CA1146079A - Wind turbine blade pitch adjustment system - Google Patents
Wind turbine blade pitch adjustment systemInfo
- Publication number
- CA1146079A CA1146079A CA000371573A CA371573A CA1146079A CA 1146079 A CA1146079 A CA 1146079A CA 000371573 A CA000371573 A CA 000371573A CA 371573 A CA371573 A CA 371573A CA 1146079 A CA1146079 A CA 1146079A
- Authority
- CA
- Canada
- Prior art keywords
- blades
- wind turbine
- hub
- adjustment system
- pitch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000012530 fluid Substances 0.000 claims abstract description 22
- 238000012546 transfer Methods 0.000 claims abstract description 18
- 210000003746 feather Anatomy 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 claims 1
- 230000001105 regulatory effect Effects 0.000 claims 1
- RLQJEEJISHYWON-UHFFFAOYSA-N flonicamid Chemical compound FC(F)(F)C1=CC=NC=C1C(=O)NCC#N RLQJEEJISHYWON-UHFFFAOYSA-N 0.000 abstract 1
- 230000007246 mechanism Effects 0.000 description 12
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03D—WIND MOTORS
- F03D7/00—Controlling wind motors
- F03D7/02—Controlling wind motors the wind motors having rotation axis substantially parallel to the air flow entering the rotor
- F03D7/04—Automatic control; Regulation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03D—WIND MOTORS
- F03D7/00—Controlling wind motors
- F03D7/02—Controlling wind motors the wind motors having rotation axis substantially parallel to the air flow entering the rotor
- F03D7/022—Adjusting aerodynamic properties of the blades
- F03D7/0224—Adjusting blade pitch
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2260/00—Function
- F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
- F05B2260/74—Adjusting of angle of incidence or attack of rotating blades by turning around an axis perpendicular the rotor centre line
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2260/00—Function
- F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
- F05B2260/79—Bearing, support or actuation arrangements therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2270/00—Control
- F05B2270/60—Control system actuates through
- F05B2270/604—Control system actuates through hydraulic actuators
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/72—Wind turbines with rotation axis in wind direction
Abstract
WIND TURBINE BLADE PITCH ADJUSTMENT SYSTEM
Abstract A lightweight system for adjusting the pitch of a plurality of variable pitch wind turbine blades. The sys-tem comprises, a rotatable hub on which the blades are mounted, an individual hydraulic actuator mounted on the hub and connected to each blade for setting the blade at a preselected pitch and an electrical feedback device pro-viding a controller with a signal indicative of the actual pitch setting of the blades. The actuators are provided with hydraulic fluid by means of a transfer bearing while the feedback device is electrically connected to the con-troller through slip rings rotatable with the hub. By this system, the requirement of relatively heavy mechanical interconnections between the actuators and blades are eliminated, and the blades are individually adjustable with regard to the pitch thereof, whereby the pitch set-ting of the various blades may simultaneously differ as called for by the controller.
Abstract A lightweight system for adjusting the pitch of a plurality of variable pitch wind turbine blades. The sys-tem comprises, a rotatable hub on which the blades are mounted, an individual hydraulic actuator mounted on the hub and connected to each blade for setting the blade at a preselected pitch and an electrical feedback device pro-viding a controller with a signal indicative of the actual pitch setting of the blades. The actuators are provided with hydraulic fluid by means of a transfer bearing while the feedback device is electrically connected to the con-troller through slip rings rotatable with the hub. By this system, the requirement of relatively heavy mechanical interconnections between the actuators and blades are eliminated, and the blades are individually adjustable with regard to the pitch thereof, whereby the pitch set-ting of the various blades may simultaneously differ as called for by the controller.
Description
114607~
Technical Field This invention relates to wind turbines and more par-ticularly to a system for selectively adjusting the pitch of variable pitch wind turbine blades.
Background Art For optimum performance it is desirable to provide wind turbines with variable pitch blades. The pitch of such blades is adjusted by selective pivoting of the blades about their own longitudinal axes, enabling the wind turbine to perform at maximum efficiency throughout a wide ran~e of wind conditions as well as aiding turbine start-up and prevention of overspeed operation (by blade feathering) in high velocity winds.
Various mechanisms have been proposed for varying the pitch of wind turbine blades. One such mechanism, dis-closed in U. S. Patent No. 4,083,651 to Cheney et al and assigned to the assignee of the present invention, employs blades which are torsionally twisted by pendulum members connected thereto, the pendulum members being centrifugally 3~' 6~79 responsive to the rotor speed of the wind turbine to twist the blades thereby varying the blade pitch throughout the operating range of the wind turbine. The blade pitch ad-~ustment range of such a system is of course automatic and incapable of being continuously controlled during operation of the turbine and may not be capable of achieving ex- ~
tremely wide ranges of pitch adjustment.
A second pitch adjusting system for wind turbine blades employs a slide block which rotates with and is longitudinally slidable on the main shaft of the wind tur-bine. The slide block is connected by means of a plurality of solid links to the wind turbine blades which are mounted on a rotational hub such that the blades are pivotable about their own axes. The block is also connected to a plurality of fixed actuators through a bearing mechanism.
When an adjustment in blade pitch is desired, the actua-tors acting through the bearing mechanism, rectilinearly move the slide block over the shaft thereby moving the links which in turn pivot the blades. It will be appreci-ated that in this prior art system, to adjust blade pitch,it is necessary not only to expend suficient energy to i overcome the resistance to such movement by the blades themsel~es but to overcome the mass of the links, slider block and bearing mechanism, and the friction losses as-sociated with the bearings and the movement of the slider block over the shaft. Inasmuch as the commercial feasi-bility of wind turbines depends not only on the amount of energy gathered, but on the losses associated with the - operation of the wind turbine, it will be appreciated that extensive losses such as those enumerated herein as-- sociated with this prior art blade pitch control system, -: could, under ma~ginal wind conditions, render the turbine commerically infeasible.
