Patent Application
20100117368
The present disclosure generally relates to wind turbines adapted for converting mechanical wind energy into electrical output energy, and in particular relates to a drive train supporting structure for a wind turbine.
A drive train of a wind turbine typically includes a rotor having a plurality of rotor blades, a hub, a speed adapter unit or a gear box and a generator. Typically, the supporting structure for said drive train is greatly contributes to the overall weight of an upper part of the wind turbine. During the operation of the wind turbine, e.g. when the rotor having the plurality of rotor blades is rotating, vibrations might occur.
Typically, the rotor rotates about a main axis which is oriented horizontally wherein the tilt, e.g. the horizontal orientation of the main axis of the rotor, cannot be changed. In order to adapt operation parameters of the wind turbine to environmental conditions, a yawing angle, e.g. an angle of rotation of a machine nacelle about a vertical axis, e.g. the tower axis and a pitch angle, e.g. a rotation of the rotor blades about their longitudinal axis, can be adjusted.
In view of the above, a drive train supporting arrangement for a wind turbine including a drive train is provided, said drive train supporting arrangement including a hinge connection means adapted for pivotably supporting the drive train, a self-supporting structure adapted for supporting the hinge connection means, and a first lattice structure adapted for supporting a counterweight, the counterweight being connected to and acting on the drive train.
According to another aspect a wind turbine including a drive train and a drive train supporting arrangement is provided, said drive train supporting arrangement including a hinge connection means adapted for pivotably supporting the drive train, a self-supporting structure adapted for supporting the hinge connection means, and a first lattice structure adapted for supporting a counterweight-damper mass, the counterweight-damper mass being connected to and acting on the drive train.
According to yet another aspect a method for adjusting a tilt angle of a drive train of a wind turbine including a drive train and a drive train supporting arrangement is provided, said method including determining a wind shear at the location of the wind turbine, measuring an actual tilt angle of the drive train of the wind turbine, and changing the tilt angle of the drive train as a function of the actual tilt angle and the measured wind shear.
Further exemplary embodiments are according to the dependent claims, the description and the accompanying drawings.
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 drawings wherein:
Reference will now be made in detail to the various exemplary embodiments, one or more examples of which are illustrated in the drawings. 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 a further embodiment. It is intended that the present disclosure includes such modifications and variations.
A number of embodiments will be explained below. In this case, identical structural features are identified by identical reference symbols in the drawings. The structures shown in the drawings are not depicted true to scale but rather serve only for the better understanding of the embodiments.
In order to obtain a good energy conversion from wind energy into rotational energy, the at least one rotor blade 101 can be adjusted with respect to a pitch angle 108. The pitch angle 108 is adjusted by rotating a respective rotor blade about its longitudinal axis. Thus, the pitch angle may determine loads as a function of the strength of the incoming wind 105 onto a specific rotor blade.
According to a typical embodiment, a vibration damper unit 114 is provided which is adapted to damp vibrations caused by varying wind forces and rotational influences. These vibrations (or oscillations) may act on the entire wind turbine 100, e.g. several portions of the wind turbine are vibrating in a combined mode. Typically, these oscillations are dependent on the design of the wind turbine 100 and on meteorological conditions.
The vibration damper unit is arranged at a position where the oscillations may be effectively damped. Therefore, specific vibration frequencies of the mechanical arrangement of portions of the wind turbine 100 or of the entire wind turbine 100 can be damped. In order to be effective, such kind of load reduction system typically is installed atop the tower 102, e.g. inside or outside the machine nacelle 103. Thus, it is possible that the vibration damper unit rotates about the vertical axis 107 together with the drive train of the wind turbine 100. A counterweight which may be formed as a counterweight-damper mass may be provided as a liquid tuned damper. In a typical embodiment the liquid tuned damper may include water.
