(19)
`
`(12)
`
`Patenta m1
`Europfiisches
`European
`Patent Office
`Office e u ropéen
`
`des brevets (11)
`
`EP 2 757 254 A1
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`EUROPEAN PATENT APPLICATION
`
`(43) Date of publication:
`23.07.2014 Bulletin 2014/30
`
`(51)
`
`Int CL:
`F030 71020005101)
`
`F030 1106(2006-01)
`
`(21) Application number: 133820225
`
`(22) Date of filing: 21.01.2013
`
`
`(84) Designated Contracting States:
`AL AT BE BG CH CY CZ DE DK EE ES FI FR GB
`GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO
`PL PT RO RS SE SI SK SM TR
`
`Designated Extension States:
`BA ME
`
`(72)
`
`Inventor: Betran, Jaume
`08172 SANT CUGAT DEL VALLES (ES)
`
`(74) Representative: ZBM Patents - Zea, Barlocci &
`Markvardsen
`
`Plaza Catalunya, 1
`08002 Barcelona (ES)
`
`(71) Applicant: Alstom Wind, S.L.U.
`08005 Barcelona (ES)
`
`
`(54) Wind turbine blade
`
`Wind turbine blade comprising at least one de-
`(57)
`formable trailing edge section having a plurality of actu-
`ators consecutively arranged substantially downstream
`from one another and a control system for controlling the
`actuators, wherein a downstream end of one actuator is
`connected by a substantially rigid link with an upstream
`
`end of the next actuator and the plurality of actuators
`comprises an upper actuator being mounted above a
`chord line ofthe blade section and a lower actuator being
`mounted below a chord line of the blade section. Wind
`
`turbines comprising such a blade and methods of con-
`trolling loads on a wind turbine blade are also described.
`
`
`
`
`
`24
`
`EP2757254A1
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`
`
`Printed by Jouve, 75001 PARIS (FR)
`
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`EP 2 757 254 A1
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`Description
`
`[0001] The present application relates to wind turbine
`blades comprising at least one deformable trailing edge
`section and wind turbines comprising such blades. Itfur—
`ther relates to methods of controlling loads on such wind
`turbine blades.
`
`BACKGROUND ART
`
`[0002] Modern wind turbines are commonly used to
`supply electricity into the electrical grid. Wind turbines
`generally comprise a rotorwith a rotor hub and a plurality
`of blades. The rotor is set into rotation underthe influence
`ofthe wind on the blades. The rotation ofthe rotor shaft
`
`drives the generatorrotoreitherdirectly("directly driven")
`orthrough the use ofa gearbox. The gearbox (if present),
`the generator and other systems are usually mounted in
`a nacelle on top of a wind turbine tower.
`[0003]
`Pitch systems are normally employed foradapt—
`ing the position of the blades to varying wind conditions.
`In this respect, it is known to rotate the position of each
`blade along its longitudinal axis in such a way that lift and
`drag are changed to reduce torque. This way, even
`though the wind speed increases, the torque transmitted
`by the rotor to the generator remains substantially the
`same. Using pitch systems may be particularly suitable
`for adapting the wind turbine blade to a varying wind
`speed. However, the control ofthe pitch systems may be
`rather slow and may not be suitable to react to a sudden
`wind gust or any other high rate changing wind condi-
`tions.
`
`Some systems change the aerodynamics of a
`[0004]
`wind turbine blade by providing the blade with a trailing
`edgeflap hinged to a main body. However, deflecting the
`aerodynamic surface about a hinged point may lead to
`flow separation which may cause abrupt aerodynamic
`changes thus decreasing load alleviation and reducing
`efficiency of the wind turbine.
`[0005] DocumentW02004/088130describesthe con-
`trol of aerodynamic forces substantially instantaneously
`and locally along the blades of a wind turbine rotor by
`continuous variation ofthe airfoil geometry in the leading
`edge region and trailing edge region along part or the
`whole blade span. It further describes the use of smart
`materials or mechanical actuators integrated in a deform-
`able material changing the outer geometry in the leading
`and trailing edge region and thereby changing the blade
`section aerodynamic forces.
