Tecnologias de controle de conversores diretos e híbridos em turbinas eólicas modernas

© Fraunhofer IWES

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Fraunhofer IWESInstitute for Wind Energy and Energy System Technology

Hybrid & direct drive technology in modern wind turbines

Hans Kyling, Dr. Jan Wenske, Hans-Georg Moll, Louis Quesnel

Jaraguá do Sul, 28.06.2012

© Fraunhofer IWES

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General Map

� About the Fraunhofer IWES

� Some wind turbine basics

� Overview of different drive train topologies

� Current drive train trends

© Fraunhofer IWES© Fraunhofer IWES

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Research spectrum:

� Wind energy from material development to grid optimization

� Energy system technology for all renewable energies

Foundation: 2009

Formerly:

� Fraunhofer Center for Wind Energy and Maritime Technology (CWMT) in Bremerhaven

� Institute for Solar Energy Supply Technology ISET in Kassel

� Directors: Prof. Dr. Andreas Reuter

Prof. Dr. Jürgen Schmid

Annual budget: € 31 million (2011)

Employees: 376

Fraunhofer IWES in figures

IWES in figures

Some basics

Drive train topologies

Current trends

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Sorted by test level according to V-model (VDI 2206)

� Material

• Climate chambers

• Offshore test field

� Component

• Rotor blade (full scaled, down scaled)

• Composite part testing and development

� Sub-system and integration

• Dynamic Nacelle Laboratory

(DyNaLab) -in development-

Portfolio example: test facilities at Fraunhofer IWES

IWES in figures

Some basics


Current trends

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Introduction: some history on wind turbines

� There was no comparable application in engineering, so that the design needed to be developed from scratch

� The first big industrial wind turbines were designed with components sourced from other industries (no wind turbine specific components available by that time)

� The different drivetrain components didn’t match perfectly with each other.

� With a growing market for wind turbines specialized components and designs were developed.

IWES in figures

Some basics


Current trends

Wind turbine

boundaryconditions

extreme highnumber ofload cycles

(N > 108)

very hightorques and

parasiteloads

slowrotational

speed

Permanently changing

service loads

flexible structure

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Some basic physics:

The kinetic energy/power of the wind is

The power extracted by a wind turbine

The theoretically extractable power grows with

the square of the rotor radius!

>>>Higher energy yield<<<

Positive influence of the rotor diameter

tcoefficienpowerswtcvRρcP

vRρvmΕP

vmΕ

pairp

air

':2

1

2

1

2

1

2

1

32

322

2

⋅⋅⋅⋅⋅=

⋅⋅⋅⋅=⋅⋅==

⋅⋅=

π

π&&

v

R

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Some basics


Current trends

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Source: Alstom

Negative influence of the rotor diameter

mBlade ~ lBlade3

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Some basics


Current trends

increased blade length

higher mass/

aerodynamical loads

strengthened drivetrain/support structure

higher turbine weight/cost

energy yield

weight/cost

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Why are there so many different drivetrain concepts?

The shown ambivalent problem regarding the blade length is a good example for explaining the variety of concepts:

� Depending on the drivetrain design the rotor loads may “flow” in a different way through the turbine structure and effect thus the component design

There are a couple of parameters that have to be considered in order to find the best suited drivetrain concept, like:

• Global/local market situation (e.g. rare earth availability)

• Site assessment (high turbulences, )

• Availability of turbine (e.g. offshore very important)

• Service & maintenance costs

• Etc.

Which drive train concept is the best?

� Answer is project-specific

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Some basics


Current trends

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How to classify drivetrains?

There are various drivetrain topologies, and different ways to classify them. A practical way to classify wind turbines is the generator speed/number of gear box stages:

• High speed generator (HSG) (approx. 500 – 2000 rpm)

These drivetrains make use of a 3-4 stage gearbox (planetary/spur)

• Medium speed generator (MSG) (approx. 40 – 200 rpm)

These drivetrains make use of a 1-2 stage planetary gearbox

• Slow speed generator (SSG) (approx. 4 – 35 rpm)

These drivetrains are called direct driven, because the rotor torque is transmitted directly (without a gearbox) to the generator.

IWES in figures

Some basics


Current trends

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Drivetrains with 3-4 stage gearbox (HSG)

Characteristics:

positive

• The generator torque is low thanks to the gearbox.

• Classical drivetrainsolution (a lot of experience available)

• High availability on the supplier’s market (resulting in lower prices)

neutral negative

• High number of rotating parts (within gearbox)

• High maintenance effort

• High drivetraintotal length

• Reduced torsionalstiffness

• Low efficiency

IWES in figures

Somebasics


Current trends

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3-4 stage gearbox – moment bearing

Example: Vestas V90-3.0

Tower head mass: approx.: 114 t

No main shaft 2 planetary, 1 spur stages

Doubly fed induction generator (DFIG)Moment bearing integrated into gearbox housing

(bending moments transmitted through gearbox)

Source: Vestas

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Somebasics


Current trends

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3-4 stage gearbox – double suspension

Example: GE 2.75-103

Tower head mass: approx.: XXX t

Double suspension

(in stiff housing)

Permanent magnet synchron generator (PMSG)

2 planetary, 1 spur stage

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Current trends

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3-4 stage gearbox – 3-point suspension

