Comparative analysis on superconducting direct-drive wind generators with iron teeth and air-gap winding

Superconducting direct-drive wind generators have been a research focus, since needs for wind energy development are more and more urgent. Generator stator can be with air-gap winding or iron teeth. Different stator concepts could yield different mechanical, thermal, and electromagnetic performances. This paper compares different stator configurations for 12-MW superconducting direct-drive wind generators with the help of finite element analysis software. Ferromagnetic materials in superconducting machines can help reduce reluctance in magnetic circuits and save costs of superconducting coils in rotor. Moreover, iron teeth could bring cogging torque and vibrations in generators, which can be greatly reduced with air-gap windings. In addition, iron teeth can lead to different losses, including damping shell, copper, and iron losses.