Modified surface impedance boundary condition applied to eddy current problems

The authors describe the use of a modified surface impedance boundary condition (IBC) for solving eddy current problems. An approximate expression for the surface impedance at sharp edges of any angle has been derived for TM conduction problems. The validity of the expression is tested by using the method of fundamental solutions (MFS) to solve selected problems with the use of IBC and in the full region (i.e. without the IBC). These results show that significant improvement in terms of accuracy can be achieved as compared with the classical IBC. By using the modified surface impedance, one can determine the distribution of power loss, forces, etc., along the conductor boundaries with excellent accuracy