MEASURING A TORSION ANGLE OF A ROTOR BLADE

Abstract

A measuring system for determining a torsion of a rotor blade, comprising a reference shaft to be arranged in the rotor blade in the longitudinal direction of the blade, at least one support for the reference shaft, for freely bearing the reference shaft in the rotor blade, so that the rotor blade can twist freely about the reference shaft, so that the reference shaft does not twist when there is twisting of the rotor blade, at least one rotary sensor, arranged on the reference shaft, for detecting a twisting of the rotor blade about the reference shaft in the region of the rotary sensor, the rotary sensor outputting a rotational angle describing the twisting of the rotor blade in relation to the reference shaft, or some other corresponding variable. A method for determining a torsion of a rotor blade, a corresponding rotor blade, a method for arranging a measuring system in a rotor blade and a corresponding wind power installation with a rotor blade and also or alternatively a measuring system.

Claims

1. A measuring system configured to determine a torsion of a rotor blade, the measuring system comprising: a reference shaft configured to be arranged in the rotor blade in a longitudinal direction of the blade; at least one support for the reference shaft, the at least one support being configured to hold the reference shaft in the rotor blade so that the rotor blade is free to twist about the reference shaft and the reference shaft does not twist when the rotor blade twists; at least one rotary sensor arranged on the reference shaft, the at least one rotary sensor being configured to detect a twisting of the rotor blade about the reference shaft in a region of the at least one rotary sensor, the at least one rotary sensor being configured to output a signal indicative of a rotational angle describing twisting of the rotor blade in relation to the rotor shaft.

2. The measuring system as claimed in claim 1, wherein the reference shaft is a hollow shaft.

3. The measuring system as claimed in claim 1, further comprising supporting means configured to arrange the reference shaft along a leading edge web of the rotor blade.

4. The measuring system as claimed in claim 1, further comprising a rotationally fixed shaft seat configured to fasten one end of the reference shaft in a rotationally fixed manner in a region of a rotor blade tip.

5. The measuring system as claimed in claim 1, wherein the reference shaft is made of an electrically non-conductive material.

6. The measuring system as claimed in claim 1, wherein the reference shaft is produced from a composite fiber material.

7. The measuring system as claimed in claim 1, wherein the reference shaft is arranged in an axially displaceable manner.

8. The measuring system as claimed in claim 1, wherein the rotary sensor has a marker element, configured to be coupled to the reference shaft, and a pickup configured to be coupled to the leading edge web of the rotor blade the pickup being configured to detect a twisting of the marker element in relation to the pickup to detect a twisting of the rotor blade in relation to the reference shaft at this location.

9. The measuring system as claimed in claim 1, wherein a number of rotary sensors for detecting a twisting of the rotor blade are arranged at a number of positions along the reference shaft.

10. The measuring system as claimed in claim 8, wherein the at least one rotary sensor is a plurality of rotary sensors, each of the plurality of rotor sensors being configured to hold the reference shaft along the longitudinal direction of the blade.

11. The measuring system as claimed in claim 3, wherein the supporting means are configured to be adhesively attached or clamped on the leading edge web.

12. The measuring system as claimed in claim 1, wherein the at least one rotary sensor is an optical rotary sensor.

13. The measuring system as claimed in claim 1, wherein the reference shaft comprises a plurality of shaft segments.

14. A method comprising: detecting a torsion of a rotor blade about a reference shaft, wherein the reference shaft is arranged in the rotor blade in a longitudinal direction of the blade, wherein the reference shaft is supported in the rotor blade in such a way that the rotor blade can twist freely about the reference shaft and the reference shaft does not twist when the rotor blade twists, detecting a twisting of the rotor blade by at least one rotary sensor arranged on the reference shaft, and outputting a signal indicative of a rotary angle describing the twisting of the rotor blade in relation to the reference shaft.

15. (canceled)

16. The method as claimed in claim 14, wherein detecting the twisting of the rotor blade by at least one rotary sensor the rotary comprises detecting a twisting of the rotor blade by a plurality of rotary sensors arranged at a plurality of positions distributed in the longitudinal direction of the blade.

17. The method as claimed in claim 14, wherein detecting the twisting of the rotor blade comprises detecting the twisting of the rotor blade continuously over time.