While various pitch change mechanisms have been pro-posed for aïrcraft propellers, such systems have beenfound to be generally inappropriate for use on wind ~- 1146Q79 ~/
turbines. Examples of such pitch change mechanisms are found in U. S. Patents Nos. 1,908,894 to Findley and 3~163,232 to Grindle~ the Grindle patent being assigned to the assignee of the present invention. In the Findley patent, the pitch of the propeller blades is changed by a hub mounted electric motor pivotally driving the propeller blades through a gear set. Such a gear connection of the electric motor to the blades contri-butes significantly to the weight of the turbine hub thereby introducing substantial lDsses into the system.
In the Grindle patent an hydraulic motor powers the blades in a pitch change mode of operation through a relatively massive rotating cam-bevel gear arrangement which adds substantial weight and significant energy losses to the system.
~herefore, it is an object of the present in-vention to provide a wind turbine blade pitch adjustment system which overcomes the deficiencies of the prior art.
It is another object of the present invention to provide such a pitch adjustment system wherein each blade may be simultaneously positioned at a different pitch angle as called for by the controller.
It is another object of the present invention to provide such a blade pitch adjustment system which is light in weight.
It is another object of the present invention to provide such a blade pitch adjustment system wherein the losses associated with any connection between the system driving means and the blades are minimized.
It is another object of the present invention to provide such a system which is characterized by an economy of structure.
~146~79 - 3a -In accordance with a particular embodiment of the invention there is provided a wind turbine blade pitch adjustment system. The system includes a rotatable hub and at least two airfoil blades extending generally S radially outward from the hub for rotation therewith.
Each o~ the blades is pivotable about the longitudinal axis thereof for varying the blade pitch, and individual actuation means are mounted on the hub and rotatable therewith and are directly connected to corresponding blades for adjusting pitch positioning of each blade individually. m e control system further includes feed-back means mounted on the hub and operatively connected to the blades for producing a signal indicative of blade pitch. Control means, removed from the hub, re-gulate the actuators in response at least in part tothe signal produced by the feedback means. First and second transfer means are adapted to provide communication acro~s a rotative-stationary interface between the control means and actuation means and feedback means 0 respectively.
m e above and other objects will become more readily apparent from the following detailed description taken in 1~46Q79 connection with the appended claims and the accompanying drawings wherein there is shown and described a wind tur-bine blade pitch adjustment system wherein each blade is driven by an individual hydraulic actuator mounted on the-hub for rotation therewi,th and connected directly to theblade thereby eliminating the necessity of intermediate connecting devices such as links, cams, gears and the like and the losses associated with such mechanisms. The actua-tors are independently controlled by a control means re-moved from the hub, the control means supplying the actua-tors with hydraulic fluid by way of suitable fluid trans-fer means such as a transfer bearing preferably disposed , on the main turbine shaft. An emergency hydraulic fluid supply for feathering may also be mounted on the hub in lS direct communication with the actuators. Feedback means such as a linear variable displacement transducer provide a continuous control system input indicative of the pitch position of the blades. Power for the feedback means is provided thereto by suitable means such as slip ring-bush assembly which may also provide connection of the feedback output to the control means.
Brief Description of The Drawings Fig. 1 is a side elevation of a large wind turbine in which the blade pitch adjustment system of the present invention is employed, a portion of this view being broken away to show structural details of the turbine.
Fig. 2 is a schematic, side elevation, partially sec-tioned and broken away, of a portion of the blade pitch adjustment system of the present invention.
Fig. 3 is a schematic, side elevation partially sec-tional and broken away, of a second portion of the blade pitch adjustment system of the present invention.
1146~79 ,:
, . .
Best Mode For Carrying Out The Invention ~ !
Referring to the drawings, the wind turbine blade pitch control system of the present invention is adapted :, for use with a wind turbine wherein two or more variable pitch blades 10 and 12 are mounted on suitable bearings (not shown~ on a rotatable hub 14 (Fig. 2) covered by spinner 15 such that the blades are selectively pivotable about the longitudinal axes thereof for controlling the , operating speed of the wind turbine throughout a wide range : 10 of wind conditions and for feathering the blades when a ::
: shutdown of the wind turbine is desired. The hub is se-. , : cured to rotating shaft 16 from which any desired load such as a dynam~.~ electric machine 18 or the like may be ::
driven. The shaft speed may be stepped up or down as de-sired by a suitable gear box 20. The load as well as gear box 20, along with various controls 50 may be disposed , within nacelle 22 mounted on a swivel or free pivot con-nection 24 on tower 26 generally upstream of blades 10 and 12.
:, The blade pitch adjusting mechanism of the present invention comprises first and second hydraulic actuators or motors 28 each controlling the pitch of a single one of ` turbine blades by direct connection thereto. While in the preferred embodiment two blades and two actuators are shown, it will be understood that the present invention contem-plates any number of blades and associated actuators. Each actuator comprises a cylinder 30 having a reciprocating piston 34 with corresponding connecting rod 36 disposed within the cylinder for reciprocal movement with respect ` 30 thereto. Hydraulic fluid is admitted into and drained ,~ from the cylinder on opposite sides of the piston through hydraulic lines 38 and 40.
As best seen in Fig. 2, each actuator at the free end ,. ` .
