光纤大电流传感器非线性误差机理与抑制  

Nonlinear Error Mechanism and Suppression Method of Fiber-Optic High-Current Sensors

作　　者：李传生[1] 邵海明[1] 许少毅[2] 陈光 王家福[1] Li Chuansheng;Shao Haiming;Xu Shaoyi;Chen Guang;Wang Jiafu(Division of Electrical and Magnetic Metrology,National Institute of Metrology,China,Beijing 100029,China;School of Mechatronic Engineering,China University of Mining and Technology,Xuzhou 310027,Jiangsu,China)

机构地区：[1]中国计量科学研究院电磁计量科学研究所,北京100029 [2]中国矿业大学机电工程学院,江苏徐州310027

出　　处：《光学学报》2023年第11期265-273,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2016YFF0102401)。

摘　　要：非线性误差是基于Faraday效应的干涉式数字闭环光纤大电流传感器基本测量准确度的主要影响因素。考虑到传感光路中偏振交叉耦合、圆偏振态不理想等因素的影响,计算了与调制信号同频的干涉信号,得到了闭环反馈相移与被测电流之间的非线性跟踪关系。仿真结果表明:传感光纤线性双折射、1/4波片方位角及相位延迟误差、相位调制器输出尾纤偏振串音是光纤大电流传感器产生非线性误差的主要原因。需根据被测电流的动态范围相应提高相位调制器输出尾纤耦合及熔接对轴精度。通过求解光纤敏感环微分模型方程,提出了波片参数与椭圆双折射光纤拍长-螺距比的匹配条件,实现了传感器对Faraday效应的线性响应,降低了椭圆偏振传感信号造成的非线性误差。实验结果表明:采用参数匹配的1/4波片后,在6~500 kA范围内,传感器比例因子随被测电流的变化量为0.2%,相比于理想1/4波片降低了一个数量级。Objective Highcurrent measurement technology is widely used in the field of industry,quality inspection,national defense,and large scientific facilities.The current up to dozens or hundreds of kA and even MA magnitude requires to be accurately measured for the process control,performance test,energy consumption reduction,and key scientific research.The fiberoptic highcurrent sensor based on the Faraday effect exhibits many attractive features in this field,including high accuracy,wide bandwidth,immunity to interference,excellent portability,as well as good value traceability.The flexible sensing coil of the sensor can be designed into a fiber cable that can be wrapped around the currentcarrying conductor to measure current,so as to avoid breaking the currentcarrying path for installation.The closedloop signaldetecting technology can be used to recover the current to be measured,which theoretically guarantees high linearity over the wide dynamic range.However,due to the parasitic polarization crosscoupling,imperfect polarization transform,and inevitable degeneration of the circular polarization state of the light wave in the sensing optical path,the linear relation between the sensor output and the current to be measured will be deteriorated,especially when the current is high.The nonlinearity can result in measurement error and waveform distortion,which severely degrade the basic measurement accuracy of the sensor.The nonlinear error mechanism of the sensor is analyzed in detail,and parameter matching conditions realizing the linear response of the sensor to the Faraday effect are presented in this paper.Methods Analysis and verification for the nonlinear error mechanism and suppression method of the sensor are performed from the perspective of polarization error.First,the Jones matrix is used for describing the total light propagation path.The key polarization characteristic parameters are contained in the optical models,including the pigtail polarization crosstalk of the phase modulator,the azimuth and retardat

关 键 词：传感器 干涉测量 光纤电流传感器 Faraday效应 大电流测量 非线性误差 

分 类 号：O436[机械工程—光学工程]