18. A rotor blade of a wind power installation the rotor blade comprising: a rotor blade root configured to fasten the rotor blade to a rotor hub; a rotor blade tip arranged on a side of the rotor blade that is facing away from the rotor blade root; a reference shaft arranged in the rotor blade in a longitudinal direction of the blade; at least one support for the reference shaft, configured to couple the reference shaft in the rotor blade so that the rotor blade freely twists about the reference shaft and so that the reference shaft does not twist as the rotor blade twists; and at least one rotary sensor arranged on the reference shaft, the at least one rotary sensor being configured to detect a twisting of the rotor blade about the reference shaft in a region of the at least one rotary sensor, the at least one rotary sensor being configured to output a signal indicative of a rotational angle describing the twisting of the rotor blade in relation to the reference shaft.

19. The rotor blade as claimed in claim 18, comprising a leading edge web extending from the rotor blade root to the rotor blade tip, wherein the reference shaft and at least a portion of the at least one rotary sensor are arranged on the leading edge web.

20. (canceled)

21. The rotor blade as claimed in claim 18, wherein the rotor blade tip has a shaft seat for bearing the reference shaft in a rotationally fixed manner.

22. The rotor blade as claimed in claim 18, wherein the reference shaft is clamped in a structural element of the rotor blade in a rotationally rigid manner.

23. The rotor blade as claimed in claim 18, wherein the rotor blade root has a shaft seat for holding the reference shaft in a rotationally fixed manner.

24. A method for mounting a measuring system as claimed in claim 3 in a rotor blade of a wind power installation, the method comprising: fastening a fitting piece in a rotationally rigid manner on a blade tip portion of the reference shaft; pushing the reference shaft with the fitting piece out in front into an installation space of a blade tip of the rotor blade, along a leading edge web; pushing the supporting means onto the reference shaft and fastening the supporting means along the leading edge web; arranging the at least one rotary sensor in a region of the reference shaft in the rotor blade.

25. The method as claimed in claim 24, wherein: first set of the supporting means are fastened in a region that cannot be reached by a person in a vicinity of the blade tip by securely clamping in the leading edge web, and second set of the supporting means are adhesively attached in a region that can be reached by a person on the structural element or the leading edge web.

26. A method comprising: for maintaining or repairing a measuring system arranged in a rotor blade, wherein the measuring system is configured to determine a torsion of the rotor blade, wherein the measuring system comprises: a reference shaft arranged in the rotor blade in the longitudinal direction of the blade, at least one support for the reference shaft for freely bearing the reference shaft in the rotor blade, so that the rotor blade can twist freely about the reference shaft and so that the reference shaft does not twist when the rotor blade twists, and at least one rotary sensor arranged on the reference shaft and for detecting a twisting of the rotor blade about the reference shaft in the region of the rotary sensor, the rotary sensor outputting a rotational angle describing the twisting of the rotor blade in relation to the rotor shaft, wherein maintaining or repairing comprises: removing at least a portion of the reference shaft from the at least one of the supports support, removing at least one of: the at least one support or the at least one rotary sensor, inspecting at least one of: the at least one support or the at least one sensor, and refitting at least one of: the at least one support, the at least one rotary sensor, or the portion of the reference shaft.

27. (canceled)

28. (canceled)

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0054] The invention is described by way of example below on the basis of embodiments with reference to the accompanying figures.

[0055] FIG. 1 perspectively shows a wind power installation in a schematic representation.

[0056] FIG. 2 shows a schematic representation of an embodiment of a measuring system according to the invention.

[0057] FIG. 3 schematically shows a supporting means given by way of example.

[0058] FIG. 4 schematically shows a supporting means arranged in a rotor blade.

[0059] FIG. 5 shows a leading edge web in a perspective representation.

[0060] FIG. 6 shows an enlarged detail of a leading edge web from FIG. 5.

[0061] FIG. 7 shows a further embodiment of a bearing means.

DETAILED DESCRIPTION

[0062] FIG. 1 shows a wind power installation 100 according to the invention with a tower 102 and a nacelle 104. Arranged on the nacelle 104 is a rotor 106 with three rotor blades 108 according to the invention and a spinner 110. During operation, the rotor 106 is set in a rotary motion by the wind, and thereby drives a generator in the nacelle 104. During the rotation, the rotor blades 108 may twist. For detecting and determining the torsion of the rotor blades 108, a measuring system is mounted in the rotor blades 108.

