U.S. patent application number 13/541862 was filed with the patent office on 2014-01-09 for fixation device.
The applicant listed for this patent is Jacob Johannes NIES. Invention is credited to Jacob Johannes NIES.
Application Number | 20140010656 13/541862 |
Document ID | / |
Family ID | 49878665 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140010656 |
Kind Code |
A1 |
NIES; Jacob Johannes |
January 9, 2014 |
FIXATION DEVICE
Abstract
A fixation device for fixing a shaft connecting a rotor and a
generator of a wind turbine, the fixation device comprising: a
rotor lock for locking the shaft providing a locking clearance; and
a rotor brake for braking the shaft; wherein the rotor lock is
arranged for positioning the shaft in a selectable angular position
within the locking clearance of the rotor lock.
Inventors: |
NIES; Jacob Johannes;
(Zwolle, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIES; Jacob Johannes |
Zwolle |
|
NL |
|
|
Family ID: |
49878665 |
Appl. No.: |
13/541862 |
Filed: |
July 5, 2012 |
Current U.S.
Class: |
416/204R ;
29/889 |
Current CPC
Class: |
F05B 2270/326 20130101;
F03D 7/0244 20130101; F03D 7/0264 20130101; Y10T 29/49316 20150115;
Y02E 10/72 20130101; F03D 80/50 20160501; F05B 2260/30 20130101;
F05B 2260/902 20130101 |
Class at
Publication: |
416/204.R ;
29/889 |
International
Class: |
F04D 29/34 20060101
F04D029/34; B21D 53/78 20060101 B21D053/78 |
Claims
1. A fixation device for fixing a shaft connecting a rotor and a
generator of a wind turbine, the fixation device comprising: a) a
rotor lock for locking the shaft providing a locking clearance; and
b) a rotor brake for braking the shaft; c) wherein the rotor lock
is arranged for positioning the shaft in a selectable angular
position within the locking clearance of the rotor lock.
2. The fixation device of claim 1, wherein the rotor lock comprises
a positioning member for positioning the shaft in the selectable
angular position.
3. The fixation device of claim 2, wherein the positioning member
comprises a spring member for a flexible positioning of the shaft
in the selectable angular position.
4. The fixation device of claim 2, wherein the positioning member
comprises a locking pin with a flexible portion for engagement with
a locking recess of the rotor lock.
5. The fixation device of claim 4, wherein the locking pin
comprises a stiff portion for an engagement with the locking recess
of the rotor lock only above a threshold torque.
6. The fixation device of claim 2, wherein the positioning member
comprises a flexible support for the locking pin of the rotor
lock.
7. The fixation device of claim 2, wherein the positioning member
comprises a positioning disk with a positioning hole.
8. The fixation device of claim 7, wherein the positioning disk
with the positioning hole is arranged for an engagement of the
positioning hole with the locking pin of the rotor lock.
9. The fixation device of claim 8, wherein the positioning hole
provides less clearance than the locking recess in case of an
engagement with the locking pin.
10. The fixation device of claim 2, the positioning member
comprising a positioning region and a locking region for an
engagement with a locking recess.
11. The fixation device of claim 2, the positioning member
comprising a pin with a profile selected from a stepped profile, an
elliptical profile and a tapered profile.
12. The fixation device of claim 2, wherein the positioning member
provides a positioning clearance smaller than the lock
clearance.
13. A method for locking a shaft of a wind turbine with a rotor
lock for locking the shaft, a rotor brake for braking the shaft and
a positioning member for a positioning of the shaft in a selectable
position, the method comprising: a) applying the positioning
member; b) waiting until the shaft is positioned in a selectable
position by the positioning member; c) applying the rotor brake;
and, d) applying the rotor lock.
14. The method of claim 13, wherein the shaft is positioned in a
selectable position within a middle range between a first limit
stop and a second limit stop of the rotor lock using the
positioning member.
15. The method of claim 14, wherein the middle range is within the
middle third of the clearance of the rotor lock.
16. A wind turbine comprising a rotor, a generator, a shaft for
transmitting torque between the rotor and the generator, and a
fixation device for fixing the shaft, the fixation device
comprising: a) a rotor lock for locking the shaft providing a lock
clearance between a first limit stop and a second limit stop; and,
b) a rotor brake for braking the shaft; c) wherein the rotor lock
is arranged for positioning the rotor shaft within the lock
clearance, wherein the positioning clearance is smaller than the
lock clearance.
17. The wind turbine of claim 16, wherein the rotor lock is
adjusted for a positioning of the shaft within a middle range
between the first limit stop and the second limit stop of the rotor
lock.
18. The wind turbine of claim 16, wherein a sum of the brake
clearance and the brake deflection is smaller than half of the sum
of the lock clearance and the lock deflection.
19. The wind turbine of claim 16, wherein the rotor lock comprises
a flexible member for a locking pin of the rotor lock.
20. The wind turbine of claim 19, wherein the flexible member of
the locking pin is arranged for an exclusive engagement with a
locking stop in case of a torque of the shaft below a threshold
torque.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter described herein relates generally to
methods and systems for wind turbines, and more particularly, to
methods and systems for fixing a shaft of a wind turbine.
[0002] At least some known wind turbines include a tower and a
nacelle mounted on the tower. A rotor is rotatably mounted to the
nacelle and is coupled to a generator by a shaft. A plurality of
blades extend from the rotor. The blades are oriented such that
wind passing over the blades turns the rotor and rotates the shaft,
thereby driving the generator to generate electricity.
