Wind turbine blade, wind turbine and method for operating wind turbine

Abstract

A wind turbine blade (10, 10 ') comprises a shell (11) and a torque transmitting member (20) arranged at least partially within the shell (11). The shell (11) comprises a root portion (12) and defines a longitudinal direction (r11). The torque transmitting member (20) comprises a root section (21) and a longitudinal axis (r20) oriented at least substantially parallel to the longitudinal direction (r11). The root section (21) of the torque transmitting member (20) is rotatable about a longitudinal axis (r20) relative to the root portion (12) of the housing (11). The torque transmission part (20) is mechanically connected to the housing (11) via a coupling (26) for providing a torsional moment ([delta] T1-[delta] T3) on the housing (11).

Description

Technical Field

[0001] The present subject matter relates generally to wind turbine blades, and more particularly to torsionally loadable wind turbine blades, wind turbines having one or more wind turbine blades, and related methods for operating wind turbines. Background Art

[0002] Wind power is considered one of the cleanest and most environmentally friendly energy sources currently available, and for this reason, wind turbines have received increasing attention. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor with one or more rotor blades. The rotor blades obtain kinetic energy from the wind using the known airfoil principle, and the kinetic energy is transferred by rotational energy to rotate a shaft, which connects the rotor blades to a gearbox, or directly to a generator if a gearbox is not used. The generator then converts the mechanical energy into electrical energy that can be deployed to the utility grid.

[0003] Rotor blade twist typically results in a non-optimal angle of attack within the operating wind speed range. As the speed of the rotor blade relative to the wind increases toward the rotor blade tip, the shape of the rotor blade is typically twisted to maintain a substantially consistent angle of attack at most points along the span of the blade.

[0004] However, a fixed twist angle can only be optimized for a set of operating parameters of the wind turbine. Furthermore, the possible means known to date for influencing the twisting of the rotor blades during operation are not flexible enough, too complex, too maintenance intensive and / or too expensive.

[0005] Hence, the present disclosure provides a wind turbine blade according to claim 1 , a method for operating a wind turbine according to claim 7 , and a wind turbine according to claim 11 . Summary of the invention

[0006] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0007] In one aspect, the present disclosure relates to a wind turbine blade comprising a shell and a torque transfer component at least partially arranged inside the shell. The shell comprises a root portion and defines a longitudinal direction. The torque transfer component comprises a root section and a longitudinal axis oriented at least substantially parallel to the longitudinal direction. The root section of the torque transfer component is rotatable about the longitudinal axis relative to the root portion of the shell. The torque transfer component is mechanically connected to the shell via a coupling for providing a torsional moment on the shell.

[0008] Therefore, a torsional moment may be provided on the shell according to the rotation angle of the root section of the torque transmission member about the longitudinal axis and / or the coupling state between the torque transmission member and the coupling.

[0009] This allows to influence the twisting of the rotor blades in a relatively simple, low maintenance and flexible manner during operation of the wind turbine, and at relatively low additional cost. Furthermore, the benefits due to the annual energy production (AEP) that can be achieved by optimizing the angle of attack of the wind turbine blade(s) over a wide range of operating conditions and wind speeds typically far outweigh the additional costs.

[0010] For example, for a 1.5 MW wind turbine under typical average conditions, the value of the AEP increase may be at least about twice the additional cost of correspondingly equipping the wind turbine.

[0011] Furthermore, the load acting on the wind turbine, and thus the maintenance effort and / or costs, may be reduced.

[0012] In particular, the load on the pitch bearing may be reduced by making a trade-off between the pitch activity through the rolling bearing and the structural deflection.

[0013] Furthermore, by appropriately twisting back the wind turbine blade(s), the sensitivity of the wind turbine blade(s) to gusts at high wind speeds may be reduced.

[0014] Furthermore, leading edge erosion during rain and hail can be reduced by adjusting the angle of attack to be as optimal as possible, or at least close to optimal, for those conditions.

[0015] As a result, the additional costs can be amortized quickly.

[0016] Furthermore, the safety of the wind turbine may be improved.

[0017] In particular, partial or full shutdown of a wind turbine may be facilitated by combining pitching and changing the twist state of the wind turbine blade(s), for example in response to a fault in a grid to which the wind turbine is connected for delivering electrical power.

[0018] Still further, by applying a suitable torque to appropriately change the twisting state of the wind turbine blade(s) during operation, the noise generated by the wind turbine may be reduced.

[0019] Note that reducing noise may be particularly important to reduce possible impacts on the environment and to increase the acceptance of wind turbines, respectively.

[0020] Furthermore, the torsional stiffness of the rotor blade may be adjusted during its service life.

[0021] As used herein, the term "torsional torque" is intended to encompass the term "twisting torque".

[0022] The expression "the longitudinal axis of the torque transmission member is oriented at least essentially parallel to the longitudinal direction of the (blade) shell" is intended to describe that if the angular deviation is determined for the root section and the root part and / or if the rotor blade is not exposed to wind at a speed causing shell bending, the angular deviation is below a few degrees, in particular below 2° or even 1°.

[0023] The root section of the torque transmitting member is typically arranged at least partially within the root portion of the shell and / or at least substantially coaxially with respect to the root portion of the shell.

[0024] However, the root section of the torque transmitting member may also be arranged in a middle section of the wind turbine blade and between the root part of the shell and the tip part of the shell, respectively, or even (partially or completely) outside the blade root, for example in the hub of a wind turbine rotor.

