Non-Contact Current Measurement Method for Multiconductor Systems based on Tunnel Magnetoresistance Sensor Array

This paper presents a non-contact current measurement method for multiconductor systems. Tunnel magnetoresistance (TMR) sensors are used to form a circular sensor array. The fundamental current phasor on each conductor along with the conductor positions can be simultaneously recovered using the voltage phasors of the TMR sensor array by solving sufficient equations. The TMR sensor is characterized with an almost constant gain factor and a zero- phase shift over a frequency range of 50 Hz- 3.05 kHz such that the time-domain current waveforms can be then recovered in real time by matrix multiplication. A prototype instrument is designed and fabricated. Experiments for fundamental current phasors measurement and time-domain current waveforms reconstruction are performed to validate the feasibility of the proposed method.