光学电流传感层叠抗外磁干扰技术研究

Research on the Technology of Optical Current Sensing Stacked-up Structure to Resist External Magnetic Interference

直通光路型磁光式光学电流传感器(magneto-optical current sensor,MOCS)因具有体积小,测量准确度高等多种优点,在智能电网中有广阔应用前景。然而,由于无法构成闭合光路,外磁场干扰一直是制约直通光路型磁光式光学电流传感器实用化的重要因素。为解决此问题,该文提出光学电流传感层叠抗外磁干扰技术。首先通过定义非连续积分路径,积分张角等概念,推导出电流位于非连续闭合路径内外时对应的磁场积分表达式,进而建立适用于含任意数量磁光传感单元、按对称多边形方式布置的MOCS所受外磁干扰分析的数学模型,提出闭合路径中心偏转模型,并得出最佳中心偏转角。在此基础上提出一种新型的层叠式MOCS结构,基本抗御传感结构外任意位置电流给MOCS带来的磁场干扰。其次,提出通用的层叠式MOCS测量误差分析方法,从理论上证明层叠式MOCS满足工程需求及标准。分别建立层叠式MOCS数值仿真模型及COMSOL有限元仿真模型。仿真结果表明,在不同干扰条件下,层叠式MOCS的测量误差均低于0.2%,证明此结构能够有效降低存在外磁干扰时MOCS的测量误差。最后,设计并搭建相应的层叠式MOCS实验平台并进行相应实验。实验结果表明,新型层叠式MOCS在多种干扰情况下其测量误差均小于0.2%,证明了所提数学模型正确性及层叠式结构应用于提高MOCS抗外磁干扰能力时的有效性。

Magneto-optical current sensor(MOCS)has a broad application prospect in smart power grid due to its advantages of small size and high measurement accuracy.However,the external magnetic field interference has always been an important factor restricting the practicability of magneto-optic optical current sensor,because it cannot form a closed optical path.To solve this problem,the optical current sensing stacked-up structure anti-external magnetic interference technology is proposed in this paper.First,by defining discrete integral path,and integral opening angle,this paper deduces the magnetic field integral expression when the current is inside or outside the discontinuous closed path.After that,a mathematical model which is suitable for the analysis of the magnetic crosstalk of MOCS is established.This model can be used to analyze the interference of external magnetic field of MOCS which contains k sensing units and is arranged in a symmetrical polygon manner.The optimal center deflection angle is calculated by using this model,and the stacked-up type MOCS structure is proposed.By using the stacked-up structure,the magnetic field interference caused by the interfering current placed at any position can be basically eliminated.Then,a general method for analyzing the measurement error of the stacked-up MOCS is given,which proves that stacked-up MOCS meets engineering requirements and standards theoretically.The numerical model simulation and COMSOL finite element simulation are carried out respectively.The results show that the measurement error of the stacked-up MOCS is less than 0.2%under different interference conditions,which proves that this structure can effectively reduce the measurement error of MOCS under external magnetic interference.Finally,the corresponding stacked-up MOCS experimental platform is designed and built and the corresponding experiments are carried out.The experimental results show that the measurement error of the new stacked-up MOCS is less than 0.2%under various interference conditions,which again proves the correctness of the mathematical model and the effectiveness of the layered structure in improving the ability of MOCS to resist external magnetic interference.