NZ556642A

NZ556642A - Wind turbine comprising a multiplied redundancy control system and method of controlling a wind turbine

Info

Publication number: NZ556642A
Application number: NZ556642A
Authority: NZ
Inventors: Ole Molgaard Jeppesen; John Bengtson; Torben Moller Hansen
Original assignee: Vestas Wind Sys As
Priority date: 2004-12-30
Filing date: 2004-12-30
Publication date: 2009-10-30

Abstract

A wind turbine is disclosed, including equipment under control, and a control system for the equipment under control. The control system is multiplied by at least one further control system for controlling the same equipment under control, with the control systems being connected by a communication bus system for exchanging control communication.

Description

556642 1 WIND TURBINE COMPRISING A MULTIPLIED REDUNDANCY CONTROL SYSTEM AND METHOD OF CONTROLLING A WIND TURBINE Background of the invention The invention relates generally to wind turbines and more particularly to a control 10 arrangement, a method of controlling a control system being multiplied by at least one further control system for controlling the same equipment under control of a wind turbine and uses hereof.

I Description of the Related Art Wind turbines are designed to face harsh and changing weather in a long period of years and still show a high dependability. Previously, the dependability has been achieved by designing wind turbines with a certain over-sizing in relation to the required under normal use of the wind turbine.

The tower, wind turbine blades and breaking systems may for example be over-sized in order to handle extreme weather situation or excessive forces during a malfunction such as loss of utility grid or control of the wind turbine rotor.

( However, it is an increasing challenge to transport and handle the wind turbine components of large modern wind turbines. Consequently, the over-sized components are a significant problem in relation to size and weight during transport and handling as well as expensive in material costs.

Previously, it has also been known to have more than one component of a kind in a wind turbine. The redundancy is especially used with the components which face significant mechanical stress e.g. a hydraulic pitch actuator. The extra component 2 3 JUL 2m P:\UsertSaskia\NZ1543Q-07 - retyped pag-es - 3 Jul 07.doc INTEofSiV5?zEm^] 556642 J I - 9 SEP 2009 I 2 I R E C E I V F nj may take on the workload in a short period after a main component has failed until the repair people arrive and thus enhances the availability and dependability of the wind turbine. However, the more than one component of a kind does not change or solve the above-mentioned problem regarding size and weight as well as material costs of wind turbine 5 components.

It would be desirable to establish a technique allowing more weight and cost efficient wind turbines to be built.

The invention According to an aspect of the present invention, there is provided wind turbine including: equipment under control, and a control system for said equipment under control, said control system being multiplied by at least one further control system for controlling the same of said equipment under control, wherein said control systems being connected by a communication bus system for exchanging control communication.

Hereby is established a wind turbine that ameliorates the above-mentioned disadvantages of the prior art. The minimization of single points of failure possibility in the control of equipment under control by securing the functionality on system level is advantageous. With the enhancing of the safety level and thus the reliability of the wind turbine it is possible to design the different wind turbine components to normal use and fatigue instead of designing 25 for extreme loads.

The wind turbine tower may for example be designed with a "normal sized" material tightness as risk of malfunctions such as the risk of dangerous rotor overspeed due to loss of control is significantly diminished. The saved materials of a "normal sized" tower and other structural 30 components of the wind turbine may exceed 25%.

The term "equipment under control" and "main components" should especially be understood as the wind turbine blades, gear (if any) and generator of the wind turbine.

C'ApofV«ord\SPEC-NZ154SG-Q7.<ioc . i - « if v Mil 556642 3 The term, "control system" should be understood as a system supervising and controlling a main component and including the necessary components in doing so.

In an embodiment of the invention, said equipment under control being main 5 components of the wind turbine such as the wind turbine blades.

In an embodiment of the invention, said control systems being operating simultaneously and independently of each other. Hereby it is possible to continuously control the main component regardless that one control system fails. The wind turbine 10 may thus continue to generate power until replacement of the failed system can be performed or be shut down in a controlled manner.

In an embodiment of the invention, said control systems being operating simultaneously with dependent supervision of each other. Hereby, it is ensured that the 15 control systems work together in an advantageously control of a main component.

In an embodiment of the invention, said equipment under control includes at least one pitch or active stall wind turbine blade. It is advantageous to use the invention in connection with large wind turbine blades as the pitch mechanism of each blade also is 20 the only brake system of the rotor.

In an embodiment of the invention, said at least one wind turbine blade is part of a wind turbine with two or three blades. It is especially advantageous to use the invention in connection with two-bladed wind turbines as loss of control in one blade 25 may result in loss of the ability to stop the wind turbine rotor as such.