[0003] Some known wind turbines include a rotor-brake and a
rotor-lock. The rotor-lock typically provides a higher load limit,
especially when both the brake and the lock are applied at the
low-speed shaft of the turbine. The load limit of the rotor-lock is
designed for a maximum expected load, e.g. during a storm. The
rotor-lock may only be applied when the rotor shaft of the wind
turbine stands still. The rotor-brake typically provides a lower
load limit, wherein higher loads do not lead to a damage of the
rotor-brake. The rotor-brake provides slip if the load gets higher
than the load limit of the rotor-brake. Rotor-brakes may sometimes
also be used when the rotor shaft is rotating slowly to stop the
rotor shaft completely. Technical background to rotor-brakes and
rotor-locks, or other methods for applying a braking force to a
rotor shaft of a wind turbine, may be found in U.S. Pat. No.
7,948,100.
[0004] The costs for the rotor-brake and the rotor-lock of a wind
turbine contribute to the total costs of the wind turbine with
several percent. There is therefore a need for a method and a wind
turbine using the rotor-brake and the rotor-lock more efficient to
maybe reduce the size and costs of the rotor-brake or the
rotor-lock.
BRIEF DESCRIPTION OF THE INVENTION
[0005] In one aspect, a fixation device for fixing a shaft
connecting a rotor and a generator of a wind turbine is provided,
the fixation device including a rotor lock for locking the shaft
providing a locking clearance, and a rotor brake for braking the
shaft, wherein the rotor lock is arranged for positioning the shaft
in a selectable angular position within the locking clearance of
the rotor lock.
[0006] In another aspect, a method for locking a shaft of a wind
turbine with a rotor lock for locking the shaft, a rotor brake for
braking the shaft and a positioning member for a positioning of the
shaft in a selectable position is provided, the method including
applying the positioning member; waiting until the shaft is
positioned in a selectable position by the positioning member;
applying the rotor brake; and, applying the rotor lock applying the
positioning member, waiting until the shaft is positioned in a
selectable position by the positioning member, applying the rotor
brake and applying the rotor lock.
[0007] In yet another aspect, a wind turbine is provided, the wind
turbine including a rotor, a generator, a shaft for transmitting
torque between the rotor and the generator, and a fixation device
for fixing the shaft, the fixation device including: a rotor lock
for locking the shaft providing a lock clearance between a first
limit stop and a second limit stop; and, a rotor brake for braking
the shaft; wherein the rotor lock is arranged for positioning the
rotor shaft within the lock clearance, wherein the positioning
clearance is smaller than the lock clearance.
[0008] Further aspects, advantages and features of the present
invention are apparent from the dependent claims, the description
and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A full and enabling disclosure including the best mode
thereof, to one of ordinary skill in the art, is set forth more
particularly in the remainder of the specification, including
reference to the accompanying figures wherein:
[0010] FIG. 1 is a perspective view of an exemplary wind
turbine.
[0011] FIG. 2 is an enlarged sectional view of a portion of the
wind turbine shown in FIG. 1.
[0012] FIG. 3 is a block diagram of an exemplary embodiment of a
wind turbine.
[0013] FIG. 4 is shows parts of the exemplary embodiment of FIG.
3.
[0014] FIG. 5 shows a tapered locking pin of typical
embodiments.
[0015] FIG. 6 depicts a stepped locking pin of typical
embodiments.
[0016] FIG. 7 shows an elliptical locking pin of typical
embodiments.
[0017] FIG. 8 is a block diagram of an exemplary embodiment of a
fixation device.
[0018] FIG. 9 is a front view of parts of the exemplary embodiment
shown in FIG. 8.
[0019] FIG. 10 is a side view of parts of the exemplary embodiment
shown in FIG. 8.
[0020] FIG. 11 is a diagram showing torques of typical rotor-brakes
and rotor-locks for load cases.
[0021] FIG. 12 is another diagram showing torques of typical
rotor-brakes and rotor-locks for load cases.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Reference will now be made in detail to the various
embodiments, one or more examples of which are illustrated in each
figure. Each example is provided by way of explanation and is not
meant as a limitation. For example, features illustrated or
described as part of one embodiment can be used on or in
conjunction with other embodiments to yield yet further
embodiments. It is intended that the present disclosure includes
such modifications and variations.
[0023] The embodiments described herein include a wind turbine,
having a rotor shaft using a rotor-brake and a rotor-lock, which is
capable of withstanding high loads. For example, during a storm the
rotor brake and the rotor lock may be used simultaneously. More
specifically, the rotor-brake and the rotor-lock are used in
parallel to yield a higher load limit. Thereby, costs of the wind
turbine may be reduced. Typical embodiments include a method of
locking a rotor of a wind turbine, wherein the method allows for
using the rotor-brake and the rotor-lock in parallel. With wind
turbines and methods of typical embodiments the capability of the
wind turbine to withstand storms may be enhanced. Alternatively or
in addition, the weight of the wind turbine, especially of the
nacelle may be reduced due to the usage of smaller rotor-brakes or
smaller rotor-locks.
