Wind turbine blade comprising means for maintaining a spoiler in a retracted position

Abstract

A wind turbine (1) is described that includes a blade (6). The blade (6) includes: a blade body (9); a movable member (10) mounted to the blade body (9) and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade (6); and a capsule (11) configured to be connected to a pneumatic or hydraulic system of the wind turbine (1) to move the movable member (10) when the capsule (11) is filled with a fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the capsule (11) by the pneumatic or hydraulic system. The wind turbine (1) includes a retaining device configured to prevent the movable member (10) from moving toward the extended position.

Description

Technical Field

[0001] The present invention relates to a wind turbine and a blade for a wind turbine, comprising a retaining device configured to prevent a movable member, such as a spoiler of the blade, from being moved to an extended position by an external force. The invention also relates to a method of controlling the wind turbine. Background Art

[0002] A conventional wind turbine includes a tower, a nacelle mounted to the top of the tower, a hub rotatably mounted to the nacelle, and at least one blade mounted to the hub. The blade includes a blade body to which a movable component, such as a spoiler, is mounted. The outer surface of the blade, including the movable component, forms a so-called airfoil. The movable component is configured to move between a retracted position and an extended position to alter the aerodynamic properties of the blade, for example, to reduce air velocity around the airfoil when the movable component is in the extended position. In the prior art, a bladder is provided that is connected to the wind turbine's pneumatic or hydraulic system to move the movable component when the bladder is filled with fluid supplied by the pneumatic or hydraulic system or when the fluid is removed from the bladder by the pneumatic or hydraulic system. The bladder is connected to the pneumatic or hydraulic system via a hose, and the pneumatic or hydraulic system includes a pump or any other type of machine capable of generating pressure and suction, such as a blower or compressor. When the airflow around the airfoil needs to be changed, the spoiler is raised by inflating the bladder. When there is no need to modify the airflow around the airfoil, the spoiler needs to remain retracted in a retracted position close to the blades in order not to disrupt the airflow around the airfoil and to minimize drag penalty.

[0003] The blades may be fitted with flow conditioning devices on their surfaces. An example of such a flow conditioning device is a vortex generator (VG). The spoiler may act in conjunction with the vortex generators, and the effect of the vortex generators may be influenced depending on the state of the spoiler. The state of the spoiler may relate to the height and / or inclination angle of the projection from which the spoiler extends or the tilt of the spoiler relative to other surface portions of the rotor blade. The spoiler may be used to actively suppress the function of the flow conditioning device, or to completely bypass the flow conditioning device and cause a local aerodynamic stall of the airfoil. In general, a flow conditioning device may be considered to include a device that is capable of, for example, increasing the lift coefficient of an airfoil section, for example, by increasing the energy level of the boundary layer of the rotor blade.

[0004] EP 1 623 111 B1 discloses a wind turbine blade comprising: an adjustable lift regulating device arranged on or at the surface of the wind turbine blade and extending in the longitudinal direction of the blade; and an activation device by which the lift regulating device can be adjusted and thereby the aerodynamic properties of the blade can be changed. The lift regulating device comprises one or more flexible flaps.

[0005] US 8,851,840 B2 discloses a wind turbine blade comprising a blade body and a device for modifying the aerodynamic surface or shape of the blade, wherein a pneumatic actuator controls the position and / or movement of the device, wherein a pressure chamber is present within the blade body. The pressure chamber can be pressurized to change the state of the device, thereby modifying the aerodynamic surface or shape of the blade.

[0006] US 5 106 265 A discloses a wind turbine blade comprising an aerodynamically actuated spoiler which is movable perpendicular to the air flow.

[0007] WO 2018 / 041420 discloses a rotor blade comprising an aerodynamic device for influencing an airflow flowing from a leading edge section to a trailing edge section of the rotor blade, wherein the aerodynamic device is mounted at the surface of the rotor blade and comprises a pneumatic or hydraulic actuator, such as a hose or a cavity, the volume of which depends on the pressure of a fluid present inside the pneumatic or hydraulic actuator. Summary of the Invention

[0008] A need may exist for a wind turbine and a blade for a wind turbine in which an active spoiler member can be maintained in a retracted position by simple and inexpensive modification. This need is met by the subject matter according to the independent claims. The invention is further improved as set out in the dependent claims.

[0009] According to a first aspect of the present invention, a wind turbine includes a tower, a nacelle mounted to a top of the tower, a hub rotatably mounted to the nacelle, and at least one blade mounted to the hub. The blade includes: a blade body; a movable member mounted to the blade body and configured to move between a retracted position and an extended position to change aerodynamic properties of the blade, such as lift or drag, or both, of a particular airfoil section; a bladder configured to be connected to a pneumatic or hydraulic system of the wind turbine to move the movable member when the bladder is filled with fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the bladder by the pneumatic or hydraulic system; and a retaining device configured to prevent the movable member from moving toward the extended position. The retaining device includes at least one of the following: a) a suction device configured to control a predetermined fluid pressure within the bladder, the predetermined fluid pressure preventing the bladder from expanding due to a pressure increase caused by centrifugal force on the fluid within the bladder generated when the hub rotates. b) the bladder is fixed to a base plate and / or the blade body and the movable member, wherein the movable member is pressed and / or held in the retracted position by a suction device configured to apply negative pressure (in this context, negative pressure means pressure at an absolute level lower than atmospheric pressure) in the bladder; and c) a suction pressure reducing element is provided at the blade body adjacent to the trailing edge of the movable member, or at the trailing edge itself, wherein the suction pressure reducing element is configured to reduce the suction pressure caused by the airflow on the movable member when the movable member is in the retracted position. The retaining devices of options a) to c) may be implemented individually or in any combination.

[0010] In the retaining device of option a), by actively applying suction pressure, for example by a pump mounted in the wheel hub, the forces that tend to inflate the bladder, namely 1) the centripetal acceleration acting on the hose and the fluid in the bladder, and 2) the subatmospheric pressure that may act on the outside of the bladder, are counteracted, thereby preventing the bladder from inflating. In this way, the use of suction pressure can make it possible to reduce spoiler preload, thereby reducing loads, simplifying the design, and increasing the life of the spoiler.

