Experimental verification of the performance of the self-tunable loop-current array shielding module

K. Goleman, T. Yamato, Ichiro Sasada

Research output: Contribution to journalArticle

Abstract

An active shielding module consisting of a self-tunable loop-current array is verified experimentally. Loop currents in the array are independently controlled by the magnetometer dedicated to each of them. Since magnetic field decays as 1 z3 along the distance z from the loop, the magnetic noise should be overcompensated at the location of the loop-current array to provide a good cancellation in the shielded area. In order to enable overcompensation in a stable feedback system, a small additional loop is combined to the magnetometer that reduces the magnetic direct coupling from the main loop current to the magnetometer. A feedback electronic circuit with a proportional-integral (PI) controller is combined with each of the array element to establish a stable canceling operation. An orthogonal fluxgate magnetometer is used to monitor incident magnetic noise. Shielding performance of an array consisting of nine loop currents arranged in a 3×3 grid was evaluated numerically and confirmed by experiments. Evaluation and measurements are done over the 1.5×1.5 m2 area 2 m in front of the array. The magnetic dipole disturbance source is placed 2 m further beyond the array. Attenuation of the magnetic field is calculated as 115. Experimental data show 110 attenuation.

Original languageEnglish
Article number08P502
JournalJournal of Applied Physics
Volume99
Issue number8
DOIs
Publication statusPublished - May 25 2006

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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