pitch control of wind turbine blades in noisy environment
TRANSCRIPT
-
8/2/2019 Pitch Control of Wind Turbine Blades in Noisy Environment
1/4
Pitch Control of Wind Turbine Blades in Noisy and
Unstable Wind Conditions
Mohsen FaridiIslamic Azad University,
Khodabandeh Branch
Khodabandeh, Iran
Roghaiyeh AnsariElectrical Engineering
Department
Tabriz University
Tabriz, Iran
seyed Ali MousaviElectrical Engineering
Department
KTH University
Sweden
Mahsa DodmanZanjan University
Zanjan, Iran
AbstractIn this paper, a new approach for control of the pitch
angle of the wind turbine is represented in an unstable and noisy
circumstance. Moreover, it is demonstrated that output power of
the wind turbine can be efficiently controlled by the proposed
control system. This method enhances (amends) the stability of
the wind turbine. Besides, it improves the regulation of the
output power. Also, a comparative study of the proposed controlsystem with a constant pitch angle wind turbines is depicted. For
modeling, real data of the wind turbine, model V74 Vestats, and
noisy wind model of Manjil area is used.
Keywords-wind turbine; induction generator; modeling; pitch
angel
I. INTRODUCTIONWind turbine is usually connected to the distribution
network like the other distributed generations. It is clear that agenerating system cannot be easily connected to the powersystem unless functionally, comprehensive knowledge and
investigations of the control preparation and grid connectionare available. Prerequisite of this mentioned knowledge isaccessibility to a proper tools for simulation and determiningthe connections dynamics of the wind turbine during theconfronting the power network. In this paper, for simulationPSCAD/EMTDC is employed. Such a wind turbine system asother types of dispersed generation is mostly connected todistribution feeders and the generation system cannot be easilyconnected to the electric power network without conductingcomprehensive evaluations of control performance and gridimpacts. This requires a reliable tool for simulating andassessing dynamics of a grid connected variable speed windturbine [6].
Albeit, numerous researches about the wind turbines andthe advantages and disadvantages of wind turbines has beenaccomplished in the literature like works on turbine models in
power dynamics simulations [1, 2], model of WT for powerquality [3], a general model for variable speed wind turbinesfor power system dynamics simulations [4] and modeling ofthe wind farms in the load flow analysis [5]. A little attention isgiven to the modeling and state control investigation of the
pitch angle of the WT in unstable circumstances that has agreat impact on stabilizing of the WT and following its effecton stabilizing the wind plant. All the mathematical and controlequations, dominating the elements in PSCAD/EMTDC, are
presented [6]. The mentioned software includes all tools forwind turbine modeling. The aim of this work is investigationon control system and modeling of the pitch angle of windturbine blade in adverse circumstances via softwarePSCAD/EMTDC. Recently, this software is widely employedto analyze the transient states.
II. MODELING OF WIND FARMA wind farm model working with variable wind speed is
composed of the following components:
a- Wind modelb- Wind turbine and induction generator modelc- Capacitive bank modeld- Transmission line model
Configuration of the mentioned model is represented inFig. 1.
Figure 1. A model wind turbine related to infinite bus
III. PROPOSED CONTROL STRATEGYIn wind turbines operating with induction machine and
variable speed, load torque is directly such controlled that therotor speed of turbine changes in its allowable bound.Advantage of a variable speed wind turbine is that the rotorspeed is adjustable with respect to the ratio of wind speed. Atthis state the speed rate is optimum. Therefore, CP is maximum,meaning that energy conversion rate is maximum. Generally,two control objectives are followed in the variable wind turbinesystems that are dependent on wind: Finally, complete content
Islamic Azad University, Khodabadeh Branch, Iran
-
8/2/2019 Pitch Control of Wind Turbine Blades in Noisy Environment
2/4
PK
IK
s
1 Filter +
4K
sBeta
Rate
Limiter
Limiter
+
gP
refP
-2.5 -2 -1.5 -1 -0.5 0-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Real
Image
-100
-50
0
50
100
Magnitude(dB)
10-3
10-2
10-1
100
101
102
-150
-120
-90
Frequency (HZ)
Phase(Deg)
wt0
R=0
Power
AB
PQ
Pbus
Qbus
wind
#1
#2
#1#2
1.0
1[MVAR]
Pbus
Qbus
Vrms
f
ph
Freq/PhaseMeasurement
fer
fer
and organizational editing before formatting. Please take noteof the following items when proofreading spelling andgrammar:
a) Obtaining a constant and optimum speed rate andobtaining maximum CP, at low speeds.
b) Maintaining the value of the output power in aconstant value for overcoming the overload problem.
Both aforementioned control strategies are feasible bycontrol of the wind speed and pitch angle control of windturbine blade.
Control of speed of wind turbine is possible by adjustingthe torque and rotor power. Furthermore, control of the blade isa conventional way to tune the aerodynamics power.
Aerodynamics model of wind turbine clarifies that variationof the blade angle has great impact on aerodynamicscoefficient which is dependent on wind blowing path ororientation of rotating pate. Any small change in blade pitchangle can lead to notable change in output power. At low windspeeds, a wind turbine has to generate as much power as
possible. Then, pitch angle must be kept invariant fixed, atoptimum pitch angle, in order to generate maximum output
power. At high speeds, pitch angle control via rotor leads tohigh amount of generated power, of course regarding thedesign calculation restrictions. For locating the blade atrequired value, variant control systems are applied. Thegovernor control diagram is depicted in Fig. 2.
Figure 2. Governor control block diagram
On the control diagram, Fig .2, Pref is the required powerMW; Pg is the output of machine p.u.; KP is the
proportional gain /p.u.; KI is the Integrating gain /p.u.;and K4 is the integrating gain of blade actuator exciter s.
