Subdomain Perturbation Finite-Element Method for Quasi-static Darwin Approximation

The subdomain perturbation (SDP) finite-element (FE) method is a very efficient numerical technique and it speeds up the analysis of magneto- and electroquasi-static problems significantly. In order to solve quasi-static Darwin models, the authors have recently developed a low-frequency stable FE A-V formulation that incorporates both capacitive and the inductive effects, thereby allowing solving for resonances. This article combines the Darwin FE formulation with the SDP strategy at the first time. It successfully validates the combined technique and demonstrates a significant run-time improvement compared to the full Darwin FE solution. The breakdown of the Darwin approximation at higher frequencies is also investigated.