[0011] Option b) without option a) may be beneficial in improving the robustness of the system in situations where the spoiler would be raised unexpectedly in the event of reverse airflow (airflow flowing from the trailing edge to the leading edge). Reverse airflow may occur, for example, on parked (non-operating) wind turbine blades, either when mounted on a wind turbine, during transport of the blades, etc.

[0012] When combined with option a), option b) makes it possible to also counteract the local lift forces acting on the spoiler, thereby further reducing the need for spoiler preload, thus further reducing loads, simplifying the design and increasing the life of the spoiler. In extreme cases, preload can be completely eliminated and the spoiler can behave like a mechanical or elastic hinge.

[0013] In the retention device of option c), if, for example, the active member of the spoiler is ramped down to the nominal surface of the blade's airfoil, the local airflow can induce a local suction force, resulting in a local lift force acting on the spoiler. The preload and / or options a) and b) need to be counteracted to keep the spoiler retracted. An additional ramped-down element in the form of a suction pressure-reducing element can be attached or mounted just behind the spoiler so that the spoiler's trailing edge rests on or beside it when the spoiler is retracted. By designing the spoiler's upper surface to be flush with (or resting on) an element positioned behind the spoiler's trailing edge, the pressure distribution along the spoiler's top side can be influenced in such a way that the overall lift on the spoiler is reduced, thereby reducing the force required by any retention device (e.g., spoiler preload) to hold the spoiler in the retracted position. This results in a simplified design, reduced loads, and an increased lifespan for the spoiler.

[0014] The suction pressure reducing element may also be implemented by a predetermined shape or profile of the blade body adjacent to the trailing edge of the movable member or the trailing edge itself, which is beneficial in reducing the local lift caused by the external flow at the movable member attempting to lift the movable member. For example, the predetermined shape or profile of the trailing edge of the movable member may be manufactured to be flush with the portion of the blade body located behind the trailing edge of the movable member.

[0015] The present invention enables a more slender design (i.e., the overall protrusion of the spoiler beyond the airfoil surface is reduced) achieved through reduced loads, achieved through the principle of pneumatic or hydraulic suction in the pneumatic (air supply) or hydraulic system, minimizing aerodynamic losses in terms of increased drag on the airfoil section. Furthermore, the life of the spoiler of the blade, measured by the number of permissible activations, can be extended due to lower loads and strains within the spoiler element.

[0016] System design is also simplified because preload can be reduced or even eliminated entirely.

[0017] The response time of the system can be reduced by moving the bladder closer to the leading edge of the spoiler and, therefore, achieving the same raised spoiler geometry but with a smaller bladder. Moving the bladder closer to the leading edge without implementing a method to reduce the preload requirement will be detrimental to the life of the spoiler due to the increased internal loads when the spoiler is raised by inflating the bladder.

[0018] The system's aerodynamic efficiency is increased, and its response time is reduced. Furthermore, fatigue loads on key components (blades, hub, tower, foundation) are reduced. This advantage is achieved with all retention devices in options a) to c).

[0019] In one embodiment, the wind turbine further comprises an abutment member arranged at one of the movable member and / or the base plate and / or the blade body, wherein when the abutment member abuts or presses against the other of the movable member, the base plate and / or the blade body, the abutment member defines a retracted position of the movable member. In one embodiment, the abutment member is shaped as a leg or a rib.

[0020] In one embodiment, a restraining member is disposed within the balloon, wherein the restraining member defines the balloon's minimum deflated state. This is particularly advantageous in a retention device utilizing partial suction pressure in option a), because the restraining member prevents the balloon from sealing airtightly under vacuum (i.e., completely collapsing to prevent flow or fluid within the balloon) and potentially prevents a portion of the balloon from fully deflated. The restraining member may be a compression rib within the balloon or an additional member placed within the balloon, such as a mesh or foam.

[0021] In one embodiment, the suction pressure reducing element is formed as a protrusion. In one embodiment, the suction pressure reducing element is combined with a vortex generator. The vortex generator can be used as a flow regulating device to regulate the air flow.

[0022] In one embodiment, the wind turbine further comprises a control device configured to control the fluid pressure within the bladder.

[0023] According to a second aspect of the present invention, a method for controlling a wind turbine is provided, wherein the wind turbine includes a tower, a nacelle mounted to a top of the tower, a hub rotatably mounted to the nacelle, and at least one blade mounted to the hub, wherein the blade includes: a blade body; a movable member mounted to the blade body and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade; and a bladder configured to be connected to a pneumatic or hydraulic system of the wind turbine to move the movable member when the bladder is filled with a fluid supplied by the pneumatic or hydraulic system or when the fluid is removed from the bladder by the pneumatic or hydraulic system. The method includes a holding step to prevent the movable member from moving toward the extended position. The retaining step includes at least one of the following steps: a) a suction step of controlling a predetermined fluid pressure within the bladder, the predetermined fluid pressure preventing the bladder from expanding due to a pressure increase caused by a centrifugal force on the fluid within the bladder, the centrifugal force being generated when the hub rotates; and b) a suction step of applying a negative pressure in the bladder to press and / or maintain the movable member in the retracted position, wherein the bladder is fixed to the blade body and the movable member.

[0024] According to a third aspect of the present invention, there is provided a blade for a wind turbine. The blade comprises: a blade body; a movable member mounted to the blade body and configured to move between a retracted position and an extended position to change the aerodynamic properties of the blade, such as the lift or drag aerodynamically generated by the blade; a bladder configured to be connected to a pneumatic or hydraulic system of the wind turbine to move the movable member when the bladder is filled with a fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the bladder by the pneumatic or hydraulic system; and a suction pressure reducing element disposed at the blade body adjacent to a trailing edge of the movable member, or at the trailing edge itself, the suction pressure reducing element being configured to reduce a suction pressure caused by an airflow on the movable member when the movable member is in the retracted position, thereby preventing the movable member from moving toward the extended position.

