An Improved Finite Element Computational Scheme for Transient Field-Circuit Coupled Systems

Time stepping simulation of transient field-circuit coupled problems is a computation-intensive area. In general, finite element (FE) modeling and simulation of a large class of engineering applications require heavy computations that are often repetitive in nature. Any deeper insight into the dependence of the FE solution or its characterization may allow significant reduction of computational efforts. This paper illustrates the possibility of characterization of the time-varying FE solutions for transient field-circuit coupled problems. The characterization leads to a significantly smaller FE model and an improved modeling and simulation scheme for such problems. Construction of the reduced FE model for the field is illustrated, along with its coupling to a general external electric circuit. Relation of the proposed approach to the well-known substructural approach based on Schur Complements is discussed. Possibilities of further improvement of the numerical properties of the FE equations, possibly leading to improved convergence of iterative solutions, are indicated. Finally, extension of the approach to nonlinear field-circuit coupled problems is illustrated. Numerical simulations using the proposed approach for a typical electromagnetic system with solid bars connected to external circuit are presented. The results are compared to those from a commercial software, and a relative assessment of the computational effort involved in the proposed and conventional methods is also presented.