In an embodiment of the invention, said wind turbine includes a teeter mechanism including teeter angle sensors.

In an embodiment of the invention, said control systems include the supervision systems for said pitch or active stall wind turbine blades. hwulectuai. property office] of n.z.

P:\User\SaskiB\NZ-1 E430-07 - retyped oag&s - 3 Jul Q7.doc 13 JUL 2007 Rece 556642 4 In an embodiment of the invention, one of said control systems includes pitch and/or teeter components e.g. sensors such as blade load sensors, pitch position sensors, azimuth sensors and/or teeter angle sensors, actuators such as pitch actuators and/or teeter actuators, power supplies including UPS and/or controllers such as 5 microcomputers. Hereby it is ensured that any type of failure is not fatal as the components of the system is multiplied and consequently that the one or more remaining control systems may continue the normal control of the wind turbine or at least stop the wind turbine in a controlled manner.

In an embodiment of the invention, sensors in one of said control system are positioned differently in relation to the positions of the corresponding sensors in further of said control systems. Hereby it is ensured that damage to a section of the wind turbine component such as a pitch wind turbine blade e.g. by a stroke of lightning at sensors of the control system does not automatically affect the sensors of the farther 15 control system.

In an embodiment of the invention, the wind turbine includes more than two control systems e.g. three or four control systems. The number of further control systems may be chosen by the risk of damage to the system in order to achieve the necessary 20 reliability of the wind turbine. The number may for example be chosen by the type of wind turbine, two or three-bladed, the place of erecting the wind turbine, frequent lightning storms, and the accessibility of the wind turbine e.g. an off-shore wind turbine.

In an embodiment of the invention, the wind turbine includes at least two control systems wherein one or more components of said systems are multiplied by at least two or three such as more than two pitch components, teeter components and/or controllers.

INTELLECTUAL property office of hz, 23 JUL 2007 RECEIVED I P:\Jser\SasKiaWZ1 &4?0-07 - retyped pages -3 Jul 07 doc 556642 In an embodiment of the invention, said control systems include a number of central controllers. Hereby, it is easier to position the controllers in a protected and safe environment.

In an embodiment of the invention, said control systems include a number of distributed controllers e.g. controllers distributed at the wind turbine hub, the main shaft, the root of the wind turbine blade and/or inside the blade. Hereby, it is possible to enhance the reliability of the control systems as they may continue working if distributed controllers of one equipment under control fail. The distributed controllers 10 of other equipment under control may take over the control from the failed controllers e.g. the controllers of one blade may control the control systems of two blades due to a failure in the controllers of one blade caused by a stroke of lightning in the blade.

In an embodiment of the invention, said control systems are connected by cables such 15 as individual cables between the components. Hereby are established separate connection circuits between the different sets and thus enhancing the high reliability of the control systems even further.

In an embodiment of the invention, control systems are connected by a communication 20 bus system e.g. using copper cables and/or fiber optic communication cables, radio and/or wireless communication connections such as bluetooth connections. The use of separate connection circuits, fiber optic communication cables and/or wireless communication especially ensures a higher reliability against malfunction after a stroke of lightning.

In an embodiment of the invention, said control systems being partly or fully identical systems. Hereby, it is possible to enhance the common safety level of the control systems. 556642 6 In an embodiment of the invention, said control systems being a multiplied redundancy system. Hereby is an advantageous embodiment of the invention achieved.

According to another aspect of the present invention, there is provided a control arrangement 5 for a wind turbine rotor including at least two wind turbine blades, wherein said arrangement includes a plurality of control systems for controlling the same wind turbine blade or the same part of the wind turbine blade, wherein at least controllers of said plurality of control systems are distributed at the wind turbine blade or the same part of the wind turbine blade being controlled, and wherein said control systems are connected by a communication bus system 10 for exchanging control communication.

Hereby, it is possible to enhance the safety of the control of the wind turbine rotor as the arrangement includes distributed but connected controllers whereby the control arrangement may continue controlling the wind turbine blades regardless of failure in one or more 15 controllers.

In an embodiment of the invention, said controllers include one or more microprocessors. i In an embodiment of the invention, said control systems are connected by a communication 20 bus system e.g. using copper cables and/or fiber optic communication cables, radio and/or wireless communication connections such as Bluetooth connections. The bus system ensures that any data may be shared among the control systems and the controllers. Hereby, it is ensured that any blade in the wind turbine rotor may remain under control regardless of failure in some of the control systems and controllers.

