Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ...

Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ... Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ...

from boschrexroth.com.ar More from this publisher

24.10.2014 Views

Bosch Rexroth AG Wind Turbine Drive Train Innovations and Load Reduction Solutions Dr.-Ing. Andreas Vath Bosch Rexroth AG 1 A. Vath | Wind Turbines Innovations | Sept. 2012 | © Bosch Rexroth AG 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, distribution, as well as in the event of applications for industrial property rights.

Wind Turbine Drive Train Innovations

and Load Reduction Solutions

Dr.-Ing. Andreas Vath

Bosch Rexroth AG

1

A. Vath | Wind Turbines Innovations | Sept. 2012 | © Bosch Rexroth AG 2010. All rights reserved, also regarding any disposal, exploitation, reproduction,

distribution, as well as in the event of applications for industrial property rights.

Content

• motivation

• combining benefits of existing drive trains for wind turbines

• direct drive

• high speed

• medium speed

• differential gearbox benefits in medium speed concepts

• Bosch Rexroth load reduction solutions

• Active Torque Control (ATC)

• Individual Pitch Control (IPC)

• summary

2

distribution, as well as in the event of applications for industrial property rights.

Motivation for drive train innovations and load reduction solutions

Design challenge: Reducing cost of energy

Onshore: Larger rotors

1.5 - 3 MW

series

4 MW

development

Offshore: Larger turbines

3 MW

series

5 -7 MW

prototype

>10 MW

transport

restrictions

future

higher drive train requirements

drive train innovations

reliable

efficient

low cost

load reduction solutions

for wind turbines

3

distribution, as well as in the event of applications for industrial property rights.

Content

• motivation

• combining benefits of existing drive trains for wind turbines

• direct drive

• high speed

• medium speed

• differential gearbox benefits in medium speed concepts

• Bosch Rexroth load reduction solutions

• Active Torque Control (ATC)

• Individual Pitch Control (IPC)

• summary

4

distribution, as well as in the event of applications for industrial property rights.

Comparison of drive train efficiencies

direct drive high speed medium speed

direct

drive

drive train efficiency

medium speed concept

high speed concept

direct drive

efficiency

medium speed concept

high speed concept

wind speed in m/s

Medium speed concepts:

- high partial load efficiency

- high drive train full load efficiency of 94%

(gearbox >98.0%; generator 98.3%;

frequency converter 97.5%)

⇒ high energy yield at high average

wind speeds

Medium-speed concepts: High efficiency leads to high energy yield

5

distribution, as well as in the event of applications for industrial property rights.

Drive train weight and raw material cost of a 3 MW wind turbine

direct drive high speed medium speed

weight in tons

drive train weight

magnets

copper

iron

cost in t€

raw material cost for drive train*

rare earth

copper

iron

0

direct

drive

medium

speed

high

speed

direct

drive

medium

speed

high

speed

*Neodymium 120 €/kg, Dysprosium 1300 €/kg, Copper 7 €/kg, Iron 1 €/kg

low amount of raw materials

low drive train material costs

Drive train weight and cost advantage with gearbox concepts

6

distribution, as well as in the event of applications for industrial property rights.

Cost of energy comparison for an example onshore turbine

Main assumptions

• rated power 3MW

• rotor diameter 115 m

• 6.5 m/s average wind speed

• 20 years design life time

• raw material cost:

- copper 7€ per kg

- steel 1€ per kg

- magnets 100€ per kg

• complete wind farm cost 1700 to

1900 € kW depending on drive

train concept

Cost of energy [€/kWh]

8.5

8.0

7.5

7.0

6.5

6.0

5.50

Innovations

for further

cost

reduction

1 2 3 4 5

• 97% availability of all concepts

• operation & maintenance costs for

complete turbine (additional costs

for gearbox oil change considered)

• same blade, hub and tower design

of different drive train concepts

• higher cost of energy of direct drives due to the high

amounts of raw and rare earth material

• lower cost of energy with high speed and medium

speed solutions

FC: frequency converter; SESG: separately excited synchronous generator, PMSG: permanently excited synchronous generator;

DFIG: doubly fed induction generator; HTS-SG: high-temperature superconducting synchronous generator,

7

distribution, as well as in the event of applications for industrial property rights.

Content

• motivation

• combining benefits of existing drive trains for wind turbines

• direct drive

• high speed

• medium speed

• differential gearbox benefits in medium speed concepts

• Bosch Rexroth load reduction solutions

• Active Torque Control (ATC)

• Individual Pitch Control (IPC)

• summary

8

distribution, as well as in the event of applications for industrial property rights.

Bosch Rexroth differential gearbox for medium speed concepts

torque splitting stage

differential stage

for torque summary

i = 10 -15

input

torque:

i = 3-4

output

torque

torque splitting topology

with equal load distribution

to 6 planets

+ equal load distribution to 6 planets

+ statically defined system

+ reduced loads on bearings/toothing

i total = 30-60

proven concept in

high speed drive train concepts

for more than 7 years and

more than 1300 installed units

+ higher reliability

+ higher power density

+ less material consumption

High gearbox ratio possible with torque splitting and differential stage

9

distribution, as well as in the event of applications for industrial property rights.