`
`SUMMARY
`
`It is an object of the present disclosure to pro-
`[0006]
`vide an improved blade allowing variation of airfoil ge-
`ometry.
`In afirstaspecta wind turbine blade is provided.
`[0007]
`The blade comprises at least one deformable trailing
`edge section having a plurality ofactuators consecutively
`
`arranged substantially downstream from one another
`and a control system for controlling the actuators, where-
`in a downstream end of one actuator is connected by a
`substantially rigid link with an upstream end of the next
`actuator; and the plurality of actuators com prises an up—
`per actuator being mounted above a chord line of the
`blade section and a lower actuator being mounted below
`a chord line of the blade section.
`
`[0008] According to this aspect, at least one upper ac—
`tuator and at least one lower actuator are provided inside
`the trailing edge section. This ensures at least two de-
`grees offreedom to the control system. Furthermore, the
`fact that two consecutive actuators are connected to each
`
`other by a rigid link ensures a leverage effect between
`them. The actuators may thus reinforce each other, or at
`least partially cancel one another’s effects. The blades
`trailing edge shape may thus be widely changed upon
`activation of the actuators. This modifies the aerodynam-
`ic surface of the blade so that it can be used to e.g. mit—
`igate the loads acting on the blades. All this may be
`achievedwithoutexcessively complicatingawindturbine
`blade structure.
`
`In some embodiments, at least one upper ac—
`[0009]
`tuator may be mounted close to an inner surface of a
`suction side of a skin of the blade trailing edge section
`and at least one lower actuator may be mounted close
`to an inner surface of a pressure side of a skin of the
`blade trailing edge section. Mounting the actuators close
`to opposite inner surfaces of the blade’ skin improves the
`shape ofthe deflected trailing edge and the leverage ac—
`tion between consecutive actuators can be increased. In
`
`some of these cases, the at leastone upperactuator may
`be mounted directly to the inner surface of the suction
`side ofthe blade skin and the at least one lower actuator
`
`may be mounted directly to the inner surface ofthe pres-
`sure side of the blade skin.
`
`In some embodiments, the rigid links connected
`[0010]
`to the upstream end of the actuators may be mounted
`substantially perpendicular to the blade skin. This way,
`the aerodynamic profile may be changed in a verysmooth
`manner, e.g. reducing or avoiding local bulging ofa pro—
`file.
`
`[0011] Another aspect provides a wind turbine com-
`prising at least one blade substantially as hereinbefore
`described.
`
`[0012] A further aspect provides a method of control-
`ling a wind turbine blade substantially as hereinbefore
`described, the method comprising activating at least one
`upperand/orat least one lower actuator such thata struc—
`tural shape of the blade trailing edge changes in at least
`two degrees offreedom, e.g. flap angle and chord length.
`[0013] Additional objects, advantages and features of
`embodiments of the present invention will become ap-
`parent tc those skilled in the art upon examination of the
`description, or may be learned by practice of the inven-
`tion.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Particular embodiments of the present inven-
`[0014]
`tion will be described in the following by way of non-lim-
`iting examples, with reference to the appended drawings,
`in which:
`
`Figure 1 shows a cross-sectional view of a wind tur-
`bine blade according to an embodiment;
`
`10
`
`Figures 23-2d show cross-sectional views of wind
`turbine blades according to other embodiments; and
`
`Figure 3 shows a cross-sectional view of a wind tur-
`bine blade according to yet another embodiment.
`
`15
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`DETAILED DESCRIPTION OF EMBODIMENTS
`
`Figure 1 shows a cross—sectional view ofa wind
`[0015]
`turbine blade 10 having a skin 1 1 . The blade section may
`comprise a deformable trailing edge portion 12 and a
`substantially non-deformable portion 13. Figure 1 shows
`two states ofthe blade section: an initial shape indicated
`by dotted lines 12a where the trailing edge is non-de-
`formed and a deformed shape indicated by solid lines
`where the trailing edge portion 12 is deformed.
`[0016] The deformable trailing edge may extend on the
`total length of the blade or it may extend on at least one
`section ofthe blade, e.g. on substantially one third ofthe
`total length, in particular the portion closest to the tip of
`the blade. In other cases, a plurality ofdeformable trailing
`edge sections may also be provided.
