An analytical model of an eddy‐current coil near the edge of a conductive plate

Abstract

Truncated region eigenfunction expansion (TREE) method is applied to the analysis of impedance change of a coil in the vicinity of the edge of a metal plate. The analysis is carried out with the second order vector potentials (SOVPs) and provided for both cylindrical and rectangular coils. By full discretisation of the eigenvalues, double series solutions are obtained for the field and coil impedance variations. To simplify the solving procedure further, a novel approach for the determination of eigenvalues is proposed by means of the 1D finite element method (FEM), which is easy to implement and works well for the plate of non-magnetic material. Numerical results for the impedance variations of cylindrical and rectangular coils are compared with those of 3D FEM simulation, by which the efficiency and accuracy of the authors’ method are confirmed, and the former is much faster and more memory efficient.