[0025] The term "torque transfer member" as used herein is intended to describe a typically substantially mechanically rigid elongated mechanical element or body for transferring a torque (to one or more couplings) that depends on the twisting of the torque transfer member relative to its longitudinal axis (the rotation angle of the root segment relative to the tip segment and the rotor blade, respectively). The transferred torque may be large enough to significantly change the torsional state of the shell of the rotor blade, i.e., up to at least one degree, more typically up to at least 5° or even up to at least 10°, when measured from the root (section) to the tip (section).

[0026] Typically, the torque transmitting member has a cylindrical outer surface.

[0027] The torque transmission component can in particular comprise a cylindrical shell and / or be embodied as a tube, such as a tube with a circular cross section.

[0028] Furthermore, the torque transmission component may comprise or even consist of fiber-reinforced plastic.

[0029] The torque transmission member is typically mechanically connected to the shell via several couplings at different locations spaced apart from each other in the longitudinal direction.

[0030] This allows for greater freedom and / or flexibility in applying torsional moments on the shell according to the span and the ordinate relative to the longitudinal direction (hereinafter also referred to as spanwise direction) and / or depending on the operating conditions of the wind turbine.

[0031] In other words, the torque transmission component can be mechanically connected to the shell via at least one coupling element in order to provide a corresponding torsional moment on the shell.

[0032] The coupling and / or the coupling state may even be controllable.

[0033] The coupled state may include a non-engaged state and / or a fully engaged state.

[0034] Furthermore, the coupled state may include a partially engaged state.

[0035] Furthermore, the stiffness of the coupling may depend on the torsional moment provided.

[0036] Furthermore, the mechanical properties of at least two of the couplings may be different.

[0037] Furthermore, the mechanical properties of the respective coupling may depend on the sign of the rotation angle and / or the value of the rotation angle.

[0038] Furthermore, the respective coupling may have at least one of the following, in particular with respect to the movement of the respective connecting portion of the torque transmission component about the longitudinal axis: gap; Linear stiffness; Increasing stiffness; and Decreasing stiffness.

[0039] According to an embodiment, the rotor blade may comprise (at least one) torque meter for measuring a torque value typically dependent on the provided torsional moment, in particular for measuring a torque value representative for a (total) torque acting at the torque transmitting component.

[0040] This may facilitate controlling the twist state of the wind turbine blade.

[0041] For example, the (at least one) torque meter may be attached to and / or provided by the coupling.

[0042] The torque meter may even be provided by an actuator connected to the root section. For example, the current of an electric motor used to rotate the root section of the torque transmitting component about the longitudinal axis may be used as a measure of the total torque.

[0043] The current of the motor can even be (pre)determined (measured) as a function of the rotation angle of the root section. This curve can then be used for control during normal operation and / or for detecting the neutral angle at any rotor position and operating point, respectively.

[0044] Furthermore, a corresponding coupling may be arranged between the load-bearing structure of the wind turbine blade and the torque transmission component.

[0045] The load-bearing structure may include a spar of the rotor blade, which typically serves as the primary load-bearing structure of the rotor blade.

[0046] However, the load-bearing structure may also comprise several substructures.

[0047] Furthermore, even the shell which typically defines the airfoil of the rotor blade may be considered to be part of the load-bearing structure.

[0048] In one aspect, the present disclosure is directed to a wind turbine comprising a wind turbine blade as explained herein, for example three respective wind turbine blades.

[0049] Wind turbines typically include an actuator, such as an electric motor, for moving a torque transmitting component relative to the shell of the rotor blade.

[0050] In particular, the actuator may comprise and / or be provided by an (electric) motor or an electric motor and a brake.

[0051] The brake may be particularly configured / used to (at least substantially) fix the root section of the torque transmission component relative to the root part of the housing (position and / or orientation) in a respectively desired arrangement, in particular a respectively desired rotation angle of the root section of the torque transmission component relative to the longitudinal axis. Thus, the electric machine can be started only in the event of a change in the desired arrangement.

[0052] More typically, a wind turbine typically includes a respective actuator for each of its rotor blades.

[0053] For this purpose, the actuator is typically connected to the root section via a gearbox and is configured to rotate the root section of the torque transmitting component about the longitudinal axis.

[0054] The gearbox may comprise or even be provided by a worm gear.

[0055] Alternatively or additionally, the actuator may be configured to move the root segment translationally relative to the shell of the rotor blade in the longitudinal direction.

[0056] By moving the root section and thus the entire torque transmission component in translation relative to the shell in the longitudinal direction, the coupling state of the coupling(s) can be changed.

[0057] Furthermore, the actuators may each be configured to measure the total torque and to provide a measure of the total torque, such as motor current.

[0058] The actuator(s) are typically connected to a controller of the wind turbine, which is configured to control the actuator.

[0059] The controller of the wind turbine may be configured to use the measured torque (representative value) for controlling the actuators, in particular such that the twisting state of the rotor blades is influenced / changed to a desired state for given operating condition(s) of the wind turbine.

[0060] The control of the wind turbine may be provided by the wind turbine controller, by a separate controller, by the pitch controllers of the respective rotor blades (integrated into the pitch controller) or any combination thereof.

[0061] In other words, the controller may be provided by a control system for the wind turbine or by a control system of the wind turbine, which control system may comprise one or more controllers.

[0062] Typically, the controller(s) of a wind turbine are configured to operate the wind turbine according to any of the methods explained herein.

