262 / 2022-03-14 22:39:52

A New Current Measurement Method Based on Circular Tunneling Magnetoresistive Sensor Array

current measurement,calibration,off-center,crosstalk,sensor array

Current measurement is crucial to the development of smart grid, which can provide basic information for power dispatching, fault diagnosis, etc. Current transformer (CT) is the most common current measurement device in power system, but it cannot measure DC current, and has the disadvantages of large size, high-cost, and easy saturation. In recent years, with the development of tunneling magnetoresistive sensing technology, current sensing technology based on non-contact magnetic field measurement has become a new solution to various current measurement situations in power system. In this paper, a new current measurement method based on circular tunneling magnetoresistive sensor array is proposed, which has the advantages of low cost, wide frequency band, low temperature drift, etc. This method has positive significance for the development of smart grid and has broad application prospects.

According to Ampere's loop law, by summing all magnetic field values of circular tunneling magnetoresistive sensing array, the current at the center of the array can be accurately measured. A simulation method based on Fourier series decomposition is used via MATLAB to verify the error of this method in the cases of off-center and crosstalk. A test platform based on Helmholtz coils is designed for the sensitivity calibration of tunneling magnetoresistive sensors. Finally, we tested the performance of the designed circular tunneling magnetoresistive sensing array.

According to the test results, the error of the proposed current measurement method does not exceed 1% in normal cases, and the error does not exceed 1.5% in the case of crosstalk. Meanwhile, the experiment results in the case of crosstalk verify the correctness of the simulation results.

This paper proposed a new current measurement method based on circular tunneling magnetoresistive sensor array, which has the advantages of large range, wide frequency band, high precision, etc. This method has broad application prospects in power system.