:
3.146~79 of the connecting rod thereof is connected to the root por-tion of the corresponding blade at a first clevis 42, the connection being spaced a distance d from the longitudinal axis a of the blade whereby, reciprocation of the piston imparts a pivoting motion of the blade about the longitudi-nal axis thereof. The opposite end of the actuator at the enclosed end of the cylinder thereof is pivotally connected at 44 to a central portion 46 of hub 14 thereby minimizing the obstruction of wind by the blade actuating mechanism.
Since each actuator must only power a single blade, the actuators are generally lightweight and compact when com-pared to various prior art ~de pitch adjustment systems wherein a single actuator drives all the blades in pitch adjustment. Accordingly, the utilization of multiple ac-tuators rather than a single more powerful actuator doesnot pose a serious weight problem to the turbine hub.
Furthermore, it will be appreciated that employment of an individual lightweight hub mounted actuator for each blade allows a direct connection of the actuator to the blade thereby eliminating the need for heavy and bulky mechanical connections between the blade and actuator such as the slide blocks, links, and bearings employed in prior art wind turbines and rotary cam and gear assemblies employed in prior art propeller pitch change mechanisms. As set forth hereinabove, such prior art pitch change mechanisms reduce the efficiency of the system by introducing into the system, losses due to the weight of the com~onents and the frictional forces incident to the interaction of such components. Moreover, the arrangement of the present in-vention allows each of the blades to be individually ad-justed with respect to the pitch thereof, whereby if re-quired, the blades may be simultaneously set by the con-troller at different pitch settings.
As seen in Figs. 2 and 3, lines 38 and 40 from each of actuators 28 extend axially through the center of hub . .
14 to control means 50 by way of first transfer means 52.
It will be understood that control means 50 regulates the operation of actuator 28. Where the actuators are hydraulic actuators such as those shown herein, the control means will of course include hydraulic fluid flow control means to selectively pressurize and drain cylin-ders 30 on opposite sides of pistons 34. A suitable control means is disclosed and claimed in Canadian patent application serial no. 372,746, filed March 11, 1981, for "Wind Turbine Blade Pitch Control System", in the name of Merritt B. Andrews.
As shown in Fig. 1, control means 50 is prefer-ably mounted in nacelle 22.
When hydraulic blade actuators are employed, first transfer means comprises a transfer bearing which includes first (outer) and second (inner) concentric members 54 and 56, inner member 56 in the preferred em-bodiment being rotatable with shaft 16 on bearings 57 and compri~ing an integral portion thereof. Inner member 56 is provided with a plurality of hydraulic fluid passages 58 each including an outer radial portion 60 and an inner longitudinally directed portion 64. Each passage 58 pro-vides pressurized hydraulic fluid to the lines associated with actuators 28 and feather means to be described here-inbelow. Each of passages 58 communicates at radial por-tion 60 thereof with an adjacent annular passage 66 in outer member 54, this passage communicating with control means 50 through lines 68 in outer member 54 and conduits extension lines 69.
The pitch adjusting system of the present inven-tion also includes feedback means 70, each such means being mounted on the hub and connected to a corresponding blade and providing control means 50 with a signal indic-ative of the pitch position of the blade, whereby the control means continuously adjusts actuators 28 based on the feedback signal to precisely position the blades.
In the A
,~., 1146~79 ^ 8 ~
preferred em~odiment, the feedback means comprises an elec-trical transducer having a movable core pivotally con-nected to the blade root at second clevis 72, the trans-ducer primary and secondary (stator) being pivotally con-nected to the hub at 74. Therefore, it will be seen thatas actuators 28 pivot the blades, the relative disposition of the core and windings varies thereby causing the output from the secondary to vary in accordance with blade pitch.
Connections from the primary and secondary coils of feed-back means 70 to control means 50 are made in part throughlines 76 which extend from the feedback means, radially inwardly and rearwardly through the hub shaft, and inner transfer bearing member 56 to second transfer means 80.
Referring to Fig. 3, when feedbac~ means 70 are electrical, second transfer means 80 comprises a plurality of slip rings 82 rotatable with the hub either at the same speed thereof or at the higher rotational speed at the out-put of gear set 20. In the preferred embodiment, the slip rings are mounted on an integral extension of inner transfer bearing member 56, although other equivalent con-structions will suggest themselves to those skilled in theart. As best seen in Fig. 3, the electric lines are brought longitudinally through inner member or shaft 56 and radially outwardly, being connected to the slip rings at the sides thereof by soldering or the like. Slip rings 82 engage stationary brushes 84 which are slidable on the : slip rings and mounted on a stationary brush holder 86.
Electric lines 88 connect the brushes to the controller.
: As set forth hereinabove, the control means 50 con-trols the supply of hydraulic fluid to actuators 28 in : response to a pitch position signal provided by feedback means 70, details of the control means not forming part of the present invention. Accordingly, it will become ap-- parent that the control means comprises cooperating elec-tric and fluid logic circuits in any suitable configuration.
.~
1~46~79 Reference may be had to the aforementioned Andrews patent application which discloses an hydraulic control circuit : suitable for use in a pitch adjustment system as taught herein. Where independent control over the actuators is required, the control means will of course be provided with redundant logic circuits which will simultaneously position each blade at a different pitch angle when operat-ing conditions so require.
The pitch adjustment system of the present invention may also be provided with means powering the blades for the feathering thereof in emergency situations independent-ly of the fluid supply for the actuators and therefore operable despite any malfunction in that supply. In the preferred embodiment, such means comprise a tank or ac-cumulator 90 of pressurized hydraulic fluid communicatingthrough line 91 and servo valve 92 with that side of the corresponding actuator which must be pressurized for feathering the associated blade. Servo valve 92 may be either fluid or electrically controlled by controller 50.
