Computation of end-winding inductances of rotating electrical machinery through three-dimensional magnetostatic integral FEM formulation

Purpose – The paper aims to illustrate a numerical technique to calculate fields and inductances of rotating electrical machines. Design/methodology/approach – The technique is based on an integral formulation of the nonlinear magnetostatic model in terms of the unknown magnetization. The solution is obtained by means of a Picard-Banach iteration whose convergence can be theoretically proved. Findings – The proposed method has been used to build a model of a large turbine generator. In particular, the influence of end effects on flux linkages has been computed. It has been demonstrated that the 2D solution underestimates the flux linkages as well as the no load voltage of 2 per cent, while the leakage fluxes are computed by the 2D solution with errors as high as 20 per cent. Originality/value – The method is advantageous in comparison to standard methods.