The Big Picture - Aalborg Universitetkom.aau.dk/project/vtcp/wt_sym_2011/slides/KatieJohnson.pdf ·...

The Big Picture: A discussion of the present and future of wind turbine control, with one example

Katie Johnson Colorado School of Mines AAU/Vestas Wind Turbine Control

Research Program National Renewable Energy Laboratory

K. Johnson – AAU/Vestas Wind Turbine Control Symposium (Nov. 28-29, 2011) 2

Aspects of “wind turbine control” (the past/present?)

Outcome from the control group at the 2010 “University Collaboration” on Wind Energy (hosted by Cornell University)

Sensors, actuators,

and monitoring

Aerodynamic control

Public perception

Policy

Grid integration

Power electronics

design

Generator design

Power electronics

control

Generator control

Structural dynamic control


Symposium topics (the present/future?)

Load Mitigation

Wind Estimation

MPC

Fault Detection

Aeroelastic Control Design

Wind Farm Control


Balance of approaches (present/future?)

Controller Driven

Application Driven

Wind Farms (3)

Lidar (2)

FDI

Load Reduction

MPC (4)

Passivity-based

LPV

Barrier Certificates

Besides the need to read abstracts…can we take anything out of this picture?

What is missing?


What is an area that you think should be a research focus in the next 5-10 years (related to wind turbine control)?

Active participation


The future – what others have told me

Transition region

Wind inflow evolution models

Smart rotor

“Regulation control” (utility grid)


Motivation/Brainstorming What do we want to get out of this symposium,

anyway? Regulation control

Another area of wind turbine control, also known as “active power control”

Conclusions

Outline


How can wind turbines help the grid?

0s Typically 5 – 10s

, Typically 15 – 30s

, Typically 5 – 15 min,

Initial slope of decline is determined by system inertia (or cumulative inertial response of all generators)

Primary Control. AGC

Time


One technique: power reserveP

ower

Wind speed

NormalDeratedRelative spinning reserveAbsolute spinning reserve


Inertial control – extracting energy from spinning rotor

Another technique: inertial control


To design and test control strategies to allow the turbine to contribute to grid regulation, where strategies are first simple and intuitive Tasked to “turn over rocks and look for snakes.”

Research objectives


Simulation turbine & baseline

Hub Height (m)

Rotor Diameter

(m)

Max Pitch Rate

(degrees / sec)

Rated Gen.Torque (N-

m)

Rated Rotor Speed (RPM)

Rated Wind

Speed (m/s)

Rated Power (kW)

36.576 40 20 3,524 37 12.5 550


Motivation/Brainstorming Regulation control

Basic control concepts for power reference following

Combined concepts for power reference following Inertial control Regulation control conclusions

Conclusions Where do we go from here?

Outline


Torque-based APC


Pitch Control 2

0 100 200 300 400 500 600400

600

800

1000

1200

1400

1600

Power (kW)

Gen

erat

or s

peed

(R

PM)


Wind profile

Power reference

Simulation setup

0 20 40 60 80 100 120 140 160 180 2008

101214161820

Time(s)

Win

d (m

/s)

0 20 40 60 80 100 120 140 160 180 200440460480500520540560

Time(s)

Pow

er d

eman

ded

(kW

)


Torque-based APC simulation results

0 20 40 60 80 100 120 140 160 180 200-5

0

5

10

15

20

Pitc

h an

gle

(deg

ree)

0 20 40 60 80 100 120 140 160 180 2000

1000

2000

3000

4000

5000

Time(s)

HS

S to

rque

(Nm

)

HSS torqueCommanded torque

0 20 40 60 80 100 120 140 160 180 2001000

1100

1200

1300

1400

1500

1600

1700

Gen

spe

ed (R

PM

)

0 20 40 60 80 100 120 140 160 180 2000

100200300400500600700800

Time(s)

Gen

pow

er (k

W)

Power producedPower demanded


Pitch Control 2 simulation results

0 20 40 60 80 100 120 140 160 180 200-5

0

5

10

15

20

25

Pitc

h an

gle

(deg

ree)

0 20 40 60 80 100 120 140 160 180 2000

1000

2000

3000

4000

5000

Time(s)

HS

S to

rque

(Nm

)


0 20 40 60 80 100 120 140 160 180 200100011001200130014001500160017001800

Gen

spe

ed (R

PM

)

0 20 40 60 80 100 120 140 160 180 2000

100

200

300

400

500

600

700

Time(s)

Gen

pow

er (k

W)



Load and actuation comparison

-20

-10

0

10

20

30

40

50

60

70

80A

vera

ge p

itch

angl

e (°

)

RM

S p

itch

rate

(°/s

ec)

RM

S g

ener

atio

n to

rque

(Nm

)

Mea

n ge

nera

tion

torq

ue (N

m)

Sta

ndar

d de

v. g

en. t

orqu

e (N

m)

Tow

er b

endi

ng D

ELs

(Nm

)

Driv

etra

in to

rsio

n D

ELs

(Nm

)

Flap

wis

e bl

ade

bedi

ng D

ELs

(Nm

)

Perc

ent C

hang

e fr

om B

asel

ine

Torque-basedPitch 0Pitch 1Pitch 2Pitch 3


Reference tracking comparison

0

100

200

300

400

500

600

700

800

900

1000

RMS power error (Nm)(best: torque-based)

