Three-Dimensional Magnetostatic Field Analysis of Electrical Machinery by the Finite-Element Method

Modern electrical plants and machinery are required to operate at high-power density levels at minimum cost and improved efficiency with a high degree of reliability. Such stringent requirements necessitate a high degree of accuracy in predicting machine performance at the design stage, for which sophisticated analytical tools are essential. In this paper, a rigorous three-dimensional magnetic field analysis based on the finite element method is presented. The correct choice of the vector potential solution is established and it is shown that the variational formulation yields an energy-related functional associated with the vector Poisson equation which, when minimized, results in the true solution to the field problem. The analysis developed is applied to illustrative geometries; the principal amongst these being a two-winding transformer and a segment of a turbine generator.