[0024] As used herein, the term rotor-brake is intended to be
representative of any brake capable of decelerating or fixing the
rotor shaft, wherein a brake provides slip in case the torque of
the rotor shaft is higher than a typical slip limit. One example
for a rotor-brake is a disk brake using one or more disks. Typical
rotor-brakes include an electro-hydraulic actuator, an
electro-mechanical actuator or a spring-operated caliper. Other
brakes providing slip are drum brakes, which may be used for
typical embodiments. The rotor-brake may be arranged at a low-speed
shaft or at a high-speed shaft in case a gearbox is incorporated in
the wind turbine drive-train of typical wind turbines described
herein. As used herein, the term rotor-lock is intended to be
representative of locking mechanisms capable of locking the rotor
shaft. Such locking mechanisms may include a hydraulically moveable
pin or a spring-actuated pin attached to a solid or fixed or
non-rotating part of the wind turbine nacelle. The term
"non-rotating" typically refers to a member not rotating with the
shaft of the wind turbine. Other locking mechanisms include pins or
plates. Disks with holes may be used for an interaction with the
bolt or the pin. Typical embodiments include a slot, a nut or a
hole in the rotor hub for an engagement with a second locking part
like a bolt, a pin or a plate. Typically, the rotor-lock may be
applied at the low-speed shaft or at the high-speed shaft in case
of a wind turbine providing a gearbox in the drive-train. Further
typical wind turbines include a direct drive, wherein the rotor is
coupled directly to the generator without a gearbox in the drive
train between the rotor and the generator.
[0025] As used herein, the term "blade" is intended to be
representative of any device that provides a reactive force when in
motion relative to a surrounding fluid. As used herein, the term
"wind turbine" is intended to be representative of any device that
generates rotational energy from wind energy, and more
specifically, converts kinetic energy of wind into mechanical
energy. As used herein, the term "wind generator" is intended to be
representative of any wind turbine that generates electrical power
from rotational energy generated from wind energy, and more
specifically, converts mechanical energy converted from kinetic
energy of wind to electrical power.
[0026] FIG. 1 is a perspective view of an exemplary wind turbine
10. In the exemplary embodiment, wind turbine 10 is a
horizontal-axis wind turbine. Alternatively, wind turbine 10 may be
a vertical-axis wind turbine. In the exemplary embodiment, wind
turbine 10 includes a tower 12 that extends from a support system
14, a nacelle 16 mounted on tower 12, and a rotor 18 that is
coupled to nacelle 16. Rotor 18 includes a rotatable hub 20 and at
least one rotor blade 22 coupled to and extending outward from hub
20. In the exemplary embodiment, rotor 18 has three rotor blades
22. In an alternative embodiment, rotor 18 includes more or less
than three rotor blades 22. In the exemplary embodiment, tower 12
is fabricated from tubular steel to define a cavity (not shown in
FIG. 1) between support system 14 and nacelle 16. In an alternative
embodiment, tower 12 is any suitable type of tower having any
suitable height.
[0027] Rotor blades 22 are spaced about hub 20 to facilitate
rotating rotor 18 to enable kinetic energy to be transferred from
the wind into usable mechanical energy, and subsequently,
electrical energy. Rotor blades 22 are mated to hub 20 by coupling
a blade root portion 24 to hub 20 at a plurality of load transfer
regions 26. Load transfer regions 26 have a hub load transfer
region and a blade load transfer region (both not shown in FIG. 1).
Loads induced to rotor blades 22 are transferred to hub 20 via load
transfer regions 26.
[0028] In one embodiment, rotor blades 22 have a length ranging
from about 15 meters (m) to about 91 m. Alternatively, rotor blades
22 may have any suitable length that enables wind turbine 10 to
function as described herein. For example, other non-limiting
examples of blade lengths include 10 m or less, 20 m, 37 m, or a
length that is greater than 91 m. As wind strikes rotor blades 22
from a direction 28, rotor 18 is rotated about an axis of rotation
30. As rotor blades 22 are rotated and subjected to centrifugal
forces, rotor blades 22 are also subjected to various forces and
moments. As such, rotor blades 22 may deflect and/or rotate from a
neutral, or non-deflected, position to a deflected position.
[0029] Moreover, a pitch angle or blade pitch of rotor blades 22,
i.e., an angle that determines a perspective of rotor blades 22
with respect to direction 28 of the wind, may be changed by a pitch
adjustment system 32 to control the load and power generated by
wind turbine 10 by adjusting an angular position of at least one
rotor blade 22 relative to wind vectors. Pitch axes 34 for rotor
blades 22 are shown. During operation of wind turbine 10, pitch
adjustment system 32 may change a blade pitch of rotor blades 22
such that rotor blades 22 are moved to a feathered position, such
that the perspective of at least one rotor blade 22 relative to
wind vectors provides a minimal surface area of rotor blade 22 to
be oriented towards the wind vectors, which facilitates reducing a
rotational speed of rotor 18 and/or facilitates a stall of rotor
18.
[0030] In the exemplary embodiment, a blade pitch of each rotor
blade 22 is controlled individually by a control system 36.
Alternatively, the blade pitch for all rotor blades 22 may be
controlled simultaneously by control system 36. Further, in the
exemplary embodiment, as direction 28 changes, a yaw direction of
nacelle 16 may be controlled about a yaw axis 38 to position rotor
blades 22 with respect to direction 28.
[0031] In the exemplary embodiment, control system 36 is shown as
being centralized within nacelle 16, however, control system 36 may
be a distributed system throughout wind turbine 10, on support
system 14, within a wind farm, and/or at a remote control center.
Control system 36 includes a processor 40 configured to perform the
methods and/or steps described herein. Further, many of the other
components described herein include a processor. As used herein,
the term "processor" is not limited to integrated circuits referred
to in the art as a computer, but broadly refers to a controller, a
microcontroller, a microcomputer, a programmable logic controller
(PLC), an application specific integrated circuit, and other
programmable circuits, and these terms are used interchangeably
herein. It should be understood that a processor and/or a control
system can also include memory, input channels, and/or output
channels.
