Finite element solution of transient eddy-current problems in multiply-excited magnetic systems

This paper presents a new finite element formulation for the solution of transient electromagnetic field problems in multiply-excited magnetic systems. The formulation given here consists of obtaining the magnetic vector potentials and current density distributions at each time instant by applying an implicit time integration technique to the diffusion equation and Ampere's Law, followed by a Galerkin's projection, given the total measurable currents flowing in the system as a function of time. The technique is illustrated by way of solving two diffusion problems. Where possible, computed results are compared with closed form solutions and published data, and excellent agreement between them is found.