Closed-loop control device and method for subway/coal stray current fiber sensor

Abstract

The invention discloses a closed-loop control device and method for a subway / coal stray current fiber sensor and can realize low cost non-contact measurement of the subway / coal stray current. The device is composed of a broadband light source, a fiber circulator, a polarization modulator, a delay fiber, a sensing fiber, a fiber mirror, a fiber framework, a photoelectric detector and a control unit. The closed-loop control method based on the device is characterized in that a rotation angle formed by the polarization modulator for the input line polarized light is equal to a rotation angle formed by the measured current, the directions are opposite, linearity of the sensor is improved, the dynamic range of the sensor is broadened, the cost of the sensor is reduced, the optical path structure of the sensor is optimized, and advantages of strong anti-electromagnetic interference capability and intrinsic explosion-proof insulation are realized.

Description

technical field [0001] The invention belongs to the technical field of subway / coal mine dangerous physical quantity sensing, and in particular relates to a closed-loop control device and method for a subway / coal mine stray current optical fiber sensor. Background technique [0002] The stray current of the subway will cause electrochemical corrosion to the steel bars of the civil construction structure, the metal casing of the equipment and the metal pipeline, and affect the service life of the civil construction structure, equipment and metal pipeline; while the stray current of the coal mine will cause the electric detonator to explode in advance and induce mine gas and dust Explosion accidents, corrosion of coal mine metal pipelines; therefore, it is urgent to study reliable, accurate and safe subway / coal mine stray current sensing devices and methods. Because subways and coal mines have the characteristics of strong electromagnetic interference and high requirements for ...

AI Technical Summary

Problems solved by technology

[0004] In the practical application of phase interference fiber optic current transformers, the quarter-wave plate and the sensing coil are easily affected by the disturbance of environmental factors such as temperature. If the quarter-wave plate is made of elliptical core optical fiber, it needs to be modified. Existing optical fiber cutting table, and it is difficult to cut accurately according to the designed length. In addition, the phase modulator is expensive, which drives the cost of phase interference optical fiber current transformer to remain high

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