[0032] In the embodiments described herein, memory may include,
without limitation, a computer-readable medium, such as a random
access memory (RAM), and a computer-readable non-volatile medium,
such as flash memory. Alternatively, a floppy disk, a compact
disk-read only memory (CD-ROM), a magneto-optical disk (MOD),
and/or a digital versatile disk (DVD) may also be used. Also, in
the embodiments described herein, input channels include, without
limitation, sensors and/or computer peripherals associated with an
operator interface, such as a mouse and a keyboard. Further, in the
exemplary embodiment, output channels may include, without
limitation, a control device, an operator interface monitor and/or
a display.
[0033] Processors described herein process information transmitted
from a plurality of electrical and electronic devices that may
include, without limitation, sensors, actuators, compressors,
control systems, and/or monitoring devices. Such processors may be
physically located in, for example, a control system, a sensor, a
monitoring device, a desktop computer, a laptop computer, a
programmable logic controller (PLC) cabinet, and/or a distributed
control system (DCS) cabinet. RAM and storage devices store and
transfer information and instructions to be executed by the
processor(s). RAM and storage devices can also be used to store and
provide temporary variables, static (i.e., non-changing)
information and instructions, or other intermediate information to
the processors during execution of instructions by the
processor(s). Instructions that are executed may include, without
limitation, wind turbine control system control commands The
execution of sequences of instructions is not limited to any
specific combination of hardware circuitry and software
instructions.
[0034] FIG. 2 is an enlarged sectional view of a portion of wind
turbine 10. In the exemplary embodiment, wind turbine 10 includes
nacelle 16 and hub 20 that is rotatably coupled to nacelle 16. More
specifically, hub 20 is rotatably coupled to an electric generator
42 positioned within nacelle 16 by rotor shaft 44 (sometimes
referred to as either a main shaft or a low speed shaft), a gearbox
46, a high speed shaft 48, and a coupling 50. In the exemplary
embodiment, rotor shaft 44 is disposed coaxial to longitudinal axis
116. Rotation of rotor shaft 44 rotatably drives gearbox 46 that
subsequently drives high speed shaft 48. High speed shaft 48
rotatably drives generator 42 with coupling 50 and rotation of high
speed shaft 48 facilitates the production of electrical power by
generator 42. Gearbox 46 and generator 42 are supported by a
support 52 and a support 54. In the exemplary embodiment, gearbox
46 utilizes a dual path geometry to drive high speed shaft 48.
Alternatively, rotor shaft 44 is coupled directly to generator 42
with coupling 50.
[0035] Nacelle 16 also includes a yaw drive mechanism 56 that may
be used to rotate nacelle 16 and hub 20 on yaw axis 38 (shown in
FIG. 1) to control the perspective of rotor blades 22 with respect
to direction 28 of the wind. Nacelle 16 also includes at least one
meteorological mast 58 that includes a wind vane and anemometer
(neither shown in FIG. 2). Mast 58 provides information to control
system 36 that may include wind direction and/or wind speed. In the
exemplary embodiment, nacelle 16 also includes a main forward
support bearing 60 and a main aft support bearing 62.
[0036] Forward support bearing 60 and aft support bearing 62
facilitate radial support and alignment of rotor shaft 44. Forward
support bearing 60 is coupled to rotor shaft 44 near hub 20. Aft
support bearing 62 is positioned on rotor shaft 44 near gearbox 46
and/or generator 42. Alternatively, nacelle 16 includes any number
of support bearings that enable wind turbine 10 to function as
disclosed herein. Rotor shaft 44, generator 42, gearbox 46, high
speed shaft 48, coupling 50, and any associated fastening, support,
and/or securing device including, but not limited to, support 52
and/or support 54, and forward support bearing 60 and aft support
bearing 62, are sometimes referred to as a drive train 64.
[0037] In the exemplary embodiment, hub 20 includes a pitch
assembly 66. Pitch assembly 66 includes one or more pitch drive
systems 68 and at least one sensor 70. Each pitch drive system 68
is coupled to a respective rotor blade 22 (shown in FIG. 1) for
modulating the blade pitch of associated rotor blade 22 along pitch
axis 34. Only one of three pitch drive systems 68 is shown in FIG.
2.
[0038] In the exemplary embodiment, pitch assembly 66 includes at
least one pitch bearing 72 coupled to hub 20 and to respective
rotor blade 22 (shown in FIG. 1) for rotating respective rotor
blade 22 about pitch axis 34. Pitch drive system 68 includes a
pitch drive motor 74, pitch drive gearbox 76, and pitch drive
pinion 78. Pitch drive motor 74 is coupled to pitch drive gearbox
76 such that pitch drive motor 74 imparts mechanical force to pitch
drive gearbox 76. Pitch drive gearbox 76 is coupled to pitch drive
pinion 78 such that pitch drive pinion 78 is rotated by pitch drive
gearbox 76. Pitch bearing 72 is coupled to pitch drive pinion 78
such that the rotation of pitch drive pinion 78 causes rotation of
pitch bearing 72. More specifically, in the exemplary embodiment,
pitch drive pinion 78 is coupled to pitch bearing 72 such that
rotation of pitch drive gearbox 76 rotates pitch bearing 72 and
rotor blade 22 about pitch axis 34 to change the blade pitch of
blade 22.
[0039] Pitch drive system 68 is coupled to control system 36 for
adjusting the blade pitch of rotor blade 22 upon receipt of one or
more signals from control system 36. In the exemplary embodiment,
pitch drive motor 74 is any suitable motor driven by electrical
power and/or a hydraulic system that enables pitch assembly 66 to
function as described herein. Alternatively, pitch assembly 66 may
include any suitable structure, configuration, arrangement, and/or
components such as, but not limited to, hydraulic cylinders,
springs, and/or servo-mechanisms. Moreover, pitch assembly 66 may
be driven by any suitable means such as, but not limited to,
hydraulic fluid, and/or mechanical power, such as, but not limited
to, induced spring forces and/or electromagnetic forces. In certain
embodiments, pitch drive motor 74 is driven by energy extracted
from a rotational inertia of hub 20 and/or a stored energy source
(not shown) that supplies energy to components of wind turbine
10.