[0025] In one embodiment, the suction pressure reducing element is shaped as a protrusion.The suction pressure reducing element may be combined with at least one vortex generator.

[0026] In one embodiment, the blade further comprises a spring or preload member configured to retract the movable member and maintain it in the retracted position. The spring may be implemented by a flexible portion of the movable member. In one embodiment, the movable member comprises a movable portion and a fixed airfoil portion, with the flexible portion positioned therebetween. Alternatively, the spring may be a component provided separately from the movable member.

[0027] In one embodiment, the blade further comprises an abutment member arranged at one of the movable member and / or the base plate and / or the blade body, wherein the abutment member defines a retracted position of the movable member when the abutment member abuts or presses against the other of the movable member and the blade body.

[0028] It should be noted that embodiments of the present invention have been described with reference to different subject matters. In particular, some embodiments have been described with reference to apparatus-type claims, while other embodiments have been described with reference to method-type claims. However, those skilled in the art will appreciate from the above and following description that, unless otherwise stated, any combination of features relating to different subject matters, in addition to any combination of features belonging to one type of subject matter, and in particular any combination of features from apparatus-type claims and features from method-type claims, are also considered to be disclosed by the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above-defined aspects of the present invention as well as further aspects will be apparent from the examples of embodiment described hereinafter and will be explained with reference to these examples of embodiment. The invention will be described in more detail hereinafter with reference to examples of embodiment, but the invention is not limited to these examples of embodiment.

[0030] Figure 1 A wind turbine and its various elements according to an embodiment are shown;

[0031] Figure 2 shows a perspective semi-transparent view of a blade according to an embodiment;

[0032] Figure 3 shows a partial cross-sectional view of a spoiler according to an embodiment;

[0033] Figure 4 A perspective view showing a portion of a spoiler mounting plate and a vortex generator according to an embodiment;

[0034] Figure 5 shows a perspective view of a portion of a movable member / bladder arrangement according to an embodiment;

[0035] Figure 6 A graph showing the pneumatic suction pressure behavior according to the prior art;

[0036] Figure 7 a graph showing pneumatic suction pressure behavior according to an embodiment of the present invention;

[0037] Figure 8 shows a cross-sectional view of a portion of a blade according to an embodiment of the present invention;

[0038] Figure 9 shows a cross-sectional view of a portion of a blade according to an embodiment;

[0039] Figure 10 shows a partial cross-sectional view of a spoiler according to an embodiment;

[0040] Figure 11 shows a partial cross-sectional view of a spoiler according to an embodiment;

[0041] Figure 12 shows a partial cross-sectional view of a spoiler according to an embodiment;

[0042] Figure 13 shows a cross-sectional view of a capsule according to an embodiment;

[0043] Figure 14 shows a cross-sectional view of a capsule according to an embodiment;

[0044] Figures 15 to 17 schematically illustrates an adaptive spoiler according to an embodiment of the present invention in a disassembled state, in a partial view or in an assembled state;

[0045] Figures 18 to 20 schematically illustrates an adaptive spoiler in a schematic sectional side view, in an assembled state and in a partial view according to an embodiment of the invention;

[0046] Figures 21 to 23 schematically illustrates an adaptive spoiler according to an embodiment of the present invention in an assembled state or in a partial view;

[0047] Figures 24 to 26 schematically illustrates an adaptive spoiler according to an embodiment of the invention in a perspective view and in a sectional side view in an assembled state;

[0048] Figures 27 to 29 In cross-sectional side view or Figure 14 and Figure 15 A perspective view of a portion of FIG schematically illustrates an adaptive spoiler according to an embodiment of the present invention;

[0049] Figures 30 to 32 An attachment portion included in an adaptive spoiler according to an embodiment of the present invention is schematically illustrated in a perspective view. DETAILED DESCRIPTION

[0050] The illustrations in the drawings are schematically shown. It should be noted that in different drawings, similar or identical elements are provided with the same reference signs.

[0051] Figure 1A wind turbine 1 is shown. The wind turbine 1 comprises a nacelle 3 and a tower 2. The nacelle 3 is mounted on top of the tower 2. The nacelle 3 is mounted so as to be rotatable relative to the tower 2 by means of a yaw bearing. The axis of rotation of the nacelle 3 relative to the tower 2 is called the yaw axis.

[0052] The wind turbine 1 further comprises a rotor blade 6 having three Figure 1 , a hub 4 is depicted with two rotor blades 6 . The hub 4 is mounted rotatably relative to the nacelle 3 by means of a main bearing 7 . The hub 4 is rotatable about an axis of rotation 8 .

[0053] Wind turbine 1 further includes a generator 5 housed within nacelle 3. Generator 5 is configured to convert rotational energy from hub 4 into electrical energy. Generator 5 is an electric machine comprising a rotor and a stator, wherein the rotor is connected to hub 4, and the stator is connected to nacelle 3. If hub 4 is directly connected to the rotor, wind turbine 1 is referred to as a gearless, direct-drive wind turbine. Such a generator 5 is referred to as a direct-drive generator 5. Alternatively, if hub 4 is indirectly connected to the rotor via a gearbox, this type of wind turbine 1 is referred to as a geared wind turbine. The present invention is applicable to both types of wind turbines 1.

[0054] Figure 2 shows a perspective semi-transparent view of a blade 6 according to an embodiment, and Figure 3 A partial cross-sectional view of a movable member 10 according to an embodiment is shown. The blade 6 includes a blade body 9, a plurality of movable members 10, which are mounted to the blade body 9 and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade 6. Figure 2 In the embodiment, the movable member 10 is in the retracted position, and in the embodiment Figure 3 In the embodiment, the movable member 10 is located in the extended position.

[0055] The blade 6 further comprises a capsule 11 which is configured to be connected to a pneumatic or hydraulic system of the wind turbine 1 so as to move the movable member 10 when the capsule 11 is filled with a fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the capsule 11 by the pneumatic or hydraulic system. The fluid is supplied to or removed from the capsule 11 via a hose 16.