[0063] In one aspect, the present disclosure is directed to a method for operating a wind turbine. The wind turbine comprises a rotor comprising a rotor blade having a shell defining a longitudinal direction, and a torque component mechanically connected to the shell via a coupling to provide a torsional moment on the shell, in particular a rotor blade as explained herein, and an actuator mechanically connected to the torque component. The method comprises determining a current torsional state of the shell during (normal) operation of the wind turbine, determining a desired torsional state of the shell, and using at least one of the actuator and the coupling to change the torsional moment on the shell such that a difference between the current torsional state of the shell and the desired torsional state of the shell is expected to be at least reduced.

[0064] The current torsional state and the desired torsional state of the shell are typically determined based on one or more current operating parameters of the wind turbine, in particular current wind conditions.

[0065] Determining the current torsional state of the shell may include measuring, calculating, simulating and / or using a lookup table, in particular a lookup table with predetermined values, which allows determining a desired rotation angle of the root section of the torque transmitting component to achieve a corresponding desired torsional state of the shell for (one or more) given current operating parameters and / or optimization criteria of the wind turbine.

[0066] The desired twisting state of the shell and the varying torque on the shell may be determined based on rotor position, wind speed, horizontal misalignment between the rotor axis of the rotor and wind direction (such as updraft), yaw misalignment, wind shear and turning, respectively.

[0067] The torsional state of the shell may be varied to counteract instabilities of the wind turbine blade, such as vortex instabilities, particularly low frequency vortex instabilities (e.g., about 0.5 Hz), to adjust the angle of attack distribution over the length of the wind turbine blade, to assist in pitching the wind turbine blade, to reduce noise, and / or to align the aerodynamic and / or mechanical properties of the wind turbine blade with another wind turbine blade of the wind turbine.

[0068] Note that (actively) counteracting (whirl) instabilities of wind turbine blades can significantly reduce loads and wear, respectively. Thus, maintenance can be reduced and / or the lifetime of components can be extended.

[0069] The method may include one or more of the following processes: Determine the current torsion state of the shell based on the ordinate; Select parameters for the rotor blades, especially the angle of attack; determining the current functional dependencies of the selection parameters in the longitudinal direction; and Select the optimization criteria.

[0070] The selection of the optimization criterion typically depends on current (actual) operating parameters of the wind turbine and / or current wind conditions, in particular wind speed.

[0071] The optimization criteria may depend on and / or be selected from noise, load, power generation, stability and any combination thereof.

[0072] For example, optimization may be performed with respect to noise and power generation at low wind speeds, with respect to noise and load at medium wind speeds, and / or with respect to noise and stability at high wind speeds.

[0073] Additionally, the method may include one or more of the following processes: determining, based on the selected optimization criterion, an expected functional dependency of the selected at least one parameter in the longitudinal direction; determining a deviation between a current functional dependency and an expected functional dependency of at least one selected parameter in a longitudinal direction; determining the desired distortion of the shell; and Determine the desired torque to be applied to the shell in order to at least reduce the deflection.

[0074] Thereafter, the torque transfer component and coupling(s) may be used to apply a desired torque on the shell.

[0075] The method may be repeated several times, for example in a cyclic manner.

[0076] In yet another aspect, the present disclosure is directed to a computer program product or a non-transitory computer-readable storage medium comprising instructions which, when executed by one or more processors of a system, in particular a controller or control system of a wind turbine as explained herein, cause the system to perform the method as explained herein.

[0077] As used herein, the term "processor" refers not only to integrated circuits as referred to in the art included in a computer, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuits. The processor may also be configured to calculate advanced control algorithms and communicate with various Ethernet or serial-based protocols (Modbus, OPC, CAN, etc.). In addition, the processor may access (one or more) memory devices, which may generally include (one or more) memory elements, including but not limited to computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disk read-only memories (CD-ROMs), magneto-optical disks (MODs), digital versatile disks (DVDs), and / or other suitable memory elements. Such (one or more) memory devices may generally be configured to store suitable computer-readable instructions, which, when implemented by (one or more) processors, configure the controller to perform various functions as described herein.

[0078] These and other features, aspects and advantages of the present invention will be further supported and described with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and together with the description serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] A complete and enabling disclosure of the invention including the best mode thereof to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0080] Figure 1 shows a perspective view of a wind turbine according to an embodiment of the present disclosure;

[0081] Figure 2A shows a schematic side view of an embodiment of a wind turbine rotor blade according to the present disclosure;

[0082] Figure 2B shows a schematic cross-sectional view of an embodiment of a wind turbine rotor blade according to the present disclosure;

[0083] Figure 2C shows a schematic side view of an embodiment of a wind turbine rotor blade and a wind turbine according to the present disclosure, and a plot of torque versus span of a wind turbine rotor blade;

[0084] Figure 3A A flowchart showing a method according to an embodiment of the present disclosure; and

[0085] Figure 3B A flow chart of a method according to an embodiment of the present disclosure is shown.

