Convergence behaviour of different formulations for time-harmonic and transient eddy-current computations in 3D

Several different formulations for the calculation of eddy-currents using the finite-element method have been proposed. For 3D applications in static cases the magnetic vector potential with edge elements is the most common case. The static formulation can be extended to account for eddy-current effects using an additional term with the same magnetic vector potential with an electric vector potential or with an electric scalar potential. The last is commonly believed to be the best in terms of stability and convergence rate. This paper considers the three different formulations in a time-harmonic and a transient case for a simple C-core model and the TEAM Workshop problem 7. The effects of time and space discretisation are analysed. The TEAM Workshop problem is also verified against measurement results obtained by Fujiwara et al.