[0056] exist Figure 3 In the embodiment of the invention, each movable member 10 comprises an airfoil portion 21 forming part of the airfoil of the blade 6, and a movable portion 22 moved by the capsule 11. The blade 6, in this case each movable member 10, also comprises a spring configured to retract the movable member 10, i.e. in particular the movable portion 22 of the movable member 10, to the retracted position. Figure 3In the embodiment of FIG. 5 , the spring is realized by a flexible portion 17 of each mobile member 10 , connecting the airfoil portion 21 to the movable portion 22 .

[0057] The wind turbine 1 further comprises a retaining device configured to prevent the movable member 10 from moving towards the extended position. Figure 3 In an embodiment of the present invention, the retaining device includes a suction device configured to control a predetermined fluid pressure within the bladder 11, the predetermined fluid pressure preventing the bladder 11 from expanding due to the increased pressure within the bladder 11 caused by the centrifugal effect on the hose 16 and the air trapped in the bladder 11 generated when the hub 4 rotates. In this case, the bladder 11 does not need to be fixed to the movable member 10, because the flexible portion 17 is generally configured to move the movable member 10 to the retracted position or to maintain the movable member 10 in the retracted position.

[0058] Figure 4 shows a perspective view of a movable member 10 and a suction pressure reducing element 12 combined with a plurality of vortex generators 120 according to an embodiment, and Figure 5 A perspective view of the movable member / bladder arrangement according to this embodiment is shown. Figure 4 and Figure 5 In the embodiment of the present invention, the retaining device is different from the retaining device of the previous embodiment. In detail, the suction pressure reducing element 12 is provided at the blade body 9 adjacent to the trailing edge of the movable member 10, wherein the suction pressure reducing element 12 is configured to reduce the suction pressure caused by the airflow on the movable member 10 when the movable member 10 is in the retracted position. The suction pressure reducing element 12 reduces the suction pressure caused on the movable member 10. The local airflow is modified by the trailing edge of the movable member 10, thereby reducing the local lift acting on the movable member 10, which will be considered later. Figures 6 to 8 The suction pressure reducing element 12 may be shaped as a protrusion, preferably a convex protrusion.

[0059] Figure 6 Graph showing aerodynamic suction pressure behavior according to prior art, where the blade is not provided with any suction pressure reducing element.The suction pressure exhibits a strong peak P' near the trailing edge T' of the movable member 10'.

[0060] Figure 7 The graph shows the aerodynamic suction pressure behavior according to an embodiment of the present invention, in which the blade (e.g. the blade body 9 or the base plate) is provided with a suction pressure reducing element 12. The suction pressure does not substantially exhibit any peak near the trailing edge T of the movable member 10. Figure 6 In contrast, reference symbol R denotes a region where the suction pressure is reduced by the suction pressure reducing element 12 .

[0061] Figure 8A cross-sectional view of a portion of a blade according to an embodiment of the invention is shown, wherein the blade (e.g. the blade body 9 or the base plate) is provided with a suction pressure reducing element 12 in combination with at least one vortex generator 120. The vortex generator 120 is shaped like a fin. The suction pressure behavior is similar to Figure 7 The behavior of is substantially similar, and the vortex generator 120 additionally generates vortices.

[0062] The suction pressure reducing element 12 works on the principle of reducing the local aerodynamic suction caused by its own outer contour on the spoiler, in particular towards the trailing edge T of the movable component 10, which is implemented here as a spoiler. The effect of this is that the total suction on the movable component 10 is reduced, i.e. the aerodynamic force trying to lift it from the surface. By using such a suction reducing element 12, part of the suction pressure distribution is transferred from the movable component 10 to the suction reducing element 12. This is achieved by appropriately adjusting the outer contours of the movable component 10 and the suction reducing element 12. The suction reducing element 12 can be constructed so that the trailing edge T of the movable component rests on it, as in Figure 7 and Figure 8 Alternatively, the suction reducing element 12 may be combined with a vortex generator 120 or any other type of flow conditioning device.

[0063] Figure 9 1 shows a cross-sectional view of a portion of a blade 6 according to an embodiment. In this embodiment, the movable member 10 further comprises a base plate 20. The airfoil portion 21 is connected by a clamping connection 23 (see also Figures 10 to 12 ) or any other force-fit or form-fit connection to the base plate 20, wherein the clamping connection 23 can serve as a fulcrum. The capsule 11 is arranged and / or fixed between the base plate 20 and the movable part 22 of the movable member 10. The base plate 20 is in turn fixed to the blade body 9, for example, by gluing. In this embodiment, the movable member 10 and the capsule 11 are realized in a single module, which can be easily mounted to the blade body 9, for example, by gluing.

[0064] Figure 10 A cross-sectional view of the movable member 10 according to an embodiment is shown, wherein the balloon 11 is inflated, and Figure 11 The movable member 10 is shown in a cross-section with the bladder 11 deflated. The blade 6 comprises a plurality of abutment members 13, which are arranged at the movable member 10, more precisely at the airfoil portion 21 and the movable portion 22, i.e., at the portions in front of and behind the flexible portion 17. The abutment members 13 define the retracted position of the movable member 10 when they abut or press against the blade body 9. The abutment members 13 may abut the blade body 9 directly, or they may be pressed against the blade body 9, for example, when a base plate 20 or another intermediate element is arranged between the abutment members 13 and the blade body 9.

[0065] The abutment members 13 can perform several functions. First, when the abutment members 13 abut the blade body 9 or are pressed against the blade body 9, the abutment members 13 define the final shape of the movable member 10. Second, the abutment members 13 can form a fulcrum, so that given a certain level of suction in the bladder 11, the contact force between the trailing edge of the movable member and the blade 6 is increased, and the pressure required in the bladder 11 to press down the movable member 10 can be reduced. Each abutment member 13 can be shaped as a leg or a rib.

