Patent Application
20120169052
The invention relates to a wind energy installation for conversion of wind energy in a wind field to electrical energy having a multiplicity of wind energy apparatuses, and to a method for controlling the wind energy installation. For this purpose, the wind energy installation has at least one wind energy apparatus, which has a wind measurement apparatus.
The document DE 101 37 272 A1 discloses an early warning system for wind energy installations or wind farms which have a multiplicity of wind energy apparatuses. For the early warning system, measurement data from a first wind energy apparatus in the wind farm, with this wind energy apparatus being that which is subject to the wind first of all, is transmitted to at least one second wind energy apparatus, which is behind the first wind energy apparatus in the wind direction. In the early warning system, the second wind energy apparatus, which is in the wind shadow of the first wind energy apparatus, is controlled as a function of the measured data relating to the wind situation in the area of the first wind energy apparatus.
This makes use of the knowledge that not only, as in the past, the wind conditions can be measured at a single wind energy apparatus by means of an anemometer, but that these measurement results can also be used for wind energy apparatuses which are arranged behind the first wind energy apparatus in the wind direction, such that they can implement a blade setting angle change when necessary, for example when gusts occur, in good time before the gust arrives at the wind farm, as a result of which the load when the gust arrives at the wind farm is not sufficiently great that this could lead to damage to wind energy apparatuses.
An early warning system such as this has the disadvantage that it protects the wind energy apparatuses in the wind energy installation only in extreme wind profile situations, such as a storm warning or a gust warning. However, this system is not able to individually control the wind energy apparatuses in the wind farm or the wind energy installation so as to allow optimum use of the wind energy installation with normal wind profiles as well.
The object of the invention is to overcome the disadvantages in the prior art and to specify a wind energy installation having a multiplicity of wind energy apparatuses for conversion of wind energy in a wind field to electrical energy, and to specify a method for controlling the wind energy installation such that, on the one hand, the multiplicity of wind energy apparatuses in the wind energy installation are protected against damage and, on the other hand, the energy yield can be optimally adapted, with the wind energy apparatuses having a long life.
This object is achieved by the subject matter of the independent claims. Advantageous developments are specified in the dependent claims.
According to the invention, a wind energy installation is provided for conversion of wind energy in a wind field to electrical energy having a multiplicity of wind energy apparatuses, and a method is provided for controlling the wind energy installation. For this purpose, the wind energy installation has at least one wind energy apparatus which has a wind measurement apparatus for predictive measurement of wind profiles. Furthermore, the wind energy installation has a central storage apparatus in which a multiplicity of wind profile patterns are stored in a wind profile pattern table.
The wind measurement apparatus predictively detects current wind measured values. The wind energy installation has a central pattern recognition apparatus which correlates the current wind measured values from the wind measurement apparatus with the stored wind profile patterns from the wind profile pattern table. A central control device individually controls each individual wind energy apparatus in the wind energy installation as a function of a wind profile pattern, which is determined by correlation.
A wind energy installation such as this has the advantage that, during operation of a wind farm having a multiplicity of wind apparatuses, all the wind apparatuses which belong to the wind farm can be controlled individually with minimal measurement effort. The storage of wind profile patterns in a central store for the wind installation makes it possible to provide, in the stored wind profile pattern table itself, and to take account of, the geographical characteristics of the region of operation of the wind energy installation, such as hillsides, canyons, elevated positions, forest firebreaks and other geographical characteristics in which the individual wind energy apparatus operates in a wind energy installation.
It is thus possible, on a hillside, to set those wind energy apparatuses which are positioned toward the hill to a lower rotor blade angle of attack because of the higher wind speed, while the wind energy apparatuses which are arranged toward the valley can still be operated with a higher angle of attack. The angles of attack of the rotor blades are also in general referred to as the “pitch”.
