Hall Effect Based Current Sensors Calibrated Against Hysteresis Effects

In this work an improved current sensor is proposed. The current sensor uses an advanced calibration algorithm and aims to achieve better than 1% accuracy. Hall effect based current sensors measure the magnetic field originating from the current. Hall element converts the field to a voltage using Hall effect. The nonlinearity of magnetic permeability in ferromagnetic core brings about nonlinearity during magnetic field generation and causes hysteresis. Thus, the accuracy of the Hall effect current sensor decreases. To prevent drop in accuracy, hysteresis characteristic of the sensor can be calibrated. The inputs are filtered to clean up noise. Creating a set of calibration polynomials, these functions can be used to improve sensor outputs. The algorithm can improve the sensor error performance from 1% in gain calibrated sensors to 0.3% for min RMS measurement error based calibration.