Wind turbine blade, wind turbine and method for manufacturing a wind turbine blade

Abstract

A wind turbine blade includes one or more electric powered modules powered by light beams so as to provide a galvanic separation between the electric powered modules and a lightning protection system in a wind turbine blade. The modules have a power supply converting an energy source in the form of light beams to electrical power for the one or more modules. A wind turbine and a method for manufacturing a wind turbine blade are also disclosed.

Claims

1. A wind turbine blade for use in a wind turbine, the wind turbine blade comprising: a blade body comprising: a lightning protection system having a lightning down conductor configured to couple with an electrical ground through one or more other components of the wind turbine; and a routing tube extending substantially along a length of the blade body, wherein the routing tube is one of (i) integrated into the blade body, and (ii) fastened to an interior surface of the blade body; at least one electric-powered module coupled with the blade body and comprising a device requiring electrical power to operate; a power supply configured to generate, using converted light energy, the electrical power for operating the device; and an optical waveguide extending through the routing tube and coupled to the power supply, the optical waveguide configured to receive light energy from a light source external to the blade body, and to transmit light energy to the power supply, wherein a galvanic separation is formed between the at least one electric-powered module and the electrical ground to mitigate a risk of current from lightning strikes from being conducted to the electrical ground through the at least one electric-powered module.

2. The wind turbine blade according to claim 1, wherein the at least one electric-powered module includes one or more sensors.

3. The wind turbine blade according to claim 1, wherein the at least one electric-powered module is integrated in the blade body, wherein the electric-powered module is surrounded by an electrically conductive mesh or casing to provide electromagnetic compatibility (EMC) protection.

4. The wind turbine blade according to claim 1, wherein the optical waveguide includes at least one optical fiber.

5. The wind turbine blade according to claim 1, wherein the power supply includes at least one photovoltaic cell.

6. The wind turbine blade according to claim 5, wherein the at least one photovoltaic cell receives the light energy from at least one optical fiber.

7. The wind turbine blade according to claim 6, wherein the at least one optical fiber is integrated in the blade body.

8. The wind turbine blade according to claim 1, wherein the power supply is configured to generate the electrical power using energy from at least one of: one or more solar cells on a surface of the blade body or integrated in the blade body beneath a fully or partly transparent cover material: and kinetic energy sources in the blade body.

9. The wind turbine blade according to claim 1, wherein the at least one electric-powered module is positioned in an outer half of the blade body.

10. The wind turbine blade according to claim 1, wherein the at least one electric-powered module comprises a microprocessor.

11. The wind turbine blade according to claim 1, wherein the electrical power for the device is generated solely by the converted light energy.

12. The wind turbine blade according to claim 1, wherein the at least one electric-powered module includes a storage means for electric power.

13. A wind turbine comprising: a tower; and at least one wind turbine blade supported by the tower, each of the at least one wind turbine blade comprising: a blade body comprising: a lightning protection system having a lightning down conductor configured to couple with an electrical ground via the tower; and a routing tube extending substantially along a length of the blade body, wherein the routing tube is one of (i) integrated into the blade body, and (ii) fastened to an interior surface of the blade body; at least one electric-powered module coupled with the blade body and comprising a device requiring electrical power to operate; a power supply configured to generate, using converted light energy, the electrical power for operating the device; an optical waveguide extending through the routing tube and coupled to the power supply, the optical waveguide configured to receive light energy from a light source disposed external to the blade body, and to transmit light energy to the power supply, wherein a galvanic separation is formed between the at least one electric-powered module and the electrical ground to mitigate a risk of current from lightning strikes from being conducted to the electrical ground through the at least one electric-powered module.

14. A method, comprising: establishing a blade body of at least one wind turbine blade with: a lightning protection system having a lightning down conductor configured to couple with an electrical ground when the at least one wind turbine blade is installed on a wind turbine; and a routing tube extending substantially along a length of the blade body, wherein the routing tube is one of (i) integrated into the blade body, and (ii) fastened to an interior surface of the blade body; integrating one or more electric-powered modules with a power supply in the blade body, the one or more electric-powered modules comprising a device requiring electrical power to operate, the power supply configured to generate, using converted light energy, the electrical power for operating the one or more electric-powered modules; and inserting an optical waveguide through the routing tube to couple to the power supply, the optical waveguide configured to receive light energy from a light source disposed external to the blade body, and to transmit light energy to the power supply, wherein a galvanic separation is formed between the one or more electric-powered modules and the electrical ground to mitigate a risk of current from lightning strikes from being conducted to the electrical ground through the one or more electric-powered modules.