`[0017] A spar box 14 may be arranged inside the sub-
`stantially non—deformable portion 13 of the blade in order
`to maintain the distance between an inner surface of a
`suction side 15 of the blade and an inner surface of a
`
`pressure side 16 ofthe blade. The spar box 14 may sup-
`port wind loads acting on the blades, and in particular
`the blade bending loads. A rigid structure 17 may further
`be arranged inside the substantially non-deformable por-
`tion 13 of the blade. Such a structure 17 may support at
`least in part the loads derived from the deformable trailing
`edge 12 and may have a substantially C-shaped cross-
`section, the upper and lower parts of the C supporting
`the blade skin.
`
`[0018] The embodiment shown in figure 1 may com-
`prise five piezoelectric actuators P1-P5 arranged inside
`the trailing edge portion 12. Actuators P1, P3 and P5 may
`be mounted below a chord line A—A of the blade cross—
`
`section thus being lower actuators and actuators P2 and
`P4 may be mounted above the chord line A-A ofthe blade
`thus being upper actuators. According to this embodi—
`ment, the lower actuators may be mounted substantially
`tangential to an inner surface of a pressure side 16 of
`the blade skin and the upper actuators may be mounted
`substantially tangential to an inner surface of a suction
`side 15 of the blade skin.
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`connecting each actuator to the next consecutive actu—
`ator. It should be understood that the rigid links may be
`structural elements, e.g. beams, having a sufficient stiff-
`ness such as not to deform, in particular under the influ-
`ence of the actuators.
`
`in figure 1, rigid link 20 may connect a down-
`[0020]
`stream end (arrow D) of actuator P1 with an upstream
`end (arrow U) of actuator P2, rigid link 21 may connect
`a downstream end of actuator P2 with an upstream end
`of actuator P3, rigid link 22 may connect a downstream
`end of actuator P3 with an upstream end of actuator P4
`and rigid link 23 may connect a downstream end of ac—
`tuator P4 with an upstream end of actuator P5. Further-
`more, an upstream end of actuator P1 may be connected
`to the rigid structure 17 provided in the non-deformable
`portion 13 and a downstream end ofactuator P5 may be
`connected to the blade skin at the trailing edge end 18
`by a relatively rigid structure 24.
`[0021]
`In addition, skin areas 19 of the trailing edge
`portion 12 that are not supporting the actuators P1-P5,
`the rigid links 20-23 or the rigid structure 24 may be made
`ofa relativelyflexible material. This ensures deformablllty
`and smoothness of the blade surface upon actuation of
`any actuator. Elastic or elastomeric materials are exam-
`ple of materials conferring the needed flexibility so that
`cracks due to fatigue loads are reduced. The rest 191 of
`the blade skin may be made out of any known composite
`material typically used in wind turbine blades construc-
`tion in order to maintain blade’s high rigidity and resist-
`ance to fatigue and wear while not compromising its
`weight.
`In an alternative example, the skin areas sup-
`[0022]
`porting the rigid links may be made from the same rela-
`tively flexible material (see figure 2d), since the rigid links
`may give sufficient support by themselves.
`[0023] A control system for controlling the actuators
`may also be provided. In the example illustrated in figure
`1 the control system may apply an electrical field on the
`piezoelectric elements so as to generate a mechanical
`strain (deformation) on the surface (blade skin) on which
`the actuators are being mounted. Based on the reverse
`piezoelectric effect, each actuator converts the input sig-
`nal received from the control system into an internal me-
`chanical deformation of the piezoelectric element thus
`deforming the surface ofthe blade on which it is mounted.
`The rigid links ensure a combined effect between the
`actuators. Loads acting on the blade may thus be easily
`compensated by adapting the shape of the blade.
`[0024]
`In the example of figure 1, many combinations
`of piezoelectric activation may be possible: each of the
`piezoelectric elements may be deformed in an upwards
`manner, a downwards manner or may be maintained in
`the default neutral position. Using the plurality of actua-
`tors, a very large number of combinations of flap angle
`and/or chord length of the blade may be available to ad-
`just lift (and drag and pitch moment) to adaptto changing
`wind loads.
