Nonlinear Eddy Current Analysis by Boundary Integral Equation of One Component Utilizing Impedance Boundary Condition

Abstract

Since the magnetic permeability of steel is comparatively high, the skin depth may be a few millimeters even at a low frequency such as 50 Hz. And so, the impedance boundary condition (IBC) works effectively in most of the eddy current analyses. However the IBC is originally defined on the basis that the material property is linear, and so, in order to apply the IBC to nonlinear materials, we introduce a nonlinear IBC. With the help of the nonlinear IBC, we lessen the unknowns of the integral equations to give the boundary value to one and derive an integral equation with a loop current as the state variable. In order to check the adequacy and effectiveness of the proposed approach, we solve a typical eddy current problem while comparing computed results by the full equations and FEM.