; 20 If fluid controlled, the servo portion or actuator of the valve will communicate with control means 50 through the : passages in the transfer bearing. If electrically operated, the valve will be operated by the electrical portion of control means 50, being connected thereto through the slip ring-brush assembly of second transfer means 80.
It will therefore be appreciated that with the system of the present invention, wind turbine blade pitch is ad-justed effectively and efficiently withou$ the heavy and often complex prior art mechanical assemblies intercon-necting the blades and actuators therefor. T~e actuators may be relatively light in weight since each performs in-dependently of other blades, being required to power no more than a single blade. Connections between the ac-tuators and control means are also made with an economyo~ structure thereby further reducing the power required ~1 46~79 by such a system and thus enhancing the overall efficiency of a wind turbine in which the pitch adjusting system is employed. ~he provision of the feather accumulators on the hub, in proximity to the blades assures the feathering capability of the system despite failure of the primary actuator fluid supply.
While there has been shown a single embodiment of the pitch adjustment system of the present invention, it will be apparent that various equivalent systems may suggest themselves to those skilled in the art and it is intended by the following claims to cover such equivalent systems as come within the true s~irit and scope oi this invention.
. .
Technical Field This invention relates to wind turbines and more par-ticularly to a system for selectively adjusting the pitch of variable pitch wind turbine blades.
Background Art For optimum performance it is desirable to provide wind turbines with variable pitch blades. The pitch of such blades is adjusted by selective pivoting of the blades about their own longitudinal axes, enabling the wind turbine to perform at maximum efficiency throughout a wide ran~e of wind conditions as well as aiding turbine start-up and prevention of overspeed operation (by blade feathering) in high velocity winds.
Various mechanisms have been proposed for varying the pitch of wind turbine blades. One such mechanism, dis-closed in U. S. Patent No. 4,083,651 to Cheney et al and assigned to the assignee of the present invention, employs blades which are torsionally twisted by pendulum members connected thereto, the pendulum members being centrifugally 3~' 6~79 responsive to the rotor speed of the wind turbine to twist the blades thereby varying the blade pitch throughout the operating range of the wind turbine. The blade pitch ad-~ustment range of such a system is of course automatic and incapable of being continuously controlled during operation of the turbine and may not be capable of achieving ex- ~
tremely wide ranges of pitch adjustment.
A second pitch adjusting system for wind turbine blades employs a slide block which rotates with and is longitudinally slidable on the main shaft of the wind tur-bine. The slide block is connected by means of a plurality of solid links to the wind turbine blades which are mounted on a rotational hub such that the blades are pivotable about their own axes. The block is also connected to a plurality of fixed actuators through a bearing mechanism.
When an adjustment in blade pitch is desired, the actua-tors acting through the bearing mechanism, rectilinearly move the slide block over the shaft thereby moving the links which in turn pivot the blades. It will be appreci-ated that in this prior art system, to adjust blade pitch,it is necessary not only to expend suficient energy to i overcome the resistance to such movement by the blades themsel~es but to overcome the mass of the links, slider block and bearing mechanism, and the friction losses as-sociated with the bearings and the movement of the slider block over the shaft. Inasmuch as the commercial feasi-bility of wind turbines depends not only on the amount of energy gathered, but on the losses associated with the - operation of the wind turbine, it will be appreciated that extensive losses such as those enumerated herein as-- sociated with this prior art blade pitch control system, -: could, under ma~ginal wind conditions, render the turbine commerically infeasible.
While various pitch change mechanisms have been pro-posed for aïrcraft propellers, such systems have beenfound to be generally inappropriate for use on wind ~- 1146Q79 ~/
turbines. Examples of such pitch change mechanisms are found in U. S. Patents Nos. 1,908,894 to Findley and 3~163,232 to Grindle~ the Grindle patent being assigned to the assignee of the present invention. In the Findley patent, the pitch of the propeller blades is changed by a hub mounted electric motor pivotally driving the propeller blades through a gear set. Such a gear connection of the electric motor to the blades contri-butes significantly to the weight of the turbine hub thereby introducing substantial lDsses into the system.
In the Grindle patent an hydraulic motor powers the blades in a pitch change mode of operation through a relatively massive rotating cam-bevel gear arrangement which adds substantial weight and significant energy losses to the system.
~herefore, it is an object of the present in-vention to provide a wind turbine blade pitch adjustment system which overcomes the deficiencies of the prior art.
It is another object of the present invention to provide such a pitch adjustment system wherein each blade may be simultaneously positioned at a different pitch angle as called for by the controller.
It is another object of the present invention to provide such a blade pitch adjustment system which is light in weight.
It is another object of the present invention to provide such a blade pitch adjustment system wherein the losses associated with any connection between the system driving means and the blades are minimized.
It is another object of the present invention to provide such a system which is characterized by an economy of structure.
~146~79 - 3a -In accordance with a particular embodiment of the invention there is provided a wind turbine blade pitch adjustment system. The system includes a rotatable hub and at least two airfoil blades extending generally S radially outward from the hub for rotation therewith.