`
`[0019]
`
`Rigid links 20-23 may further be provided for
`
`[0025] As used herein the chord line is the imaginary
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`EP 2 757 254 A1
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`straight line defined between the leading and trailing
`edge when the flap angle is zero. Considering a sign
`convention in which a minus sign is used for deformation
`of the trailing edge towards the suction side and a plus
`sign is used for a deformation ofthe trailing edge towards
`the pressure side, the following cases are only some of
`several possible combinations available for the embod-
`iment of figure 1:
`
`Case 1: actuators P1, P3 and P5 may be deformed
`towards the pressure side and actuators P2 and P4
`may be deformed towards the suction side, then the
`flap angle may be substantially maintained but the
`chord length may be extended. The lift coefficient
`may thus be slightly modified with a larger chord
`length. This may provide higher lift.
`
`Case 2: actuators P1, P3 and P5 may be deformed
`towards the suction side and actuators P2 and P4
`
`may be deformed towards the pressure side, then
`the flap angle may be substantially maintained and
`the chord length may be reduced. The lift coefficient
`may thus be slightly modified with a shorter chord
`length. This may provide lower lift.
`
`Case 3: actuators P1, P3, P4 and P5 may be de-
`formed towards the suction side and actuator P2 may
`be deformed towards the pressure side, the flap an-
`gle may thus be reduced while the chord length may
`be only slightly modified. The lift may be lowered.
`
`Case 4: actuators P1, P3, P4 and P5 may be de-
`formed towards the pressure side and actuator P2
`may be deformed towards the suction side, the flap
`angle may thus be increased while the chord length
`may be only slightly modified. The lift may be in-
`creased.
`
`Case 5: only actuator P1 may be deformed. In this
`case, the deformable trailing edge may act substan-
`tially as a hinged flap.
`
`Case 6: all actuators may be deformed towards the
`pressure side.
`in this case, the chord length may
`remain substantially the same and the lift may be
`increased.
`
`[0026] Clearly, many other options are available.
`[0027]
`in general for blades having a positive angle of
`attack, actuating the trailing edge portion towards its pos-
`itive position (pressure side) increases the lift. The loads
`on a blade may thus be increased, but this may be ac—
`ceptable and/or desirable,
`in accordance with circum-
`stances (e.g. sudden temporary decrease in wind
`speed). The increase of the lift increases the aerodynam-
`ic torque of the rotor. Furthermore, actuating a trailing
`edge portion towards its negative position (suction side)
`decreases the lift. The decrease in lift reduces the aero-
`
`dynamic torque and the loads on the blade in general.
`Deforming the trailing edge towards suction side may
`thus be used to counteract e.g. temporary high loads on
`a blade (sudden wind gusts).
`[0028]
`Figures 2a—2d show alternative embodiments.
`The same reference numbers will be used for matching
`parts.
`[0029] The alternative illustrated in figure 2a differs
`from that of figure 1
`in that inner areas 30 of the blade
`trailing edge portion 12 may be filled with a material with
`a honeycomb structure. This kind of material may be rel-
`atively lightweight and display a desirable anisotropic be—
`havior: it may be relatively stiff in a direction substantially
`perpendicular to the chord line, i.e. it is stiff so as to main-
`tain the airfoil thickness and not deform under aerody-
`namic pressure. At the same time, it may be more flexible
`in a direction substantially parallel to the chord line, thus
`allowing proper movement of the actuators. in other im-
`plementations, instead of a honeycomb structure mate—
`rial, other kinds of lightweight materials having such an-
`isotropic properties so as to permit an internal structural
`behavior may also be used.
`[0030] The alternative illustrated in figure 2b differs
`from that of figure 2a in that the rigid links 20-23 may be
`mounted substantially perpendicular to the blade skin at
`their end 20u, 21 u, 22u and 23u connecting upstream
`ends U ofactuators P2—P5. By having the rigid links sub—
`stantially perpendicular to the skin of the blade, the aer-
`odynamic profile may be deformed in a smoother man-
`ner, e.g. local bulging may be avoided or reduced.
