Design And Research Of Reflective Fiber Optical Current Transducer

The research of the fiber optical current transducer(FOCT)has been entered into the practical stage gradually.In order to solve the stability problems of the FOCT,and improve the measurement accuracy of current,the research trend is mainly due to the use of special fiber or the innovative design of system structure.There are a large of advantages in the reflective fiber optical current transducer(Re-FOCT),such as good linearity,large measurement range and so on.Therefore,the thesis focused on the reflective fiber optical current transducer.In the thesis,two different design schemes are proposed,and the corresponding modeling research is carried out.Two technical solutions can achieve 0.2 measurement accuracy.The thesis spreads out discussions around the design and research of the Re-FOCT.The main work of the thesis includes the following aspects.(1)The thesis summarizes the development and the status of the fiber optical current sensing technology.Some innovative design schemes of FOCT in the process of advancing practical application are discussed.(2)The basic principle of Faraday Effect is introduced in the thesis.With the study of the Re-FOCT,every component of all optical fiber current sensor has been represented by Jones matrix.The relationship between the output light intensity and the Faraday deflection angle is deduced.Besides,the effect of phase modulation on the output waveform is discussed.(3)The error sources of the reflective fiber current sensor are studied.Jones vector operation was used to set up the mathematical model of the error in the light system.It is analyzed by using the model how to do the process error,temperature error and strain error influence the system normalized ratio.On this basis,two kinds of design schemes using twisted fiber or few-mode fiber(FMF)are proposed.(4)According to the two technical schemes,the software Simulink is used to establish the model,which reflects the working condition of the system concisely.In the simulation,the test results show that the system meets the 0.5 measurement accuracy standard,thus verifying the feasibility of the two schemes.Further,the error factor is added and the compensation module is added to simulation model accordingly.The compensation module can raise the measurement accuracy of the system to 0.2 level.