15. The method of claim 14, further comprising: enclosing the one or more electric-powered modules inside an electrically conductive mesh or casing to provide electromagnetic compatibility (EMC) protection to the one or more electric-powered modules.

16. The method of claim 14, wherein inserting the optical waveguide includes installing at least one optical fiber.

17. The method of claim 14, further comprising: installing the at least one wind turbine blade onto a tower of the wind turbine; providing the light energy from the light source through the optical waveguide to the power supply; and powering the device using solely the converted light energy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in the following with reference to the figures in which:

(2) FIG. 1 illustrates a large modern wind turbine,

(3) FIG. 2 illustrates schematically a wind turbine blade according to the invention,

(4) FIG. 3 illustrates an embodiment of power supply means for an electric powered module such as a sensor in a wind turbine blade according to the invention,

(5) FIG. 4 illustrates a more detailed embodiment of an electric powered module in a sensor application of a wind turbine blade according to the invention, and

(6) FIG. 5 illustrates schematically a wind turbine blade according to the invention with a plurality of electric powered modules implemented, and

(7) FIG. 6 illustrates a cross sectional view of a wind turbine blade with illustrating different solutions of integrating optical fibres and power electrical modules.

DETAILED DESCRIPTION

(8) FIG. 1 illustrates a wind turbine 1, comprising a tower 2 and a wind turbine nacelle 3 positioned on top of the tower 2. The wind turbine rotor 4 comprises at least one wind turbine blade, e.g., three wind turbine blades 5 as illustrated in the figure. The rotor is mounted on a hub 6, which is connected to the nacelle 3 through the low speed shaft extending out of the nacelle front.

(9) FIG. 2 illustrates schematically a wind turbine blade according to the invention.

(10) The figure especially illustrates the optical fibre connection 10 between a light source 12 positioned outside the wind turbine blade 5 and an electric powered module 9 positioned in or inside the wind turbine blade 5. At least one lightning receptor 32 may be included as part of the wind turbine blade 5 and disposed proximate to a tip 8 of the wind turbine blade 5. The at least one lightning receptor 32 may be electrically connected to a lightning down conductor 33 which may extend from the root 7 of the wind turbine blade 5 to the at least one lightning receptor 32.

(11) The light source 12 may, for example, be positioned in the hub 6 or in the nacelle 3 (not illustrated in the figure) and facing one end 11 of the optical fibre 10. The light source may be any kind of light source with the possibility of emitting light of a certain and defined power density, e.g., a high power Xenon lamp or a laser source.

(12) The optical fibre (or plurality of fibres) 10 may be integrated in the blade structure or positioned in the interior of the wind turbine blade. See FIG. 6 for non-limiting implementing methods of the optical fibre 10 integrated in the blade structure or in the interior of the wind turbine blade 5. As illustrated, the fibre extends from the root 7 of the blade to any location in the blade of the electric powered module 9, e.g., in proximity of the blade tip 8.

(13) FIG. 3 illustrates an embodiment of a power supply means 13 for an electric powered module 9 such as a sensor in a wind turbine blade according to the invention.

(14) As illustrated in the enlarged part of the figure, the power supply means 13 especially comprises a photovoltaic cell 15 for converting light beams to electrical power. The light beams are emitted from the optical fibre end 14 facing the power supply means wherein the optical fibre end is final part of the optical fibre 10, preferably stretching from the light source 12 in the hub or another part of the wind turbine outside the blade 5.

(15) Further, the power supply means 13 may comprise a power supply part 16 for controlling the electric power of the photovoltaic cell 15 as well as storage means 17 for electrical power such as one or more capacitors.

(16) FIG. 4 illustrates a more detailed embodiment of an electric powered module 9 in a sensor application.

(17) The sensor module comprises power supply means 13, e.g., as explained above, having light beams emitted from an optical fibre 10, to an included photovoltaic cell, which is further illustrated by the arrow and Power (light). The converted electric power is supplied to a microprocessor means 18 such as an ultra low power microprocessor. The microprocessor also receives and controls electric signals from a sensor part 19 of the electric powered module 9. The signals are transferred by the microprocessor to a light source 21 in the module, which converts the signals to optical data communication for an optical fibre 20 illustrated by the arrow and Data (light).

(18) The data communication is transferred to processing means positioned in other parts of the wind turbine or even outside the wind turbine, e.g., via a SCADA connection to a control center.

(19) By the optical fibre connections 10, 20 is established a galvanic separation 22 between the electric powered module 9 and any ground potential outside the wind turbine blade which is schematically indicated at the reference number 22.

