Computation of three-dimensional electromagnetic field including moving media by indirect boundary integral equation method

Abstract

We present a general analysis method for three-dimensional (3-D) eddy current problems with a moving conductor. The indirect boundary integral equation method (IBIEM) is employed for 3-D electromagnetic field problems including an arbitrarily shaped conductor with constant relative velocity. Since the 3-D motion effect is taken into account in the fundamental Green's function for the governing equation of diffusion type, this approach gets rid of spurious oscillations which usually occur in solutions obtained by the Galerkin finite element method. That is, the proposed method uses an elaborate fundamental Green's function for magnetic diffusion instead of artificial upwind techniques of the finite element method. In addition, a new accurate integration technique for very local functions related to the Green's function for magnetic diffusion is adopted, a technique that plays an important role in accuracy and stability of numerical solutions. The electromagnetic field and eddy current at any point are calculated through the numerical integration of the equivalent magnetic surface sources obtained by the integral system equation. The proposed method is numerically tested and validated through the analysis model where a conducting slab under a fixed rectangular coil moves with a constant velocity.