Title: Explicit Time Integration of Transient Eddy Current Problems,
Abstract: For time integration of transient eddy current problems commonly implicit
time integration methods are used, where in every time step one or several
nonlinear systems of equations have to be linearized with the Newton-Raphson
method due to ferromagnetic materials involved. In this paper, a generalized
Schur-complement is applied to the magnetic vector potential formulation, which
converts a differential-algebraic equation system of index 1 into a system of
ordinary differential equations (ODE) with reduced stiffness. For the time
integration of this ODE system of equations, the explicit Euler method is
applied. The Courant-Friedrich-Levy (CFL) stability criterion of explicit time
integration methods may result in small time steps. Applying a pseudo-inverse
of the discrete curl-curl operator in nonconducting regions of the problem is
required in every time step. For the computation of the pseudo-inverse, the
preconditioned conjugate gradient (PCG) method is used. The cascaded Subspace
Extrapolation method (CSPE) is presented to produce suitable start vectors for
these PCG iterations. The resulting scheme is validated using the TEAM 10
benchmark problem.