3D finite element models and external circuits using the Aψ scheme with cuts

Many devices can only be accurately modelled using a combined circuit and finite element model (FEM), This paper describes the coupling of massive conductor circuits modelled using 3D finite elements and the Aψ scheme with an external circuit model. The massive conductor circuits by their nature lead to the fact that the magnetic scalar region becomes multiply connected. The cuts which are introduced to deal with the multiply connected magnetic scaler regions lead naturally to the current and voltage variables required to couple the field model and lumped circuit model.