Optimum 7 MW HTS direct-drive wind turbine synchronous generator designs with different rotor and stator iron topologies

Abstract

AbstractPartially superconducting direct-drive wind turbine generators with high-temperature superconducting excitation winding enable an increase of the rated unit power, higher efficiency, and a high, adjustable power factor. The high excitation ampere-turns allow for iron topologies that differ from conventional permanent magnet-excited generators. This study compares four different iron topologies for $$7\,\mathrm{MW}$$ 7 MW rated power and 8.33 rpm with a slotted stator or stator air gap winding regarding technical key characteristics and economic aspects. The generator designs are numerically optimized based on 2D finite element simulations. Maximum efficiency and the most lightweight designs are obtained with the stator air gap winding, whereas all-iron topologies prove advantageous regarding the trade-off between small active mass and high-temperature superconductor material consumption. The costs of the cryogenic cooling system and of the full converter are both found to be less than $$15\%$$ 15 % for a wide range of generator designs.