The document discusses high-temperature superconducting generators (HTSGs) for direct drive applications in wind turbines. It provides background on the discovery of superconductivity and important superconductor materials like YBCO. It then examines various HTSG designs, including rotating DC, homopolar, axial bipolar, and transversal flux machines. The document concludes by noting design challenges for reliability and comparing the costs of HTSGs to traditional permanent magnet generators.

1. High-Temperature Superconducting Generators for Direct Drive Applications OZAN KEYSAN [email_address] Institute for Energy Systems The University of Edinburgh April 2011

2. Superconductor? Abolish the OHM’s Law Kakani2009 Zero Resistivity

3. MERCURY The First Superconductor Material Discovered in 1911 Critical Temp = 4.2 K (-269 C)

4. Infinite Current? Unfortunately NOT. www.superox.ru

5. YBCO (YBa 2 Cu 3 O 7 ) Current Density > 200 A/mm2 (5-10 A/mm2 for copper)

6. Perfect Diamagnetism

7. Applications: MagLev Train

8. Applications: Large Hadron Collider Superconducting Magnets Up to 16 T, Normal PM ~1.5 T

9. Applications: MRI

10. Power Applications Courtesy AMSC, InnoPower Superconductor Transmission Lines Fault Current Limiter

11. Power Applications : Electrical Machines Courtesy of Siemens, Converteam (ALSTOM) Siemens: 400 kW Converteam (ALSTOM): 5 MW HTS

12. Power Applications : Electrical Machines 36.5 MW, 120 rpm (U.S. Navy, AMSC) Courtesy of AMSC

13. Wind Turbine Applications? M. Lesser, J. Müller, “Superconductor Technology – Generating the Future of Offshore Wind Power,” BARD 5MW

14. Direct-Drive Solutions EESM: Electrically excited Synchronous Machine HTSG: High-Temperature Superconducting Generator PMG: Permanent-Magnet Generator Bubble Size: Power Rating

15. Cost Comparison (HTSG vs. PMG) Lesser2009

16. Types of HTS Machines Rotating DC Superconducting Field Most Common Type Transient Torques on HTS wire Cryocooler Coupler + Brushes  Low Reliability Cooling Times Magnetized Bulk HTS Very Difficult to Handle Demagnetization All Superconducting Machines AC Losses on HTS wire

17. Reliability? Stationary SC Coil No Cryogenic Coupler No Brushes No Transient Torque on SC Simplified Cooling, Isolation DC Field No AC losses Maximized Current

18. Homopolar HTSG

19. Homopolar HTSG

20. Axial Bipolar HTS Machine

21. Bonus: Bipolar Linear HTSG Suitable for WECs

22. Transversal Flux HTSG

23. Thanks. OZAN KEYSAN [email_address] www.see.ed.ac.uk/~okeysan