Each o~ the blades is pivotable about the longitudinal axis thereof for varying the blade pitch, and individual actuation means are mounted on the hub and rotatable therewith and are directly connected to corresponding blades for adjusting pitch positioning of each blade individually. m e control system further includes feed-back means mounted on the hub and operatively connected to the blades for producing a signal indicative of blade pitch. Control means, removed from the hub, re-gulate the actuators in response at least in part tothe signal produced by the feedback means. First and second transfer means are adapted to provide communication acro~s a rotative-stationary interface between the control means and actuation means and feedback means 0 respectively.
m e above and other objects will become more readily apparent from the following detailed description taken in 1~46Q79 connection with the appended claims and the accompanying drawings wherein there is shown and described a wind tur-bine blade pitch adjustment system wherein each blade is driven by an individual hydraulic actuator mounted on the-hub for rotation therewi,th and connected directly to theblade thereby eliminating the necessity of intermediate connecting devices such as links, cams, gears and the like and the losses associated with such mechanisms. The actua-tors are independently controlled by a control means re-moved from the hub, the control means supplying the actua-tors with hydraulic fluid by way of suitable fluid trans-fer means such as a transfer bearing preferably disposed , on the main turbine shaft. An emergency hydraulic fluid supply for feathering may also be mounted on the hub in lS direct communication with the actuators. Feedback means such as a linear variable displacement transducer provide a continuous control system input indicative of the pitch position of the blades. Power for the feedback means is provided thereto by suitable means such as slip ring-bush assembly which may also provide connection of the feedback output to the control means.
Brief Description of The Drawings Fig. 1 is a side elevation of a large wind turbine in which the blade pitch adjustment system of the present invention is employed, a portion of this view being broken away to show structural details of the turbine.
Fig. 2 is a schematic, side elevation, partially sec-tioned and broken away, of a portion of the blade pitch adjustment system of the present invention.
Fig. 3 is a schematic, side elevation partially sec-tional and broken away, of a second portion of the blade pitch adjustment system of the present invention.
1146~79 ,:
, . .
Best Mode For Carrying Out The Invention ~ !
Referring to the drawings, the wind turbine blade pitch control system of the present invention is adapted :, for use with a wind turbine wherein two or more variable pitch blades 10 and 12 are mounted on suitable bearings (not shown~ on a rotatable hub 14 (Fig. 2) covered by spinner 15 such that the blades are selectively pivotable about the longitudinal axes thereof for controlling the , operating speed of the wind turbine throughout a wide range : 10 of wind conditions and for feathering the blades when a ::
: shutdown of the wind turbine is desired. The hub is se-. , : cured to rotating shaft 16 from which any desired load such as a dynam~.~ electric machine 18 or the like may be ::
driven. The shaft speed may be stepped up or down as de-sired by a suitable gear box 20. The load as well as gear box 20, along with various controls 50 may be disposed , within nacelle 22 mounted on a swivel or free pivot con-nection 24 on tower 26 generally upstream of blades 10 and 12.
:, The blade pitch adjusting mechanism of the present invention comprises first and second hydraulic actuators or motors 28 each controlling the pitch of a single one of ` turbine blades by direct connection thereto. While in the preferred embodiment two blades and two actuators are shown, it will be understood that the present invention contem-plates any number of blades and associated actuators. Each actuator comprises a cylinder 30 having a reciprocating piston 34 with corresponding connecting rod 36 disposed within the cylinder for reciprocal movement with respect ` 30 thereto. Hydraulic fluid is admitted into and drained ,~ from the cylinder on opposite sides of the piston through hydraulic lines 38 and 40.
As best seen in Fig. 2, each actuator at the free end ,. ` .
:
3.146~79 of the connecting rod thereof is connected to the root por-tion of the corresponding blade at a first clevis 42, the connection being spaced a distance d from the longitudinal axis a of the blade whereby, reciprocation of the piston imparts a pivoting motion of the blade about the longitudi-nal axis thereof. The opposite end of the actuator at the enclosed end of the cylinder thereof is pivotally connected at 44 to a central portion 46 of hub 14 thereby minimizing the obstruction of wind by the blade actuating mechanism.
Since each actuator must only power a single blade, the actuators are generally lightweight and compact when com-pared to various prior art ~de pitch adjustment systems wherein a single actuator drives all the blades in pitch adjustment. Accordingly, the utilization of multiple ac-tuators rather than a single more powerful actuator doesnot pose a serious weight problem to the turbine hub.
Furthermore, it will be appreciated that employment of an individual lightweight hub mounted actuator for each blade allows a direct connection of the actuator to the blade thereby eliminating the need for heavy and bulky mechanical connections between the blade and actuator such as the slide blocks, links, and bearings employed in prior art wind turbines and rotary cam and gear assemblies employed in prior art propeller pitch change mechanisms. As set forth hereinabove, such prior art pitch change mechanisms reduce the efficiency of the system by introducing into the system, losses due to the weight of the com~onents and the frictional forces incident to the interaction of such components. Moreover, the arrangement of the present in-vention allows each of the blades to be individually ad-justed with respect to the pitch thereof, whereby if re-quired, the blades may be simultaneously set by the con-troller at different pitch settings.
As seen in Figs. 2 and 3, lines 38 and 40 from each of actuators 28 extend axially through the center of hub . .
14 to control means 50 by way of first transfer means 52.
It will be understood that control means 50 regulates the operation of actuator 28. Where the actuators are hydraulic actuators such as those shown herein, the control means will of course include hydraulic fluid flow control means to selectively pressurize and drain cylin-ders 30 on opposite sides of pistons 34. A suitable control means is disclosed and claimed in Canadian patent application serial no. 372,746, filed March 11, 1981, for "Wind Turbine Blade Pitch Control System", in the name of Merritt B. Andrews.
As shown in Fig. 1, control means 50 is prefer-ably mounted in nacelle 22.
