Research on the simplified direct-current fluxgate sensor and its demodulation

A simplified fluxgate current sensor used for DC current measurement is presented in this paper. The proposed self-oscillating fluxgate sensor operates in a closed-loop manner with only one coil for the excitation, feedback and detection. The sensor utilizes the linear dependence between the measured current and duty cycle of the exciting voltage. Originating from the exciting voltage branch, this novel feedback structure can eliminate the feedback errors introduced by the excitation coil on the toroidal core. Meanwhile, a prototype of the proposed sensor was built and the proposed operation was experimentally verified. For the transfer characteristic, a superior linear fitting in the range of −48 A to 48 A has been achieved on this prototype. To extend the measurement range, in a future study, power dissipation should be considered.