saica presentation
TRANSCRIPT
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Introduction
Increasing attention to wind power electricity generation
dependence of global economies on fossil fuels concern about the environment
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Introduction
Increasing attention to wind power electricity generation
dependence of global economies on fossil fuels concern about the environment
Prevailing goal of WT with rudimentary control systems
minimization of the cost
minimization of the maintenance
of the installation.
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Introduction
Increasing attention to wind power electricity generation
dependence of global economies on fossil fuels concern about the environment
Prevailing goal of WT with rudimentary control systems
minimization of the cost
minimization of the maintenance
of the installation.
Recently,
increasing size of the WT use of mechanical actuators
opened the door to active control of the captured power.
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Introduction
There are two types of wind control for turbines
constant speed control
variable speed control
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Introduction
There are two types of wind control for turbines
constant speed control
variable speed control
Constant speed rotors
are designed to deflect high wind gust loads
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Introduction
There are two types of wind control for turbines
constant speed control
variable speed control
Constant speed rotors
are designed to deflect high wind gust loadsVariable wind turbines
are designed to control strong and gusty winds
Some WT are able to operate at variable pitch
A new control strategy for variable-speed, variable pitchhorizontal-axis wind turbines (HAWTs) is proposed in thiswork.
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Introduction
Office of Energy Efficiency and Renewable Energy Copyright.
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Introduction
Control strategy summary
nonlinear dynamic chattering torque control linear blade pitch angle control
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Introduction
Control strategy summary
nonlinear dynamic chattering torque control linear blade pitch angle control
The proposed controllers allow
a rapid transition of the WT generated power betweendifferent desired set values
electrical power tracking with a high-performancebehavior for all other state variables
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Introduction
Control strategy summary
nonlinear dynamic chattering torque control linear blade pitch angle control
The proposed controllers allow
a rapid transition of the WT generated power betweendifferent desired set values
electrical power tracking with a high-performancebehavior for all other state variables
The proposed controllers are validated using
the National Renewable Energy Laboratory (NREL) WTsimulator FAST (Fatigue, Aerodynamics, Structures, andTurbulence) code.
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Brief simulator description (FAST)
NRELs National Wind Technology Center develops CAE tools
that support the wind industry with state-of-the-art designand analysis capability
that have become the industry standard for analysis anddevelopment
that are free, publicly available, open-source,professional-grade products
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Brief simulator description (FAST)
NRELs National Wind Technology Center develops CAE tools
that support the wind industry with state-of-the-art designand analysis capability
that have become the industry standard for analysis anddevelopment
that are free, publicly available, open-source,professional-grade products
In particular, the FAST code
is an aeroelastic simulator
was evaluated in 2005 by Germanischer Lloyd WindEnergie and found suitable for the calculation of onshoreWT loads for design and certification
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Brief simulator description (FAST)
FAST main features
Computes structural-dynamic and control-systemresponses as part of the aero-hydro-servo-elastic solution
Uses a combined 24-DOF modal and multi-body
representation
Control system modeling through subroutines, DLLs, orSimulink R with MATLAB R
Nonlinear time-domain solution for loads analysis
Linearization procedure for controls and stability analysis
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Brief simulator description (FAST)
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Control strategy: Torque Control
The electrical power-tracking error is defined as
e = Pe Pref, (1)where Pe is the electrical power and Pref is the reference power.
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Control strategy: Torque Control
The electrical power-tracking error is defined as
e = Pe Pref, (1)where Pe is the electrical power and Pref is the reference power.Let us impose a first-order dynamic to this error [B. Boukhezzar etal., 2007], e = ae Ksgn(e) a, K > 0, (2)and let us take in account that the electrical power is given by
Pe = cg, (3)
where c is the torque control in the rotor side and g is thegenerator speed.
