Double Coil-Less Fluxgate in Bridge Configuration

Abstract

In this paper, a new method for excitation of coil-less fluxgate is presented. The purpose of this method is to reduce the spurious component of the output voltage, allowing us to increase the amplification. The method is based on the employment of two coil-less fluxgates in a double bridge, which injects pulsing current in opposite direction in each wire. By taking the difference of the voltages on the two wires, we suppress the component of the voltages, which does not change under application of external measured field. The sensitive axes are in opposite direction, so the wire feels opposite field. As a result, we will obtain an output voltage with low peak value, including only the component of the voltage that changes when we apply external field. Finally, we propose an improved version of the double bridge to allow the employment of two sensing elements with difference characteristics. This is obtained by optimizing the suppression of the spurious voltages and, at the same time, setting independently chosen values of exciting current for each wire.