Design and realization of fluxgate sensor signal processing unit

This paper firstly discusses the magnetic fluxgate sensor´s principle of work, then conducts an in - depth analysis to the magnetic fluxgate sensor output signal from the aspect of its mathematical model, the paper proposes the second harmonic detecting method. In this way, the paper gives the implementation plan for the fluxgate magnetometer, and complete signal detection and processing circuit design of the closed - loop fluxgate sensor. The circuit modulates the fluxgate signal into direct voltage signals of a characterization of magnetic field size by resonance, second harmonic amplification, band - pass filtering and phase - check spread of second order Butterworth low - pass filter. To improve the dynamic performance of a magnetic field measurement and temperature stability, closed - loop circuit uses digital PID control method.