GMM-FBG光纤电流传感器结构优化及温补模型

Structural optimization and temperature characteristic analysis of GMM-FBG fiber current sensor

为解决FBG中心波长和GMM磁致伸缩系数温度敏感而影响GMM-FBG光纤电流传感器交流响应灵敏度和准确度的问题,提出在GMM-FBG传感模型中引入温度参数校准电流输出值的方法。依据法拉第电磁理论,采用有限元分析方法设计提高GMM磁耦率和均化磁场分布的磁路结构。构建波长解调系统实验平台,测试温度在20~70 ℃范围传感器不同电流对应的波长响应幅值,实验研究表明:GMM-FBG电流传感器灵敏度随温度升高而下降,且与被测电流值大小正相关。在分析传感器温度响应特性基础上,利用数学拟合方法建立了具有温度补偿系数的GMM-FBG电流传感数学模型,且将该模型用于40 ℃时60 A电流检测实验,电流检测准确度提高了4.8%。

To solve the problem that the sensitivity and accuracy of GMM-FBG current sensor are affected by temperature influencing center wavelength of FBG and magnetostriction coefficient of GMM, the GMM-FBG sensing model with temperature parameter is presented to calibrate current values. According to Faraday electromagnetic theory, the magnetic structure was designed to increase the magnetic coupling efficiency and homogenize magnetic distribution using finite element method (FEM). Then, the experimental platform was constructed by using the wavelength demodulation system. At the temperature of 20 to 70 degrees Celsius, wavelength response amplitudes of the sensor were tested under different current values. The experimental results show that the sensitivity of GMM-FBG current sensor decreases with the increase of temperature, and it is positively correlated to the target current. Analyzing the law of sensor response versus temperature, a GMM-FBG sensing mathematical model with temperature compensation coefficient was established based on mathematical fitting method. Then, according to the model, the current detecting accuracy is increased by 4.8% during measuring 60 A current at the temperature of 40 ℃.