[0040] Pitch assembly 66 also includes one or more overspeed
control systems 80 for controlling pitch drive system 68 during
rotor overspeed. In the exemplary embodiment, pitch assembly 66
includes at least one overspeed control system 80 communicatively
coupled to respective pitch drive system 68 for controlling pitch
drive system 68 independently of control system 36. In one
embodiment, pitch assembly 66 includes a plurality of overspeed
control systems 80 that are each communicatively coupled to
respective pitch drive system 68 to operate respective pitch drive
system 68 independently of control system 36. Overspeed control
system 80 is also communicatively coupled to sensor 70. In the
exemplary embodiment, overspeed control system 80 is coupled to
pitch drive system 68 and to sensor 70 with a plurality of cables
82. Alternatively, overspeed control system 80 is communicatively
coupled to pitch drive system 68 and to sensor 70 using any
suitable wired and/or wireless communications device. During normal
operation of wind turbine 10, control system 36 controls pitch
drive system 68 to adjust a pitch of rotor blade 22. In one
embodiment, when rotor 18 operates at rotor overspeed, overspeed
control system 80 overrides control system 36, such that control
system 36 no longer controls pitch drive system 68 and overspeed
control system 80 controls pitch drive system 68 to move rotor
blade 22 to a feathered position to slow a rotation of rotor
18.
[0041] A power generator 84 is coupled to sensor 70, overspeed
control system 80, and pitch drive system 68 to provide a source of
power to pitch assembly 66. In the exemplary embodiment, power
generator 84 provides a continuing source of power to pitch
assembly 66 during operation of wind turbine 10. In an alternative
embodiment, power generator 84 provides power to pitch assembly 66
during an electrical power loss event of wind turbine 10. The
electrical power loss event may include power grid loss,
malfunctioning of the turbine electrical system, and/or failure of
the wind turbine control system 36. During the electrical power
loss event, power generator 84 operates to provide electrical power
to pitch assembly 66 such that pitch assembly 66 can operate during
the electrical power loss event.
[0042] In the exemplary embodiment, pitch drive system 68, sensor
70, overspeed control system 80, cables 82, and power generator 84
are each positioned in a cavity 86 defined by an inner surface 88
of hub 20. In a particular embodiment, pitch drive system 68,
sensor 70, overspeed control system 80, cables 82, and/or power
generator 84 are coupled, directly or indirectly, to inner surface
88. In an alternative embodiment, pitch drive system 68, sensor 70,
overspeed control system 80, cables 82, and power generator 84 are
positioned with respect to an outer surface 90 of hub 20 and may be
coupled, directly or indirectly, to outer surface 90.
[0043] FIG. 3 is a block diagram of an exemplary embodiment of a
wind turbine. FIG. 3 will be explained with reference to FIG. 1 and
FIG. 2 showing several similar parts as shown in FIG. 3. The
embodiment of FIG. 3 comprises a rotor 18 with a rotor hub 20 to
which rotor blades 22 are attached. The rotor hub 20 is mounted to
a rotor shaft 44 for transmitting torque of the rotor to a
generator.
[0044] Typical embodiments include a rotatable hub with at least
one rotor blade coupled to and extending outward from the hub. Some
embodiments of wind turbines comprise three rotor blades. Other
exemplary embodiments comprise two or four rotor blades or another
number of rotor blades. Typical embodiments comprise a rotor shaft
coupled to a gearbox. The gearbox is connected with a generator.
Further exemplary embodiments comprise a rotor shaft coupling the
rotor hub directly to the generator, wherein the gearbox may be
omitted.
[0045] The exemplary embodiment of a wind turbine, parts of which
are shown in FIG. 3 includes a rotor-lock 210. The rotor-lock 210
shown in FIG. 3 includes a locking pin 212. The locking pin 212 is
moveable by a locking actuator 214. In case the locking pin 212 is
actuated by the locking actuator 214, the locking pin 212 is forced
into a locking recess 216 of the rotor hub 20. By doing so, the
rotational position of the rotor hub 20 is locked relative to the
nacelle. The locking recess 216 has a diameter slightly higher than
the outer diameter of the locking pin 212. With this arrangement
the locking pin 212 can easily be urged into the locking recess 216
in case the rotor hub 20 is close to or in a correct position for
locking.
[0046] Typical embodiments include a rotor-lock with a locking
mechanism including a locking pin and a locking recess. Further
embodiments include a rotor-lock with a locking plate which may be
urged into a locking nut. Exemplary embodiments include one
rotor-lock; other exemplary embodiments include two or more
rotor-locks to enhance the load limit of the lock. Different types
of rotor-locks are combined in exemplary embodiments. Typical rotor
locks include an actuator such as a motor or a solenoid for moving
a locking pin or a locking plate. Further embodiments include a
manually actuated rotor lock.
[0047] The embodiment shown in FIG. 3 includes a rotor-brake 220.
The rotor-brake 220 of the exemplary embodiment shown in FIG. 3 is
a disk brake allowing a considerable amount of slip in case a load
limit for slipping is reached. Both the rotor-lock 210 and the
rotor-brake 220 are fixed to a nacelle of the wind turbine. In
embodiments, the rotor brake and the rotor lock are arranged at the
low-speed shaft of the gearbox or between the rotor and the gearbox
of the wind turbine. In embodiments, the rotor-brake, the rotor
lock or both may be at the high-speed shaft of a gearbox or between
the gearbox and the generator of the wind turbine.
