Design of Uniform Field Coils Based on the Ferromagnetic Coupling Effect Inside Single-Ended Open Magnetic Shielding Cylinder
Weiqian Wang, Fengwen Zhao, Xiangyang Zhou, Xiaoxuan Xie
Abstract
This research proposes a novel method for designing uniform field coils (UFCs) inside a single-ended open magnetic shielding cylinder (MSC). It solves the problems of distorted magnetic field distribution and decreased uniformity resulting from the coupling between the coils and the single-ended open MSC. The magnetic field analytical model of the UFCs inside the single-ended open MSC with high-permeability materials is first established. Then, minimizing the sum of relative errors of the magnetic field in the target area is taken as the objective function, and the improved particle swarm optimization (PSO) algorithm is adopted to optimize the structural parameters for ensuring high uniformity of the coils. The results of the simulation indicate that comparing this work with the Lee-Whiting coil in the single-ended open MSC, the maximum relative error of the magnetic field is reduced from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${6} \times {10}^{-{3}}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${2.3} \times {10}^{-{4}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${6.1} \times {10}^{-{5}}$ </tex-math></inline-formula> . The experimental results also demonstrate the efficacy of the proposed method and practicality for real-time compensation of magnetic field fluctuations within single-ended open MSC. The research content provides the basis for improving the performance of the magnetocardiography (MCG) device.