A time-domain finite-element method for solving dynamic hysteretic magnetic fields under non-sinusoidal excitations

Accurate iron loss calculation in electrical equipment under non-sinusoidal excitation necessitates stable finite element methods incorporating dynamic hysteresis properties. First, this paper addresses numerical instability at high flux densities by integrating an exponential extrapolation technique into the inverse Preisach hysteresis model, preventing divergence beyond the Everett function limit. Second, memory effects during magnetization are considered by tracking extreme states in time-domain finite element analysis. Meanwhile, to improve convergence near reversal points, a correction method of reluctivity at reversal points is proposed. Finally, comparisons of experimental and computational results on an Epstein frame demonstrate that the proposed time-domain finite-element scheme reduces the average computation time at reversal points by 40% compared to conventional methods, while maintaining high accuracy in magnetic field and loss calculations, significantly improving the overall convergence rate.