In order to rotate the drive train of the wind turbine 100 about the tilt axis 118 being perpendicular to the vertical axis 107 and the rotor axis 115, a drive train supporting arrangement is provided according to typical embodiments shown in
In the typical embodiment shown in
Therefore, the hinge connection means 201 is adapted for pivotly supporting the drive train. A tilt angle detection unit 210 is provided in order to measure an actual tilt angle 116, and/or a change of the tilt angle 116. the tilt angle 116 is thus a measure of the orientation of the rotor axis 115. The self-supporting structure may form a part of a machine nacelle 103 (shown in
As shown in
At its top end, the first lattice structure 202 may include an anemometer support unit 205 for supporting an anemometer 206. The anemometer support unit 205 is adapted for arranging the anemometer 206 distant from air turbulences caused by the rotating rotor blades. The anemometer 206 which is installed at this location distant from the main rotor having the plurality of rotor blades 101 is less influenced by wind deviations caused by the rotating rotor blades 101 and thus provides a better measurement accuracy as compared to anemometers which are installed closer to the tower axis (vertical axis) 107.
It is noted here that besides adapting the tilt angle 116 of the rotor axis 115 with respect to a horizontal wind shear of the incoming wind 105, the tilt angle 116 of the rotor axis 115 may be adapted according to loads measured at different locations within the wind turbine 100. Furthermore, it is noted that the drive train supporting arrangement 200 having a self-supporting structure 207 and a first lattice structure 202 is a lightweight construction which saves yaw energy and eases installation of the wind turbine. The movement of the counterweight in the counterweight movement direction 208 may be used to counteract thrust changes caused by the incoming wind 105.
It is noted here that components or steps which have been described with respect to previous drawings, are not repeated in the following sections in order to avoid a redundant description. Furthermore, an explanation of reference numerals which have been explained in previous drawings in the description, are not extensively repeated in the description of succeeding drawings.
As in the typical embodiment shown in
Again, the self-supporting structure 207 is at a fixed position wherein in the embodiment shown in
The counterweight 203 now acts on three different portions of a cable 204. The first portion of the cable 204 is connected to the drive train, wherein the second and third portions of the cable 204 are connected to the second lattice structure 211.
As the first lattice structure 202, the second lattice structure 211 is lightweight such that the entire drive train supporting arrangement 200 has a reduced weight as compared to a machine nacelle without any lattice structure.
A flexible bellow 209 is provided as a connection means between the drive train and the fixed self-supporting structure 207. Again, the counterweight 203 may be moved in a direction of the arrows 208 such that the tilt angle 116 of the rotor axis 115 may be varied.
In the following, drive train supporting arrangements 200 according to further typical embodiments are explained with respect to
More precisely,
As shown in
As in the embodiment shown with respect to
At step S2, the wind at different heights of the wind turbine 100 is measured. Furthermore, a calculation and/or estimation of wind shear, e.g. from bending moments at the rotor blades, is carried out. Such kind of wind measurement results in a wind shear determination which may be used for appropriate adjustment of the rotor axis 115. The procedure advances to step S3 where the actual tilt angle 116 of the rotor axis 115 is measured. If the actual tilt angle 116 is adapted to the measured wind shear (“Yes” at step S4), the procedure proceeds to step S6.
It is noted here that wind shear can be measured using anemometers at different hub heights. Moreover wind shear can be calculated from measurements of loads or deflections of at least one rotor blade.
When it is determined at step S4 that the actual tilt angle 116 is not adapted for the measured wind shear (“No” at step S4), then the procedure advances to step S5 where the tilt angle is changed according to the measured wind shear. The tilt angle may be changed by moving the counterweight 203 in the counterweight moving direction 208 (see
Then the procedure advances to step S6 where it is determined whether the wind shear has changed or not. The determination of any change of wind shear again may be performed by wind velocity sensors installed at different heights at the wind turbine 100. If the wind shear has changed (“Yes” at step S6), the procedure returns to step S2, and the procedural steps S2 to S5 (S4) are repeated. If it is determined that the wind shear did not change (“No” at step S6), the procedure is ended at step S7.
The invention has been described on the basis of embodiments which are shown in the appended drawings and from which further advantages and modifications emerge. However, the disclosure is not restricted to the embodiments described in concrete terms, but rather can be modified and varied in a suitable manner. It lies within the scope to combine individual features and combinations of features of one embodiment with features and combinations of features of another embodiment in a suitable manner in order to arrive at further embodiments.
It will be apparent to those skilled in the art, based upon the teachings herein, that changes and modifications may be made without departing from the disclosure and its broader aspects. That is, all examples set forth herein above are intended to be exemplary and non-limiting.
