further research on the rotating magnetic characteristics and losses of motors and transformers.