In an embodiment of the invention, said controllers are distributed at the wind turbine hub, the main shaft, the root of the wind turbine blade and/or inside the blade. By positioning the controllers locally in proximity of the equipment under control a simpler and more reliable construction of a control arrangement is achieved.

A further aspect of the present invention relates to a method of controlling a control system being multiplied by at least one further control system for controlling the same equipment under control of a wind turbine, said method comprising the steps of: controlling said equipment with the control systems, and operating said control gygtem ami at least one further W:\Kathy\Speci\NZ154S0-07\amencfsd pages.doc INTELLECTUAL PROPERTY OFFICE OF N.Z. 13 MAY 2009 d p n p i w p n 556642 7 control system by exchanging control communication on a communication bus system connecting the control systems.

In embodiments of the invention, said control systems are operated simultaneously and 5 independently of each other or in dependency of each other by exchanging control communication. Hereby are advantageous embodiments of the invention achieved.

In an embodiment of the invention, control communication is transferred on a communication bus system connecting said control systems. In a further aspect of the invention, said 10 communication is transferred on a communication bus system between central or distributed controllers. Hereby are advantageous embodiments of the invention achieved.

Yet another aspect of the present invention relates to uses of a wind turbine, control arrangement and method in connection with emergency stop of the wind turbine during 15 extreme situations such as weather situations or loss of utility grid.

Figures The invention will be described in the following with reference to the figures in which fig. 1 illustrates a large modern wind turbine including three wind turbine blades in the wind turbine rotor, fig. 2 illustrates schematically a section of a wind turbine according to the invention, fig. 3 illustrates schematically a central control system of a three-bladed wind turbine, W:\Kathy\Sped\NZ15480-07\amended pages.doc INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 3 MAY 2M9 RECEIVED 556642 8 fig. 4 fig. 5 fig. 6 10 fig. 7 fig. 8 Detailed description Fig. 1 illustrates a modern wind turbine 1 with a tower 2 and a wind turbine nacelle 3 positioned on top of the tower. The blades 5 of the wind turbine rotor are connected 20 to the nacelle through the low speed shaft which extends out of the nacelle front.

As illustrated in the figure, wind over a certain level will activate the rotor and allow it to rotate in a perpendicular direction to the wind. The rotation movement is converted to electric power which usually is supplied to the transmission grid as will 25 be known by skilled persons within the area.

Fig. 2 illustrates schematically the equipment under control, i.e. the wind turbine blades 5, the gear 9, and the electric generator 7. The equipment under control are supervised and controlled by control systems 14 of a wind turbine according to the 30 invention. The wind turbine further comprises the low and high speed shafts 10, 8 illustrates the control system of fig. 3 in further details, illustrates the control system of fig. 3 in details for a two bladed wind turbine, illustrates schematically a control arrangement including distributed control systems of a three-bladed wind turbine, illustrates the control arrangement including distributed control systems of a two-bladed wind turbine in details, and illustrates another embodiment of the control arrangement including distributed control systems of a two-bladed wind turbine. 556642 9 connecting the wind turbine blades 5, the gear 9, and the electric generator 7. Teeter mechanism allows the wind turbine blades to be angled in relation to a vertical plane.

The control systems 14 may supervise and control any of the equipment under 5 control, such as the wind turbine blades 5, during normal use and stopping of the wind turbine.

According to the invention the control systems 14 comprise a first control system 14A which is multiplied by at least one further control system 14B for supervising 10 and controlling the same equipment under control.

The control systems 14A, 14B are preferably identical systems in construction and performing the same functionality. They may operate simultaneously and independently of each other in supervising and controlling the same equipment under 15 control.

Fig. 3 illustrates schematically a central control system of a three-bladed wind turbine.

The figure illustrates how the wind turbine blades are centrally controlled from control systems wherein communication between components in the control systems and the blades are performed on a communication bus. The communication bus may be wired connections e.g. a communication bus system using copper cables and/or fiber optic communication cables. Further, the communication bus may include radio 25 and/or wireless communication connections such as bluetooth connections between the control systems. The communication bus may for example use standard LAN technique.

The connection between the individual components of the control systems and the 30 blades may be established by separate or common cables e.g. separate power cables transferring power to each relevant component. 556642 Fig. 4 illustrates the central control system of fig. 3 in further details wherein the control systems 14A, 14B are part of a three-bladed wind turbine.

