Material Characterization and Stator Core Loss Computation of Synchronous Generators with Stacking Force Accounted

In synchronous generators, stacking pressure of stator core can be up to 10MPa. This stacking force alters magnetic properties of laminated steel, and consequently changes the core loss. Core loss computation can have more error if the stacking force is not considered. This paper investigates the impact of stacking force on stator core loss of synchronous generators. Magnetic properties (magnetization and loss) of the electrical steel M400-50A are measured in a ring core test, and during the test, the ring core is subjected to a controllable axial pressing force. Two core loss models are used to compute the stator core loss of a 100kVA synchronous generator. Lab tests in this generator show that, both models have an averaged absolute error less than 5%, and the computational accuracy is obviously improved after taking into account the stacking force.