Research On The Physical Field Analysis And Coupling Characteristics Of Optical Fiber Voltage Sensor For Electric Locomotive

A voltage transformer is a significant high voltage electrical equipment in the electric locomotive.And Fiber-optic voltage sensor has the advantages of small size,high voltage resistance,high safety,no magnetic saturation,which presents the inevitable development trend of electric locomotive voltage transformer in the future.However,fiber optic voltage sensor is still in the theoretical and experimental stage through the years of development.And there are still many key issues to be solved before putting it into practical application.And one of the first issues that should be addressed is its adaptability in complex environments.This paper takes the all-fiber voltage sensor based on inverse piezoelectric effect as the research object,and is dedicated to solving its environmental adaptability in the field of voltage sensing of electric locomotives and promoting its practical application in engineering.An all-fiber optic voltage sensor based on the inverse piezoelectric effect,whose sensing medium is not only sensitive to the electric field to be measured,and also be sensitive to environmental temperature field,stress field.And there is an energy exchange between different physical fields coupling each other,which seriously affects the output performance of the system and limits its practicality.Based on the theory of polarization optics,this paper establishes a mathematical model of the system output using the Jones matrix.On this basis,a numerical analysis model of the system under the action of environmental physical fields is established,and the output characteristics of the system under the action of coupled multi-physical fields are calculated and analysed using the finite element method,laying a theoretical foundation for improving the accuracy of the system output and environmental adaptability.Firstly,the paper analyzes the functional characteristics of the key optical elements in the optical path system and the voltage sensitivity mechanism,deduces the mathematical model of the voltage to be measured and the system output by using the Jones matrix,and then obtains the photoelectric conversion relationship inside the sensing head,and gives the multi-physical field coupling analysis method.Secondly,the physical field factors affecting system output and the coupling relationship between physical fields are analyzed based on the mathematical model of system output.In research analysis for electric locomotive actual runtime environment load parameters of the optical fiber voltage sensor,on the basis of combining the theory of electromagnetism,heat transfer,such as solid mechanics analysis of the environmental physical field numerical analysis method.And combined with various physical fields of numerical analysis method,the numerical analysis model of the system output is set up under the effect of the temperature field and stress field.The influence law of the environmental physical field on system output is analyzed by finite element numerical analysis method to verify the importance of physical field stability in quartz crystal to improve system output stability.Finally,based on the single physical field analysis,further analysis of the distribution and coupling characteristics of the electric-thermal-force multi-physical fields inside the quartz crystal,establish a numerical analysis model of the system output under the coupling effect of multi-physical fields,and analysis of the relationship between the coupling effect of multi-physical fields and the system output performance under different operating environments.The research of this paper provides theoretical reference and basis for solving the multi-physical field environment disturbance problem of the optical fiber voltage sensor in the application field of electric locomotive.It is also helpful to improve the environmental adaptability of the optical fiber voltage sensor and promote its engineering application.