[0086] Individual features depicted in the figures are shown relative to each other and are therefore not necessarily to scale. Similar or identical elements in the figures are denoted by the same reference numerals even if they are shown in different embodiments. DETAILED DESCRIPTION

[0087] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided in a manner to explain the present invention, which should not limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention, for example, the features illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0088] Figure 1 1 is a perspective view of a portion of an exemplary wind turbine 100. In the exemplary embodiment, wind turbine 100 is a horizontal-axis wind turbine. Alternatively, wind turbine 100 may be a vertical-axis wind turbine. Wind turbine 100 includes a housing for a generator ( Figure 1 The nacelle 102 is mounted on a tower 104 ( Figure 1 104 is a wind turbine 100 having a plurality of rotor blades 108 attached to a rotating hub 110. The wind turbine 100 also includes a rotor 106 including three wind turbine blades 108 attached to a rotating hub 110. The wind turbine blades are also referred to as wind turbine rotor blades and are simply referred to as rotor blades hereinafter. Alternatively, the wind turbine 100 includes any number of blades 108 that facilitates the operation of the wind turbine 100 as described herein. In the exemplary embodiment, the wind turbine 100 includes a gearbox ( Figure 1 not shown) and a generator ( Figure 1 not shown).

[0089] Rotor blades 108 are spaced about hub 110 to facilitate rotation of rotor 106 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy.

[0090] According to an embodiment, each rotor blade 108 includes a respective torque transfer component that is mechanically connected with the outer shell via a coupling for providing a twisting moment on the shell, if desired.

[0091] In one embodiment, rotor blades 108 have a length ranging from about 15 meters (m) to about 91 m. Alternatively, rotor blades 108 may have any suitable length that enables wind turbine 100 to function as described herein. For example, other non-limiting examples of blade lengths include 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or a length greater than 91 m. As wind strikes rotor blades 100 from wind direction 28, rotor 106 rotates about axis of rotation 30. As rotor blades 108 rotate and are subjected to centrifugal forces, rotor blades 108 are also subjected to various forces and moments. Thus, rotor blades 108 may deflect and / or rotate from a neutral position or a non-deflected position to a deflected position.

[0092] Furthermore, the pitch angle of rotor blades 108 (i.e., the angle that determines the projection of rotor blades 108 relative to the wind direction) may be varied by pitch system 109 to control loads and the power generated by wind turbine 100 by adjusting the angular position of at least one rotor blade 108 relative to the wind vector. During operation of wind turbine 100, pitch system 109 may vary the pitch angle of rotor blades 108 such that rotor blades 108 are moved to a feathered position such that the projection of at least one rotor blade 108 relative to the wind vector provides a minimum surface area of ​​rotor blade 108 oriented toward the wind vector, which facilitates reducing the rotational speed and / or facilitating stalling of rotor 106.

[0093] The blade pitch of each rotor blade 108 may be individually controlled by wind turbine controller 202 or a pitch control system. Alternatively, the blade pitch of all rotor blades 108 may be controlled simultaneously by the control system.

[0094] Moreover, in the exemplary embodiment, as wind direction 28 changes, the yaw direction of nacelle 102 may be rotated about yaw axis 38 via yaw system 105 to position rotor 106 relative to wind direction 28 .

[0095] The yaw system 105 may include a yaw drive mechanism provided by the nacelle 102 .

[0096] Furthermore, yaw system 105 may also be controlled by wind turbine controller 202 .

[0097] In order to properly position the nacelle 102 with respect to the wind direction 28 and detect the wind speed, the nacelle 102 may also include at least one meteorological mast 107, which may include a wind vane and anemometer. The mast 107 may provide information about environmental conditions to the wind turbine controller 202. This may include wind direction and / or wind speed as well as ambient temperature, ambient humidity, precipitation type and / or precipitation amount (if any).

[0098] In the exemplary embodiment, wind turbine controller 202 is shown as being centralized within nacelle 102, however, wind turbine controllers may also be distributed throughout wind turbine 100, in support systems ( Figure 1 The wind turbine controller 202 includes a processor and may be configured to perform the methods and / or steps described herein.

[0099] View now Figure 2A and Figure 2B 1 and 10. The wind turbine blade 10 may be used as described above with reference to FIG. Figure 1 A rotor blade 108 of a wind turbine 100 is illustrated.

[0100] The exemplary wind turbine blade 10 has a shell 11 defining an airfoil.

[0101] The wind turbine blade 10 is axially spaced along the longitudinal direction r 11 The base portion 12 extends from the tip portion 14 and extends in the direction r 11 The wing has a span width L. The root portion 12 and the tip portion 14 are connected to each other via a middle portion 13 of the shell 11 .

[0102] An exemplary tubular torque transmission member 20 (eg, a fiber reinforced plastic tube) is arranged inside the shell 11 such that its longitudinal axis r 20 At least substantially in the longitudinal direction r 11 Coaxial.

[0103] The tubular torque transmission member 20 is respectively 20 and the longitudinal direction r 11 The longitudinal extension on may be approximately the span width L of the rotor blade 10 and thus be greater than 10 m or even 50 m.

[0104] Typically, the longitudinal extension of the tubular torque transfer member 20 is less than the span width L, for example in the range from about 30% to about 99%, more typically in the range from about 60% to about 80%, but may also be greater than the span width L if the torque transfer member 20 protrudes beyond the root portion 12.

[0105] The root section 21 of the torque transmission member 20 is rotatable relative to the root portion 12 of the shell 11 about the longitudinal axis r20 .

[0106] In the exemplary embodiment, torque transfer component 20 is mechanically coupled to tip portion 14 of shell 11 via coupling 26 to provide a twisting moment (for significantly affecting twisting of wind turbine blade 10 during wind turbine operation).

[0107] like Figure 2A As shown in FIG. 1 , this can be achieved by adjusting the root section 21 of the torque transmission member 20 about the longitudinal axis r 20 This can be achieved by a rotation angle φ.

