Design and Comparison of Segmented Armature Windings for Superconducting Wind Turbine Generators with Multiple Converters

Superconducting synchronous generators (SCSGs) are being considered to be applied in large direct-drive wind turbines. SCSGs can be lightweight and compact but their short circuit torque can be too high for wind turbine constructions. One possible solution is to segment the armature winding and connect each winding segment to an individual converter. This paper presents four possible and most realistic designs of armature windings that are considered for segmentation of SCSGs for 10 MW direct-drive wind turbines. Fractional-slot distributed and concentrated windings which are unconventional for SCSGs are included and studied. Then, this paper comprehensively compares the performance of these winding designs in both normal operation and a three-phase short circuit. The results show that the two integral-slot distributed windings have superior overall performance in normal operation. However, their short circuit torque without segmentation is excessive, and segmentation must be implemented to reduce the short circuit torque. The fractional-slot distributed and concentrated windings have acceptably low short circuit torque even without segmentation but they cause too high AC losses in the superconducting field winding.