Nonlinear eddy current analysis by the integral equation method

Nonlinear eddy currents in a ferromagnetic conductor are formulated by surface and volume integral equations which are derived from Maxwell´s equations by using Green´s theorem. As the periodic electromagnetic quantities in the conductor vary nonsinusoidally, the quantities are expanded by Fourier series, whose fundamental and harmonic components are determined by solving the corresponding integral equations with the surface magnetic fields given as the boundary values. The surface fields are determined by using the boundary impedance condition. The internal and surface fields are obtained alternately until convergence by an iterative method