[0108] Thus, the twisted state of the rotor blade 10 may be varied as desired according to current operating conditions of the wind turbine in which the one or more rotor blades 10 are provided.

[0109] For example, the tip portion 14 may be twisted to shed the wind, for example, at higher wind speeds, to reduce noise without reducing energy capture too much.

[0110] like Figure 2B As shown in , the coupling 26 may be arranged between the torque transfer component 20 and the primary load-bearing structure of the wind turbine blade 10 . In an exemplary embodiment, the primary load-bearing structure is implemented as a spar 50 attached to the shell 11 .

[0111] Note that the rotor blade 10 is typically manufactured by securing various "shell" and / or "rib" portions to one or more "spar" components that extend in the spanwise direction along the inside of the blade to carry the majority of the weight and aerodynamic forces on the blade. The spar is typically constructed as an I-shaped beam having a web (called a "shear web") that extends between two flanges (called "caps" or "spar caps") that are secured to the inside of the suction and pressure surfaces of the blade. However, other spar configurations may be used, including but not limited to "C-shaped," "D-shaped," "L-shaped," "T-shaped," "X-shaped," "K-shaped," and / or box beams, such as Figure 2B As shown in . The shear web can also be used without a cap.

[0112] "Angle of attack" is a term used to describe the angle α between the chord line 15 of the blade 10 and the vector 28' representing the relative motion between the blade and the air. "Pitch" refers to the angle of attack along the spanwise axis and the longitudinal direction r 11 The angle of attack of the entire blade 10 is rotated into the wind or away from the wind, respectively, to control the rotational speed and / or the energy absorbed from the wind. For example, pitching the blade "towards feathering" will rotate the leading edge of the blade 10 into the wind, while pitching the blade "towards stalling" will rotate the leading edge of the blade away from the wind.

[0113] Since the speed of the blade 10 relative to the air is in the longitudinal direction r of the rotating blade 11 As the span increases, torque transfer members 20 and couplings 26 are typically used to distort the shape of the blade in order to maintain a desired angle of attack at several or even most points along the span of the blade.

[0114] Figure 2CIn the upper part a rotor blade 10 ′ and a wind turbine 100 ′ according to the present disclosure are shown, and in the lower part a rotor blade 10 ′ and a wind turbine 100 ′ according to the longitudinal axis r of the rotor blade 10 ′ are shown. 20 Corresponding exemplary graph of torque T measured in the ordinate (span) r in the direction.

[0115] Wind turbine 100' is typically similar to that described above with reference to Figure 1 Likewise, the rotor blade 10' is typically similar to that described above with reference to Figure 2A , 2B A rotor blade 10 is illustrated.

[0116] However, in Figure 2C In the exemplary embodiment of FIG. 1 , the actuator 40 provided by the wind turbine 100 ′ is mechanically connected to the root section 21 of the torque transfer component 20 of the rotor blade 10 ′.

[0117] For example, the actuator 40 may be provided by a hub of the wind turbine 100 ′ to which the rotor blades 10 ′ are connected.

[0118] Alternatively, the actuator 40 may be arranged completely inside the rotor blade 10', for example in the root section 21 or even in the middle section 13. In these embodiments, the actuator 40 may be attached to the main load-bearing structure of the wind turbine blade. Furthermore, the longitudinal extension of the torque transmission component 20 may be correspondingly smaller.

[0119] Furthermore, the torque transmission member 20 is 11 The blade shell 11 is mechanically connected to the blade shell 11 via three coupling pieces 26a-26c at corresponding positions spaced apart from each other.

[0120] The actuator 40 is typically firmly connected to the root section 21 of the torque transmitting member 20 and can be used to adjust the root section 21 about the longitudinal axis r 20 The rotation angle φ.

[0121] Depending on the angle φ and the coupling characteristics (coupling state) of the coupling members 26a, 26b, 26c, torsional moments ΔT1, ΔT2, and ΔT3 may be applied to the housing 11 via the coupling members 26a, 26b, 26c.

[0122] Although in the embodiment represented by curve a, the corresponding parts ΔT1, ΔT2 and ΔT3 (T0=ΔT1+ΔT2+ΔT3) of the total torque T0 are applied at three different vertical coordinates r, in the embodiment represented by curve b, the total torque T0 is applied to the tip portion 14 only via the connecting member 26c.

[0123] Thus, the twisting state of the rotor blade 10 ′ may be varied by varying the total torque T 0 (via the angle φ) and by varying the coupling state of one or more of the couplings.

[0124] In one embodiment, the actuator 40 can be used to move the actuator 40 in the longitudinal direction r 11 Moving the torque transfer member 20 (e.g., by Figure 2C The coupling state of one or more of the couplings 26a-c can be controllably changed by retraction and outward push indicated by Δr in the figure.

[0125] For example, only the coupled state of the coupling members 26a, 26b can be changed by using the actuator 40 in the longitudinal direction r 11 The torque transmission member 20 is moved to change (for switching between curves a, b).

[0126] Alternatively, corresponding individual actuators may be used to actively control the coupled state of the respective couplings.

[0127] Since the mechanical coupling characteristics of the coupling are known in advance or even adjustable (for each coupling state), for a given total torque T0 , the torsional moment exerted on the shell 11 is known.

[0128] This information may be used for feedback control of the twist state of the rotor blade 10 ′.

