T 3.1 - Superconducting direct drive generators

This task aims at designing superconducting generators for direct drive turbines. Superconducting coils in wind generators is a promising technology, because the high magnetic flux and current densities compared to conventional generators will enable a considerable reduction of the generator weight and volume at large power levels. Additionally superconducting direct drive generators will have no or a 100 times smaller dependence on Rare Earth metals compared to permanent magnet direct drive generators. The challenges of integrating the superconducting technology in 3 MW-5MW direct drive turbines will be used in the designs at P= 10-20 MW.

Subtask 3.1.1.

Design of SC generators (DTU&TUD): Different superconducting wires (Nb3Sn, MgB2 ,YBa2Cu3O7 and Bi2Sr2Ca2Cu3O10), different electromagnetic generator designs, and different cryogenic cooling systems will be investigated. Scaling equations for generator designs will be derived to make comparisons at 10 and 20 MW power levels. Recommendations for in-field demonstration of the technology will be formulated and a roadmap for large scale utilization will be given in terms of price and production volume development of the superconducting wires and the cooling technology.

Subtask 3.1.2.

Industrial investigation of SC generators (Siemens): SWP will design, construct and test a superconducting direct drive generator pole pair targeted at the 3-6 MW direct drive nacelle structure currently equipped with permanent magnets. The performance indicators such as size, weight, efficiency and cost will be extrapolated to P = 10-20 MW from the experimental demonstration and provided to the INNWIND.EU consortium for assessment of the turbine concepts being investigated.

Subtask 3.1.3.

Experimental assessment of MgB2 coils (SINTEF): Coils made of wires containing the MgB2 superconductor can become a new cost effective alternative operating at T = 20 K. A rotor coil design will be developed, constructed and tested in order to assess the feasibility.