A Simple Noninvasive Current Measurement Technique for Single-Phase Systems Using Magnetic Sensors

This article presents a novel noninvasive method for measuring currents in single-phase dual-parallel-conductor systems using a two-axis magnetic sensor (MS), achieving accurate and noninterfering measurements between conductors. The proposed isosceles triangle design of the sensor probe positions the two-axis MS to measure voltages proportional to the sum and difference of currents, enabling computation of the unknown currents in a simple way. An interface circuit employing a phase-sensitive rectifier (PSR) approach extracts and processes the sensor outputs to determine the unknown currents. The probe features multiple grooves to accommodate varying conductor spacings and includes two additional sensors to detect potential misalignments with the conductors’ plane. Using a 16-bit analog-to-digital converter (ADC) and an MS with 280-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> gauss resolution and 1 mV/V/gauss sensitivity, the 3D-printed current probe achieved a 15 mA resolution over a 0–50 A range. Error analysis highlights the impact of ADC resolution, sensor gain, and tilt on measurements, particularly at lower currents. The prototype probe demonstrated 1% accuracy for currents in the 5–50 A range, showcasing its effectiveness for noninvasive and accurate current measurements.