Research On Technologies Of GMI Sensor Based On Constant Bias Magnetic Field

GMI(Giant Magneto-Impedacne)effect means that the AC impedance of soft magnetic material changes dramatically with the change of external magnetic field under the excitation of higher frequency alternating current.With the Holzer effect,fluxgate,magnetoresistance effect based on the common traditional magnetic sensor,magnetic sensor based on GMI effect has the advantages of high sensitivity,fast response speed,small volume,low power consumption and high application prospect in distance measurement and target mining field of brain magnetic signal detection has wide.However,under the non magnetic shielding condition,the applications of GMI magnetic sensors are confronted with many new challenges.This paper uses Co-based amorphous wire,the Co-based amorphous wire GMI signal excitation module,GMI on magnetic sensor,magnetic transmission device GMI conditioning circuit structure and bias magnetic field feedback control system to conduct a comprehensive research,design based on a bias magnetic field feedback GMI magnetic sensor control system,and the magnetic sensor of several main performance experiments and analysis.The main research cotents are as follows:1.The Co-based amorphous wire is studied.The effect of GMI mechanism and the theoretical model,the Co-based amorphous wire GMI characteristics were tested and analyzed,and optimized through experiments in driving current amplitude and driving current frequency on GMI characteristics test system and the impedance analyzer,composed of a Helmholtz coil and a DC power supply of Co-based amorphous wire experiments on the relevant parameters the parameters of GMI,characteristics of the driving current amplitude and driving current frequency effect of Co-based amorphous wire were determined by experiments and analysis of chanting.2.The design and implementation of the integration of the bias magnetic field of amorphous wire magnetic probe based on feedback control system,and put forward the general structure scheme of the bias magnetic field feedback GMI control system based on magnetic sensor,and a detailed analysis of the working principle of each function module of the circuit of the GMI magnetic sensor.The whole circuit of GMI magnetic sensor by sine signal module,voltage and current conversion circuit,signal conditioning circuit(including peak detector circuit,differential amplifier,low pass and band stop filter circuit)and bias magnetic field feedback control system,according to this paper makes a detailed and systematic analysis,and related to each of the elements of the circuit are analyzed and selected,on this basis,the overall design of the magnetic sensor circuit GMI.Based on the characteristics of amorphous wire,which is monotonic near the zero point,the structure of bias magnetic field feedback control system based on integrated amorphous wire magnetic probe is designed,which is also the core point of magnetic sensor design.In order to reduce the influence of external background noise and internal circuit noise,anti-interference design of the gardware circuit of magnetic sensor(mainly circuit board)is also carried out.3.To measure the characteristic curve of GMI magnetic sensor,and adjusting the bias magnetic field feedback control system based on the measurement range of the magnetic sensor,the spirit of the degree of linearity and performance experiment,testing experiment combined with noise performance in magnetic shielding tea under,finally calculate the magnetic sensor resolution.The SpinIC magnetic sensor calibration,and the characteristic curves of the GMI magnetic sensor to test the drawing,after calibration tests on the bias coil,by bias magnetic field feedback control system to regulate the work,finally completed the debugging of the bias magnetic field feedback GMI control system based on magnetic sensor.Experiment and analysis of measurement range,so that sensitive and linear properties of GMI magnetic sensor is debugged,and the magnetic sensor output frequency characteristics and stability experiment and analysis.In combination with the above experimental and analytical results,the noise performance of GMI magnetic field is measured in the magnetic shielding chamber,and the measured correlation curve is referenced.Finally,the resolution of the GMI magnetic sensor is obtained.