Strong Coupling of an Electromagnetic Transients Program and a Finite Element Magnetic Field Solver Including Eddy Currents

An improved scheme for coupling electromagnetic transients programs with finite element magneto-dynamic field programs is presented. The proposed scheme uses the compensation approach to build up a strong coupling between domains, with no time delay. This permits to fully take into account the spatial field distribution in the magnetic device as well as eddy currents in the conducting materials. The scheme is developed starting with the field equations for the Cartesian plane and axisymmetric cases, which are combined with the reduced circuit equations. The solution of the simplified circuit-field system is achieved by an efficient sequence of time discretization followed by the iterative solution of the resulting nonlinear equation. The implementation of the scheme and its validation are discussed. The results show a very competitive performance of the new approach.