Effect of higher gear ratio for medium speed concepts

Investment costs

100 %

generator

gearbox

i=40

generator

gearbox

i=60

• higher generator speed means less

torque at same rated power

• generator costs are proportional to

the generator torque

⇒ generator cost reduction with

Bosch Rexroth differential

gearbox REDULUS GPV

conventional

design

Bosch Rexroth

Design REDULUS GPV

⇒ Reduced drive train costs with differential gearbox REDULUS GPV

10

distribution, as well as in the event of applications for industrial property rights.

Content

• motivation

• combining benefits of existing drive trains for wind turbines

• direct drive

• high speed

• medium speed

• differential gearbox benefits in medium speed concepts

• Bosch Rexroth load reduction solutions

• Active Torque Control (ATC)

• Individual Pitch Control (IPC)

• summary

11

distribution, as well as in the event of applications for industrial property rights.

Load reduction solutions

Active Torque Control (ATC)

Active damping of

dynamical loads

1

Active torque control

1

2

Active torque

control

Individual pitch

control

• Dynamic control of

drive train torque to

reduce peak loads and

Future wind turbines:

Load-reduced operation

torque oscillations

2

1

⇒ higher drive train

lifetime and reliability

Preventing and reducing

loading by means of

innovative approaches

⇒ lower cost of energy

Load reduction for torque with active torque control

12

distribution, as well as in the event of applications for industrial property rights.

Sensor and control system for Active Torque Control

SCU

Control unit

Sensor

Drive train

torque

Generator torque

adjustment

• Dynamic measurement of

drive train speed by using

adapted automotive

sensors

• Calculation of the drive

train torque

Patented by Bosch Rexroth

• Control strategy to reduce

drive train torque and

speed oscillations by

generator torque

adjustment

13

distribution, as well as in the event of applications for industrial property rights.

Torque [kNm]

Measurement results of Active Torque Control

Drive train torque and speed

1750

1500

1250

1000

750

500

250

without

ATC

Drive train torque

with ATC

0

0 10 20 30 40

Time [s]

Speed [rpm]

15

14.9

14.8

Drive train speed

with ATC

without ATC

14.7

15 16 17 18 19

Time [s]

Reduction of drive train

speed oscillations as a

result of less drive train

torque oscillations

High reduction of drive train torque and speed oscillations

14

distribution, as well as in the event of applications for industrial property rights.

Active Torque Control of wind turbines

Drive train torque

without ATC

with ATC

1-10%

F

without

ATC

with

ATC

Force at tooth x

Damaging loads

1-10%

F

Bearing force

without

ATC

Damaging loads

Reduction of equivalent damage loads at toothing and bearings

with

ATC

15

A. Vath | Active Torque Control| Sept. 2012 | © Bosch Rexroth AG 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, distribution, as

well as in the event of applications for industrial property rights.

Active Torque Control of wind turbines

Drive train benefits

Benefits of active torque control

• Increase of nominal power when using active torque control

⇒ higher energy yield

• Less blade oscillations and therefore better aerodynamics

⇒ higher energy yield

• Advantages for gears and

bearings due to lower

torque oscillations

• Structural advantages due

to less deformations

caused by oscillations

• Increase of bearing

lifetime because of less

speed oscillations

16

distribution, as well as in the event of applications for industrial property rights.

Drive train innovations and load reduction solutions

Load reduction: Individual pitch control

Active damping of

dynamic loads

2

Individual Pitch Control

1

2

1

Active torque

control

Individual pitch

control

Preventing and reducing

loading by means of

innovative approaches

2

• Measurement of bending

moments in each blade

• Controller for bending

moment reduction

• Continuously pitching of

each blade

Bending moment

reduction in %

blades tower

main

shaft

Future wind turbines:

Load-reduced operation

Effect on wind turbines:

Reduced weight and cost and

increased energy generation

Load reduction for bending moments up to 25% with individual pitch control

17

distribution, as well as in the event of applications for industrial property rights.

Content

• motivation

• combining benefits of existing drive trains for wind turbines

• direct drive

• high speed

• medium speed

• differential gearbox benefits in medium speed concepts

• Bosch Rexroth load reduction solutions

• Active Torque Control (ATC)

• Individual Pitch Control (IPC)

• summary

18

distribution, as well as in the event of applications for industrial property rights.

Summary

Drive train innovations

• Wind turbines with reliable high speed and medium speed drive concepts

will provide the lowest cost of energy

• High drive train cost reduction with the Bosch Rexroth differential gearbox

REDULUS GPV in medium speed solutions

Load reduction solutions

• Bosch Rexroth active torque control significantly reduces drive train

torque and speed oscillations higher reliability, higher energy yield

and reduction in cost of energy

• Individual pitch control contributes to load reduction

• Load-reduced operation necessary for further optimization of future wind

turbines

19

distribution, as well as in the event of applications for industrial property rights.

Bosch Rexroth: Components and solutions for wind turbines

electric

pitch systems

gearbox cooling & filtration

gearboxes

service

hydraulic

pitch systems

rotor blade

condition monitoring

brake and hydraulic

power Units

Thank you very much for your attention!

See you at our booth! Hall3 D12

20

distribution, as well as in the event of applications for industrial property rights.

Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ...

Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ... ... View more Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ...

Delete template?

Save as template ?

Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ... Dr.-Ing. Andreas Vath Bosch Rexroth AG Wind Turbine Drive Train ...