[0066] Figure 10 and Figure 11 The embodiment can be used with a suction device configured to control a predetermined fluid pressure within the bladder 11 that prevents the bladder 11 from expanding due to the centrifugal force generated when the hub 4 rotates. In this case, the bladder 11 does not have to be fixed to the movable member 10. In one modification, Figure 10 and Figure 11 An embodiment may use Figure 13 The bladder 11 shown (described later) is combined with a suction device that is configured to apply negative pressure in the bladder 11 to actively press or maintain the movable member 10 in the retracted position. In this case, the bladder 11 is mechanically fixed to the movable member 10 and (directly or indirectly) to the blade body 9.

[0067] Figure 12 shows a partial cross-sectional view of the movable member 10 according to the embodiment, and Figure 13 FIG shows a cross-sectional view of a capsule 11 according to an embodiment. Figure 12 and Figure 13 In the embodiment, the holding means is different from Figure 3 The holding device. Figure 12 and Figure 13 In the embodiment of the present invention, the retaining means are implemented in that the capsule 11 is fixed to the blade body 9 and the movable member 10, in particular to the movable portion 22 of the movable member 10, wherein the movable member 10 is configured to be pressed and / or retained in the retracted position by a suction device that applies negative pressure in the capsule 11. In an embodiment, a control device (not shown) may be provided that is configured to control the fluid pressure in the capsule 11.

[0068] exist Figure 12 In the embodiment, the capsule 11 is sucked into a recess in the support element / base plate 20 of the blade body 9 or the movable component 10; however, the recess is not necessary, and the capsule 11 can also be installed on the nominal (smooth, non-recessed) surface of the support element / base plate 20 of the blade body 9 or the movable component 10.

[0069] Figure 14A cross-sectional view of a bladder 11 according to an embodiment is shown. A restriction member 14 is disposed within the bladder 11, wherein the restriction member 14 defines a minimum deflated state of the bladder 11. The restriction member 14 is particularly advantageous in a holding device using option a) of partial suction pressure because the restriction member 14 prevents the bladder 11 from sealing airtightly under vacuum and potentially prevents a portion of the bladder 11 from fully deflated. The restriction member 14 can be a compression rib within the bladder 11 or an additional member placed within the bladder 11, such as a mesh or foam.

[0070] Several modifications and combinations are conceivable. For example, Figure 12 The embodiment can be achieved by Figure 9 The features of the embodiments are modified.

[0071] Preferably, the attachment portions 18, 19 of the capsule 11 (see Figures 11 to 14 ) provides a positive or force-fit connection between the capsule 11 and the base plate 20 on the one hand and between the capsule 11 and the movable member 10 (movable part 22) on the other hand. For example, the capsule 11 can be slid in the longitudinal direction of the blade into corresponding receiving parts of the base plate 20 and the movable member 10 (movable part 22).

[0072] These embodiments may be modified in that the movable member 10 is formed by a plurality of channels such as a Figure 12 The movable member 10 is hinged to the blade body 9 by a hinge 24 in which a separate spring presses the movable member 10 into the retracted position.

[0073] These embodiments can be obtained from Figures 15 to 32 The features of the embodiment are structurally modified:

[0074] like Figure 15 The adaptive spoiler 100 schematically shown in a sectional side view along the longitudinal axis 101 of the rotor blade 103 comprises a base element 105 adapted to be connected at or integrated with a rotor blade surface 107 of the rotor blade 103, which is partially shown in FIG. Figure 15 The adaptive spoiler 100 also includes an airfoil element 109 that is attachable (eg, reversibly or permanently) to a base structure 105 (eg, as shown in FIG. Figure 17 ), and has an airfoil shaped surface 111 which will be exposed to an airflow 113 during operation of the wind turbine. The airfoil element 109 comprises an encapsulated core 110 which provides reinforcement.

[0075] The rotor blade 103 has a longitudinal axis 101 which, during operation of the wind turbine, is substantially perpendicular to an air flow direction 113. The base element 105 comprises at least one attachment portion 115, and the airfoil element 109 also comprises at least one attachment portion 117. Thus, the attachment portions 115 and 117 of the base element 105 and the airfoil element 109 can be engaged with each other, as for example Figure 17 As shown in .

[0076] As from Figure 15 As can be seen, the attachment portion 115 of the base element 105 is arranged in an upstream region 119 of the base element 105, in particular in a region between 5% and 50% of the entire extension lbe of the base element in the flow direction 113. Furthermore, the attachment region 117 of the profile element 109 is also arranged in an upstream region 121 of the profile element 109, in particular in a region between 0% and 50% of the entire extension lae of the profile element.

[0077] Figure 15 The diagram shows a disassembled state, wherein the airfoil element 109 is not attached to the base element 105. Figure 15 It will be appreciated that the airfoil element 109 is pre-bent so that when the airfoil element 109 is attached to the base element 105 (e.g. Figure 17 ), the trailing edge 123 of the profile element 109 presses against the surface 107 of the rotor blade 103. Thus, the profile element 109 is pressed against the rotor blade surface 107 in the downstream region 125, or against the base element 105 in other embodiments.

[0078] Reference is made below to the chordwise direction 113, which is the direction pointing from the leading edge to the trailing edge of the rotor blade. During normal operation, the chordwise direction 113 is in the direction of the airflow. Hereinafter, the airflow direction is intended to be equivalent to the chordwise direction.

[0079] The attachment portion 115 of the base element 105 comprises, in the illustrated embodiment, two noses 127, 129 which are spaced apart in the chordwise direction or the airflow direction 113 and which point downstream according to the flow direction 113. Furthermore, the attachment portion 117 of the airfoil element 109 also comprises two noses 131, 133 which are also spaced apart in the flow direction 113 but point upstream. When the airfoil element 109 is attached to the base element 105 (see Figure 17 ), the noses 131, 133 of the attachment area 117 of the profile element 109 engage under the noses 127, 129 of the base element 105. Furthermore, the elastic tongues 137 of the attachment area 117 of the profile element 109 are bent in the assembled state and contact a projection 139 comprised in the attachment portion 115 of the base element.