When hydraulic blade actuators are employed, first transfer means comprises a transfer bearing which includes first (outer) and second (inner) concentric members 54 and 56, inner member 56 in the preferred em-bodiment being rotatable with shaft 16 on bearings 57 and compri~ing an integral portion thereof. Inner member 56 is provided with a plurality of hydraulic fluid passages 58 each including an outer radial portion 60 and an inner longitudinally directed portion 64. Each passage 58 pro-vides pressurized hydraulic fluid to the lines associated with actuators 28 and feather means to be described here-inbelow. Each of passages 58 communicates at radial por-tion 60 thereof with an adjacent annular passage 66 in outer member 54, this passage communicating with control means 50 through lines 68 in outer member 54 and conduits extension lines 69.
The pitch adjusting system of the present inven-tion also includes feedback means 70, each such means being mounted on the hub and connected to a corresponding blade and providing control means 50 with a signal indic-ative of the pitch position of the blade, whereby the control means continuously adjusts actuators 28 based on the feedback signal to precisely position the blades.
In the A
,~., 1146~79 ^ 8 ~
preferred em~odiment, the feedback means comprises an elec-trical transducer having a movable core pivotally con-nected to the blade root at second clevis 72, the trans-ducer primary and secondary (stator) being pivotally con-nected to the hub at 74. Therefore, it will be seen thatas actuators 28 pivot the blades, the relative disposition of the core and windings varies thereby causing the output from the secondary to vary in accordance with blade pitch.
Connections from the primary and secondary coils of feed-back means 70 to control means 50 are made in part throughlines 76 which extend from the feedback means, radially inwardly and rearwardly through the hub shaft, and inner transfer bearing member 56 to second transfer means 80.
Referring to Fig. 3, when feedbac~ means 70 are electrical, second transfer means 80 comprises a plurality of slip rings 82 rotatable with the hub either at the same speed thereof or at the higher rotational speed at the out-put of gear set 20. In the preferred embodiment, the slip rings are mounted on an integral extension of inner transfer bearing member 56, although other equivalent con-structions will suggest themselves to those skilled in theart. As best seen in Fig. 3, the electric lines are brought longitudinally through inner member or shaft 56 and radially outwardly, being connected to the slip rings at the sides thereof by soldering or the like. Slip rings 82 engage stationary brushes 84 which are slidable on the : slip rings and mounted on a stationary brush holder 86.
Electric lines 88 connect the brushes to the controller.
: As set forth hereinabove, the control means 50 con-trols the supply of hydraulic fluid to actuators 28 in : response to a pitch position signal provided by feedback means 70, details of the control means not forming part of the present invention. Accordingly, it will become ap-- parent that the control means comprises cooperating elec-tric and fluid logic circuits in any suitable configuration.
.~
1~46~79 Reference may be had to the aforementioned Andrews patent application which discloses an hydraulic control circuit : suitable for use in a pitch adjustment system as taught herein. Where independent control over the actuators is required, the control means will of course be provided with redundant logic circuits which will simultaneously position each blade at a different pitch angle when operat-ing conditions so require.
The pitch adjustment system of the present invention may also be provided with means powering the blades for the feathering thereof in emergency situations independent-ly of the fluid supply for the actuators and therefore operable despite any malfunction in that supply. In the preferred embodiment, such means comprise a tank or ac-cumulator 90 of pressurized hydraulic fluid communicatingthrough line 91 and servo valve 92 with that side of the corresponding actuator which must be pressurized for feathering the associated blade. Servo valve 92 may be either fluid or electrically controlled by controller 50.
; 20 If fluid controlled, the servo portion or actuator of the valve will communicate with control means 50 through the : passages in the transfer bearing. If electrically operated, the valve will be operated by the electrical portion of control means 50, being connected thereto through the slip ring-brush assembly of second transfer means 80.
It will therefore be appreciated that with the system of the present invention, wind turbine blade pitch is ad-justed effectively and efficiently withou$ the heavy and often complex prior art mechanical assemblies intercon-necting the blades and actuators therefor. T~e actuators may be relatively light in weight since each performs in-dependently of other blades, being required to power no more than a single blade. Connections between the ac-tuators and control means are also made with an economyo~ structure thereby further reducing the power required ~1 46~79 by such a system and thus enhancing the overall efficiency of a wind turbine in which the pitch adjusting system is employed. ~he provision of the feather accumulators on the hub, in proximity to the blades assures the feathering capability of the system despite failure of the primary actuator fluid supply.
While there has been shown a single embodiment of the pitch adjustment system of the present invention, it will be apparent that various equivalent systems may suggest themselves to those skilled in the art and it is intended by the following claims to cover such equivalent systems as come within the true s~irit and scope oi this invention.
. .
Claims (10)
1. Wind turbine blade pitch adjustment system comprising a rotatable hub, at least two airfoil blades extending generally radially outwardly from said hub for rotation therewith, each of said blades being pivot-able about the longitudinal axis thereof for varying the blade pitch, individual actuation means mounted on said hub and rotatable therewith and being directly connected to corresponding blades for adjusting pitch positioning of each blade individually, said control system further comprising feedback means mounted on said hub and operatively connected to said blades for producing a signal indicative of blade pitch, control means removed from said hub, said control means regulat-ing said actuators in response at least in part to the signal produced by said feedback means and first and second transfer means, adapted to provide communication across a rotative-stationary interface between said control means and actuation means and feedback means respectively.
2. Wind turbine blade pitch adjustment system according to Claim 1 wherein said actuation means com-prises hydraulic actuation means responsive to pressur-ized hydraulic fluid supplied thereto.