`[0031] The alternative illustrated in figure 20 differs
`from that of figure 1
`in that those inner areas 31 of the
`blade trailing edge portion 12which are immediately next
`to the flexible material used forskin areas 19 ofthe trailing
`edge portion may comprise a honeycomb structure ma-
`terial (or similar) lying over the flexible material. The skin
`surface may thus be particularly stiff to withstand aero-
`dynamic loads, but more easily allow deformation of the
`skin in a direction perpendicular to that. If e.g. the most
`upstream lower actuator is activated, the rigid link be-
`tween this actuator and the consecutive upper actuator
`will move axially. An anisotropic material such as the one
`described may be particularly suitable.
`[0032] The alternative illustrated in figure 2d differs
`from that of figure 2a in that actuators P2—P4 although
`being respectively upper or lower actuators as explained
`in connection with figure 1, are not mounted tangential
`to the blade skin but they may be horizontally mounted
`in between two rigid links,
`i.e. P2 may be mounted in
`between rigid links 20 and 21, P3 in between rigid links
`21 and 22 and P4 in between rigid links 22 and 23a. With
`this internal structure, a suction side 15 of the blade skin
`along almost the whole trailing edge 12 may be made of
`a substantially flexible material 19’ (with the exception of
`the trailing edge end 18 and the area on which structural
`element 24 rests) and a pressure side 16 of the blade
`skin along almost the whole trailing edge 12 (with the
`exception ofthe areas on which actuators P1 and P5 and
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`rigid link 20 rest) may also be made of a flexible material
`19". Furthermore, the alternative illustrated in figure 2d
`may comprise inner areas 30 of the blade trailing edge
`portion 12 that may be filled with a honeycomb structure
`material as explained above in connection with figure 2a.
`[0033] Contrary to previous examples, the rigid links
`are not supported by "normal" skin material
`i.e. any
`known composite material typically used in wind turbine
`blades construction. Because of the rigidity of the links,
`no stiff skin material is needed and thus manufacture of
`
`the blade may be simplified. Alternatively, the rigid links
`may be supported by normal skin material.
`[0034]
`Figure 3 shows a cross-sectional view ofa wind
`turbine blade 10’ according to another embodiment. The
`same reference numbers will be used for matching parts.
`[0035] The embodiment of figure 3 may comprise two
`piezoelectric actuators P1’ and P2’ that may be arranged
`respectively below (lower actuator) and above (upper ac-
`tuator) a chord line (not shown) of the blade section. In
`this case a substantially rigid element in the form of a
`rigid beam 17’ may emerge from the spar box 14 towards
`the trailing edge end 18. In order to arrange both actua-
`tors P1’ and P2’ substantially downstream from one an—
`other, the lower actuator P1' may be mounted in between
`such a rigid beam 17’ and a rigid link 20’ connecting a
`downstream end D1 of actuator P1’ with an upstream
`end U2 of actuator P2’ and a downstream end D2 of
`
`actuator P2’ may be connected to a further structural el-
`ement 24’ connected to the trailing edge end 18. In this
`case inner areas 30’ of the blade trailing edge portion 12
`may also be filled with a honeycomb structure material.
`Furthermore, the blade skin of almost the whole trailing
`edge portion 12 may be made of a flexible material 19‘"
`with the exception of the trailing edge end 18 and that
`area on which structural element 24’ rests.
`
`[0036] As explained above, the basic principle lies on
`having at
`least
`two actuators arranged substantially
`downstream from one another and connected to each
`
`other by a substantially rigid link conforming an internal
`structure arranged inside a trailing edge portion ofa blade
`section such that upon activation of any of the actuators
`a structural shape of the trailing edge portion changes.
`[0037] Although the actuators described are piezoe-
`lectric elements, it should be understood that other type
`ofactuators having a substantially instantaneously lineal
`behavior such as bistable elements or mechanical actu-
`
`ators such as pneumatic or hydraulic cylinders may also
`be foreseen. Furthermore, other combinations and/or
`quantity of actuators are also possible as long as there
`are at least two actuators, one being an upper actuator
`and the other being a lower actuator. This way, whenever
`three or more actuators are being used a substantially
`zig-zag shape can be defined.
