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Superconducting Generators for Large Wind Turbines. markus.mueller@ed.ac.uk o.keysan@ed.ac.uk Institute for Energy Systems The University of Edinburgh. Markus Mueller Ozan Keysan – Joe Burchell. 19/03/2012. Motivation.
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Superconducting Generators for Large Wind Turbines markus.mueller@ed.ac.uk o.keysan@ed.ac.uk Institute for Energy Systems The University of Edinburgh Markus Mueller Ozan Keysan – Joe Burchell 19/03/2012
Motivation In 2020, 85% of offshore wind turbine installations will be larger than 5 MW BARD 5MW Global Offshore Wind Energy Markets and Strategies,2009
Wind Turbines: Constantly Growing • How big? • UpWind Project: A 20 MW Wind Turbine is Feasible www.upwind.eu
Mass of Direct-Drive Generators Enercon 4.5 MW, 13 rpm 220 tonnes Harakosan 1.5MW,18 rpm,47 tonnes All data available at goo.gl/ZZivv (*) D. Bang et.al. “Review of Generator Systems for Direct-Drive Wind Turbines,” 2008,
Mass of Direct-Drive Generators All data available at goo.gl/ZZivv
Reliability of Wind Turbines ~1MW, 1500 onshore turbines Hahn, B., & Durstewitz, M. (2007). Wind Energy-Reliability of Wind Turbines.
Types of HTS Machines • Rotating DC Superconducting Field • Most Common Type • Transient Torques on HTS wire • Cryocooler Coupler + Electrical Brushes Low Reliability + Maintenance • Magnetized Bulk HTS • Very Difficult to Handle • Demagnetization? • All Superconducting Machines • AC Losses on HTS wire
Reliability? Issues with Superconducting Generators SeaTitan AMSC, 10 MW, 10 rpm Direct-drive superconducting generator • Cooling System • Cryogenic Couplers • Electric Brushes • Transient torques on SC • Demagnetization for Bulk SC • AC losses on SC wire
Homopolar HTSG • Pros • Stationary SC Field • No Brushes • No Transient Torque on SC • Simplified Cooling, Isolation
Homopolar HTSG • Cons • Uni-directional flux density • Reduced power density
Bipolar HTSG • Pros • Bidirectional Flux • Increased Power Density • Cons • Double SC field winding • Mechanical Issues
Transverse Flux HTSG • Pros • Single Stationary SC Coil • Bidirectional flux • High Torque Density • Cons • Magnetic Attraction Forces • 3D Flux (Soft magnetic composites needed)
THANKS Some Publications • "A Homopolar HTSG Topology for Large Direct-Drive Wind Turbines", Keysan O., and Mueller M., 2011. IEEE Transactions on Applied Superconductivity, 21(5), 3523 - 3531. doi:10.1109/TASC.2011.2159005. • "Superconducting Generators for Renewable Energy Applications", Keysan O., and Mueller M., 2011, IET Renewable Power Generation Conference, Edinburgh. • "A Transverse Flux High-Temperature Superconducting Generator Topology for Large Direct Drive Wind Turbines", Keysan O., and Mueller M., 2011. Superconductivity Centennial Conference, 2011, Den Haag, The Netherlands.