Medium-Speed Wind Turbine Generators with HTS Excitation Winding

Medium-speed geared synchronous generators for wind turbine applications with either PM excitation or HTS excitation winding are compared for rated operation at P = 6MW, n = 480rpm. Due to the higher power factor cosφ
s
= 1, the rated efficiency is by about 0.5% higher in case of HTS excitation. The generators’ overload operation is examined up to 170% of rated stator current loading by applying intensified stator winding cooling. HTS excited medium-speed generators are particularly promising in case of high current loadings regarding high efficiency, high power factor and reduced overall system cost.