Example: Vestas V112-3.0

Tower head mass: approx.: 120 – 130 t

4-stage gearbox

Main bearing

Shrink disc

Support bearing integrated into first gearbox stage

PMSG generator

Source: Vestas

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Somebasics


Current trends

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Drivetrains with 1-2 stage gearbox (MSG)

Characteristics:

positive neutral

• Moderate generator torque

• Moderate generator size, weight and cost

• Moderate number of rotating parts (within gearbox)

• Moderate maintenance effort

• Moderate drivetraintotal length

• Moderate torsionalstiffness

• Moderate efficiency

negative

• Smallest global market share (little experience available)

• Limited generator availability on the supplier market

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Somebasics


Current trends

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1-2 stage gearbox, moment bearing

Example: Fuhrländer FL 3000


Source: Fuhrländer

PMSG

Winergy HybridDrive (flexible bolted to bedplate)

2 stage planetary gearbox (1:43)

Moment bearing (3 row cylindrical roller bearing)

Flexible coupling (elastic bolts)

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Somebasics


Current trends

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1-2 stage gearbox, double suspension

Example: Gamesa G10X-4.5


2 stage planetary gearbox (1:38, flanged to bearing case)

PMSG (housing flanged to gearbox)Double bearing in common stiff case,

Planet carrier is supported by main shaft’s rear bearing

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Somebasics


Current trends

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1-2 stage gearbox, double suspension

Example: DSME 7 MW Offshore

• Integrated power unit “FusionDrive”

• (approx. 90 t, from Moventas/TheSwitch)

� 2 stage planetary gearbox

� PMSG

• Prototype installation scheduled for Q1-2013

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Somebasics


Current trends

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Drivetrains without a gearbox (direct drive) (SSG)

Characteristics:

positive

• Simple drivetrain design (no gearbox, coupling and main shaft necessary)

• Less dynamic loads due to higher torsional stiffness (lower safety factor, lighter design, better controllability)

• Modularization and Standardization applicable (mass production)

• higher efficiency, especially for under rated conditions (no gearbox losses)

• Mechanically little maintenance needed

• Short design

• Small number of rotating parts (within gearbox)

neutral

• Moderate experience on the market

negative

• High generator torques lead to a bigger and thus heavier generator

• Generator relatively expensive (higher material demand)

• Wind turbine’s purchase cost relatively high compared to geared solutions

IWES in figures

Somebasics


Current trends

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Direct drive, moment bearing

Example: Siemens SWT-2.3-113, SWT-3.0-101


Moment bearing

(3 row cylindrical bearing)

PMSG

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Somebasics


Current trends

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Direct drive, double suspension

Example: Enercon E-101


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Somebasics


Current trends

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Direct drive, double suspension

Example: GE 4.0-110, Alstom PureTorque 6 MW

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Current trends

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Which company uses which drivetrain concept?

DFIG

Direct Drive

Geared

EESG

PMSGDouble-Fed

Electrical Excited Synchronous Gen.

Vestas (old),

Sinovel,

REpower

Siemens (new),

Goldwind,

GE Offshore,

Alstom

Vestas

(new),

Samsung,

GEKenersys

Enercon,

MTorres

3-4 Stages 1-2 Stages

Areva Wind,

Gamesa

Offshore,

Vestas V164,

Fuhrländer

Permanent Magnet Synchronous Generator

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Somebasics


Current trends

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Efficiency of different drivetrain/generator systems

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Current trends

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PMSG Volume and weight vs. gear ratio

0,01

0,1

1

0 10 20 30 40 50 60 70 80 90 100

D ~ 6m

P = 3,8MW

16rpm

total

81.000kg D ~ 0,8m

P = 2,7MW

1650 rpm

total 7750 kg

D ~ 1,8m

D ~ 0,7m

P = 1,7MW

150 rpm

total

17.000kgP = 1,0MW

1200 rpm

total

3.400kg

Rotor volume per power:

(related to „direct drive“)elp

vδ

iTransmission gear ratio

( )[ ]MPMmassMagnets

el

LDhDM

ii

p

v

ραπ

δ

22

_2

4

1)(

−+=

≈

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Current trends

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Drivetrain concepts of the global TOP15 OEMs

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Current trends

1900n1900r00l

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Commercialized

through 2010

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Global gearbox/generator segmentation

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Somebasics


Current trends

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Nacelle weight trend

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Somebasics


Current trends

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Drivetrain mass contribution for key concepts

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Somebasics


Current trends

data derived from 3 MW turbines

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Generator weight trend

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Somebasics


Current trends

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Rare earth material price development in 2011

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Somebasics


Current trends

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Cost structure for onshore wind turbine

no logistics cost included

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Current trends

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Newly installed power capacities in South America

+4%

+19%

+23%

-5%

+9%

+6%+4%

1900n1900r00l

1900n1900r00l

1900n1900r00l

1900n1900r00l

1900n1900r00l

1900n1900r00l

global growth rate

+5%

Source: Make Consulting

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Estimated compound annual growth rate (2012 – 2016)

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Current trends

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Some impressions from Asian fabrication sites

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Current trends

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End of presentation

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Tecnologias de controle de conversores diretos e híbridos em turbinas eólicas modernas