Study And Design Of The Ring-core Fluxgate Sensor

This paper describes the basic principles and classification of fluxgate sensor under a large amount of relative research. Mathematic models of single-rod and ring-core fluxgate can be established based on Faraday's electromagnetic induction principle. A one-dimensional open-loop ring-core magnetometer is established with Co-based amorphous alloy for the core material, and with machinable glass material for support. The second harmonic analog method is applied to measure the sensor signal. Drive circuit generates a square wave at the frequency of 15.625 kHz, which drives the sensor to operate at its best, and finally output a signal that is in proportion to the measured magnetic field. Afterwards a measuring system is setup and applied to calibrate the sensor.The calibration result shows that the scheduled goal for the magnetometer is achieved with a measuring range of±0.55 Gs, and a full scale linearity error of 3.945%, and the sensitivity of 100nT.It can be seen from the noise analysis that the core material and the construction of the sensor are the main factors that affect the performance of the magnetometer. The first and the third harmonic components interference output signal mostly. Besides the complexity of the drive signal can also increase the output noise. This paper gives some methods for suppressing the noise.Some suggestion about how to improve the performance of the fluxgate magnetometer and design high precision triaxial fluxgate sensor are given based on a careful analysis for this fluxgate sensor.