[0080] Figures 15 to 17 The adaptive spoiler 100 shown in FIG also includes an inflatable container 141, which is configured as a bag or a hose and is made of an elastically deformable material. Figure 15 is shown in the disassembled and collapsed state and in Figure 17 1 is shown in an assembled state. The expandable container 141 includes a lumen 143 that can be filled with a fluid, such as air. Filling the lumen 143 of the container 141 to different degrees causes the container 141 to expand to different degrees, thereby contacting and pushing the rear surface 145 of the airfoil element 109, causing the airfoil-shaped surface 111 of the airfoil element to flex upward, thereby achieving different states of the adaptive spoiler 100.

[0081] The container 141 can be fixed at or to the base element 105. Thus, the container 141 comprises an engagement portion 147, and the base element comprises a corresponding engagement portion 149, in particular in the downstream region 151 of the base element 105. The corresponding engagement portions 147 and 149 of the container 141 and the base element 105 can engage with each other. In particular, the engagement portion 147 of the container also comprises noses that lock or capture under the noses of the engagement portion 149 of the base element.

[0082] Figure 16 A portion of the profile element 109 showing the attachment area 117 is schematically illustrated in more detail.

[0083] When the inflatable container 141 is inflated to different degrees, Figure 17 In particular, the container is now marked with reference numeral 141 ' and the airfoil-shaped surface of the airfoil element 109 is marked with reference numeral 111 '. Figure 17 It can be seen that the position and / or orientation and / or shape of the downstream portion 125 of the profile element 109 is changed, while the position and / or orientation and / or shape of the profile element 109 is substantially unchanged in the upstream region 121 .

[0084] As in Figure 15 As can be seen in FIG, the rotor blade surface has a slight depression in the region of the attached base element 105 , as indicated by Δ. Consequently, the base element 105 is slightly sunken into the rotor blade 103 .

[0085] Figures 18 to 20 An adaptive spoiler 200 according to another embodiment of the present invention is shown in a cross-sectional side view, wherein: Figure 19 and Figure 20 The diagram shows a partial view. Similar to Figures 15 to 17In the embodiment of the adaptive spoiler 100 shown in FIG, the base element 215 of the spoiler 200 also includes an attachment portion 215 in an upstream region 219. Thus, the attachment portion 215 includes hook-shaped projections 227, 229 that engage with the attachment portion 217 of the profile element 209 having the airfoil-shaped surface 211. Thus, the attachment portion 217 includes a downstream-pointing front nose 231 and another nose 235 (or hook) pointing upstream. In contrast, the nose 227 of the base element 205 points upstream, thereby engaging with the downstream-directed nose 231 of the profile element 209. The downstream-directed nose or hook 229 of the base element 205 engages with the upstream-directed nose 235 of the profile element 299.

[0086] The adaptive spoiler 200 also includes an inflatable container 241 located between the downstream portion 225 of the base element 205 and the airfoil element 209 (see Figure 20 ). Furthermore, the container 241 is also attached to the base element 205 in the downstream region 225 via the joining portion 247 and via the joining portion 249. However, in addition to Figures 15 to 17 In addition to the embodiment of the spoiler 100 shown in FIG, the airfoil element 209 further includes an engagement portion 253 that engages with another engagement portion 255 of the container 241. Specifically, the engagement portions 247, 255 of the base element 205 and the airfoil element 209 are respectively configured as recesses, into which the projections of the corresponding engagement portions of the container 241 are inserted, thereby being retained by a locking or interlocking mechanism. In order to insert the projections 255, 247 of the container 241 into the recesses 249, 253, the projections 255, 247 may be formed with slightly expanded heads.

[0087] Figure 18 and Figure 19 The base element 205 shown in FIG. 2 is slightly sunken into the rotor blade 203 by an amount Δ.

[0088] Figures 21 to 23 Another adaptive spoiler 300 according to an embodiment of the present invention is illustrated, wherein: Figure 22 and Figure 23 The diagram shows a partial view. Figure 15 、 Figure 18 and Figure 19 The base elements 105, 205 shown in FIG are sunken over their entire length, but Figures 21 to 20The majority of the base element 305 of the adaptive spoiler 300 shown in FIG is arranged on a constant rotor blade surface that has no depressions over the entire extension of the base element 305. However, a depression of the rotor blade surface is present in the downstream region 357, wherein said depression amounts to a value Δ. Outside the downstream region 357, there is no depression of the rotor blade surface 307. This depression Δ allows the accompanying inflatable container 341, which can be connected to the rotor blade surface 307. Figures 18 to 20 2. The container 241 of the adaptive spoiler 200 shown in FIG. 3 is similarly configured. Furthermore, the attachment portion 315 of the base element 305 includes an upstream-directed nose 327 that engages with a downstream-directed nose 331 of the profile element 309. Furthermore, the base element 305 includes a downstream-directed nose 329 that engages with an upstream-directed nose 335 of the profile element 305. In the recessed region 357 of the rotor blade, the base element 305 is sunken into the rotor blade.

[0089] Figures 24 to 26 An adaptive spoiler 400 according to an embodiment of the present invention is shown. The airfoil element 409 can be attached to the base element 405 by a hinge mechanism 465 forming a corresponding attachment portion. Both the base element and the airfoil elements 405, 409 include through holes 459, 461 through which a pin 463 can be inserted to establish the hinge 465 (see Figure 25 and Figure 26 ). The pin 463 and the through holes 459, 461 are oriented substantially along the longitudinal axis 401 of the rotor blade at which the adaptive spoiler 400 is mounted. Figures 24 to 26 In the adaptive spoiler 400 shown in FIG, the attachment portions 417 and 415 of the airfoil element 409 and the base element 405, respectively, are formed by portions having through holes 459, 461, respectively.

[0090] The downstream area of ​​the base element 405 and the airfoil element 409 is connected to, for example Figure 23 There are similarities to those portions of the adaptive spoiler 300 illustrated in detail in FIG. Figure 25 The spoiler is shown as the container 441 is collapsed, but Figure 26 A condition is illustrated wherein the reservoir 441 is inflated such that the airfoil-shaped surface 411 of the airfoil element 409 tilts upwardly away from the rotor blade surface 407 , thereby placing the adaptive spoiler 400 in a particular activated state.