`[0038] Although only a number of particular embodi-
`ments and examples of the invention have been dis-
`closed herein, itwill be understood by those skilled in the
`art that other alternative embodiments and/or uses of the
`
`thereofare possible. Furthermore, the present invention
`covers all possible combinations of the particular embod-
`iments described. Thus, the scope of the present inven-
`tion should not be limited by particular embodiments, but
`should be determined only by a fair reading of the claims
`that follow.
`
`Claims
`
`1. Wind turbine blade comprising at least one deform-
`able trailing edge section having
`a plurality of actuators consecutively arranged sub-
`stantially downstream from one another and a con-
`trol system for controlling the actuators,
`wherein a downstream end of one actuator is con—
`
`nected by a substantially rigid link with an upstream
`end ofthe next actuator and the plurality of actuators
`comprises an upper actuator being mounted above
`a chord line ofthe blade section and a lower actuator
`
`being mounted below a chord line of the blade sec-
`tion.
`
`2. Wind turbine blade according to claim 1, wherein the
`actuators are alternatingly upper and lower actua-
`tors.
`
`3. Wind turbine blade according to any of claims 1 or
`2, wherein the actuators are linked such that upon
`activation of at least one upper and/or at least one
`lower actuator a structural shape of the blade trailing
`edge section changes in at least two degrees offree-
`dom.
`
`4. Wind turbine blade according to claim 3, wherein the
`actuators are linked such that upon activation of at
`least one upper and/or at least one lower actuator
`at leastone of a flap angle and a chord length of the
`blade is changed.
`
`5. Wind turbine blade according to any of claims 1—4,
`wherein at leastone upper actuator is mounted close
`to an inner surface of a suction side of a skin of the
`
`blade trailing edge section and at least one lower
`actuator is mounted close to an inner surface of a
`
`pressure side of a skin of the blade trailing edge sec-
`tion.
`
`6. Wind turbine blade according to claim 5, wherein the
`actuators are mounted substantially parallel to the
`blade skin.
`
`7. Wind turbine blade according to any of claims 1-6,
`wherein the rigid links connected to the upstream
`end of the actuators are mounted substantially per-
`pendicular to the blade skin.
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`invention and obvious modifications and equivalents
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`8. Wind turbine blade according to any of claims 1-7,
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`wherein the actuators are selected among a group
`consisting of piezoelectric elements, bistable ele-
`ments and pneumatic or hydraulic actuators.
`
`Wind turbine blade according to any of claims 1—8,
`wherein the deformable trailing edge section ex-
`tends on one third of the total length of the blade,
`towards a tip of the blade.
`
`Wind turbine blade according to any of claims 1-9,
`wherein the deformable trailing edge section spans
`on a range between 30% and 40% of the chord line
`of the blade section.
`
`Wind turbine blade according to any of claims 1-10,
`wherein at least portions ofa skin ofthe blade trailing
`edge section, not supporting the actuators, nor the
`rigid links, are made ofa relatively flexible material.
`
`Wind turbine blade according to claim 11, wherein
`substantially the whole blade trailing edge section
`skin is made of a relatively flexible material.
`
`Wind turbine blade according to any of claims 11-12,
`wherein at least inner areas of the blade trailing edge
`section next to the flexible material are filled with an
`
`anisotropic material.
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`Wind turbine blade according to claim 13, wherein
`the anisotropic material is a honeycomb structure.
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`Wind turbine comprising at leastone blade according
`to any of claims 1-14.
`
`Method of controlling loads on a wind turbine blade
`according to any of claims 1-14, wherein the method
`comprises activating at least one upper and/or at
`leastone lower actuator such that a structural shape
`of the blade trailing edge section changes in at least
`two degrees of freedom.
