Analysis of the air-gap asymmetry in axial-flux permanent magnet generators

One of the most important drawbacks to the application of the axial flux permanent magnet generator is represented by the relevant mechanical stresses due to the electromagnetic attraction between the stator and the rotor parts, which may arise even in double-side configurations, due to slight air-gap asymmetries. In the paper, a time-effective procedure is presented to analyze the unbalanced condition, based on a simplified 2D rectified geometry and on the implementation of a circuit model, which can take also into account the circulation currents due to the e.m.f. unbalancing.