[0129] In particular, the total torque T0 can be determined by the actuator 40 , which in this embodiment also serves as a torque meter.

[0130] More specifically, the drive current of the motor used to rotate the root section 21 of the torque transfer component 20 may be used as a measure of the total torque T0.

[0131] Alternatively or additionally, one or more separate torque meters may be used.

[0132] For example, a corresponding torque meter may be provided by one or more couplings and / or arranged next to a corresponding coupling, e.g. Figure 2B On the lower part and / or upper part of the connecting piece 26 in the.

[0133] In the following, the explained method may be performed by a wind turbine having one or more rotor blades as explained herein and / or controlled by a control system of the wind turbine.

[0134] Figure 3AA flow chart of a method 1000 for operating a wind turbine is shown, the wind turbine having a rotor with one or more rotor blades, each rotor blade comprising a shell extending in a longitudinal direction. The torque component is mechanically connected to the shell via at least one coupling for providing a corresponding torsional moment on the shell. The rotor blade may in particular be as described above with reference to Figure 2A-2C The illustrated rotor blade 10, 10'. The actuator is mechanically connected to the torque (transmitting) component.

[0135] In a first block 1100, the current torsion state of the shell is determined.

[0136] The current twist state may be determined based on one or more current operating parameters of the wind turbine, in particular current wind conditions.

[0137] Determining the current torsional state of the shell may include at least one measurement, such as using a look-up table, calculation and / or simulation, of the wind speed in front of the wind turbine and of the total torque applied to the shell and the torque member, respectively.

[0138] For example, the current torsional state may be determined from a lookup table using the above-mentioned measurements and / or one or more other operating parameters of the wind turbine such as rotor position and horizontal misalignment between the rotor axis of the rotor and the wind direction (such as updrafts), yaw misalignment, shear and / or steering of the wind as input and optionally subsequent interpolation.

[0139] Alternatively, a trained neural network may be used to determine the current torsional state.

[0140] Thereafter, in block 1200, a desired torsional state of the shell is determined. The desired torsional state of the shell may in particular be the current desired torsional state of the shell or the desired torsional state of the shell for the next time window (of the control loop).

[0141] Determining the desired torsional state of the shell may also include at least one measurement using additional lookup tables, additional calculations, additional simulations, and / or additional trained neural networks.

[0142] Furthermore, the desired torsional state is typically determined not only from operating parameters such as rotor position, wind speed and / or horizontal misalignment between the rotor axis and wind direction, but also from one or more optimization criteria such as noise generation, energy production and stability criteria.

[0143] Note that, especially for larger rotors, updrafts, yaw misalignment, shear and turn can result in a high angle of attack induced stall in one region and a low angle of attack stall in another of the rotor blades. As explained herein, this can be avoided by changing the twist state of the wind turbine blade(s).

[0144] Thereafter, in box 1300, actuators and / or (one or more) couplings are used to change (one or more) torsional moments acting on the shell adjacent to the (one or more) couplings ((one or more) connection points) such that the difference between the current torsional state of the shell and the desired torsional state of the shell is expected to at least be reduced, and typically expected to be minimized.

[0145] For this purpose, the actuator may rotate the root section of the torque transmitting component.

[0146] Alternatively or additionally, the coupling state of the coupling(s), ie the state / mechanical properties of the coupling between the torque transmitting component and the coupling, such as stiffness, play or engagement, may be varied.

[0147] Thus, varying the torque moment(s) acting on the shell typically involves determining (and applying) appropriate drive parameter(s) for the actuator and / or linkage(s).

[0148] The driving parameter(s) may be determined, for example, by another look-up table or using another trained neural network.

[0149] It is even conceivable that, upon receiving as input one or more operating parameters and one or more optimization criteria, the drive parameter(s) are determined directly as the output of a single trained neural network which only implicitly determines the current torsional state and the desired torsional state (e.g. in a hidden layer).

[0150] In particular, the torsional state of the shell may be varied to counteract instabilities of the wind turbine blade (such as vortex instabilities), to adjust the angle of attack distribution over the length of the wind turbine blade, to assist in pitching the wind turbine blade, to reduce noise, and / or to align the aerodynamic and / or mechanical properties of a wind turbine blade of the wind turbine with another wind turbine blade.

[0151] like Figure 3A As shown by the dashed arrow in , method 1000 can be executed several times (loops).

[0152] Depending on the optimization criteria, the cycle time of one cycle of method 1000 may vary.

[0153] For example, to counteract forward and / or reverse whirl instabilities, the cycle time may be less than one second, such as about 0.5 s, while optimizing power generation may be performed only once per minute, and so on.

[0154] Figure 3B A flow chart of a method 1001 for operating a wind turbine is shown. The method 1001 is typically similar to the method 1000 explained above with reference to Figure 6A, but in more detail.

[0155] In block 1101 , a current twist state of a shell of a rotor blade is determined from ordinates (space coordinates relative to the longitudinal direction and axis of the shell, respectively).

[0156] In a subsequent block 1111 , parameters may be selected for the rotor blade, in particular the angle of attack α.

[0157] In subsequent block 1121, the selected parameter α may be determined. c (r) Current functional dependencies in the vertical direction.

[0158] In block 1105 , one or more optimization criteria oc may be selected for a rotor blade.

[0159] The selection of the optimization criterion(s) typically depends on one or more current operating parameters {P} of the wind turbine and / or the current wind conditions wc, in particular the wind speed.