The root locus of transfer function Y= (Pitch Angle)/Pg isdepicted in Fig .3.
Figure 3. Root locus
Consider that on the presented root locus KP=0.523,KI=0.523 and K4=0.1. Also, the Bode Diagram related toaforementioned transfer function is represented in Fig .4.
Figure 4. Bode Plot relate to transfer function
IV. SIMULATION RESULTS AND ITS INVESTIGATIONConfiguration of the system connection to the transmission
line is depicted in Fig .5.
Figure 5. Configuration of the transmission line
Regarding the Fig .5, the transmission system includesthe wind turbine, a local load and an infinite bus. The
parameters of the lines and the transformers can be found inFig .5. Fig .6 presents a power system for simulating inPSCAD/EMTDC software.
Figure 6. Model of a power system for simulation
-
8/2/2019 Pitch Control of Wind Turbine Blades in Noisy Environment
3/4
A. Investigation on the Pitch Angle Control SystemOperation During the Installation
Schema of Fig .7 shows the pitch angle changes wherethe wind speed is constant, 10 m/s. As demonstrated in theschema, the pitch angle reaches its steady state after 20 second.Also, Fig .8 presents the active power diagram where thespeed is 10 m/s.
Figure 7. The pitch angle changes where the wind speed is constant, 10m/s
Figure 8. The active power changes of wind turbine generator where the
wind speed is constant, 10 m/s
In Fig .9, the pitch angle is depicted at the different timesfor the constant wind speed equal 15 m/s. Considering Fig .9, the pitch angle reaches its steady state in 20 second, but incomparison to Fig .8 it has an overshot at the time about 12.The active power at the mentioned state is shown in Fig .10.
Figure 9. The pitch angle changes where the wind speed is costant, 15 m/s
Figure 10. The active power changes of wind turbin generator where the wind
speed is constant, 15 m/s
B. Investigation on the Pitch Angle Control SystemOperation During a Gust Wind
Fig .11 illustrates a constant wind speed, 10 m/s, whicha gust wind on interval 40 s, with maximum 6 m/smagnitude occurs. Diagram depicted in Fig .12 represents the
pitch angle variation where the wind speed changes. Also, itsactive power variation for mentioned state is illustrated in Fig .13.
Figure 11. A constant wind speed, 10 m/s, which a gust wind with
maximum 6 m/s magnitude
Figure 12. The pitch angle variation for mentioned state
0 10 20 30 40 50 60 70 80 90 100
0
2
4
6
8
10
12
14
16
18
20
Time (s)
PitchAngle(Degree)
0 5 10 15 20 25 30 35 40 45 50-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
Time (s)
ActivePower(p.u.)
0 5 10 15 20 25 30 35 40 45 500
1
2
3
4
5
6
7
8
Time (s)
PitchAngle(degree)
0 5 10 15 20 25 30 35 40 45 50-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
Time (s)
ActivePower(p.u.)
0 5 10 15 20 25 30 35 40 45 500
5
10
15
20
Time (s)
PitchAngle(Degree)
0 10 20 30 40 50 60 70
9
10
11
12
13
14
15
16
17
Time (s)
WindSpeed(m/s)
-
8/2/2019 Pitch Control of Wind Turbine Blades in Noisy Environment
4/4
Figure 13. The active power changes for mentioned state
C. Investigation on the Pitch Angle Control System Duringthe Noise Wind
Fig .14 depicts a noise wind and Fig .15 portrays thereaction of the pitch angle to the noise wind .In addition, active
power variation is represented in Fig .16.
Figure 14. Model of noisy wind
Figure 15. The reaction of the pitch angle to the noisy wind
Figure 16. The active power changes of wind turbine generator providingoutbreak noisy wind
V. CONCLUSIONAn appropriate control system was proposed for varying the
pitch angle in an unstable and noisy circumstance. Achieved
results represents that output power regulation can be improvedby proposed control system. The proposed control system isexperimented on a real wind turbine by using the practical dataof the noisy and gust wind of the Manjil area. Experimentalresults show that the system reaches the steady state within lessthan 20 second.
REFERENCES
[1] R. P. Mukund, Wind and Solar Power Systems, CRC Press, USA, pp.8182, 1999.
[2] J. G. Slootweg, H. Polinder and W. L. Kling, Initialization of WindTurbine Models in Power System Dynamics Simulations, IEEE PortoPower Tech Conference, 2001.
[3] D. H. Anca, P. Sorensen, L. Janosi and J. Bech, Wind Farm Modellingfor Power Quality, The 27th Annual Conference of The IEEE IndustrialElectronics Society, 2001, pp. 19591964.
[4] J. G. Slootweg, S. W. H. Haan, H. Polinder and W. L. Kling, GeneralModel for Representing Variable Speed Wind Turbins in Power SystemDynamics Simulations, IEEE Transactions on Power Systems, vol. 18,no. 1, 2003, pp. 144-151.
[5] A. E. Feijoo and J. Cidras, Modelling of Wind Farms in the Load FlowAnalysis, IEEE Transactions on Power Systems, vol. 15, no. 1, 2000,pp. 110-115.
[6] Manitoba HVDC Research Center, PSCAD/EMTDC Power SystemSimulation Software Users Manual Version 4, 2004 Release.
0 5 10 15 20 25-2
-1
0
1
2
Time (s)
ActivePower(p.u.)
0 10 20 30 40 50 60
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
Time (s)
ActivePower(p.u.)
0 5 10 15 20 2511.7
11.8
11.9
12
12.1
12.2
12.3
12.4
Time (s)
SpeedWind(m/s)
0 5 10 15 20 250
5
10
15
Time (s)
PitchAngle(Degree)