Design of a superconducting DC demonstrator for wind generators

The trend to reduce the cost of offshore wind energy is to develop large wind turbines. Turbine sizes of 6-8 MW have already been seen in the wind market. Even larger turbine sizes are managing to pave their way from studies to market. Due to the high current-carrying capability and no dc losses of the superconductors, superior power to weight/volume ratio of a superconducting generator can be achieved. Hence, in this paper, a superconducting dc generator is proposed. In this generator, the superconducting coils are used mainly to generate the main air gap flux density and silicon steel iron cores are employed by the stator and rotor. In order to study the feasibility of the proposed generator and to design the generator, the critical current of the superconducting material and electromagnetic properties of the silicon steel iron core are first measured. Then, a demonstrator of the superconducting dc generator is designed through the developed process, which integrates the analytical method into the particle swarm optimization. As a preliminary step toward the demonstrator, a test for a key component of the demonstrator, the superconducting coil, has been made.