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Control strategy: Torque Control
The electrical power-tracking error is defined as
e = Pe Pref, (1)where Pe is the electrical power and Pref is the reference power.Let us impose a first-order dynamic to this error [B. Boukhezzar etal., 2007], e = ae Ksgn(e) a, K > 0, (2)and let us take in account that the electrical power is given by
Pe = cg, (3)
where c is the torque control in the rotor side and g is thegenerator speed.Substitution of(1) and (3) in (2) yields the torque control
c =1g
[c(ag + g) aPref + Ksgn(Pe Pref)].
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Control strategy: Torque ControlTheorem
The proposed controller
c =1g
[c(ag + g) aPref
+K
sgn(Pe
Pref
)].
ensures finite time stability.
Moreover, the settling time can bechosen by properly defining the
values of the parameters a and K.
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Control strategy: Torque ControlTheorem
The proposed controller
c =1g
[c(ag + g) aPref
+Ksgn(Pe
Pref
)].
ensures finite time stability.
Moreover, the settling time can bechosen by properly defining the
values of the parameters a and K.Proof mainly based on
Lyapunov functions and S. P. Bhat andD. S. Bernstein, ACC, 1997.
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Control strategy: Torque ControlTheorem
The proposed controller
c =1g
[c(ag + g) aPref
+Ksgn(Pe
Pref
)].
ensures finite time stability.
Moreover, the settling time can bechosen by properly defining the
values of the parameters a and K.Proof mainly based on
Lyapunov functions and S. P. Bhat andD. S. Bernstein, ACC, 1997.
Pref
Asymptotically stable
Finite time stability
0 5 10
200
400
600
800
1000
1200
1400
1600
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Control strategy: Torque Control
How can we approximate g?
1.- Use the one-mass model of a wind turbine
g
Jtg = Tang Ktg Tgng
Jt: Turbine total inertia, Kg m2
Kt: Turbine total external damping, Nm rad1 s
Ta: Aerodynamic torque, NmTg: Generator torque in rotor side, Nm
g: generator speed, rad s1
ng: gearbox ratio
[B. Boukhezzar et al., 2007]
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Control strategy: Torque Control
How can we approximate g?
1.- Use the one-mass model of a wind turbine
g
Jtg = Tang Ktg Tgng
Jt: Turbine total inertia, Kg m2
Kt: Turbine total external damping, Nm rad1 s
Ta: Aerodynamic torque, NmTg: Generator torque in rotor side, Nm
g: generator speed, rad s1
ng: gearbox ratio
[B. Boukhezzar et al., 2007]
2.- Use the estimator (transfer function in the Laplace domain)s
0.1s + 1
[M. W. Spong, and M. Vidyasagar, John Wiley and Sons, 1989]
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Control strategy: Pitch Controller
A pitch proportional controlleris added upon the rotor speed tracking error
= K(r n), K > 0,
where r is the rotor speed and n is the nominal rotor speed.
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Control strategy: Pitch Controller
A pitch proportional controlleris added upon the rotor speed tracking error
= K(r n), K > 0,
where
r is the rotor speed and
n is the nominal rotor speed.As we want to disable this control when r < n the finalproposed controller is given by the following expression
=
1
2 K(r n) [1 + sgn(r n)] , K > 0.
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Simulation results
The 1.5 MW WT used for numerical validation using FAST.Installation of a General Electric 1.5 MW WT at the NationalWind Technology Center (left), and comparison (scale inmeters) with the Statue of Liberty (right)
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Simulation results
Wind speed profile
0 5 10 15 20 25 30 358
9
10
11
12
13
14
15
time (s)
wind(m/s)
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Simulation results
Wind speed profile
0 5 10 15 20 25 30 358
9
10
11
12
13
14
15
time (s)
wind(m/s)
WT Characteristics
Number of blades 3
Height of tower 82.39 m
Rotor diameter 70 m
Rated power 1.5 MW
Nominal rotor speed (n) 20 rpm
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Torque Control
0 5 10 15 20 25 30 350
200
400
600
800
1000
1200
1400
1600
time (s)
Pe(kW)
Pref
Boukhezzar
K=1.5 10
6
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Torque Control
0 5 10 15 20 25 30 3520
25
30
35
40
45
50
time (s)
r
(rp
m)
Boukhezzar
K=1.5 10
6
d i h C l
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Torque and Pitch Control
0 5 10 15 20 25 30 350
200
400
600
800
1000
1200
1400
1600
time (s)
Pe(k
W)
Pref
Boukhezzar
K=1.5 10
6
T d Pi h C l
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Torque and Pitch Control
0 5 10 15 20 25 30 3520
20.5
21
21.5
22
22.5
23
23.5
time (s)
r
(rp
m)
Boukhezzar
K=1.5 10
6
T d Pit h C t l
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Torque and Pitch Control
0 5 10 15 20 25 30 350
2
4
6
8
10
12
14
time (s)
(de
g)
Boukhezzar
K=1.5 10
6
C l i
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Conclusions
A WT controller is presented for a turbulence windcondition.
