【作者】 王刚；

【导师】 李绪友；

【作者基本信息】 哈尔滨工程大学 ， 精密仪器及机械， 2010， 硕士

【摘要】 光纤电流传感器作为一种新型的电力检测设备,以其特有的优势,有着良好的市场与应用前景。本文以光纤电流传感器的研制为应用背景,主要针对Sagnac式光纤电流传感器的原理和特性开展深入的研究。首先,在详细论述Faraday磁光效应原理的基础上,利用琼斯矩阵,构建光纤电流传感器的理论数学模型,并对传感器系统关键光学器件进行偏振误差分析,指出传感器系统指标参数的主要影响因素及相关的改进措施。其次,对光纤电流传感器几种常见的信号调制解调方案原理进行阐述,并加以比较分析。在数字闭环光纤电流传感器中,信号处理系统的主要作用是构建闭环反馈系统及进行信号的时序控制和数据处理,实时产生偏置相位及用于补偿外部Faraday磁光旋转信号,并实时跟踪检测实际载流体中电流情况。为了满足系统的检测精度与实时性处理的要求,系统中采用方波+阶梯波闭环信号调制方案进行数字信号处理较为理想。再次,创新性地应用光纤系统仿真软件对传感器系统进行功能实时仿真,以达到实时验证的目的,同时进行系统参数合理设置,可以有效地缩短了其产品化、工程化进程,节约成本与时间。针对闭环系统的稳态性能和动态性能设计数字控制器,并在MATLAB/SIMULINK环境下完成整个控制系统模块设计与仿真。仿真结果表明数字闭环光纤电流传感器采用PID控制规律,可以提高系统的动态响应速度。另外,为了对光纤电流传感器系统的性能参数有更好的理解,搭建实验样机,对系统中关键器件(如光纤传感头、1/4λ波片)进行了方案设计与实验,提出了光纤传感头振动补偿方案,同时进行初步的电路调制系统设计。最终,又提出了一种新型的双模光纤电流传感器结构,摒弃了通常的光纤电流传感器中运用相位调制器外加相位偏置的方法,运用双模光纤中的古依相移提供固定的π/2相位偏置,又利用模式选择耦合器进行分束设计。系统结构更加简单灵活,更利于开环系统的设计与实现。更多还原

【Abstract】 As a new type of electrical testing equipment, fiber optic current sensor with its unique advantages has a good market and application prospects. In this paper, it takes all-fiber optic current sensor’s application as the background, and makes researches on the principles and characteristics of the system in-depth, mainly for Sagnac-type fiber optic current sensor.Firstly, based on the principle of Faraday magneto-optical effect, it used the theory of Jones matrix to build up the mathematical models of fiber-optic current sensor and make polarization error analysis of key optical device in sensor system, then pointed out the main factors of the target parameters of sensor system and gave related improvements.Secondly, it is elaborated several common kinds of signal modulation and demodulation principles of fiber optic current sensor, with making comparative analysis. In the system of fiber-optic current sensor with digital closed-loop, signal processing system’s main role is to build closed-loop feedback system and make signal timing control and data processing, for real-time generating bias phase and compensating for the external Faraday magneto-optical rotation phase which real-time tracks and detects the current situation of the real fluid. In order to meet the system’s detection accuracy and real-time processing requirements, the system adopted the signal processing program of digital closed-loop square-wave + ladder-wave signal modulation, and the result is more desirable.Thirdly, it is the innovative application of optical system simulation software for sensor systems functional real-time simulation in order to achieve real-time verification purposes, while system parameters can be reasonably set, which will effectively shorten its product-oriented, engineering process, and save costs and time. It is designed the digital controller of closed-loop system on the steady-state and dynamic performance, and used of the MATLAB/SIMULINK to complete the control system of modules’design and simulation. Simulation results show that the all-digital closed-loop fiber-optic current sensor which used PID control law can improve the system dynamic response speed.In addition, in order to have a better understanding of performance parameters in fiber-optic current sensor system, the experimental prototype is built. The key components of the system (such as optical fiber sensing head, 1/4 wave plate) is designed to make related experiment, then it is proposed a new vibration compensation program of optical fiber sensing head and a preliminary circuit modulation system design.In the end, a new type of dual-mode fiber-optic current sensor structure is also proposed, which abandons the method of using phase modulator to produce theπ/ 2 phase bias in the usual fiber-optic current sensor system. In the new sensor system, it is used of Gouy phase shift in dual-mode optical fiber to produce fixedπ/ 2 phase shift, and used of mode selector coupler for splitter design. System structure is more simple, flexible and more conducive to open-loop system design and implementation.更多还原