These geographically dependent differences within the region of operation of the wind energy installation or of the wind farm can even lead to some of the rotor blades in the wind energy installation already being set to a feathered position, for the sake of safety, while other areas of the wind energy installation can be maintained in full operation. In order to allow this, at least one of the wind energy apparatuses is preferably provided for predictive detection of an active wind profile. However, in extreme geographical conditions, a plurality of the multiplicity of wind energy apparatuses may also be equipped with appropriate wind measurement apparatuses, which are each arranged at extreme locations at the edge of the wind farm.
However, the number of wind energy apparatuses in the wind energy installation is preferably greater than the number of wind measurement apparatuses being operated. This makes it possible to achieve a considerable cost reduction. Furthermore, this results in the entire wind energy installation or wind farm being matched to the wind conditions at an early stage, by matching the pitch on the one hand and the pitch angle of each individual installation on the other hand in each case optimally and appropriately to the determined wind profile pattern.
In order to achieve a safe and reliable correlation between predictively measured current wind measured values and the stored wind profile patterns, it is advantageous to detect a multiplicity of wind profiles as a wind profile pattern in the region of operation of the wind energy installation. The multiplicity of detected wind profile patterns makes it possible to ensure that the wind energy installation optimally matches the individual wind apparatuses to the wind conditions, even in extraordinary wind conditions.
In order to predictively determine the current values, the wind energy installation has a predictive wind sensor system as the wind measurement apparatus, preferably a SODAR (sound detection and ranging) or a LIDAR (light detection and ranging) anemometer. These wind sensor systems can preferably be mounted on the hub of the rotor of that wind energy apparatus in the wind energy installation which is equipped with the wind measurement system, since it can then cover the area and the wind conditions without any disturbance, at a time before they arrive, and physically upstream of the wind energy apparatus. It is therefore also advantageous for the individual wind energy apparatus which is equipped with a wind measurement apparatus such as this to be arranged at an exposed location in the wind farm or the wind energy installation.
In one preferred embodiment of the invention, the wind energy apparatuses in the wind energy installation each have an apparatus for pitch angle adjustment of a nacelle to which a rotor is fitted, and the respective control device sets the pitch angle of the nacelle in reaction to wind profile pattern recognition. The invention also provides that the wind energy apparatuses in the wind energy installation each have an apparatus for adjusting the angle of attack of rotor blades, and the respective control device sets the angle of attack or pitch of the rotor blades in reaction to wind profile pattern recognition. Finally, each wind energy apparatus in the wind energy installation has an azimuth adjustment apparatus in order to rotate the rotor blades to the respective wind direction, with the aid of the nacelle.
Furthermore, it is possible for the wind energy apparatuses in the wind energy installation to have a braking apparatus in the drive train for braking the rotor, and the respective control device to set the rotor blades to the feathered position, and to brake the rotor, in reaction to wind profile pattern recognition with a storm or gust warning. As already mentioned above, this can, however, be provided in an advantageous manner only for specific exposed positions of wind energy apparatuses in the wind farm, using the wind energy installation according to the invention, when the conditions of a wind profile require this, while other areas are still operating.
A method for controlling a wind energy installation having at least one wind energy apparatus has the following method steps. First of all, a multiplicity of wind profiles are detected by a multiplicity of wind measurement apparatuses in a geographical region of operation of the wind energy installation, preferably even before individual wind energy apparatuses are constructed. The multiplicity of wind profiles are stored in a central storage apparatus in the wind profile installation in the form of wind profile patterns in a wind profile pattern table.
Finally wind measured values are detected and evaluated, currently and predictively, with the aid of a predictive wind measurement apparatus by at least one wind energy apparatus in the wind farm, after it has been constructed. For this purpose, the current wind measured values are correlated with a wind profile pattern in the wind profile pattern table, by means of pattern recognition methods. The wind energy apparatuses in the wind energy installation can then each be operated individually, thus making it possible to match the loads on the components of the wind energy apparatuses and the energy yield of the wind energy apparatuses optimally to the wind profiles.
