Development and Challenges of Permanent Magnet Wind … Workshop... · 1 stg GBX 2 stg GBX 3 stg...
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WORKSHOP ON NEXT-GENERATION WIND POWER May 12, 2010 Rensselaer Polytechnic Institute Development and Challenges of Permanent Magnet Wind Generators Ronghai Qu GE Global Research Center
Transcript of Development and Challenges of Permanent Magnet Wind … Workshop... · 1 stg GBX 2 stg GBX 3 stg...
WORKSHOP ON NEXT-GENERATION WIND POWERMay 12, 2010Rensselaer Polytechnic Institute
Development and Challenges of Permanent Magnet Wind Generators
Ronghai Qu
GE Global Research Center
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3
3GEAR BOX
WOUND ROTORINDUCTION GENERATOR TRANSFORMER
GRID
IGBT POWER CONVERTORS
3
Doubly-Fed Variable Speed System
Variable Speed Systems Becoming Industry Standard at High PowerVariable Speed Systems Becoming Industry Standard at High Power
3
GEAR BOX
INDUCTION GENERATOR TRANSFORMER
GRID
Fixed Speed System
3
3GEAR BOX
WOUND ROTORINDUCTION GENERATOR TRANSFORMER
GRID
IGBT RControl
Rectifier
Variable Slip System
GEAR BOX
SYNCHRONOUSGENERATOR TRANSFORMER
GRID
Rectifier
33
IGBTInverter
Full Conversion Variable Speed System
PM machines
Electrical Power Conversion
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Permanent Magnet Generator
PMs
Stator
Rotor
Flux driven by PMs
Surface PM machine
Surface PM w/
Pole cap
Spoke PM
Interior PM
Design Considerations•Excitation
•Physical Magnet protection
•Rotor mechanical
•Magnet cooling
•Demagnetization protection
•Manufacturing
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Permanent Magnet vs. Doubly-fed Asynchronous Machines
PM
• Permanent magnets on rotor
• High Efficiency / Low Cost of Energy
• High reliability
• Lighter machine
• Sample rotor pole structure –suitable for high pole number
• Full power conversion
Doubly-fed
• Variable frequency current on rotor
• Partial power conversion
• Large rotor loss/exciting current
• Slipping ring
• Low Reliability
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Drivetrain Weight – Geared vs. Direct Drive
Input torque (kNm)
Driv
etra
in W
eigh
t (m
T)
6000
300
Geared
Direct Drive
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Drivetrain Cost
•Gearbox stage changes as gear ratio increases
•Gearbox cost jumps as stage changes
•Generator cost decreases as speed/gear ratio increases
•Drivetrain cost varies
Drivetrain cost
Gear ratio
Co
st1 stg GBX 2 stg GBX 3 stg GBX PM Gen DT
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PM Generator Application Trend
• More PM generators, more companies with PM
• Small Wind Generators (<100kW)– Simple design, easy manufacturing and control
• High efficiency generator ( large turbines, >2MW)– Low cost of energy
• Light & high pole number generator (direct drive)– Simple pole structure
• High reliability– Direct Drive, no gearbox, high pole number,
simple rotor structure
SKT Wind PM Generator (200W~99kW) www.alxion.com
Siemens 3MW DD PM Gen, 73mt
www.renewableenergyfocus.com
The Switch 4250Kw 15RPM DD PM
Generator
www.theswitch.comABB high speed PM Generator (2~5MW)
www.abb.com
GE offshore DD turbine
inhabitat.com
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PM materialsGlobal Deposit of Rare Earth Oxide (REO) ---128 M tons in total
China55%
Russia15%
US10%
India1%
Other13%
Australia5%
Canada1%
( Optimistic Estimation: > 200 MMtons )
• Ferrite and rare earth • 128MMton REO deposit has been explored in the world • 55% of global REO deposit (>70MMton) is in China• 90-95% of annual output from China • 0.1MMton REO is consumed in 2008 • Existing output capability larger than 0.15MMton• Anticipated usage in 2015: ~ 0.16MMton
NdFeB Output Growth
010000
2000030000
4000050000
6000070000
80000
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
Output in China
Output in the world
Prediction
www.marketwatch.com; www.businessinsider.com; www.smenet.org;geo-nsdi.er.usgs.gov
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Challenges and Risks
Challenges and Risks
• Less experience for the industry with PM machines
• Demagnetization
• Magnet corrosion and aging loss
• Future material shortage/high price?
• Unknown risks
Ways to address
• More prototypes, more time
• Live with it,
Better Gen design, or
More reliable converter.
• Not an issue?
Better coating?
• Optimize magnet mass
•
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Manufacturing Site Assembly
WTG Assembly
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Summary
• More PM Generators to be installed
• More Direct Drive PM generators to come
• More issues to be addressed