3. Wind turbine blade pitch adjustment system according to Claim 2 wherein said hydraulic actuation means comprises at least a pair of hydraulic actuators the pitch of each blade being adjusted individually by at least one of said hydraulic actuators whereby said blades may be simultaneously positioned at different pitch angles.
4. Wind turbine blade pitch adjustment system according to Claim 2 wherein said first transfer means comprises an hydraulic transfer bearing comprising first and second concentric members, one of said members being rotatably driven with said hub and provided with fluid passages communicating with said hydraulic actuation means, the other of said members being stationary and provided with fluid passages communicating with said passages in said one bearing member and further commun-icating with said control means.
5. Wind turbine blade pitch adjustment system according to Claim 3 wherein each of said hydraulic actuators comprises an hydraulic cylinder having a reciprocal piston disposed therein said actuator being pivotally connected to said blade at a root portion thereof and said hub at a central portion thereof.
6. Wind turbine blade pitch adjustment system according to Claim 2 and further comprising feather means mounted on said hub for rotation therewith, said feather means, in response to a signal from said primary control means, providing pressurized hydraulic fluid to said actuation means such that said actuation means effect feathering of said blades.
7. Wind turbine blade pitch adjustment system according to Claim 6 wherein said feather means comprises a reservoir of pressurized hydraulic fluid and a servo valve communicating with said hydraulic fluid reservoir and said hydraulic actuation means for controlling the flow of hydraulic fluid therebetween in response to command signals from said primary control means.
8. Wind turbine blade pitch adjustment system according to Claim 1 wherein said feedback means comprises a linear variable differential transducer operatively connected to said blades such that the output of said transducer varies in accordance with the pitch position of said blades.
9. Wind turbine blade pitch adjustment system according to Claim 8 wherein each blade is connected to a single linear variable differential transducer.
10. Wind turbine blade pitch adjustment system according to Claim 8 wherein said second transfer means comprises a plurality of slip rings rotatable with said hub and connected electrically to said linear variable differential transducer, said second transfer means further comprising a plurality of stationary brushes, each of said brushes being in slidable electrical contact with a corresponding one of said slip rings and adapted for electrical connection to said primary control means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US13065980A | 1980-03-17 | 1980-03-17 | |
| US130,659 | 1980-03-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146079A true CA1146079A (en) | 1983-05-10 |
Family
ID=22445730
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000371573A Expired CA1146079A (en) | 1980-03-17 | 1981-02-24 | Wind turbine blade pitch adjustment system |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS57376A (en) |
| KR (1) | KR850000935B1 (en) |
| AU (1) | AU541909B2 (en) |
| BR (1) | BR8101493A (en) |
| CA (1) | CA1146079A (en) |
| DE (1) | DE3110266A1 (en) |
| DK (1) | DK105181A (en) |
| ES (1) | ES8207282A1 (en) |
| FR (1) | FR2478217A1 (en) |
| GB (1) | GB2071779B (en) |
| IL (1) | IL62271A (en) |
| IT (1) | IT1137203B (en) |
| NL (1) | NL8101235A (en) |
| NO (1) | NO810842L (en) |
| SE (1) | SE446654B (en) |
Families Citing this family (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59228034A (en) * | 1983-06-07 | 1984-12-21 | 東洋紡績株式会社 | Composite sewing machine yarn |
| SE458293B (en) * | 1987-09-15 | 1989-03-13 | Svenning Konsult Ab S | CONTROL DEVICE FOR CONSUMPTION OF TURBIN SPEED |
| GB8916714D0 (en) * | 1989-07-21 | 1989-09-06 | Dowty Rotol Ltd | A propeller blade pitch control mechanism |
| FR2748296B1 (en) * | 1996-05-06 | 1998-11-20 | Richer Bertrand Louis Isidore | SYSTEM FOR CONTROLLING THE ADJUSTMENT OF THE BLADES OF AN AEROGENERATOR WITH DYNAMIC AND EXTREME LOAD REDUCTION EFFECT |
| DE19720025C5 (en) * | 1997-05-13 | 2008-02-28 | Fritz Fahrner | Drive for angle adjustment of rotor blades in wind turbines |
| DE19948997B4 (en) * | 1999-10-11 | 2005-04-14 | Aerodyn Engineering Gmbh | Single blade adjustment for wind turbines |
| ES2178955B1 (en) * | 2001-01-22 | 2003-12-01 | Fundacion Fatronik | ROTOR DEVICE FOR INDEPENDENT CONTROL OF THE PASSAGE VARIATION OF EACH PALA |
| ES2181572B1 (en) * | 2001-01-31 | 2003-12-01 | Fundacion Fatronik | ROTOR DEVICE FOR INDEPENDENT CONTROL OF THE PASSAGE VARIATION OF EACH PALA. |
| WO2003091577A1 (en) * | 2002-04-24 | 2003-11-06 | Vestas Wind Systems A/S | Wind turbine, hydraulic system, air bleed system and method of controlling at least two wind turbine blades |