C l i
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Conclusions
A WT controller is presented for a turbulence windcondition.
The nonlinear torque control leads to a good powerregulation, however it generates large rotor speed
fluctuations.
Conclusions
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Conclusions
A WT controller is presented for a turbulence windcondition.
The nonlinear torque control leads to a good powerregulation, however it generates large rotor speed
fluctuations. When the pitch controller is added upon the torque
controller then a good performance is obtained in rotorspeed and electrical power regulation.
Conclusions
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Conclusions
A WT controller is presented for a turbulence windcondition.
The nonlinear torque control leads to a good powerregulation, however it generates large rotor speed
fluctuations. When the pitch controller is added upon the torque
controller then a good performance is obtained in rotorspeed and electrical power regulation.
The proposed controller is easily applicable to other WTs.
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Chattering Control Design on aVariable-Speed Horizontal-Axis Wind Turbine
L. Acho, Y. Vidal, M. Zapateiro,
F. Pozo and N. LuoCoDAlab, www-ma3.upc.edu/codalabDepartament de Matematica Aplicada III
Escola Universitaria dEnginyeria Tecnica Industrial de BarcelonaUniversitat Politecnica de Catalunya, Barcelona, Spain
Department of Electrical Engineering, Electronicsand Automatic Control,
Institute of Informatics and Applications,University of Girona, Girona, Spain
Control strategy: Torque Control
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Control strategy: Torque Control
Proof.
Let us take the Lyapunov function V=
1
2 e
2
. Then,
V= ee = e(ae Ksgn(e)) = ae2 K|e| < 0. (4)
That is, the equilibrium is globally asymptotically stable.
Moreover, finite time stability can be proven. From (4),
V K|e| = K
2
V.
Thus, from Theorem 1 in [S. P. Bhat and D. S. Bernstein, (1997)],
the origin is a finite time stable equilibrium and
ts 1K
2(V)1/2, ts e
K
Control strategy: Torque Control
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Control strategy: Torque Control
ComparisonResistor-Capacitor circuit Error dynamic K = 0
Cv + vR = 0 e + ae = 0
v(t) = v0 exp(tRC ) e(t) = e0 exp(at)Capacitor discharged after 5 sec. Settling time after 5 sec.
where = RC where = 1/a
Control strategy: Torque Control
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Control strategy: Torque Control
Objective
Choose the values of the parameters a and K in the proposedcontroller to obtain the desired value in just 0.2(5) seconds.
Control strategy: Torque Control
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Control strategy: Torque Control
Objective
Choose the values of the parameters a and K in the proposedcontroller to obtain the desired value in just 0.2(5) seconds.
Assuming that in a neighborhood oft = 0 the error is boundedby |e| = |Pe Pref| < 1.5 106 (rated power of the WT)
ts e
K 1.5 106.
Torque Control
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Torque Control
0 5 10 15 20 25 30 350
1
2
3
4
5
6
7
8
time (s)
c
(kNm)
Boukhezzar
K=1.5 10
6
Torque and Pitch Control
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Torque and Pitch Control
0 5 10 15 20 25 30 350
1
2
3
4
5
6
7
8
time (s)
c
(kNm)
Boukhezzar
K=1.5 10
6