Performance Analysis Of The Facility For Nearly Zero Magnetic Field Environment Baced On The Hysteresis Model

The extremely weak magnetic field environment is called near-zero magnetic field environment,and the near-zero magnetic field environment has been applied in many fields such as cutting-edge science,national defense,and aerospace.Harbin Institute of Technology undertakes the construction of the national major basic science and technology facilities "space magnetic environment simulation and research system",through the shielding of geomagnetism and other types of magnetic field interference,thus simulating the zero magnetic field environment.The project has built a highprecision,high-controllable the facility for nearly zero magnetic field environment,which is an important component of the ground-based simulation facility in China.The main work of the large-scale the facility for nearly zero magnetic field environment studied in this subject is to study the analysis method of the facility to accurately analyze the performance of the facility,provide a theoretical basis for the construction of the the facility for nearly zero magnetic field environment,and then build a world-class facility.Before the facility for nearly zero magnetic field is analyzed,it is necessary to measure the magnetic properties of the materials used in the facility.This subject measures the magnetic properties of the permalloy materials used in the facility according to the common test standards in the industry.This topic is based on the test principle and improves the existing test system.Using the improved system,the test accuracy of the magnetic properties of the material is improved.A high-precision hysteresis model was established for the permalloy material,and experiments were carried out on the material samples.The parameters of the hysteresis model were obtained by particle swarm optimization.This paper introduces the method of calculating the shielding factor of the facility for nearly zero magnetic field under static and time-varying conditions.The shielding ability of the infinite-length shielding cylinder and the square shielding room is analyzed by analytical method and equivalent surface finite element method respectively.Aiming at the calculation of internal dynamic magnetic field waveforms under non-sinusoidal periodic or non-periodic external magnetic field waveforms,a method combining finite element and JA model,called JA-FEM,is proposed.In order to improve the accuracy of the theoretical analysis of the shielding ability of the actual facility for nearly zero magnetic field,a lap structure finite element model with air gap is established.Based on the model,the equivalent hysteresis model parameters of the shielding layer of the actual facility are solved,and then the shielding factor of the facility is calculated by JA-FEM method.Finally,the shielding ability of the the facility for nearly zero magnetic field in Harbin Institute of Technology is analyzed theoretically.The theoretical analysis results are compared with the experimental results,which validates the validity of the JA-FEM method and the lap structure model with air gap.Using this method,the dynamic internal magnetic field waveform of the MSR under arbitrary external magnetic field waveform is calculated,which is basically consistent with the experimental waveform.So a valid method for analyzing the shielding ability of actual facility for nearly zero magnetic field is proposed.