A Circuit Coupling Method Based on a Temporary Linearization of the Energy Balance of the Finite Element Model

In this paper, a versatile method for modeling coupled magnetic field and circuit problems is presented. The field problem is solved by applying the finite element (FE) method. The nonlinear circuit equations are solved by applying the Newton-Raphson method. The finite element model and the circuit are solved separately, which in turn gives the possibility of considering different time constants for each domain. The idea is to extract values of the slowly varying lumped parameters describing the finite element model in the circuit equations at a rate related with the time constant of the finite element system, and to use them to iterate the circuit equations between two updates with a time step adapted to the significantly smaller time constant of the electric system. Contrary to the widely used numerically strong coupled methods, this paper introduces a different approach by applying an energy-based parameter identification.