Wide-range TMR current sensor based on magnetic shielding design

Large current detection is the critical enabler of safety, efficiency, and precision control in high-power systems, preventing catastrophic failures while optimizing performance. While traditional Hall sensors provide a wide measurement range, they suffer from low sensitivity and considerable temperature drift. In contrast, tunneling magnetoresistance (TMR) sensors excel in sensitivity and thermal stability, though their measurement range is limited. To bridge this gap, we introduce a TMR-based current sensor that leverages a compact magnetic shielding structure to push the linear magnetic field range from ±80 Oe to an impressive ±2000 Oe. Experimentally characterized from 0 to 200 A at a distance of 2 centimeters from the conductor, this current sensor achieves a sensitivity of 0.106 mV/A and a nonlinearity error of less than 1%. Based on reasonable extrapolation from the sensor's saturation output characterized under magnetic field testing, it can theoretically detect fault currents as high as 16.8 kA when placed at the same distance from the conductor. Consequently, it proves invaluable for investigating failure mechanisms and asset degradation under realistic fault scenarios.