A Time-Stepping Volume Integral Formulation for Nonlinear Field-Circuit Coupled Problems

A B-conforming time-stepping Volume Integral Method (VIM) formulation for nonlinear 3D field-circuit coupled problems is presented in this paper. The advantage of the VIM with respect to the Finite Element Method (FEM) is that only the ferromagnetic regions have to be discretized, thus avoiding to mesh the air. It is an appealing approach given that it avoids numerical errors that can arise from meshing the air. A direct formulation is explained, assembling in a system the magnetic field and the circuit contributions when coils are present. An application to a current transformer is shown, comparing it to the FEM to validate its accuracy.