The Research On Signal Processing Method Of Fiber Optic Current Transducer

The energy consumption of production energy consumption is 94% in the aluminum electrolysis process. Reducing energy consumption is an important issue in the research of aluminum electrolysis. Anode current distribution is one of the important parameters in the process of aluminum electrolysis. Judging the anode current distribution and mastering electrolysis operation state can provide the basis for improving production efficiency. Contronling operation state of electrolysis, by judging the anode current distribution, can provide the basis for improving production efficiency. The existing methods of field measuring anode current distribution have a large degree of deficiency. Measurement of anode current by optical fiber current transducer is a new method which has more advantages, compared with the traditional measurement methods. Optical fiber current transducer is small size, high precision, strong anti-interference ability and high security.Because of the characteristics of structure of optical fiber current tranducer. the impact of nonreciprocal drift and environment noise on the output is small. Random noise is one of the main reasons that affect the measurement accuracy of optical fiber current transducer. Random noises are mainly including quantization noise, angle random walk noise, bias instability noise, rate random walk noise and rate ramp noise. This paper analyzed the source of noise in the optical fiber current transducer. Refering to Allan variance analysis in the noise of other precision instruments, this paper calculated each random noise coefficients of the optical fiber current transducer. Filtered the output of the optical fiber current transducer by using the five point three smoothing method and the wavelet transform. Compared to the five point three smoothing method, the wavelet transform has better filtering effect, which can effectively reduce the random noise coefficients and futher improve the precision of measuring current of the optical fiber current transducer.This paper design a portable optical fiber current transducer user interface based on weinview 8070iE for data display and storage. The data acquisition system based on LabVIEW is designed, which realizes the real-time collection of the data of multi channel and different protocols. This paper design a on-line Allan Variance system by Matlab GUI. This paper analyzed data of the actual cell and proved that using the optical fiber current transducer to measure the anode current distribution is an accurate and convenient method.