【作者】 李俊；

【导师】 谢楠；

【作者基本信息】 福州大学 ， 电气工程（专业学位）， 2023， 硕士

【摘要】 基于Pockels效应的无源式光学电压传感器(Optical Voltage Sensor,OVS)凭借绝缘性能佳、动态测量范围广、易小型化和智能化等优点,成为未来智能电网及能源物联网一次测量设备的发展方向。但是多年研究表明,电光晶体的温度漂移和线双折射扰动问题阻碍了光学电压传感器的实用化进程。对此本文提出了基于异构电极和任意电场调控模式的研究方法,旨在抑制电光晶体的线双折射,消除温度对测量结果的干扰,改善光学电压传感器长期运行稳定性。论文主要研究工作包括:(1)提出了一套适用于光学电压传感器多物理场耦合的分析方法,深入研究温度与线双折射的关系。阐述了多物理场耦合作用对电光晶体传感特性的影响,重点推导了热应力线双折射的数学公式并开展理论分析,通过COMSOL有限元仿真平台构建多物理场耦合传感单元模型,探究电光晶体的热应力来源和分布机理,实现电光晶体热应力双折射的量化分析。(2)提出了一种基于中心对称异构电极和电场调控的线双折射抑制方法。通过调整晶体两侧电极的形状和结构,改善晶体内部的应力分布,并借助有限元分析方法探究不同电极结构下BGO晶体的内电场分布,得到中心对称异构电极与电场方向的角度关系。根据构建的多场耦合传感模型研究中心对称异构电极下晶体的热应力分布,并搭建实验系统验证方案的可行性。仿真与实验结果均表明采用透明电极的晶体线双折射比金属电极小一个量级,且在透明电极下电场角度为82.37°时晶体受热应力线双折射影响最小。(3)设计了一种基于旋转异构电极和电场调控的光学电压传感器。利用直流电机驱动旋转接地电极在其平面内高速旋转,实现对BGO晶体内电场周期性调制,将测量信号的频段移至2k Hz,采用有限元法分析旋转电极结构下晶体内电场分布机理,结合电光效应耦合波理论计算调制后的输出光强信号,将调制后的测量信号与未参与调制的线双折射信号严格区分,并基于锁相放大技术检测和提取目标信号,通过Simulink建立仿真模型进行验证。仿真结果表明该方案可以有效抑制温度、线双折射等低频噪声(<50Hz)干扰,恢复原始电压信号。更多还原

【Abstract】 The passive Optical Voltage Sensor(OVS)based on Pockels effect has the advantages of good insulation performance,wide dynamic measurement range,easy miniaturization and intelligence,which has become the development direction of primary measurement equipment for smart power grid and energy Internet of Things in the future.However,many years of research have shown that the problems of temperature drift and linear birefringence disturbance of electro-optical crystal hinder the practical process of optical voltage sensor.In this paper,a research method based on heterogeneous electrodes and arbitrary electric field control mode is proposed,which aims to suppress the linear birefringence of electro-optical crystals,eliminate the interference of temperature on measurement results,and improve the long-term stability of optical voltage sensors.The main research work of this paper includes:(1)A set of analysis methods for multi-physical field coupling of optical voltage sensors is proposed,and the relationship between temperature and linear birefringence is studied deeply.The influence of multi-physical field coupling on the electro-optical crystal sensing characteristics was described,and the mathematical formula of thermal stress line birefringence was deduced and theoretical analysis was carried out.The multi-physical field coupling sensing unit model was constructed by COMSOL finite element simulation platform to explore the source and distribution mechanism of thermal stress of electro-optical crystal,and the quantitative analysis of thermal stress birefringence of electro-optical crystal was realized.(2)A linear birefringence suppression method based on center symmetric isomerism electrode and electric field regulation is proposed.By adjusting the shape and structure of the electrodes on both sides of the crystal,the stress distribution inside the crystal was improved,and the internal electric field distribution of BGO crystal under different electrode structures was explored by the finite element analysis method,and the Angle relationship between the center symmetric isomerized electrode and the direction of the electric field was obtained.According to the constructed multi-field coupling sensing model,the thermal stress distribution of crystal under the central symmetric heterogeneous electrode was studied,and an experimental system was established to verify the feasibility of the scheme.The simulation and experimental results show that the crystal wire birefringence of transparent electrode is one order of magnitude smaller than that of metal electrode,and the influence of crystal line birefringence with thermal stress line is minimal when the electric field Angle under transparent electrode is 82.37°.(3)An optical voltage sensor based on rotating isomerization electrode and electric field regulation is designed.The rotating grounded electrode is driven by a DC motor to rotate at high speed in its plane to realize periodic modulation of the electric field in the BGO crystal.The frequency band of the measured signal is moved to 2k Hz.The electric field distribution mechanism in the crystal under the rotating electrode structure is analyzed by finite element method,and the output light intensity signal after modulation is calculated by combining the electro-optical effect coupled wave theory.The measured signal after modulation is strictly distinguished from the linear birefringence signal which is not involved in modulation,and the target signal is detected and extracted based on phase-locked amplification technology.The simulation model is established by Simulink for verification.The simulation results show that this scheme can effectively suppress the temperature,linear birefringence and other low frequency noise(<50Hz)interference,and restore the original voltage signal.更多还原