Transient Finite Element Analysis of a SPICE-coupled Transformer with COMSOL Multiphysics

T. Bödrich[1], H. Neubert[1], and R. Disselnkötter[2]
[1]Technische Universität Dresden, Germany
[2]ABB AG, Forschungszentrum Deutschland, Ladenburg, Germany

The operation of transformers is characterised by strong dynamic interactions between the magnetic system and the electric circuits that are connected to the primary and econdary windings. Transient finite element modelling (FEM) of the transformer with coupling to SPICE circuit models containing the electrical sources and loads is a powerful means for analysis and design. This paper describes the approach followed in COMSOL with 3D magnetic FEM and transient simulation of a current transformer with a non-linear core characteristic that has both windings coupled to external circuitry via a SPICE netlist. This is a configuration which is quite challenging with respect to numerical stability. Further focus is on how to model the multi-turn winding.