[0063] In FIG. 2, the components of the measuring system 10 are schematically represented. The measuring system 10 comprises a reference shaft 12. The reference shaft 12 is arranged in a rotor blade, on a leading edge web 13. The reference shaft 12 is preferably formed as a hollow shaft, so that a low weight is achieved, with at the same time a great stiffness of the reference shaft 12. The reference shaft 12 has an outer diameter of approximately 25 millimeters and an inner diameter of approximately 21 millimeters.

[0064] For a better overview, only three schematic profile sections 14, 15, 16 of the rotor blade are shown, the profile section 14 schematically representing a profile section in the region of a rotor blade root, the profile section 15 schematically representing a profile section in a region of the middle of the rotor blade and the profile section 16 schematically representing a profile section in a region of the rotor blade tip. For the sake of better overall clarity, particularly the profile 16, which is intended to represent such a profile in the vicinity of the blade tip, is shown enlarged. Also respectively indicated in the profile sections 14, 15, 16 by a dashed line is a profile chord, in order to represent a twisting of the profile section 16 with respect to the profile section 15 and the profile section 14. The profile section 15 is also twisted with respect to the profile section 14. The rotor blade is consequently twisted.

[0065] At one end, the reference shaft 12 is clamped in a shaft seat 18 in a rotationally fixed manner. The shaft seat 18 prevents a rotational movement of the reference shaft 12 about its longitudinal axis. In the exemplary embodiment shown, the reference shaft 12 is clamped in the region of the rotor blade root in a rotationally fixed manner. Provided along the reference shaft 12 are further bearings, which fasten the reference shaft 12 on the leading edge web 13. The further bearings are formed by supporting means 22 (see FIG. 3), which guide the reference shaft 12 but do not secure it in a rotationally rigid manner. Consequently, the rotor blade can twist about the reference shaft 12, without the reference shaft 12 twisting when there is twisting of the rotor blade.

[0066] Arranged along the reference shaft 12 are a number of rotary sensors 20. The rotary sensors 20 are merely represented schematically. The rotary sensors 20 may be fastened with a marker element on the reference shaft 12 and with a pickup on the leading edge web 13.

[0067] FIG. 2 also illustrates that the profile sections 14, 15, 16 are twisted to different degrees. With a number of rotary sensors 20 arranged along the reference shaft 12, consequently regions of the rotor blade with torsion angles of different magnitudes can also be determined.

[0068] FIG. 3 shows a schematic view of a supporting means 22 or a support. Such a supporting means 22 serves for arranging, guiding and bearing the reference shaft 22 on the leading edge web 13 or some other structural element of the rotor blade. The supporting means 22 are formed substantially as a tube. An inner diameter 24 of a preferred supporting means 22 is approximately 30 millimeters, and is consequently approximately 5 millimeters greater than the outer diameter of the preferred reference shaft 12. As a result, a free rotation of the rotor blade about the reference shaft 12 is possible with little to no friction. An outer diameter 26 of a preferred supporting means 22 is approximately 35 millimeters. A length 28 of a preferred supporting means 22 is approximately 250 millimeters.

[0069] FIG. 4 shows a supporting means 22, which is arranged on a leading edge web 13. The leading edge web 13 has an upper flange 30 and a lower flange 32. The supporting means 22 is clamped between the upper flange 30 and the lower flange 32 in order to arrange the reference shaft 12 on the leading edge web 13. To prevent a great flexural deflection of the reference shaft 12, supporting means 22 are provided approximately at a spacing of 2000 to 2500 millimeters along the leading edge web 13 for bearing the reference shaft 12.

[0070] FIG. 5 shows a leading edge web 13 in a perspective representation from a blade root region 51 to a blade tip region 52. An upper flange 30 and a lower flange 32 particularly form only toward the blade tip region 52.

