Finite element modelling of thin skin depth problems using magnetic vector potential

A technique for modelling thin skin depth eddy currents in 3D devices using the magnetic vector potential A is presented. An analytic solution for the magnetic field in the thin skin is used to develop a surface impedance which appears as a surface integral at faces of elements which interface the thin skin eddy current region. The method has been implemented using classical nodal variable finite elements. Results are compared with an analytic solution and measurements from a nonlinear test rig.