November 2011
Innovative Axial Flux Air Cored Permanent
Magnet Generator suitable for Slow,
Medium Speed and Direct Drive Wind
Turbines
Dr Makhlouf Benatmane
CEO – NGenTec Ltd
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Starting from a blank sheet, we created the
foundation of the technology with only one
objective in mind:
“To design a generator that specifically meets
the requirements for wind turbines”
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Focused Characteristics
High contribution to lowering Cost of Energy
Highly modular in manufacturing, assembly and
transport both rotor and stator
Easily “stacked” for higher power ratings
Flexibility in operation - High availability, redundancy
Easy integration into any wind turbine mechanical
structure
Simpler bearing arrangement
Standard materials allowing multiple sourcing - wide
supply chain – price competitiveness
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Focused Characteristics
Lightweight rotor and stator modules
Can be handled using turbine internal crane
Repeatable process - Progressive high quality checks
Safe method of magnets insertion and assembly
Magnetic forces are neutralised within the rotor
Zero Cogging Torque
The rotor can literally be turned
by a single hand around the stator
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Flexible Generators / converters systems
configurations
Each stage can be operated independently
A number of stages can be operated to suit
wind conditions and availability
G1
G2
G3
G4
C1
Converters
Tx
Higher Redundancy, Efficiency, Availability
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Independent study confirmed significant cost savings and
Internal Rate of Return “IRR” improvement by using axial flux air
cored generator in a typical offshore wind farm:
LCOE reduced by up to 6% over the life of the wind farm;
NGenTec fault tolerant design reduces O&M and
increases availability compared to baseline
Lower the turbine cost by approx. 1.3%
Reduced wind farm CapEx by 0.8%
O&M costs down 12% to 20% for the whole wind park
Availability: up 0.7%
Internal Rate of Return: up to 20% increase
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
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November 2011
Successfully designed, manufactured
and tested 1MW prototype
Full-scale 1MW prototype that rotates at the speed and diameter of a
6MW machine
The prototype represents a single “stage” of a 6MW direct drive
generator, it consists of four 250kW stacks that can operate
independently, in pairs or in full with a voltage output of 690V
Prototype has been built by NGenTec and David Brown Gear
Systems and the diameter is similar to the diameter of a full 6MW
rated machine
The machine has been tested for over seven months and achieved
over 200 hours of load testing
Conducted tests:
Open circuit – No Load
Performance – Temperature Rise
Partial Load
Single Stage Load Tests
Multiple Stage Load Tests
Full Load
Waveform Analysis
Efficiency
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November 2011
Innovative Axial Flux Air Cored permanent magnet generator
Design and Operation
• Increased reliability and availability
• High efficiency across full operating
range
• Scalability by simple common
components
• Flexible system design, high capacity
factor
• Flexibility to suit wind conditions/wind
turbine output
• Zero cogging torque - minimal vibration
and generator noise
• Easy adaption to any wind turbine
design and requirements
• No risk of “ovalisation” during magnets
insertion or generator UMP
• Designs suitable for direct, slow and
medium speed Increased accessible
market
• Avoids needs for large manufacturing
investments
Factory to Installation
Operation and Maintenance
• Easy module manufacturing,
assembly and installation
• High advantage in transport and
overall logistics.
• Minimum part count and use of
standard parts - rewarding impact
on supply chain and costs
• Assembly possible by reasonably
skilled operators (vs highly skilled
workforce for traditional PMG)
• Progressive testing prior to full
machine assembly – enhanced
quality and reliability
• Reduced weight and size, with
positive impact on required nacelle
size, tower structure and
foundations for new installations.
• flexibility of assembly at the wind
turbine maker facility if required
• Higher energy yield
• Low or medium generator voltage
designs
• Inter-changeability, redundancy
• Higher flexibility and availability
• Reduced maintenance: easy
replacement of single module
resulting in reduced downtime,
resulting in reduced O&M costs
• Low spare parts holdings
• Flexibility to locate generator
assembly facilities with wind turbine
manufacturing facility at quayside
location
• Cost competitive – initial and
through life
Simplification Across All Stages
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November 2011
Thank you for your attention
Should you require any further information, please contact
Dr Makhlouf Benatmane - CEO
Office Tel:
+44 (0)131 524 9444
Mobile:
+44 (0) 741 512 4641
Email:
makhlouf.benatmane@ngentec.com
Web:
www.ngentec.com
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