[0160] The optimization criteria are typically selected from noise, load, power generation, stability, and any combination thereof.

[0161] For example, the optimization criteria may relate to noise and power generation at low wind speeds, noise and load at medium wind speeds, and noise and stability at high wind speeds.

[0162] Hence, the optimization criterion may be selected depending on the wind speed and the threshold(s) of the wind speed.

[0163] Block 1105 may be executed at the same time t as block 1101 , or may be executed after or before block 1101 .

[0164] As indicated by the dashed arrow, when method 1001 is performed several times, block 1105 may be entered even less frequently than block 1101 .

[0165] In a block 1125 following block 1125, an expected functional dependency α of the selected at least one parameter α in the longitudinal direction may be determined according to the selected optimization criterion oc. d (r).

[0166] In block 1120 , a deviation Δα(r) between a current functional dependency and a desired functional dependency of the selected at least one parameter α is determined.

[0167] Thereafter, a desired torsional moment T(r) to be applied to the shell is determined in order to at least reduce the deviation Δα(r), typically to minimize the deviation Δα(r).

[0168] Thereafter, in block 1301 , the torque acting on the shell may be varied accordingly using actuators and / or linkages.

[0169] The above technique provides various advantages over conventional methods. It allows the rotor blade to be effectively twisted and deformed so that the twisted state of the rotor blade is closer to the corresponding optimal twisted state of the rotor blade depending on one or more operating parameters and one or more optimization criteria. In particular, the desired (optimal) angle of attack over the length of the rotor blade can be achieved under a wider range of (one or more) operating parameters. Therefore, energy capture can be enhanced at a lower additional cost.

[0170] Exemplary embodiments of rotor blades and methods for operating a wind farm are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather, components of the systems and / or steps of the methods may be used independently and separately from other components and / or steps described herein.

[0171] Although specific features of various embodiments of the present invention may be shown in some drawings and not in other drawings, this is only for convenience. According to the principles of the present invention, any feature of the accompanying drawings may be combined with any feature of any other drawing to reference and / or present.

[0172] Embodiments of the present invention have been described above with reference to block diagrams and flowchart illustrations of methods, apparatus (i.e., systems), and computer program products. It will be understood that each block in the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, may be implemented by various means including computer program instructions. These computer program instructions may be loaded onto a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, such that the instructions executed on the computer or other programmable data processing device create means for implementing the functions specified in one or more flowchart blocks.

[0173] These computer program instructions may also be stored in a non-transitory computer-readable memory that can instruct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including computer-readable instructions for implementing the functions specified in one or more flowchart blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flowchart blocks.

[0174] Therefore, the blocks in the block diagrams and flowchart illustrations support combinations of devices for performing specified functions, combinations of steps for performing specified functions, and program instruction devices for performing specified functions. It should also be understood that each block in the block diagrams and flowchart illustrations and combinations of blocks in the block diagrams and flowchart illustrations can be implemented by a computer system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs the specified functions or steps.

[0175] Unless otherwise expressly stated, it is not intended that any method presented herein be interpreted as requiring that its steps be performed in a specific order. Therefore, in the event that a method claim does not actually recite the order in which its steps should be followed, or the claim or specification does not otherwise expressly state that the steps should be limited to a specific order, no order is intended to be inferred in any way. This applies to any possible non-express basis for interpretation, including: logical issues regarding the arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.

[0176] This written description uses examples, including the best mode, to disclose the invention, and also enables any person skilled in the art to practice the invention, including making and using any device or system, and performing any incorporated method. Although various specific embodiments have been disclosed above, those skilled in the art will recognize that the spirit and scope of the claims allow for equally effective modifications. In particular, the mutually non-exclusive features of the above-described embodiments may be combined with each other. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. For example, a control system for a wind farm may be provided by a centralized controller or by a plurality of interconnected controllers. Such other examples are expected to be within the scope of the claims if they have structural elements that are not different from the written language of the claims, or if they include equivalent structural elements that are not substantially different from the written language of the claims. Reference Numbers Rotor Blades 10, 10', 108 Rotor blade shell 11 Root portion of blade shell 12 The middle part of the blade shell 13 The tip portion of the blade shell 14 Torque transmission component 20 Root section 21 Connecting piece 26-26c Rotor axis 30 Spar 50 Actuator 40 Wind turbine 100, 100' Cabin 102 Tower 104 Yaw system 105 Rotor 106 Weather Mast 107 Pitch system 109 Hub 110 Method, method steps 1000-1301

Claims

1. A wind turbine blade (10, 10'), comprising: including a root portion (12) and defining a longitudinal direction (r 11 ) shell (11); as well as a torque transmission member (20) arranged at least partially inside the shell (11) and comprising a root section (21) and a longitudinal direction (r 11 ) oriented parallel to the longitudinal axis (r 20 ), the root section (21) of the torque transmission member (20) is rotatable relative to the root portion (12) of the shell (11) about the longitudinal axis (r 20 ), and the torque transmission component (20) is mechanically connected to the shell (11) via a coupling (26) for providing a torsional moment (ΔT1-ΔT3) on the shell (11).

2. A wind turbine blade (10, 10') according to claim 1, wherein the torsional moment on the shell is dependent on the rotation of the root section (21) of the torque transmission member (20) about the longitudinal axis (r 20 ) and at least one of a rotation angle (φ) of the torque transmission component (20) and a connection state between the torque transmission component (20) and the connection member (26).

