Concentrated windings for wind generators with solid rotor iron and redundant feeding

Abstract

This paper deals with parasitic eddy current losses in massive outer rotor high pole count gearless permanent magnet synchronous wind generators of 8 MW especially under fault condition, when parts of 3-or 6-phase stator windings are idling. For simple manufacturing concentrated windings are investigated in comparison to an existing integer slot winding, and are analytically evaluated concerning additional eddy current losses in the solid rotor yoke. Eventually, machines with a 3-phase q=1/2 and q=2/5 winding with thermally permissible rotor losses are optimized by a multi-objective genetic algorithm. Two final machine designs were checked at rated operation by 2D transient, nonlinear finite element simulations concerning efficiency, power factor and torque ripple.