[0048] The sum of a brake clearance of the rotor-brake 220 and a
brake deflection at maximum brake load of the rotor-brake 220 is
usually smaller than the sum of a lock clearance and a lock
deflection at maximum lock load of the rotor-lock 210. In the
exemplary embodiment shown in FIG. 3 the sum of the lock clearance
and the lock deflection at maximum lock load is 2.0 or at least 2.0
times the sum of the brake clearance of the rotor-brake 220 and the
brake deflection at maximum brake load. Further embodiments
comprise a rotor lock and a rotor brake, wherein the sum of the
lock clearance and the lock deflection at maximum lock load is at
least 2.5 or at least 3.0 of the sum of the brake clearance of the
rotor-brake 220 and the brake deflection at maximum brake load.
[0049] With the sum of a brake clearance of the rotor-brake and a
brake deflection at maximum brake load being smaller than two times
the sum of a lock clearance and a lock deflection at maximum lock
load of the rotor-lock, it is possible to use the rotor-lock and
the rotor-brake in parallel for a maximum load. Such maximum load
cases may be a extreme event load. Such an extreme event load may
by way of example include wind conditions, grid failures, turbine
malfunctioning and maintenance conditions. Typically, load cases
are defined per regulations. As an example, the IEC 61400 guideline
may be named. It shows several Design Load Cases (DLCs), wherein
also extreme wind conditions including storms, gusts and wind
direction changes, also in combination with the parked position,
are named. With clearance combinations of typical embodiments, the
rotor-lock, the rotor-brake or both may be smaller compared to
other wind turbines. The brake clearance of the rotor-brake refers
to the amount of rotation which is necessary before the rotor-brake
has an effect. The brake deflection at maximum brake load depends
on the stiffness of the rotor-brake and the stiffness of the
mounting of the rotor-brake in the nacelle. The lock clearance
depends mainly on the type of the rotor-lock. Exemplary embodiments
having a rotor-lock with a locking pin have a lock clearance
depending on the difference of the diameters of the locking recess
and the locking bolt. Again, the lock deflection at maximum lock
load depends on the rotor-lock and the mounting of the rotor-lock
in the nacelle. One possibility used in embodiments to manipulate
the sum of the lock clearance and the lock deflection is to vary
the lock clearance. This can be done by reducing the diameter of
the locking bolt. Another possibility is to enlarge the diameter of
the lock recess. Furthermore, the mounting of the rotor-brake can
be made very stiff to reduce the brake deflection at maximum brake
load. Typically, the maximum brake load refers to the load at which
slipping occurs. This load can also be referred to as the slip load
of the rotor-brake.
[0050] The rotor-brake 220 and the rotor-lock 210 are controlled by
control unit 230. Typical embodiments comprise a control unit 230
arranged in a housing of a control system of the wind turbine. The
control system is used for controlling at least a part of the main
functions of the wind turbine. The control unit 230 as a part of
the control system coordinates the actions of the rotor-lock 210
and the rotor-brake 220. Typical embodiments include a control unit
for positioning of the rotor in a locking position, inserting the
rotor lock, forcing the rotor to turn in a first direction and
applying the rotor-brake.
[0051] The rotor-lock of the embodiment shown in FIG. 3 includes a
positioning member for positioning the shaft in a pre-determined
angular position within the locking clearance of the rotor-lock
210. The locking clearance of the rotor-lock 210 is based on a
flexible support of the locking pin 212 in the locking actuator
214. In detail, a flexible support 240, including two O-rings, is
used to fix the locking pin 212 in the locking actuator 214. By
doing so, the rotor is positioned in a middle position by the
flexible support 240 in case no torque acts on the rotor. Typical
methods of embodiments include a positioning of the rotor such that
the locking pin may be shifted into the locking recess. Then, the
torque is released and the rotor is positioned in a selectable
angular position by the flexible supports. Afterwards, the
rotor-brake is applied. In case of an extreme load, the torque is
firstly acting on the brake and on the flexible support. At a
certain load, further movement of the locking pin is blocked. The
movement of the locking pin may be blocked by an end stop of the
flexible support or by the housing of the locking actuator. Then,
both the rotor-brake and the rotor-lock act together to withstand
the high torque.
[0052] Typical embodiments comprise a flexible support for a
locking pin of the rotor-lock. The flexible support represents a
positioning member for positioning the shaft in a selectable
angular position. Some embodiments include a flexible support for
positioning the shaft in a middle position of the locking clearance
of the rotor-lock. Other embodiments include a positioning member
for positioning the shaft in an asymmetric position of the locking
clearance of the rotor-lock. By doing so, asymmetric maximum loads
on the rotor may be addressed. Further typical embodiments of
fixation devices include a locking-pin with a flexible portion for
engaging with a locking recess of the rotor-lock. The flexible
portion may be used as positioning member for positioning the shaft
in a selectable angular position within the locking clearance of
the rotor-lock. Furthermore, the locking pin includes a stiff
portion for an engagement with the locking recess of the rotor-lock
only above a threshold torque. The terms "flexible" and "rigid"
have to be construed as relative terms. The term "flexible" denotes
typically a member being at least twice as flexible as the "rigid"
member. Typical flexible members like flexible supports, or like
flexible portions, include plastics or synthetic materials, wherein
typical rigid elements or rigid portions include metal, steel or
metal alloys. Typical flexible members provide a shape which allows
a flexible reaction. Typically, the positioning member comprises a
spring member for a flexible positioning of the shaft and the
selectable angular position. By doing so, no additional energy must
be expended for positioning the shaft in the selectable angular
position.
