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Different techniques are investigated to improve the performance of the solution process of 3-D, time-periodic, nonlinear, voltage-driven eddy current problems under the influence of dc bias by the means of the finite-element method. The underlying nonlinear iteration technique is the time-periodic fixed-point method. The benefit of a static approximation to generate an initial solution, i.e., of a static initialization is pointed out. A secant method and a Schur complement technique to carry out the static initialization are compared. The procedures developed are applied to 3-D models of one- and three-phase benchmark transformer problems with dc bias. [ABSTRACT FROM AUTHOR]

Abstract: Two different techniques for the analysis of nonlinear, periodic eddy‐current problems are compared using a three‐dimensional benchmark problem. The methods are the parallel time periodic finite element method and the time periodic fixed‐point technique. [ABSTRACT FROM AUTHOR]

Solving electromagnetic wave propagation problems with the finite-element method results in a large number of unknowns due to the necessity of modeling an extensive portion of the surroundings of the conducting structures. These equation systems are often ill-conditioned because of the great material differences as well as changes in size between neighboring elements. In addition, the resulting matrices are indefinite. Common iterative methods exhibit poor convergence due to these conditions. Direct solution techniques result in high memory requirements. The aim of this article is to present an approach with smaller memory demand than the direct methods and better convergence properties than common iterative techniques. An iterative method based on domain decomposition is presented and compared to various conventional iterative and direct solution techniques. [ABSTRACT FROM AUTHOR]