An open-loop signal detection method and device for an all-fiber-optic current transformer

Abstract

The invention discloses an all-fiber current transformer open loop signal detection method which comprises the following steps: employing an asymmetric square wave with a period of 2t and an amplitude of Vpi/2 as a modulation signal, carrying out phase modulation on an optical signal, wherein the t is a transit time of the all-fiber current transformer; after the optical signal after phase modulation is subjected to interference, converting the optical signal into an electric signal; subjecting the electric signal to a sampling treatment; in a period 2t, calculating difference between sampling sum of electric signal positive half cycle and sampling sum of electric signal negative half cycle, defining a difference result as S1, defining sampling sum of the electric signal as S2, dividing S1 by S2, and defining a divide resultant as an open loop signal detection result of the all-fiber current transformer. An embodiment of the invention also discloses an all-fiber current transformer open loop detection apparatus. Since the asymmetric square wave is employed as a modulation signal, in a demodulation process, factors related to light source power and circuit gain in an interference output result are eliminated through a specific algorithm, thus the open loop signal detection result is only related to Faraday phase shift, and accuracy of a measuring result is raised.

Description

Technical field [0001] The invention relates to the field of optoelectronics technology, and in particular to an open-loop signal detection method and device for an all-fiber current transformer. Background technique [0002] The all-fiber current transformer is a new type of current sensing device based on the Faraday effect and using optical fibers as sensitive and conductive components. The structure of the all-optical current transformer is as figure 1 As shown, the working principle is as follows: the light emitted by the light source is polarized by the fiber polarizer into linearly polarized light after passing through the circulator; the pigtail of the above-mentioned light polarizer and the pigtail of the phase modulator are welded at 45°, linearly polarized light The polarization-maintaining fiber injected into the fiber polarizer at 45° is decomposed into two linearly polarized beams of orthogonal mode, which are respectively transmitted along the X-axis and Y-axis of ...

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Problems solved by technology

The fluctuation of light output power of the light source and the drift of the gain of the signal detection circuit wi

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