[0053] In FIG. 4, the actuator 214 with a part of the locking pin
212 of FIG. 3 is shown in more detail. In FIG. 4, a frame 244 of
the rotor-lock 210 is shown. The frame 244 maybe moved by control
of the control unit 230 to retract or to engage the locking pin
210. The locking pin 210 is of rigid material wherein the flexible
support 240 includes O-rings of flexible material. The frame 244
may be retracted or moved in the direction of an arrow 246
depicting the direction of movement. The locking pin 210 has a
constant diameter for engagement with the locking recess.
[0054] Typical embodiments comprise a locking pin with a constant
diameter or a constant profile over an engagement region of the
locking pin. Further typical embodiments of fixation devices of
wind turbines include a locking pin with a conical pin surface or a
stepped pin surface. Typically, the positioning member includes a
positioning region and a locking region for an engagement with a
locking recess. The positioning member may be construed as being
part of a locking pin or a locking bolt. The positioning region is
typically a region used for positioning the rotor in a selectable
angular position. In case of a conical pin, the region with the
larger diameter may be used for an engagement with a locking recess
such as a locking hole or a locking groove, wherein the region with
the smaller diameter may be used as the locking region for
providing a bigger locking clearance. Typically, the positioning
clearance is smaller than the lock clearance. Typical embodiments
comprise positioning members having a positioning clearance which
is only half or only one fifth or only one tenth of the lock
clearance. Such proportions may be achieved by using conical or
stepped pins or by using flexible supports for the pin or by other
measures described herein. Typical positioning members include the
locking pin. Typically, the positioning member and the locking pin
are realized in one part or one group of elements of the fixation
device on the wind turbine. Typically, the pin or the locking pin
of the positioning member provides a profile providing a
positioning region and a locking region. Such profiles may be
chosen from a step profile or a tapered or a conical profile. By
using a locking pin with a step profile or a tapered or conical
profile different positioning and locking clearances may be
achieved with minimal effort. By doing so, the rotor-lock and the
rotor-brake may be used together in an optimal combination.
[0055] In FIG. 5, a tapered locking pin 250 is shown. The conical
locking pin 250 may be used with the embodiment shown in FIG. 3.
However, since the conical locking pin comprises a positioning
region with a larger diameter of the conical surface and a locking
region with the smaller diameter of the conical surface of the
conical locking pin, the flexible support shown in FIG. 3 may be
omitted. However, also a combination of the flexible support with
the conical locking pin is used in typical embodiments.
[0056] In FIG. 6, a stepped locking pin 260 is shown. The stepped
locking pin 260 is shown in a side view and a front view. The
stepped locking pin 260 includes a positioning region 262 with a
larger diameter and a locking region 264 with a smaller diameter.
By pushing the stepped locking pin 260 completely into a hole of
the rotor-lock, the positioning region 262 gets in engagement with
the hole. By doing so, the rotor is positioned in a selectable
angular position.
[0057] Typical embodiments comprise a method, wherein after
applying the positioning member, it is waited until the rotor is in
a selected or a selectable position. The term "waiting" typically
includes a forcing of the rotor to move in the selected position.
In further typical embodiments during "waiting" it is just waited
until the rotor reaches the selected position, e.g. by chance or by
turning the rotor blades such that the wind drives the rotor in the
selected position. Typical examples of forcing the rotor into a
selected position include a turning of the rotor by hand, by an
elastic member or by a generator used as a motor or other turning
means. Then, the rotor-brake is supplied. After applying the
rotor-brake, the rotor lock may be applied. One possibility is that
the stepped locking pin is retracted, such that the locking region
is in the region of the hole of the rotor-lock. Now, with the
rotor-brake still in engagement, regular torque acting on the rotor
or the shaft may be absorbed by the rotor-brake. In case the load
excesses a selectable limit, namely the slipping limit of the rotor
brake, the rotor lock gets in full engagement. In embodiments with
a stepped locking pin, the locking region of the rotor-lock gets in
engagement. By doing so, the forces or torques of the rotor-brake
and the rotor-lock are added such that with this combination, the
wind turbine may withstand higher loads.
[0058] In FIG. 7, an elliptical locking pin 270 is shown in a front
view. The elliptical locking pin 270 includes an elliptical profile
providing a locking region in the region of the elliptical profile
with the smaller diameter. The elliptical locking pin 270 may be
used in connection with actuators which are not only capable of
retracting or pushing the elliptical locking pin but also are of
rotating the elliptical locking pin 270. In case the elliptical
locking pin 270 is rotated, one may choose which one of the regions
of the positioning region 262 or locking region 264 gets in
engagement with a recess or a hole of the rotor-lock. Further
embodiments may use a cylindrical or conical pin where on one or
two sides a shape is provided that is within the cylinder of cone
and that has a locally larger radius than the cylinder or cone.
[0059] In typical embodiments, the positioning member is adjusted
for a positioning of the shaft within a middle range between a
first limit stop and a second limit stop of the rotor-lock. Further
embodiments include a positioning member being adjusted for a
positioning of the shaft outside of the middle range. Such a
positioning may also be construed as an asymmetric positioning
between the first limit stop and the second limit stop. Typically,
the middle range is the middle third of the clearance between the
first limit stop and the second limit stop. In further embodiments
the middle range is 20% of the range between the first limit stop
and the second limit stop. Typical flexible members, like a
flexible support or a spring, are arranged for an exclusive
engagement of the locking region of the locking pin, or of the
locking pin itself with a locking stop in case of a torque of the
shaft above a threshold torque. By doing so, the rotor is kept in a
selectable angular position between different limit stops like the
first limit stop and the second limit stop in case of small loads.