(20) The optical fibres 10, 20 illustrated on FIG. 4 are only to illustrate that one or more optical fibres connect the electric powered module 9 with the other parts in or outside the wind turbine. It should be noted that in relation to all embodiments of the present invention, different combinations of use of one or more optical fibre are available. Hence as illustrated on FIG. 4, one optical fibre 10 is used for power up and/or upstream communication and one optical fibre 20 is used for downstream communication relative to the electrical powered module 9.

(21) Beside or in combination with the illustrated embodiment on FIG. 4, the following examples are just to indicate that a plurality of different solutions could be used according to the scope of the invention.

(22) In a not illustrated embodiment of the invention, one optical fibre is used for power (power up) to the electrical powered module 9 and two further optical fibres are used for full duplex communication between the electrical powered module 9 and other parts in or outside the wind turbine.

(23) In a further not illustrated embodiment of the invention, one optical fibre is used for power (power up) to the electrical powered module 9 and one further optical fibre is used for bi-directional (half duplex) communication between the electrical powered module 9 and other parts in or outside the wind turbine.

(24) Hence, as described, any combination of the number optical fibres and the use of the optical fibres is possible within the scope of the invention, even having only one optical fibre between the electrical powered module 9 and other parts in or outside the wind turbine.

(25) FIG. 5 illustrates schematically a wind turbine blade according to the invention with a plurality of electric powered modules 9 implemented.

(26) The plurality of electric powered modules 9 may be sensors scattered over the full length of the wind turbine blade or concentrated in parts of the blade with an increased risk of strain or damage to the blade, e.g., the wind turbine tip. Further, sensors in a blade part may sense the same type of information, e.g., vibrations, and hereby establish a redundancy by the high number of sensors.

(27) As illustrated in the enlarged part of the figure, the electric powered module 9 may be integrated in the blade structure 24, e.g., the blade shell or beam structure.

(28) The integration may be established as part of the blade manufacturing method, e.g., by being positioned between the glass or carbon fibre material mats when they are applied in the blade manufacturing.

(29) The invention described has been exemplified above with reference to specific examples. However, it should be understood that the invention is not limited to the particular examples, but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims, e.g., with different data and/or power connections between a plurality of modules such as a cascade connection. Further, the power supply means may be positioned in another location within the wind turbine blade instead of being an integrated part of the module, e.g., in close proximity of the module, but not integrated in the module. Even further, the power supply means may be combined with local electric power sources such as one or more solar cells 26 integrated in the blade structure 24 beneath a fully or partly transparent cover material, as illustrated in FIG. 5, or kinetic energy sources in the blade.

(30) As mentioned, it is possible to include a further energy source to support or backup the supply from the optical fibre 10. Beside the mentioned technologies also, e.g., electrochemical technologies such as, e.g., batteries, could be used. By implementing such rechargeable energy storages the optical fibres 10 may be supplemented, hence, when, e.g., a solar cell is able to provide more energy than, e.g., the micro processor has to use, the solar cell may charge one or more batteries.

(31) FIG. 6 illustrates a cross view of a wind turbine blade 5 illustrating examples of how optical fibres 10 and or one or more electric powered modules 9 may be integrated in wind turbine blade 5.

(32) The integration of one or more optical fibres 10 and/or one or more electric powered modules 9, in the blade structure 29, could, e.g., be interpreted as the one or more optical fibres 10 and/or one or more electric powered modules 9 is, at least partly casted in the material constituting the wind turbine blade 5.

(33) The blade structure 29 is defined between a most inner part 30 and a most outer part 31 of the wind turbine blade 5.

(34) The wind turbine blade 5 may, e.g., be built up layer-wise and hence between the most outer 31 and the most inner layer/part 30 the optical fibre 10 or the one or more electric powered modules 9 may by located. It should be noted that it is not necessary to fully cast the electric powered modules 9 and the optical fibre 10 into the wind turbine blade 5.

(35) The wind turbine blade 5 may, e.g., be made based on variations on glass-fiber reinforced polymer composite, carbon, wood or preferably epoxy based composites which may lead to shorter curing time than using other traditional resins, which is also possible.

(36) As illustrated, the electric powered modules 9 may be integrated in the wind turbine blade 5 in a way where the electric powered modules 9 are partly located in the structure of the wind turbine blade 5 and partly located in the interior of the wind turbine blade 5.