Each set of control systems 14A, 14B comprises one or more microcontroller 17, jiCtrl A, jaCtrl B collecting, treating and transmitting data such as collecting data from the control system sensors in the relevant equipment under control and transmitting control data to control system components controlling the relevant equipment under control.

Examples of control system sensors and components are pitch position and blade load sensors as well as pitch actuators in relation to one wind turbine blade 5. The blade arrangement is replicated in all the blades 5.

Further, each set of control systems 14A, 14B may comprise an azimuth sensor 15 transmitting data to the blade microcontrollers 17.

The two microcontrollers 17 of the sets of control systems 14A, 14B are power supplied from their own separate power supplies 16 in which each power supply 20 includes an uninterruptible power supply UPS A, UPS B. The two UPS power the control systems and allow the wind turbine to be controlled and stopped at a power blackout e.g. caused by a direct stroke of lightning on a power line, The control system sensors of different sets may be positioned in proximity of each 25 other e.g. one blade load sensor close to the next blade load sensor but preferably not at the same position on the wind turbine blade 5.

Fig. 5 illustrates the central control system of fig. 3 in a two-bladed wind turbine.

The structure of the control systems 14A, 14B of fig. 4 substantially corresponds to the systems of fig. 4. The situation of one blade less may initiate the use more than 556642 11 two identical control systems e.g. three or four control systems in order to enhance the security level against the wind turbine being damaged as a subsequent consequence of more than one control system malfunction.

The control system according to the invention may also be used in relation to other main components beside the wind turbine blades. The control system may for example also be used in connection with supervising and controlling the electric generator and thus ensuring that the generator does not face damaging work conditions as a subsequent consequence of a control system malfunction.

Fig. 6 schematically illustrates a control arrangement including distributed control systems of a three-bladed wind turbine.

The figure illustrates how each wind turbine blade is controlled from control systems 15 positioned locally at each blade. The communication between components in the control systems and the blades are performed on a communication bus e.g. corresponding to the communication bus mentioned in connection with fig. 3.

Fig. 7 illustrates a control arrangement including the distributed control systems of a 20 two-bladed wind turbine in details.

The figure illustrates how the control system of each blade is multiplied e.g. in relation to sensors, controllers and power supplies including UPS. The controllers are connected in a local area network LAN and such may communicate and supervise 25 each others functionality.

Fig. 8 illustrates another embodiment of the control arrangement including distributed control systems in a two-bladed wind turbine. 556642 12 The controllers of the figure are connected by a communication bus in a LAN and as such establish multiplied controllers; controller 1, controller 2 and controller of the figure.

The wind turbine according to the invention may be part of a wind park where every wind turbine is connected to a central control station that responds to failure messages from the wind turbines such as a failed control system e.g. by sending maintenance people or a stop signal to the wind turbine.

The invention has been exemplified above with reference to specific examples of a wind turbine with control systems. The system may control the wind turbine in use or during a stopping process at a malfunction of one control system e.g. an emergency stop. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude 15 of varieties within the scope of the invention as specified in the claims. 556642 13 List 1.

Wind turbine or wind turbine system 2.

Wind turbine tower 3.

Wind turbine nacelle 4.

Wind turbine hub .

Wind turbine blade 6.

Rotor 7.

Electric generator 8.

High speed shaft 9.

Gear .

Low speed shaft 11.

Teeter mechanism 12.

Pitch mechanism for a wind turbine blade 13.

Yaw mechanism 14.

Control system for wind turbine blades 14A, 14B. Control system and a further control system .

Two sets of azimuth sensors 16.

Two sets of power supplies including UPS 17.

Two sets of microcontrollers 18.

Two sets of teeter angle sensors

Claims

556642 14 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. Wind turbine including: equipment under control, and 5 a control system for said equipment under control, said control system being multiplied by at least one further control system for controlling the same of said equipment under control, wherein said control systems being connected by a communication bus system for exchanging control communication. 10

2. Wind turbine according to claim 1, wherein said equipment under control being main components of the wind turbine such as the wind turbine blades.

3. Wind turbine according to claim 1 or 2, wherein said control systems being operating 15 simultaneously and independently of each other.

4. Wind turbine according to claim 1 or 2, wherein said control systems being operating simultaneously with dependent supervision of each other.

5. Wind turbine according to any one of claims 1 to 4, wherein said equipment under 20 control includes at least one pitch or active stall wind turbine blade,

6. Wind turbine according to claim 5, wherein said at least one wind turbine blade is part of a wind turbine with two or three blades.

