Study On Measurement Technology Of Axial Non-uniform Magnetic Field In Amorphous Wire

As the Internet of Things is gradually deepening into our social production and social activities,sensors related to signal acquisition become more and more important.Among them,magnetic sensors are widely used to detect,collect,store,convert,reproduce and monitor various magnetic fields.In the current wave of informationization,magnetic sensors play an irreplaceable role in the information society as primary electronic components.The miniaturization,accuracy,and adaptability to complex environments of electronic devices place h igher demands on the comprehensive performance of magnetic sensors.As an amorphous alloy wire,amorphous wire has attracted the attention of many magnetic sensor researchers due to its good soft magnetic properties and special giant magneto-impedance effect.At present,the modeling and measurement studies of amorphous wires are concentrated in a uniform magnetic field and neglect the influence of the demagnetizing field on the magnetization of the amorphous wire,and lack of study on the impedance characteristics of the amorphous wire in the non-uniform magnetic field are considered in consideration of the demagnetizing field.In order to improve the resolution of the amorphous magnetic sensor to the non-uniform magnetic field,this thesis proposes a method for measuring the amorphous wire under non-uniform magnetic field.In this thesis,we mainly study how to measure the axial non-uniform magnetic field by using the giant magnetoimpedance characteristic of amorphous wire,that is,to model the impedance tensor of the amorphous wire in the axial non-uniform magnetic field.In the thesis,combined with the electromagnetic theory,the impedance tensor model of the amorphous wire in the uniform axial magnetic field under high frequency excitation is obtained by solving the Maxwell equation.The amorphous wire demagnetizing field model is established according to the demagnetization theory and the distribution curve of the demagnetization factor in the amorphous wire.According to the magnetic effect of the current,a non-uniform magnetic field model is constructed by using the spatial magnetic field distribution around the long straight wire.By uniformly processing the amorphous wire segments,the impedance expression in the axial non-uniform magnetic field of the amorphous wire is obtained according to the demagnetizing field model and the non-uniform magnetic field model using the impedance model in the axial uniform magnetic field of the amorphous wire.After the axial non-uniform magnetic field impedance modeling is completed,according to the analysis of the giant magneto-impedance effect and voltage response of the amorphous wire,the experimental measurement platform is constructed to measure the impedance value of the amorphous wire in the non-uniform magnetic field,and combined with the amorphous wire.The theoretical and experimental data in a non-uniform magnetic field are differentially analyzed for giant magneto-impedance.How to construct the non-uniform axial magnetic field impedance model of amorphous wire and use the measurement platform for differential analysis will be the key of this thesis,which will be described in detail in the thesis.