| ES2206028B1 (en) * | 2002-06-13 | 2005-03-01 | Manuel Torres Martinez | PERFECTION IN THE ELECTRICAL PRODUCTION AIRCRAFTERS. |
| US7717673B2 (en) | 2003-09-03 | 2010-05-18 | General Electric Company | Redundant blade pitch control system for a wind turbine and method for controlling a wind turbine |
| ES2321252B1 (en) * | 2006-06-21 | 2011-02-14 | GAMESA INNOVATION & TECHNOLOGY, S.L. | ROTATING UNION FOR AEROGENERATORS. |
| ES2327695B1 (en) * | 2006-10-11 | 2010-09-06 | GAMESA INNOVATION & TECHNOLOGY, S.L. | SPINNING SYSTEM OF A WINDER SHOVEL. |
| JP5199607B2 (en) * | 2007-05-25 | 2013-05-15 | 三菱重工業株式会社 | Pitch drive device of wind power generator and wind power generator |
| KR101302200B1 (en) * | 2007-11-09 | 2013-08-30 | 무그 인코포레이티드 | Wind turbine |
| JP4796039B2 (en) * | 2007-11-22 | 2011-10-19 | 三菱重工業株式会社 | Wind power generator |
| DE102007060985A1 (en) * | 2007-12-14 | 2009-06-18 | Innovative Windpower Ag | Device for the transmission of provisioning means |
| US8038395B2 (en) * | 2008-03-28 | 2011-10-18 | General Electric Company | Pulsed torque control of wind turbine pitch systems |
| NO328590B1 (en) * | 2008-07-03 | 2010-03-29 | Hydra Tidal Energy Technology | Turbine blade pitch control device |
| US8439640B2 (en) * | 2008-07-15 | 2013-05-14 | Hamilton Sundstrand Corporation | Propeller blade pitch control system |
| DE102008039862B4 (en) * | 2008-08-27 | 2015-07-09 | Schunk Bahn- Und Industrietechnik Gmbh | Gleitkontakthaltevorrichtung |
| WO2011063815A1 (en) * | 2009-11-25 | 2011-06-03 | Avn Energy A/S | Method of mounting a hydraulic pitch control system in a wind turbine hub |
| NZ601691A (en) * | 2010-03-26 | 2013-09-27 | Siemens Ag | Direct drive wind turbine, transport system and method of construction of a direct drive wind turbine |
| WO2011117081A2 (en) * | 2010-03-26 | 2011-09-29 | Siemens Aktiengesellschaft | Wind turbine and method of construction of a wind turbine |
| JP4875770B2 (en) * | 2010-05-14 | 2012-02-15 | 三菱重工業株式会社 | Windmill semi-flexible mount |
| EP2392819B1 (en) * | 2010-05-31 | 2013-04-03 | HAWE Hydraulik SE | Device for an electrohydraulic adjustment of a pitch angle of rotor blades on a rotor of a wind turbine |
| BRPI1100021A2 (en) * | 2011-02-15 | 2016-05-03 | Mitsubishi Heavy Ind Ltd | wind turbine blade pitch control system, and wind turbine rotor and wind turbine generator provided with it. |
| MD4219C1 (en) * | 2012-09-06 | 2013-11-30 | Технический университет Молдовы | Wind turbine with horizontal axis |
| MD4213C1 (en) * | 2012-11-27 | 2013-10-31 | Технический университет Молдовы | Wind turbine |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1139658A (en) * | 1966-08-31 | 1969-01-08 | United Aircraft Corpration | A fluid pressure servomotor control system |
| GB1374756A (en) * | 1971-10-13 | 1974-11-20 | Hawker Siddeley Dynamics Ltd | Fluid pressure servo system |
| DE3009922A1 (en) * | 1980-03-14 | 1981-09-24 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Wind power generating station with servo control of blades - uses measuring instrument of safety monitoring system producing pulses processed electronically |
-
1981
- 1981-02-24 CA CA000371573A patent/CA1146079A/en not_active Expired
- 1981-03-03 IL IL62271A patent/IL62271A/en unknown
- 1981-03-03 GB GB8106576A patent/GB2071779B/en not_active Expired
- 1981-03-09 DK DK105181A patent/DK105181A/en not_active Application Discontinuation
- 1981-03-12 NO NO810842A patent/NO810842L/en unknown
- 1981-03-13 BR BR8101493A patent/BR8101493A/en not_active IP Right Cessation
- 1981-03-13 NL NL8101235A patent/NL8101235A/en not_active Application Discontinuation
- 1981-03-13 SE SE8101615A patent/SE446654B/en unknown
- 1981-03-16 AU AU68411/81A patent/AU541909B2/en not_active Ceased
- 1981-03-16 FR FR8105171A patent/FR2478217A1/en active Granted
- 1981-03-16 ES ES500374A patent/ES8207282A1/en not_active Expired
- 1981-03-17 KR KR1019810000863A patent/KR850000935B1/en active
- 1981-03-17 JP JP3929481A patent/JPS57376A/en active Pending
- 1981-03-17 IT IT20375/81A patent/IT1137203B/en active
- 1981-03-17 DE DE19813110266 patent/DE3110266A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| GB2071779B (en) | 1983-06-22 |
| BR8101493A (en) | 1981-09-15 |
| GB2071779A (en) | 1981-09-23 |
| ES500374A0 (en) | 1982-09-01 |
| NL8101235A (en) | 1981-10-16 |
| ES8207282A1 (en) | 1982-09-01 |
| SE446654B (en) | 1986-09-29 |
| FR2478217B1 (en) | 1985-01-11 |
| KR850000935B1 (en) | 1985-06-28 |
| FR2478217A1 (en) | 1981-09-18 |
| DK105181A (en) | 1981-09-18 |
| JPS57376A (en) | 1982-01-05 |
| AU6841181A (en) | 1981-09-24 |
| NO810842L (en) | 1981-09-18 |
| IL62271A0 (en) | 1981-05-20 |
| SE8101615L (en) | 1981-09-18 |
| IL62271A (en) | 1983-09-30 |
| IT1137203B (en) | 1986-09-03 |
| IT8120375A0 (en) | 1981-03-17 |
| DE3110266A1 (en) | 1982-02-25 |
| AU541909B2 (en) | 1985-01-31 |
| KR830005484A (en) | 1983-08-20 |
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