(37) According to an aspect of the invention, a tube 28 could also be cast in the wind turbine blade structure 29. Hence, after the wind turbine blade 5 is cast, it is possible to drag one or more optical fibres 10 through the tube 28. This could be an advantage if the optical fibre 10 is to be changed when the wind turbine 1 is put into operation.

(38) Of course, such tube may be located elsewhere in the wind turbine blade 5. One example of such location is in the interior of the blade 5. A further example (not shown) is, if the construction of the blade 5 allows this, to locate the tube in a cavity within the material of which the blade 5 is constructed. It should be noted that in such cavity, also light guides, such as optical fibres 10, could be located.

(39) As mentioned above, the optical fibre 10 may also, according to an embodiment of the invention, be positioned in the interior of the wind turbine blade 5. According to such embodiment, it may also be possible to remove and replace the optical fibres 10 after the wind turbine blade 5 is cast.

(40) According to the above, care should be taken when choosing the type of optical fibre 10 because of the environment present inside and in relation to a wind turbine blade 5. The optical fibre (or plurality of optical fibres) may, e.g., be exposed to vibrations, change in temperatures, pressure and humidity, etc.

(41) Furthermore, the route (cast in the blade in form of, e.g., a tube or in the interior of the blade) of the optical fibre has to be considered carefully. Because of the long term effect of the mentioned factors in relation to the environment in and in relation to wind turbine.

(42) It should be noted that the wind turbine blade 5 may be provided with an internal support structure 27 as indicated on FIG. 6. The form or shape of the internal support structure 27 may vary, but the internal support structure 27 may be used in relation to the integration of the optical fibre 10 and/or the one or more electric powered modules 9.

(43) It is possible to integrate more than one optical fibre 10 if needed. Having more than one fibre allows separating supply and data communication, and if one of the optical fibres is damaged, this does not have to have any effect since another optical fibre then can be used.

(44) Throughout this document, the term optical fibres 10 has been used to describe the means for transporting energy optically to the electric powered modules 9. It should be noted that optical fibres are just a preferred embodiment of an optical waveguide (also referred to as light guide). An optical waveguide includes, when appropriate, but is not limited to, glass, plastics or polymers, mirrors, crystals etc.

(45) In alternative embodiments of the invention, the optical energy may be transferred to the electric powered module 9 only by means of a laser beam. This embodiment would require some calibration or adjusting means, electrically or optically, to ensure that the laser beam is received so that the energy of the laser beam is used optimally. Such calibration or adjusting could e.g. be one or more optical lenses, mirrors, prisms, etc. and be located somewhere in between the source and receiver or at the source or receiver.

(46) In a further alternatively embodiment of the invention, the optical energy may be transferred to the electric powered module 9 only by means of a laser beam directed from the source to the receiver by means of one or more mirrors. Such mirrors may, according to an embodiment of the invention, be movable.

(47) In relation to the above mentioned examples of routing tubes 28 and/or optical fibres 10 inside a wind turbine blade, it should be noted that the tubes 28 and/or optical fibres 10 may be fastened. Such fastening could preferably be made by means of an adhesive material such as, e.g., glue, paste, etc., but also mechanical fastening means such as, e.g., clips or buoys may be used. The fastening may advantageously be performed at least partly along the length of the optical fibre 10.

LIST

(48) 1. Wind turbine 2. Wind turbine tower 3. Wind turbine nacelle 4. Wind turbine rotor 5. Wind turbine blade 6. Wind turbine hub 7. Root section of the wind turbine blade including the hub connection flange 8. Tip section of the wind turbine blade 9. Electric powered modules 10. Optical fibre for transmission of light beams for power supply 11. Optical fibre end facing a light source positioned outside the wind turbine blade, e.g., in the hub 12. Light source transmitting light beams as an energy source 13. Power supply means 14. Optical fibre end facing the power supply means 15. Photovoltaic cell for converting light beams to electrical power 16. Power supply 17. Storage means for electrical power such as one or more capacitors 18. Microprocessor means (P) such as ultra low power microprocessor 19. Sensor part of the electric powered module 20. Optical fibre for at least data communication 21. Light source for optical data communication from the electric powered module 22. Galvanic separation (schematically illustrated) between the electric powered module and any ground potential 23. Exterior of the wind turbine blade 24. Wind turbine blade structure, e.g., a blade shell or beam 25. Interior of the wind turbine blade 26. Solar cell and partly or fully transparent blade surface layer 27. Internal support structure of the wind turbine blade 28. Tube 29. Wind turbine blade structure 30. Most inner part of the wind turbine blade 31. Most outer part of the wind turbine blade.