Project Status SPEEDY_HTS – An HTS retrofit rotor for a mid-speed wind power generator

HTS excitation coils in wind power generators are an interesting alternative to state-of-the-art permanent-magnet-excited offshore wind generators. These generators need a high amount of permanent magnet material: roughly 50 kg of rare-earth magnets per MW for geared mid-speed solutions (400-600 rpm) and even 0.5 tons per MW for gearless low-speed solutions (<10 rpm). The amount of HTS material is, in comparison, much smaller for the same power rating. Using HTS in a mid-speed generator indicates a potentially improved business case by restricting the HTS tape need to less than 3 km for a 13 MW generator.
In this work, we report on the status of development of an HTS excited rotor, replacing the conventional rare-earth permanent-magnet rotor in an existing 6 MW, 24-pole generator operating at 602 rpm and 3-phase, 750 V AC. This extends the generator's power to up to 13 MW at the same generator size, according to our simulations in an existing stator and housing with the 3-phase AC copper winding. This power density is far beyond the limits of conventional generator technology.
We will focus on details of the electromagnetic design (using a high-current stator, the air-gap flux density will be the same as in the conventional machine), the cooling system and the 2G-HTS coils not only in design but first measurements.
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This work is funded by the German Ministry of Economy and Climate, FKZ03EE3094E, and by the Program Oriented Funding by the German Ministry of Research, Program MTET, High-Temperature Superconductivity, 38.05.03.