Fluxgate Current Sensor Based on H-Bridge

In order to solve the technical problem that the detection accuracy of electric vehicle BMS current sensor is not high enough to accurately measure large current and small current at the same time, a design scheme of a fluxgate current sensor with a single excitation core was provided. The topology design and working principle of the scheme were expounded, and the advanced nature of the scheme was proved. Compared with the current scheme, the H-bridge circuit was used to drive the excitation coil, which enabled the power supply of a single power supply and simplified the design of the power supply for the sensor. Moreover, an excitation detection circuit with double measurement resistors was constructed, which equivalently converted the excitation current ie flowing in the excitation coil into the difference between the two currents $\mathrm{i}_{\mathrm{e}1}$ and $\mathrm{i}_{\mathrm{e}2}$, and obtained the average value of the excitation current through the equivalent current difference $\mathrm{i}_{\mathrm{e}1}-\mathrm{i}_{\mathrm{e}2}$, thereby eliminating the zero drift of the current sensor, so that the small current identification and measurement accuracy of the current sensor can be improved.