[0091] Figures 27 to 29 An adaptive spoiler 500 according to yet another embodiment is schematically illustrated. Figure 28 The base element 505 is illustrated in FIG, and wherein Figure 29Only the profile element 509 is shown in the figure. The attachment portion 515 of the base element 505 includes a hole 567 and a guide edge (not shown in detail). The elastic support protrusions or locking noses 569 included in the profile element 509 represent the corresponding attachment portion 517 of the profile element 509. These elastically retained noses 569 are to be slid into the openings 567 for attaching the profile element 509 to the base element 505 (reversibly or permanently).

[0092] Figures 30 to 32 The figure shows further variants or embodiments of the base element 605 on the one hand and the attachment portion of the airfoil element 609 on the other hand that can be included in the adaptive spoiler according to an embodiment of the invention. In the embodiment shown, the base element 605 has a nose directed downstream as the attachment portion 615, which engages with the noses 631, 635 directed upstream of the airfoil element 609. Although Figure 30 and Figure 31 A resilient tongue 637 is shown, the end of which interlocks with a protrusion 639 at or on the base element 605, but Figure 32 , the front portion 671 of the profile element 609 is interlocked with the front portion 673 of the base element to avoid accidental release of the profile element by sliding it in the downstream direction.

[0093] Embodiments of the present invention may provide several benefits:

[0094] · Simple and fast installation,

[0095] · Simple and fast component repair / replacement / repair,

[0096] Simple manufacturing,

[0097] Increase resistance levels when desired,

[0098] Fast power control,

[0099] Additional degrees of freedom for controlling the aerodynamic forces on the blades.

[0100] The embodiment may be applicable to at least one of the following:

[0101] Selectively reduce loads at different spanwise locations at different wind speeds,

[0102] Increase aerodynamic damping at high wind speeds or when otherwise needed,

[0103] Reduce aerodynamic loads during overspeed conditions,

[0104] Reduce aerodynamic loads during idling,

[0105] Reduce aerodynamic loads during manual, emergency or normal shutdown events,

[0106] · Reduce pitch activity by combining pitch with activation of flow conditioning devices,

[0107] · Spoiler activation combined with individual pitch control.

[0108] There are several possible activations:

[0109] · Activation according to the turbine's rotor speed,

[0110] Slow activation (e.g. based on wind speed only),

[0111] Rapid activation (e.g., 1P or 3P for combination with IPC),

[0112] On / off activation (e.g. for overspeed, standstill events, events with extremely high turbulence),

[0113] · continuously activated (e.g. for idling),

[0114] · Independent activation of different spoiler sections on the blade,

[0115] Independent activation of different spoiler sections on the blades to maintain the rotor speed at nominal levels.

[0116] Possible pressure supply system characteristics include the following:

[0117] · activation by means of a pressurized fluid, in particular pressurized air, pressurized dry air or any other gas such as an inert gas (for example nitrogen or helium),

[0118] Low air volume requirement (e.g. achieved by controlling the shape change of the pressurized chamber rather than the expansion of the chamber),

[0119] Pressurized reservoirs close to the activation point (to react quickly and reduce the power demand on the supply system). This can be done, for example, by placing a larger diameter tube inside the blade close to the pressure supply point,

[0120] Connect to both pressure and vacuum chambers to increase reaction speed,

[0121] · Continuous flow through the purge valve to avoid accumulation of moisture / dust / compressed oil etc.,

[0122] Use preheated air where icing may be a problem,

[0123] Independent activation of different radial segments,

[0124] Use of control valves at specific stations to prevent / allow pressurized air to flow from one radial position to another,

[0125] Use pneumatically activated pneumatic valves (to avoid electrical signals),

[0126] Use stagnation pressure as input to pneumatic control valves at certain radial stations,

[0127] Use pitch position as input for pneumatic control valves (e.g. a high pitch position opens the valve and thus activates the spoiler),

[0128] Using rotor speed as input to pneumatically controlled valves (e.g. high rotor speed can cause the valve to open and thus activate the spoiler),

[0129] Use turbulence level as input to pneumatic control valves.

[0130] In the flow spoiler, no electrical or mechanical components may be required.

[0131] According to an embodiment of the present invention, the following features are provided, which can be applied to all the above embodiments individually or in combination:

[0132] The shape of the container can be optimized to reduce the friction distance with the airfoil element. Therefore, the container can generally be asymmetric;

[0133] The feet of the container may also be asymmetrical to inhibit installation in the wrong orientation;

[0134] Low-friction strips can be attached to the profile element and / or container at specific locations to reduce wear; the base element can be made as one element to ensure a consistent relative positioning between the profile element and the container, or conversely as two elements to enable different relative positioning and, therefore, different lift heights to be achieved for the same container and / or profile element;

[0135] The container may incorporate resilient elements, such as fiber reinforcements, to assist in collapsing.

[0136] For example, the movable member 10 may be implemented as the adaptive spoiler 100, 200, 300, 400, 500, 600. The bladder 11 may be implemented as the inflatable container 141, 241, 341, 441. The attachment portions 18, 19 may be implemented as the joining portions 147, 247, 347 and the further joining portions 255, 355, respectively. The base plate 20 may be implemented as the base element 105, 205, 305, 405, 505. The clamping connection 23 may be implemented as Figures 15 to 19 , 21, 22, 30 to Figure 32 Implement as shown.

[0137] The suction pressure reducing element 12 can be designed as the above-mentioned flow conditioning device or vortex generator 120 .

