Reducing Losses Due to Fringing Flux in an Axial-Flux Permanent-Magnet Synchronous Machine

This paper deals with iron losses caused by fringing fluxes generated by the concentrated stator windings of an axial-flux permanent-magnet synchronous machine. Fringing fluxes enter the laminated stator stack perpendicularly to the plane of the laminated silicon steel sheets. They cause additional eddy currents and losses in the sheets. Three approaches for reducing these losses are compared experimentally with a dedicated setup. The setup has no moving parts and makes accurate iron loss measurement possible. The first method directly restricts the eddy-current losses by segmenting the lamination surface. The second method deflects the fringing flux by using soft magnetic composite. The third method magnetically short circuits the fringing flux using ferromagnetic wires. The first method gives the best results, with a reduction of 6% of the total iron loss at an induction level of 0.6 T and a frequency of 200 Hz.