[0071] FIG. 6 shows an enlarged detail of the blade tip region 52 of the leading edge web 13 from FIG. 5. It can be seen there that a fitting piece 60 is clamped between the upper and lower flanges 30, 32 and receives the reference shaft 12 in a rotationally rigid manner. To this extent, this represents a different embodiment in comparison with FIG. 2. The fitting piece 60 therefore forms a shaft seat for the reference shaft 12. The fitting piece 60 is quite similar in its construction to the supporting means 22 from FIG. 4, the reference shaft 12 not reaching through the fitting piece 60 and being received in a rotationally rigid manner.

[0072] FIG. 7 shows a further embodiment of a supporting means 22. In this case, additionally arranged on the reference shaft 12 are clamping parts 70, which can absorb tensile and shearing forces of the reference shaft 12, which is formed as a hollow shaft. The clamping parts 70 are intended to prevent the reference shaft 12 from slipping out. The clamping parts should as far as possible be installed in such a way that contact of the clamping parts 70 with the support is avoided. In order in the event that contact does in fact occur to keep the friction as little as possible, it is proposed to provide a ball-bearing support between the clamping part 70 and the supporting means 22, in order in this way to avoid a torsion of the reference shaft.

[0073] Otherwise, for simplicity, the same reference signs may be used for the embodiments shown for elements that are similar but not necessarily identical.

[0074] For mounting the measuring system 10, the reference shaft 12 is pushed in the direction of the blade tip on the leading edge web 13. For this, the reference shaft 12 is preferably formed by a number of segments, which are individually connected to one another one after the other. At the end of the reference shaft 12 that is arranged in the region of the blade tip, the fitting piece 60 is fixedly mounted. The fastening element 22 is pushed in along the leading edge web until it is clamped between the upper flange 30 and the lower flange 32. The fastening element 22 is therefore fastened on the leading edge web 13 in an interlocking and frictionally engaging manner. In the case of this embodiment, the reference shaft 12 is therefore mounted in the region of the blade tip in a rotationally fixed manner.

[0075] Alternatively, it is however provided that, with a rotationally fixed support for the reference shaft 12 in the blade root, the fitting piece 60 only provides a final supporting of the reference shaft 12 in the blade tip, but allows a relative turning of the reference shaft. In this case, the fitting piece 60 is formed in such a way that the fitting piece 60 turns about the reference shaft 12 when there is torsion of the rotor blade.

[0076] Once the reference shaft 12 is mounted, the further supporting means 22 for bearing the reference shaft 12 are pushed on one after the other and, with the aid of an auxiliary tube, are brought to the prescribed setpoint position and pushed firmly into place. Clamping of the supporting means 22 takes place in regions of the rotor blade that are not accessible. In accessible regions, the supporting means 22 are adhesively attached. On the last segment of the reference shaft 12, a supporting element 22 as shown in FIG. 7 for absorbing the tensile forces and shearing forces of the reference shaft 12 may be provided or adhesively attached.

[0077] At prescribed positions, a corresponding rotary sensor 20 is respectively provided. It may be sufficient to provide a rotary sensor 20 only at the opposite end of the rotationally fixed support for the reference shaft 12.

[0078] The fixed restraint of the reference shaft 12 at one end of the leading edge web 13 has the effect that the torsion angles that are obtained along the radius of the rotor blade during the operation of the wind power installation are transmitted directly to the rotary sensors 20 along the leading edge web. Such a measuring system is unsusceptible to simultaneous occurrence of torsion and bending of the rotor blade, since exclusively twisting is detected by the rotary sensors 20. Since the supporting means 22 do not clamp the reference shaft in a fixed manner, the measuring system is also unsusceptible to different thermal expansions of the rotor blade and the reference shaft 12. Since the system is permanently integrated in the rotor blade, the torsion angle can be determined at any point in time during the operation of the wind power installation. Consequently, operating states of the installation can be monitored and simulation models that were used for designing the rotor blade and/or the wind power installation can be subsequently checked and thereby improved. As a result, the torsion angle can be used for controlling the operational control of the wind power installation.

[0079] It is also advantageous that, from the knowledge of the torsion angle, an operating state of the wind power installation can be derived, which is proposed according to one embodiment according to the invention. In addition, with the aid of the torsion angle, control of the wind power installation can be optimized with regard to operating loads. The torsion angle may also serve as a reference for the output delivered by the wind power installation and the noise emitted by the rotor blades.