Research On A New Low-cost Fiber Optical Current Sensor

The fiber optical current sensors have the advantages of good accuracy,high bandwidth,and little electromagnetic interference.The existing optical fiber current sensor can't meet the needs of low-cost applications.Accuracy and temperature stability are important indicators of fiber optical current sensors.In this paper,the phase modulator and photodetector components of the fiber optical current sensor are researched and improved,and a new low-cost fiber optical current sensor scheme is proposed.According to the modulation and demodulation principle of the new low-cost fiber optical current sensor,the current Signal demodulation algorithm is designed.The accuracy and temperature stability of the new low-cost fiber optical current sensor are verified by writing the host computer program and the construction and testing of the engineering prototype.The main research work and results of this paper are as follows:The phase modulation mechanism of the PZT fiber phase modulator was studied,the production of the PZT fiber phase modulator and the design of the drive circuit were completed.The function realization of the PZT drive amplifier circuit and the stability of modulation performance of the manufactured PZT fiber phase modulator was verified through experiments.The signal conditioning circuit of the PIN photodetector was designed,including the selection of the PIN photodetector,the selection and the circuit design of the transimpedance amplifier and the operational amplifier.The technical indicators of the PIN photodetector component are verified through simulation and testing.For the new low-cost fiber optical current sensor,the principle of modulation and demodulation was studied.A two-way quadrature demodulation algorithm for current signal demodulation and calculation of harmonic amplitude was proposed and the host computer program for current signal demodulation was written.A new low-cost fiber optical current sensor engineering prototype was built,and comprehensive tests were conducted.The test results show that the accuracy and stability of the new low-cost fiber optic current sensor meets the 0.5 level technical requirements of the national standard GB/T20840.8-2007.The research results of the thesis are helpful to realize the low cost of fiber optical current sensor and the market expansion of the application field.