基于隧穿磁阻效应的非侵入式高灵敏度电流传感器研究

Research on the nonintrusive high sensitivity surface mount current sensor based on tunneling magnetoresistance

隧穿磁阻器件是新一代磁半导体传感器,其具有高灵敏度、可实现交直流混合测量的特点。该研究介绍一种基于隧穿磁阻器件的高灵敏度非侵入式表贴电流传感器设计方法。该传感器可非侵入式安装在铜排表面实现毫安级微弱电流的测量。计算毫安级电流在铜排表面产生的感应磁场大小并提出了隧穿磁阻器件的参数选型依据。进一步设计信号调理电路并提出利用分段拟合算法弥补高灵敏度隧穿磁阻器件线性范围较小的缺陷。最后,搭建测试验证平台验证传感器设计方法。结果表明,所设计的传感器可覆盖毫安至1A的测量范围,在百毫安范围内,绝对误差小于1mA,在百毫安至1A范围内,传感器的相对误差小于2%。

Tunneling magneto-resistive(TMR)devices are new generation magnetic semiconductor devices,whose sensitivity is relatively higher and be capable of measuring hybrid AC/DC current.This research demonstrates a method to design the surface mount current sensor based on TMR devices,which can be non-intrusively assembled on the busbar to sense the current with milli-ampere magnitude.The magnetic field induced by the current with milli-ampere magnitude flowing through the busbar was first simulated and then the needed parameters of the TMR device were analyzed.Furthermore,a signal conditioning circuit was designed and a segmented fitting algorithm was proposed to compensate the limited detection range of the TMR device.Finally,a test platform was built to verify the performance of the proposed design.The results showed that the designed current sensor was capable of measuring the current with the magnitude at range between mA to 1 A.The absolute error was 1 mA when busbar current was below 100 mA and the relative error was below 2%when busbar current was between 100 mA to 1 A.