Impedance Variation of an Induction Coil Near the Edge of a Right-Angled Steel Wedge

The quasi-static electromagnetic field of a cylindrical coil in the vicinity of the edge of a steel block is analyzed by the truncated region eigenfunction expansion (TREE) method. The analysis is carried out with the second-order vector potential (SOVP) and the eigenvalues for the magnetic metal wedge are calculated by an efficient approach based on the 1-D finite element method (1D FEM). The efficiency of the eigenvalue computation is guaranteed by the sparsity of the stiffness matrix generated by the 1D FEM basis functions. Numerical results for the coil impedance variations are compared with the 3-D FEM simulation, and good agreement is achieved.