Periodic solutions of nonlinear eddy current problems in three-dimensional geometries

The collocation and the Galerkin methods are used for the finite-element computation of T-periodic nonlinear eddy currents in three-dimensional geometry. The periodic solutions are computed by using two static methods and are compared with the solution obtained by the brute-force method. The algorithms are very simple. It is found that they require a CPU time much smaller than that required by the brute-force method if the system is lightly damped, and it is also shown that they are robust only if the norm-reducing procedure is used. Furthermore, the Galerkin method provides a satisfactory solution even with few harmonics