7. Wind turbine according to any one of claims 1 to 6, wherein said control systems include supervision systems for said pitch or active stall wind turbine blades. 25

8. Wind turbine according to any one of claims 1 to 7, wherein said wind turbine includes a teeter mechanism including teeter angle sensors. C:\pof\word\SPEC-NZ15480-07.doc 556642 10 15

9. Wind turbine according to any one of claims 1 to 8, wherein one of said control systems includes pitch and/or teeter components e.g. sensors such as blade load sensors, pitch position sensors, azimuth sensors and/or teeter angle sensors, actuators such as pitch actuators and/or teeter actuators, power supplies including UPS and/or controllers such as microcomputers,

10. Wind turbine according to claim 9, wherein sensors in one of said control system are positioned differently in relation to the positions of the corresponding sensors in further of said control systems.

11. Wind turbine according to any one of claims 1 to 10, wherein the wind turbine includes more than two control systems e.g. three or four control systems.

12. Wind turbine according to any one of claims 1 to 11, wherein the wind turbine 15 includes at least two control systems wherein one or more components of said systems are multiplied by at least two or three such as more than two pitch components, teeter components and/or controllers.

13. Wind turbine according to any one of claims 1 to 12, wherein said control 20 systems include a number of central controllers,

14. Wind turbine according to any one of claims 1 to 12, wherein said control systems include a number of distributed controllers e.g. controllers distributed at the wind turbine hub, the main shaft, the root of the wind turbine blade 25 and/or inside the blade.

15. Wind turbine according to any one of claims 1 to 14 wherein said control systems are connected by cables such as individual cables between the components. 30

16. Wind turbine according to any one of claims 1 to 15, wherein said control systems are connected by a communication bus system using copper cables and/or fiber optic communication cables, radio and/or wireless communication connections such as bluetooth connections. P:\U&ei^askia\N21J>4 30-07 - retyped - 3 Jul 07.doe intellectual property ofice OF NX 23 JUL 2007 \ g g™ g«^ 556642 16

17. Wind turbine according to any one of claims 1 to 16, wherein said control systems being partly or fully identical systems.

18. Wind turbine according to any one of claims 1 to 17, wherein said control systems being a multiplied redundancy system. 5

19. Control arrangement for a wind turbine rotor including at least two wind turbine blades, wherein said arrangement includes a plurality of control systems for controlling the same wind turbine blade or the same part of the wind turbine blade, wherein at least controllers of said plurality of control systems are distributed at the wind turbine blade or the same part of the wind turbine blade being controlled, and 10 wherein said control systems are connected by a communication bus system for exchanging control communication.

20. Control arrangement according to claim 19, wherein said controllers include one or more microprocessors.

21. Control arrangement according ,to claim 19 or 20, wherein said control systems are 15 connected by a communication bus system using copper cables and/or fiber optic communication cables, radio and/or wireless communication connections such as bluetooth connections.

22. Control arrangement according to any one of claims 19 to 21, wherein said controllers are distributed at the wind turbine hub, the main shaft, the root of the 20 wind turbine blade and/or inside the blade.

23. Method of controlling a control system being multiplied by at least one further control system for controlling the same equipment under control of a wind turbine, said method comprising the steps of: controlling said equipment with the control systems, and 25 operating said control system and at least one further control system by exchanging control communication on a communication bus system connecting the control systems.

24. Method according to claim 23 where said control systems are operated simultaneously and independently of each other. W:\Kathy\Speci\NZ1548007\amen<Jeel p INTELLECTUAL PROPERTY OFFICE OF N.Z. 13 MAY 2009 556642 17

25. Method according to claim 23 or 24 where said control systems are operating simultaneously and in dependency of each other by exchanging control communication. 5

26. Method according to any one of claims 23 to 25 where control communication is transferred on a communication bus system connecting said control systems.

27. Method according to claim 26 where said communication is transferred on a communication bus system between central or distributed controllers. 10

28. Use of a wind turbine according to any one of claims 1 to 18 in connection with emergency stop of the wind turbine during extreme situations such as weather situations or loss of a utility grid. 15

29. Use of a control arrangement according to any one of claims 19 to 22 in connection with emergency stop of the wind turbine during extreme situations such as weather situations or loss of a utility grid.

30. Use of a method according to claim 23 or 27 in connection with emergency 20 stop of a wind turbine during extreme situations such as weather situations or loss of a utility grid. intellectual property office OF Mi 23 JUL 2007 RECEIVED P:\User\Saskia\NIZ15480-C7 ■ retyped pages - 3- Jul 07.(Joc