The first limit stop and the second limit stop include the sides of
a locking recess or of a locking hole. Further embodiments include
different locking stops like noses or projections.
[0060] FIGS. 8 to 10 show a further embodiment of a fixation device
for a wind turbine. FIG. 8 is an overview of a fixation device
wherein FIG. 9 is a front view of a detail of the fixation device
and FIG. 10 is a sectional view of a detail of the fixation
device.
[0061] The fixation device of FIG. 8 includes some similar points
as the fixation device of FIG. 3. It should be noted that the
locking pin 212 of the fixation device of FIG. 8 is only
retractable in one direction by the actuator 214. The locking pin
212 is moveable for an engagement with a positioning disk 280 and a
lock disk 282. The positioning disk 280 may be construed as being
the positioning member for positioning the rotor 18. The
positioning disk 280 and the lock disk 282 are mounted on the rotor
shaft 44. The positioning disk 280 includes positioning holes 284
wherein the lock disk 282 includes locking holes 286. The locking
holes 286 of the lock disk 282 provide more slack or more locking
clearance compared to the positioning clearance of the positioning
holes 284 of the positioning disk 280. Hence, by choosing the
retracted position of the locking pin 212, it is possible to engage
the positioning hole 248 for positioning the rotor 18 in a
selectable angular position. By retracting the locking pin a bit
the engagement with the positioning disk is released. However, the
locking pin 212 is still in a position for an engagement with the
locking disk 282. The rotor-brake 220 is actuated before the
locking pin is retracted from the positioning disk 280. Hence, the
rotor shaft 44 keeps its position. In case of a torque or load
above a threshold, namely the slipping torque of the rotor-brake
220, the locking pin 212 gets in engagement with the edge of the
locking hole 286 of the lock disk 282. By choosing the rotor-brake
deflection and the clearance of the rotor-lock (lock disk 282 with
locking pin 212) the rotor-brake 220 will be loaded first, reach
its maximum torque and then starts to slip until the rotor-lock
gets loaded.
[0062] Typical embodiments use lock disks with locking holes having
a greater diameter or tangential clearance compared to the
positioning holes. Further possible arrangements include slots in
the lock disk. The positioning disk 280, of typical embodiments,
includes circular or conical holes. The holes in the positioning
disk must not be lined with the holes of the locking disk exactly.
By shifting the positioning hole with respect to the locking hole,
the selectable angular position can be chosen outside of the centre
of the clearance band of the locking clearance. Thereby, the
fixation device benefits from asymmetric loads. Typically, most
extreme loads on wind turbines are different and such asymmetric in
both rotational directions. These are usually known by simulating
different load conditions. Hence, usually it is known, in which
direction the maximum torque is acting. Further embodiments of
fixation devices of wind turbines include a spring between the
rotor shaft and the positioning disk. With such a spring, a
retraction of the locking pin from an engagement with the
positioning disk may be omitted. Therefore, the locking pin may be
left in the position for an engagement with the positioning disk.
With this, the maximum torque of the rotor-lock may be
enhanced.
[0063] FIG. 9 and FIG. 10 are described in connection with FIG. 8
since the same parts and the same embodiment is shown in FIGS. 8 to
10.
[0064] FIG. 11 and FIG. 12 depict the torques of the rotor-brake
and the rotor-lock for different load cases. The horizontal axis of
FIG. 11 and of FIG. 12 depicts the shaft rotation, wherein the
vertical axis represents the reacting torque, respectively. FIG. 11
relates to a positioning of the rotor in a middle position between
the limit stops of the locking clearance. FIG. 12 relates to an
asymmetric positioning of the rotor between the limit stops of the
rotor-lock. The line 400 in FIG. 11 shows the maximum load of the
combination of the rotor-lock and the rotor-brake for the symmetric
case. It should be noted, that the sum of the lock clearance and
the lock deflection at maximum load (line 400) is more than twice
the sum of the brake deflection and the brake clearance at maximum
load. The torque acting on the rotor-brake is depicted by line 410,
wherein line 420 relates to the torque acting on the rotor-lock.
The line 430 is the sum of the torques acting on the rotor-brake
and the rotor-lock. For the asymmetric case in FIG. 12, the angular
position of the rotor at the beginning is near to one of the limit
stops of the rotor-lock. Hence, the brake (line 410) is not at its
full load, when the rotor-lock reaches its limit. The limit of the
rotor-lock is depicted by lines 440. Due to the asymmetric
arrangement, the maximum combined load is bigger in a first
direction (402) than in the second opposite direction (line
403).
[0065] Exemplary embodiments of systems and methods for wind
turbines are described above in detail. The systems and methods are
not limited to the specific embodiments described herein, but
rather, components of the systems and/or steps of the methods may
be utilized independently and separately from other components
and/or steps described herein. For example, the exemplary methods
for locking or braking of wind turbines are not limited to practice
with only the wind turbine systems as described herein. Rather, the
exemplary embodiment can be implemented and utilized in connection
with many other rotor blade applications.
[0066] Although specific features of various embodiments of the
invention may be shown in some drawings and not in others, this is
for convenience only. In accordance with the principles of the
invention, any feature of a drawing may be referenced and/or
claimed in combination with any feature of any other drawing.
[0067] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. While various specific embodiments have been disclosed in
the foregoing, those skilled in the art will recognize that the
spirit and scope of the claims allows for equally effective
modifications. Especially, mutually non-exclusive features of the
embodiments described above may be combined with each other. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal language
of the claims.
* * * * *