®
A MAGNETICALLY-GEARED COMPACT 3MW DIRECT DRIVE GENERATOR
EWEC 2010
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Overview
1. Pseudo direct drive PDD®
2. Wind generator development
3. Benefits for wind energy
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Magnetic gearing&
PDD®
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Video presentation
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• Three components• Two are free to rotate, the third is mechanically earthed
High torque magnetic gear
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0
0.1
0.2
0.3
0.4
0.5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Harmonic number
Nor
mal
flux
den
sity
(T
)
-0.4-0.3-0.2-0.10.00.10.20.30.4
0 100 200 300
Angular position (degrees)
Nor
mal
flux
den
sity
(T)
Field of inner magnets without pole-pieces
4 pole-pair spatial harmonic (fundamental)
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-0.7-0.5-0.3-0.10.10.30.50.7
0 100 200 300
Angular position (degrees)
Nor
mal
flux
den
sity
(T)
0
0.1
0.2
0.3
0.4
0.5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
Harmonic number
Nor
mal
flux
den
sity
(T
)
Harmonic at 27-4=23
Field of inner magnets with pole-pieces
Original 4 pole-pair fundamental
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No pole-pieces
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With pole-pieces
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• Improved reliability • Improved efficiency• Reduced maintenance • No gear wear • Lighter for large torques• Inherent overload protection• Unlikely to jam• Reduced noise/vibration
Magnetic gear benefits
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A combination of two magnetic transmissions
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• Highest torque-density electrical machine• Removes gearbox• Overload protection• Very high efficiency• Requires little or no cooling• High power factor• Standard power electronic control
PDD® benefits
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3MW wind turbine PDD® generator
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3MW PDD®
• 3.8m diameter • 1.8m length • 40T mass
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Advanced DD PMG 3MW5m OD 2.5m length75 tonnes
Geared DFIG 3MW Magnomatics PDD 3.8m OD 1.8 length40 tonnes.
Size reduction
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Annual energy output
Taken from Garrad Hassan study
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Benefits for wind energy
• Removes gearbox -> increases turbine reliability
• High efficiency
• Light weight
• Low maintenance
• Torque fuse protects drivetrain
• Scalable for larger WTs
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Next steps
• Design, build and test 500kW demonstrator
• Evaluate technical and economic benefit
• Develop 3MW generator
• Test on turbine
• Certification and production engineering
• Develop 6-7MW generator for offshore