Design of NewGenDesign of NewGenDirect-Drive Generator for Direct-Drive Generator for

Demonstration in a 3,5 MW Demonstration in a 3,5 MW Wind TurbineWind Turbine

Staffan Engström, Ägir Konsult AB

Stefan Lindgren, VG Power AB

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

• Founded in 2002 • Today 60 mostly ex-ABB

employees.• Specialists in large scale

hydropower rehabilitation and service

• Full expertise in electrical and mechanical calculation and design of generator equipment

• Voith Siemens Hydro is majority owner

VG Power AB, Västerås, Sweden

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

• Consultant in wind power technology and siting.

• Originator of the NewGen electrical generator

Ägir konsult, Lidingö, Sweden

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Demonstration project

GOALS

1. To develop a 3.5 MW generator, test in lab together with electrical converter equipment

2. Demo project with generator in a wind turbine based on existing design, field test, routine operation

Financial support from the EU and from Energimyndigheten, Sweden

Wind turbine to be erected at Vattenfalls’s test site at Näsudden, Gotland

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Partners in project

VG Power, Sweden Generator

Scanwind, Norway Wind turbine

Verteco, Finland Frequency converter

SKF, Sweden Wheels and bearings

Teknikgruppen, Sweden Analysis and evaluation

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Scanwind 3 MW wind turbine at Hundhammerfjell, Norway

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Project milestones

Project start May 2007

Generator design completed May 2008

Manufacture, workshop testing completed July 2009

Wind turbine erected October 2009

Commissioning completed January 2010

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

• The largest wind turbine suppliers during 2006

Market - wind turbines

Direct drive

Source BTM Consult

Installed MW %Vestas, Denmark 4239 28,2Gamesa, Spain 2346 15,6GE Wind, US etc 2326 15,5Enercon, Germany 2316 15,4Suzlon, India 1157 7,7Siemens, Denmark 1103 7,3Nordex, Germany 505 3,4Repower, Germany 480 3,2Acciona, Spain 426 2,8Goldwind, China 416 2,8Others 689 4,6total 16003 106,5

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Reference technology – Enercon

• Extremely heavy due to stiffness requirements

• 4,5 MW - 220 ton generator weight

• See man for comparison!

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Large diameter beneficial for amount of active material

• The amount of electrically and magnetically active material decreases with increased air gap diameter.

Diameter

We

igh

t

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

… but not for the structure (in conventional design)

• With conventional design the weight of the structure increases rapidly with diameter

• High total weight• Relatively small optimal

diameter

Diameter

We

igh

t

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Schematic picture of conventional direct driven generator

• Air gap ca 5 mm, tolerance ca 0,5 mm.• Long load path means a heavy design

due to stiffness requirement

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Schematic picture of NewGen

• Generator bearings adjacent to the air-gap• Minimised load-path and stiffness need• Which reduces need for construction

material• And enables further increase of diameter• With further reduced need for electrical

material

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Overview NewGen (1)

• Rotor and stator form two narrow rings

• Push-pull rods for low stator weight

• Weight 37 tons, 70% less than conven-tional 4 MW, 19 rpm

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Overview NewGen (2)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Cross section NewGen

• Outside rotor of solid steel with Neodym magnets

• Pairs of steel wheels support rotor

• Stator with conventional windings

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

NewGen installation

• Extremely low weight• Extremely short - ca 0.7 m

(4 MW)• Direct rotor/hub connection

- saves weight also in hub • Wide generator body

benefits aerodynamics• Mechanical brake possible

to integrate in generator

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Weight of alternative 3 MW 15 rpm drive train solutions

36 449 35 057

116 600

0

20 000

40 000

60 000

80 000

100 000

120 000

kg

NewGen Gear and high-speed generator Conventional direct drive

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Pilot generator in relation to full scale (4 MW)

• Same peripheral speed• Same wheel diameter• Half active length• 1/5 diameter• 1/30 power

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Pilot generator ready for testing (July 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

The pilot generator stator before winding (April 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Winding the pilot generator (April 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Stator with bearing wheels (June 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Assembly completed (June 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Detail of wheels and race (June 2004)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Testing the pilot generator (July-August 2004)

Test test up:

•DC machine•Gear-box•Pilot generator

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Test programme

Conventional

•Measurement of winding resistance•Idling without magnets (measurement of friction)•Idling with magnets (voltage as a function of rpm)•Short circuit tests, at reduced rpm•Endurance test at full power•Idling with magnets (check of no change)

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Test results

•Runs smoothly, little noise•Little friction (130 watts at rated rpm)•Low winding temperatures•Top efficiency 96,7% at half power•Full power efficiency 94,9%

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Efficiency measurement, at 100 rpm

1,0 p.u. = 140 kW

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

Main voltage at idling, 100 rpm

- Preferred manufacturing partner - Ägir Konsult ABÄgir Konsult AB VG Power ABVG Power AB

• Benefits of direct drive • Weight and installation cost as geared solution • Well proven design of electrical and magnetic active

components• Mechanical design with wheels and bearings based on

in-house railway technology • Reliability comparable with in-house hydro technology• Feasible for large wind turbines - 20 MW• Excellent experience from designing, building and

testing the 140 kW pilot scale NewGen• Ongoing 3.5 MW demo project

Summary – the offer of the NewGen concept