Boundary Element Formulation Enforcing High-order Surface Impedance Boundary Conditions for Axisymmetric Eddy Current Problems

This paper presents a boundary element method (BEM) formulation coupled with high-order surface impedance boundary conditions (SIBCs) for axisymmetric eddy current problems. The formulation is based on perturbation theory (PT) and on the reduced magnetic scalar potential. A big advantage of the proposed approach is that if the solution is sought at different frequencies, the boundary integral equations can be solved only once and then the fields are easily computed at any frequency using a series expansion according to PT. Three test problems are solved, for which the reference solution is given by the standard finite element method (FEM). The convergence of BEM-SIBC results towards FEM solution with respect to frequency is verified. The proposed approach requires reduced memory and computational times compared to the standard FEM and can be applied with linear, isotropic, and homogeneous materials.