A Contactless Current Sensor Based on TMR Chips
Peng Li, Bing Tian, Licheng Li, Zhiming Wang, Qiancheng Lv, Ke Zhou, Changbao Xu, Zhong Liu, Xu Yin, Jiaming Zhang
Abstract
Inexpensive, nonintrusive, and easy-installation current sensors are of great help in the economical and reliable operation of power systems. In this article, a novel contactless current sensor with small size, ultramicro power consumption, and self-power capability is proposed based on tunnel magnetoresistance (TMR). For measuring arbitrary line currents under an interference magnetic field, the single-axis TMR chips array and anti-interference method are introduced. Then, the designs of software and hardware are given for ultralow-power consumption and self-power. The experimental results showed that the measuring range of the current sensor is from 0 to 1500 A, and the error is less than 0.6% when the measured current is over 150 A.