3. A wind turbine blade (10, 10') according to any preceding claim, wherein the coupling (26-26c) and / or the coupling state is controllable, and / or wherein the rotor blade (20) comprises a device for measuring a torque value (T v ) of at least one torque meter.

4. A wind turbine blade (10, 10') according to any of the preceding claims, wherein the torque transfer component (20) is mechanically connected to the shell (11) via respective couplings (26-26c) at different positions spaced apart from each other in the longitudinal direction, and / or wherein respective couplings (26-26c) are arranged between a load-bearing structure of the wind turbine blade (10, 10'), the load-bearing structure typically comprising a spar (50) of the wind turbine blade (10, 10'), and the torque transfer component (20).

5. A wind turbine blade (10, 10') according to any of the preceding claims, wherein the mechanical properties of at least two of the couplings (26-26c) are different, wherein the mechanical properties of the respective coupling (26-26c) depend on at least one of: the sign of the rotation angle (φ) and the value of the rotation angle (φ), and / or wherein the respective coupling (26-26c) comprises a respective connection portion around the longitudinal axis (r ), in particular with respect to the torque transmission component (20). 20 ) of the movement of at least one of the following: ·Void; Linear stiffness; Increasing stiffness; and Decreasing stiffness.

6. A wind turbine blade (10, 10') according to any preceding claim, wherein the torque transmission component (20) comprises a cylindrical outer surface, wherein the torque transmission component (20) comprises a cylindrical shell, wherein the torque transmission component (20) is embodied as a tube (20), and / or wherein the torque transmission component (20) comprises fiber reinforced plastic.

7. A method (1000; 1001) of operating a wind turbine (100, 100'), the wind turbine comprising a rotor (110), the rotor (110) comprising rotor blades (108, 20), the rotor blades comprising a longitudinal direction (r 11 ), and a torque component (20) mechanically connected to the shell (11) via a coupling (26) for providing a torsional moment (ΔT1-ΔT'3) on the shell (11), in particular a rotor blade (20) according to any of the preceding claims, and an actuator (40) mechanically connected to the torque component (20), the method comprising: During operation of the wind turbine, determining (1100, 1001) a current torsional state of the shell (11); · determining (1200, 1201) a desired torsional state of the shell (11); and Using (1300, 1301) at least one of the actuator (40) and the coupling (26) to change the torsional moment on the shell (11) such that a difference between a current torsional state of the shell (11) and a desired torsional state of the shell (11) is expected to be at least reduced.

8. A method according to claim 7, wherein at least one of a current torsional state and a desired torsional state of the shell (11) is determined based on one or more current operating parameters ({P}) of the wind turbine, in particular current wind conditions, wherein determining (1100) the current torsional state of the shell (11) comprises at least one of measurement, use of a lookup table, calculation and simulation, wherein determining the desired torsional state of the shell (11) and / or the torsional moment on the shell (11) varies depending on at least one of: rotor position, wind speed, horizontal misalignment between a rotor axis (30) of the rotor and a wind direction (28) such as updraft, yaw misalignment, wind shear and steerage.

9. A method according to claim 7 or claim 8, wherein the torsional state of the shell (11) is changed to counteract instabilities of the wind turbine blade, such as vortex instabilities, to adjust the angle of attack (α) distribution over the length of the wind turbine blade, to assist in pitching the wind turbine blade, to reduce noise, and / or to make the aerodynamic performance and / or mechanical performance of the wind turbine blade of the wind turbine consistent with another wind turbine blade.

10. The method according to any one of claims 7 to 9, comprising at least one of the following: · According to the longitudinal direction (r 11 ) by determining (1101) the current torsion state of the shell (11); · selecting (1111) parameters for the rotor blades, in particular the angle of attack (α); · Determine (1121) the selected parameter (α c (r)) in the longitudinal direction (r 11 ) on the current functional dependencies; selecting (1105) an optimization criterion (oc), the selection of said optimization criterion typically depending on current operating parameters ({P}) of said wind turbine and / or current wind conditions (wc), in particular wind speed, said optimization criterion typically depending on and / or selected from noise, load, power generation, stability and any combination thereof; Determine (1125) at least one selected parameter (α) according to the selected optimization criterion (oc) d (r)) in the longitudinal direction (r 11 ) on the expected functional dependencies; Determine (1170) the at least one selected parameter in the longitudinal direction (r 11 ) between the current functional dependency and the expected functional dependency (Δα(r)); and Determining (1201) at least one of a desired distortion of the shell (11) and a desired torque (T(r)) to be applied to the shell (11) in order to at least reduce the deflection.

11. A wind turbine (100, 100') comprising a wind turbine blade (20) according to any one of claims 1 to 6.

12. The wind turbine (100, 100') according to claim 11, further comprising an actuator (40), such as an electric motor, which is typically connected to the root section (21) via a gearbox and is configured to rotate the root section (21) of the torque transfer member (20) about the longitudinal axis.

13. The wind turbine (100, 100') according to claim 12, wherein the actuator (40) is configured to at least one of: translate the root section (21) in the longitudinal direction, and measure a total torque (T0).

14. The wind turbine (100, 100') according to any one of claims 11 to 13, further comprising a controller (202) connected to the actuator (40) and configured to perform at least one of the following: controlling the actuator (40), and using the measured torque to control the actuator (40).

15. The wind turbine (100, 100') of claim 14, wherein the controller (202) is configured to operate the wind turbine according to the method of any one of claims 7 to 10.

Images