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`FIG.20
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`FIG.2d
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`EP 2 757 254 A1
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`12
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`EP 2 757 254 A1
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`Europiisches
`Patent: mt
`European
`Patent offlre
`Office européen
`
`des brevets
`
`EU ROPEAN SEARCH REPORT
`
`Application Number
`EP 13 38 2022
`
`
`DOCUMENTS CONSIDERED TO BE RELEVANT
`
`Categon/
`
`of reievant assaes
`Citation of document with indication, where appropriate,
`
`toclaim
`Relevant
`
`APPLICATION UPC)
`CLASSIFICATION OF THE
`
`Y
`
`Y
`
`A
`
`A
`
`A
`
`
`
`N E
`
`POFORM15030382(P011001)
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`55
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`us 2007/036653 A1 (BAK DAN c
`BAK DAN CHRISTIAN [DK] ET AL)
`15 February 2007 (2007-02-15)
`*
`* paragraphs [0057]
`-
`[0060]; figures 6-8
`
`[DK] ET AL
`
`(PEREZ JUAN [DE])
`US 2002/100842 Al
`1 August 2002 (2002-08-01)
`[0039],
`* paragraphs [0029],
`[0038],
`[0049],
`[0050]; figures 19,20 *
`
`US 2001/052287 A1 (PEREZ JUAN [DE] ET AL)
`20 December 2001 (2001-12-20)
`* paragraph [0056]; figures 12,13 *
`
`us 6 375 127 01 (APPA KARI
`23 Aprii 2002 (2002-04-23)
`* coiumn 6,
`line 8 - Tine 61; figures
`2,4,5 *
`
`[03])
`
`US 2010/247314 A1 (NARASIMALU SRIKANTH
`[50]) 30 September 2010 (2010-09-30)
`* paragraphs [0028]
`-
`[0030]; figures *
`-----
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`1-6,8-16 INV.
`F03D7/02
`F03D1/06
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`1-6,8-16
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`1,16
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`1,16
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`1,16
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`TECHNICALFIELIIILSC
`SEARCHED
`I
`F030
`B64C
`
`’
`
`
`
`The present search report has been drawn up for ail claims
`Place of Search
`Date of completion cf the search
`
`Examiner
`
`The Hague
`CATEGORY OF CITED DOCUMENTS
`X: particuiarly relevant iftaken alone
`V : particuiorly relevant if combined With another
`document of the same category
`A : technoiogical background
`0: non-written disclosure
`P : intermediate document
`
`Area] Caiama, A
`8 Juiy 2013
`T : theory or principle underlying the invention
`E: eariier patent document, but pubiished on, or
`after the filing date
`D ' document cited in the application
`L ' document cited for other reasons
`
`tit:nienrherofthesamerpatemiarriiiy,oorfispohding N
`document
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`1
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`1
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`13
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`EP2757254A1
`
`ANNEXTOTHEEUROPEANSEARCHREPORT
`ON EUROPEAN PATENT APPLICATION NO.
`
`EP 13 38 2022
`
`This annex lists the patent family members relating to the patent documents cited in the above-mentioned EJropean search report.
`The members are as contained in the European Patent Office EDP file on
`The European Patent Office is in no way liable for these particulars which are merely given for the purpose of information
`08-07-2013
`
`Patent document
`citedIn search report
`
`Publication
`date
`
`Patent family
`member(s)
`
`Publication
`date
`
`US 2007036653
`
`A1
`
`15- 02- 2007
`
`FORMP0459
`
`E For more details about this annex :see Official Journal ofthe European Patent Office, No 12/82
`
`14
`
`2004225883A
`2521045A
`1780983
`1613860
`2007036653
`2004088130
`
`286474
`10055961
`1205383
`2234749
`2002100842
`
`341716
`10009157
`1128072
`2270909
`2001052287
`
`CN
`CN
`EP
`US
`
`101865076
`201757024
`2233735
`2010247314
`
`14- 10- 2004
`14- 10- 2004
`31- 05- 2006
`11-01-2006
`15-02-2007
`14-10-2004
`
`15—01—2005
`23-05-2002
`15-05-2002
`01-07-2005
`01-08-2002
`
`15-10-2006
`13-09-2001
`29-08-2001
`16-04-2007
`20-12-2001
`
`20-10-2010
`09-03-2011
`29-09-2010
`
`30-09-2010
`
`10
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`15
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`20
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`25
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`30
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`50
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`REFERENCES CITED IN THE DESCRIPTION
`
`EP 2 757 254 A1
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`This list of references cited by the applicant is for the reader’s convenience only. it does not form part of the European
`patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be
`excluded and the EPO disclaims all liability in this regard.
`
`Patent documents cited in the description
`
`- WO 2004088130 A [0005]
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`15
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