[0138] It should be noted that the term "comprising" does not exclude other elements or steps, and the wording "a", "an" or "an" does not exclude a plurality. Furthermore, elements described in connection with different embodiments may also be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

1. A wind turbine (1) comprising a tower (2), a nacelle (3) mounted to a top of the tower (2), a hub (4) rotatably mounted to the nacelle (3), and at least one blade (6) mounted to the hub (4), the blade (6) comprising: Blade body (9); a movable member (10) mounted to the blade body (9) and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade (6); a bladder (11) configured to be connected to a pneumatic or hydraulic system of the wind turbine (1) to move the movable member (10) when the bladder (11) is filled with fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the bladder (11) by the pneumatic or hydraulic system; as well as retaining means configured to prevent the movable member (10) from moving toward the extended position, wherein the retaining device comprises a suction pressure reducing element (12) which contacts the movable member and the blade body adjacent to the trailing edge of the movable member (10) or at the trailing edge itself, the suction pressure reducing element (12) being configured to reduce the suction pressure caused by the airflow on the movable member (10) when the movable member (10) is in the retracted position; Wherein, the holding device further includes at least one of the following: a) a suction device configured to control a predetermined fluid pressure within the bladder (11), the predetermined fluid pressure preventing the bladder (11) from expanding due to a pressure increase caused by centrifugal forces on the fluid within the bladder (11), the centrifugal forces being generated when the hub (4) rotates, wherein the bladder (11) is mechanically fixed to the movable member (10) and directly or indirectly fixed to the blade body (9), or wherein a flexible portion (17) is provided, the flexible portion (17) being configured to move the movable member (10) to the retracted position or to maintain the movable member (10) in the retracted position; b) the capsule (11) is fixed to a base plate (20) and / or the blade body (9) and the movable member (10), wherein the movable member (10) is pressed into and / or held in the retracted position by a suction device configured to apply negative pressure in the capsule (11), wherein the wind turbine further comprises a limiting member (14) arranged in the capsule (11), wherein the limiting member (14) defines a minimum deflated state of the capsule (11).

2. The wind turbine (1) according to claim 1, further comprising: A spring or preload member is configured to retract the movable member (10) and maintain it retracted to the retracted position.

3. The wind turbine (1) according to claim 1 or 2, further comprising: An abutment member (13) is arranged at one of the movable member (10) and / or the base plate (20) and / or the blade body (9), wherein when the abutment member (13) abuts or presses against the other of the movable member (10) and the base plate (20) and / or the blade body (9), the abutment member (13) defines the retracted position of the movable member (10).

4. A wind turbine (1) according to claim 3, wherein The abutment members (13) are shaped as legs or ribs.

5. A wind turbine (1) according to claim 1 or 2, wherein The movable component (10) comprises a movable portion (22), an airfoil portion (21) and a flexible portion (17) therebetween.

6. The wind turbine (1) according to claim 1 or 2, further comprising: A limiting member (14) is arranged within the bladder (11), wherein the limiting member (14) defines a minimum deflated state of the bladder (11).

7. A wind turbine (1) according to claim 1 or 2, wherein The suction pressure reducing element (12) is shaped as a protrusion.

8. A wind turbine (1) according to claim 1 or 2, wherein: The suction pressure reducing element (12) is combined with at least one vortex generator (120).

9. The wind turbine (1) according to claim 1 or 2, further comprising: A control device is configured to control the fluid pressure within the bladder (11).

10. The wind turbine (1) according to claim 6, wherein: The limiting member (14) is formed as an extruded rib or a separate member placed inside the bladder (11).

11. The wind turbine (1) according to claim 6, wherein: The restriction member (14) is formed as a net placed inside the bag (11).

12. A method of controlling a wind turbine (1) according to any one of claims 1 to 11, the wind turbine (1) comprising a tower (2), a nacelle (3) mounted to a top of the tower (2), a hub (4) rotatably mounted to the nacelle (3), and at least one blade (6) mounted to the hub (4), the blade (6) comprising: Blade body (9); A movable member (10) mounted to the blade body (9) and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade (6); a capsule (11) configured to be connected to a pneumatic or hydraulic system of the wind turbine (1) to move the movable member (10) when the capsule (11) is filled with fluid supplied by the pneumatic or hydraulic system or when the fluid is removed from the capsule (11) by the pneumatic or hydraulic system, the method comprising: A holding step of preventing the movable member (10) from moving toward the extended position, wherein the holding step comprises at least one of the following steps: a) a pumping step of controlling a predetermined fluid pressure within the bladder (11), the predetermined fluid pressure preventing the bladder (11) from expanding due to a pressure increase caused by centrifugal force on the fluid within the bladder (11), the centrifugal force being generated when the hub (4) rotates, wherein the bladder (11) is mechanically fixed to the movable member (10) and directly or indirectly fixed to the blade body (9), or wherein a flexible portion (17) is provided, the flexible portion (17) being configured to move the movable member (10) to the retracted position or to maintain the movable member (10) in the retracted position; and b) a suction step of applying negative pressure in the bladder (11) to press and / or hold the movable member (10) in the retracted position, wherein the bladder (11) is fixed to the blade body (9) and the movable member (10).

13. A blade (6) for a wind turbine (1), comprising: Blade body (9); a movable member (10) mounted to the blade body (9) and configured to move between a retracted position and an extended position to change the aerodynamic characteristics of the blade (6); a bladder (11) configured to be connected to a pneumatic or hydraulic system of the wind turbine (1) to move the movable member (10) when the bladder (11) is filled with fluid supplied by the pneumatic or hydraulic system, or when the fluid is removed from the bladder (11) by the pneumatic or hydraulic system; as well as A suction pressure reducing element (12) contacts the movable member and the blade body adjacent to the trailing edge of the movable member (10) or at the trailing edge itself, the suction pressure reducing element (12) being configured to reduce the suction pressure caused by the airflow on the movable member (10) when the movable member (10) is in the retracted position, thereby preventing the movable member (10) from moving toward the extended position.

14. The blade (6) according to claim 13, wherein The suction pressure reducing element (12) is shaped as a protrusion.

15. The blade (6) according to claim 13 or 14, wherein: The suction pressure reducing element (12) is combined with at least one vortex generator (120).

16. The blade (6) according to claim 13 or 14, further comprising: A spring or preload member is configured to retract the movable member (10) to the retracted position.

17. The blade (6) according to claim 13 or 14, further comprising: An abutment member (13) is arranged at one of the movable member (10) and / or the base plate (20) and / or the blade body (9), wherein when the abutment member (13) abuts or presses against the other of the movable member (10) and the blade body (9), the abutment member (13) defines the retracted position of the movable member (10).

Images