Rise time (0.1 – 0.9) (sec)* (best: Pitch 3)

Settling time (2%) (sec)*(best: torque-based)

Perc

ent C

hang

e fr

om B

est C

ase

Torque-basedPitch 0Pitch 1Pitch 2Pitch 3


Field test results: Pitch Control 2

400 500 600 700 800 900 10005

10

15

20

25

Seconds

m/s

Met wind speed 36.6m

400 500 600 700 800 900 1000200

300

400

500

600

Seconds

kW, n

one

PE Line powerPower Reference

Thanks to Dr. Paul Fleming, NREL


Field test results: Pitch Control 2

400 500 600 700 800 900 10000

5

10

15

20

Seconds

degr

ees

Blade 1 pitch angle

400 500 600 700 800 900 1000-1000

0

1000

2000

Seconds

kN-m

Tower bending E/W


Combined Controller 1


Combined Controller 1 simulation results

0 20 40 60 80 100 120 140 160 180 200-5

0

5

10

15

20

25

Pitc

h an

gle

(deg

ree)

0 20 40 60 80 100 120 140 160 180 2000

1000

2000

3000

4000

5000

Time(s)

HS

S to

rque

(Nm

)


0 20 40 60 80 100 120 140 160 180 200100011001200130014001500160017001800

Gen

spe

ed (R

PM

)

0 20 40 60 80 100 120 140 160 180 2000

100

200

300

400

500

600

700

Time(s)

Gen

pow

er (k

W)



Load and actuation comparison

-15

-10

-5

0

5

10

15

20

25

30

Ave

rage

pitc

h an

gle

(°)

RM

S p

itch

rate

(°/s

ec)

RM

S g

ener

atio

n to

rque

(Nm

)

Mea

n ge

nera

tion

torq

ue (N

m)

Sta

ndar

d de

v. g

en. t

orqu

e(N

m)

Tow

er b

endi

ng D

ELs

(Nm

)

Driv

etra

in to

rsio

n D

ELs

(Nm

)

Flap

wis

e bl

ade

bedi

ng D

ELs

(Nm

)

Perc

ent C

hang

e fr

om B

asel

ine

Torque-basedPitch 2Combined 1Combined 2Combined 3


Reference tracking comparison

0

50

100

150

200

250

300

350

400

450

500

RMS power error (Nm)(best: Combined 3)

Rise time (0.1 – 0.9) (sec)* (best: Combined 3)

Settling time (2%) (sec)*(best: torque-based)

Perc

ent C

hang

e fr

om B

est C

ase

Torque-basedPitch 2Combined 1Combined 2Combined 3


Motivation/Brainstorming Regulation control

Basic control concepts for power reference following

Combined concepts for power reference following Inertial control Regulation control conclusions

Conclusions Where do we go from here?

Outline


Wind profile used (11.4 m/s average)

Power referenceNone to 450 kW at 60, 80, 100, 120, 140, 160, 180,

and 200 s

Inertial control simulation setup

0 50 100 150 200 250 3006

8

10

12

14

16

18Wind

Time(s)

m/s


Simulation Setup


Simulation Result (60 – 120 s)

0 50 100 150 200 250 300-500

0

500

1000

Genpower


0 50 100 150 200 250 300-500

0

500

1000

0 50 100 150 200 250 3006

8

10

12

14

16

18Wind

Time(s)m

/s

0 50 100 150 200 250 300-500

0

500

1000

0 50 100 150 200 250 300-500

0

500

1000


Simulation Result (140 – 200 s)

0 50 100 150 200 250 300-500

0

500

1000

0 50 100 150 200 250 300-500

0

500

1000

time(s)

0 50 100 150 200 250 3006

8

10

12

14

16

18Wind

Time(s)m

/s

0 50 100 150 200 250 300-500

0

500

1000

0 50 100 150 200 250 300-500

0

500

1000


Time above 60% of power reference

0

10

20

30

40

50

60

70

60 80 100 120 140 160 180 200

Dur

atio

n (s

)

Time (s)

Available time in s (E/450kW) Duration of time above 60% of power reference


Loads: blades, tower, and drive train

-15

-10

-5

0

5

10

73.825 116.8675 162.945 163.3625 163.36 168.84 195.015 226.84

Perc

ent c

hang

e fr

om b

asel

ine

Time to stop calculation (s): at 60% of demanded

Tower DEL increaseDrivetrain DEL increaseBlade DEL increase


Pros Cons

Torque-based APC Fast tracking performance Region 2 control

Pitch Control 2 Performs well in all regions

Slightly slow tracking performance

Combined Control 1 Better performance Overshoot

Combined Control 3 Best Performance More overshoot

Inertial Control

Able to provide >60% for extended time scale of primary control in these

tests

Turbine stopped – re-start was not part of research

Regulation control conclusions


Design and analysis using more sophisticated control architectures

Strategies for generating power reference signals Requires strong understanding of the utility grid

Field testing

Regulation control: future work needed


Colorado School of Mines Including M.S. student Yunho Jeong

National Renewable Energy Laboratory

Aalborg University

Vestas

Acknowledgments


White paper/proposal? Attempt to influence funding agencies? Book? Home?

Where do we go from here?

The Big Picture - Aalborg Universitetkom.aau.dk/project/vtcp/wt_sym_2011/slides/KatieJohnson.pdf ·...

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