Finite-Element Analysis for Magnetic Flux in End Region of Synchronous Machine Using End-Winding Model

Designers of the synchronous machine are required to quickly and accurately predict its characteristics. 2-D finite-element analysis (FEA) is subject to error caused by neglecting the magnetic flux in the end region composed of the end winding and the space surrounding it. For accurate prediction using 2-D FEA, it is necessary to calculate the end inductance due to the magnetic flux of the end region and to correct the armature inductance. This article proposes a modeling method, which introduces the Neumann boundary to calculate the end inductance correctly by the partial 3-D FEA simulating only the end region, and a correction method for 2-D FEA using the end inductance. Comparison reveals that the calculated characteristics obtained from the corrected 2-D FEA are in good agreement with the measured characteristics. It is demonstrated that the end inductance given by the partial 3-D FEA has reliable accuracy and the corrected 2-D FEA can achieve the same level of accuracy as full 3-D FEA in a computation time less than 1/10.