A finite element technique for voltage driven devices

The authors present a 2D finite element technique for predicting the steady-state alternating behaviour of electrical devices where the terminal voltages and the supply circuits are assigned (voltage driven devices). The method, which also takes into account the eddy current effects, expresses the induced electromotive forces in terms of the unknown magnetic vector potential and so inserts the circuit equations into the field problem. The proposed technique allows for the connection of complicated external networks of voltage sources and dissipative parameters. The introduction of fictitious electromotive forces related to a single conductor makes circuit manipulation easier. The possibilities of imposing supply currents and of neglecting eddy currents are included. The proposed procedure is applied to the behaviour of multiconductor busbar systems. A three-phase system under short circuit conditions; and an AC electromagnet with shaded rings under rated and reduced supply conditions