A central control device for the wind farm, for each individual wind energy apparatus in the wind energy installation, can set a pitch angle of a rotor and/or of a nacelle, taking account of reactive load measurements on the components in the wind energy apparatus, in reaction to wind profile pattern recognition. It is also possible to in each case set different angles of attack or rotor blade pitches for individual wind energy apparatuses, taking account of reactive load measurements on the components in the individual wind energy apparatus, with the aid of the control device and in reaction to wind profile pattern recognition, with the azimuth angle, the pitch and the pitch angle being regulated as a function of the wind profile pattern recognition.
Furthermore, the respective control device for each individual wind energy apparatus in the wind energy installation can appropriately vary damping of oscillations in a drive train in reaction to wind profile pattern recognition, in order to minimize such oscillations. Finally, the invention provides for the respective control device for each individual wind energy apparatus in the wind energy installation to set the rotor blades to the feathered position, and to brake the rotor by means of a braking apparatus in the braking train, in reaction to wind profile pattern recognition with a storm warning. However, this is envisaged only for protection of the individual energy apparatus in the case of extreme wind profiles.
The invention will now be explained in more detail with reference to the attached figures, in which:
At least one wind energy apparatus 3 of the multiplicity of wind energy apparatuses 311 to 3nm preferably has a wind measurement apparatus which can predictively detect current wind measured values. These current wind measured values are correlated by a central pattern recognition apparatus 7 with a multiplicity of wind profile patterns stored in a wind profile pattern table in a central storage apparatus 5.
These profile patterns have the wind speeds and wind directions to be expected for each of the wind energy apparatuses 311 to 3nm in the region of operation 8. Instead of a fixed association between a wind measurement apparatus and one of the wind energy apparatuses, it is also possible for one or more of the wind measurement apparatuses to be provided independently of the individual wind energy apparatuses in the area of the wind energy installation.
Individual control devices 411 to 4nm, which are arranged at the wind energy apparatuses 311 to 3nm, are supplied with control signals m by a central control unit 4, such that each wind energy apparatus 311 to 3nm can be set for the wind strength and wind direction to be expected. For this purpose, the control unit 4 has appropriate control lines 2011 to 20nm and one or more bus lines, via which control signals can be transmitted to the multiplicity of wind energy apparatuses 311 to 3nm in the wind energy installation 1, using a multiplexing method.
As input signals, the IPC regulator receives loads on the wind energy apparatus 3 measured by sensors 15, such as blade root bending moments in the shock and/or pivoting direction, yaw and/or pitch moments on the rotor shaft etc., and is designed such that it minimizes the measured loads and/or characteristic variables derived from this, by adjusting the individual pitch angles. However, the IPC regulator is initially reactive, as a result of which it reacts only when a load has already been measured. According to the invention, as
These calculated pitch angles β1, β2 and β3 are now set by the wind energy apparatus 3. This signal path is predictive, that is to say it reacts by means of the disturbance variable application 13 before any loads can be reactively measured at all. In this case, the wind energy apparatus 3 is set such that, at the moment when the measured wind arrives, the loads on the components remain within the desired limits, with the maximum possible energy yield. This disturbance variable application 13 now results in considerably lighter loads being applied to the wind energy apparatus 3.
The loads cannot be avoided completely, since the wind field 10 changes before it arrives at the wind energy apparatus 3, and model errors cannot be precluded. The IPC regulator 18 for each individual wind energy apparatus now has to regulate out only these lighter loads via a signal path 21, with the sensor values from the sensors 15 being made available in the IPC regulator 18 via the signal line 22. Overall, a considerable load reduction is possible in comparison to conventional wind energy apparatuses 3, in which a regulator 18 such as this has to manage without any disturbance variable application 13. In this case, the two signal paths 21 and 23 are joined together at the adder 17.
The result, in the form of one of the stored wind profile patterns, is converted by block 29 in a central controller to a multiplicity of control commands, which are transmitted to each of the energy apparatuses 311 and 3nm shown in block 30, such that these wind energy installations 311 and 3nm can be individually set to the current wind profile.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 030 886.5 | Jun 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/003297 | 5/31/2010 | WO | 00 | 3/23/2012 |
