JP5006186B2 - How to reduce axial power changes in wind farms - Google Patents

Description

The present invention provides a wind farm in which the thrust of the rotor on the tower is controlled and maintained so that the average power generation of the wind farm is not affected to a significant degree within the range of the target value. The method of adjusting the angle of the rotor blade about its own longitudinal axis. This has the advantage that load changes on the rotor blades and tower are reduced, thereby essentially reducing the fatigue of these heavily loaded components.

In this patent application, the following definitions are used:
1) The instantaneous maximum wind speed is defined as the instantaneous maximum wind speed measured at a specific time.
2) The average or averaged wind speed is defined as the average or near average of the instantaneous maximum wind speed for a specific period. This period is generally longer than 3 seconds and is usually in the range of 10 minutes to 1 hour, but it can also be longer. When wind speed is used to control a wind turbine, such measurement scaling or fraction is also applied by this definition.
3) The pitch angle of this patent application is defined as the torsion of the rigid body of the rotor blade around its own longitudinal axis in relation to the fixed starting position of this angle. By tilting the blade to one side, the force on the rotor with the instantaneous maximum wind speed provided can be varied.
4) The axial force of the rotor is defined as the thrust that is transferred from the rotor towards the mill housing and is essentially guided along the axis of rotation of the rotor shaft. This force is composed of the overall thrust of the wind direction from the rotor blades and may be positive and negative at different times during the operation of the wind farm.
5) Nominal wind speed is defined as the wind speed at which the wind farm first achieves full power generation. This is generally in the range of 12-14 m / s.
6) A converter unit is a unit that generates or converts energy from wind / rotor blade rotation into electrical power or other mechanical power. This unit is typically a generator, mechanical pump, gear unit or the like.

In the following description, the term “generator” is most often used, but it is clear that the generator can be replaced by any type of suitable converter unit, as mentioned herein. is there.

It would be desirable to be able to place a large, commercially available horizontally-axis wind turbine deeply in the water. This increases the potential area of wind development, gaining access to areas with high average wind speeds, and wind so that wind can be used to provide electricity to them in close proximity to oil and gas facilities. This is desirable because it is possible to build a park.

In the deep sea, floating structures are convenient to limit the size and cost of towers and foundations.
This type of floating structure is initially affected by two types of forces that control movement patterns and stresses on the floating structure. These are the wave forces on the floating part of the structure and the thrust on the rotor from the wind, referred to herein as the rotor axial force.

For wind farms on land or in shallow water that are fixed to the ground or sea floor, the dominant force acting on the structure is usually the thrust on the rotor from the wind in addition to gravity.

In large wind farms (generally having a power generation above 1 MW), the nominal power generation of the equipment due to the higher wind speed required to achieve maximum power generation (nominal power generation) There are today two main types of adjustment mechanisms used to control a rotor that provides a constant output power equal to the force.

One of the methods is stall adjustment of the rotor blade. Since this method turns the blades into wind, the relative wind angle of attack relative to the blade profile increases and the rotor blades stall. That is, the wind gradually loses its ascending force and the flow across the lamellar rotor blade becomes turbulent. Therefore, excess energy is released.

Another adjustment method is blade pitch adjustment, whereby the blade is turned in the opposite direction of that of stall adjustment, so that the wind is released by reducing the angle of attack of the wind relative to the wing profile. The Thus, the lifting force of the rotor blades is reduced and less energy is recovered from the wind.

The present invention relates to this second adjustment method, referred to in this application as pitch adjustment.

For large rotor diameters, the change in wind speed across the rotor area, both vertically and horizontally, tends to be large. This can cause fatigue problems in larger blades than in smaller installations if the individual thrust of the blades in the wind direction is not controlled and adjusted for convenience. If the wind speed (around the vertical axis) at a given time is essentially greater than one of the rotors facing the other, a large moment of turning the rotor from the wind can also occur. In the prior art including pitch adjustment as described above, the rotor speed / min for wind speed above the nominal wind speed is adjusted so that the rotor equal to the rotor torque multiplied by the angular speed (radian speed) The output is always kept as equal as possible to the nominal power generation of the wind farm. To achieve this, the control device continuously controls the pitch angle of the rotor blades. The power and axial force of the rotor are non-linear values as a function of changes in wind speed. When the wind speed changes and the output from the rotor is kept constant by tilting the rotor blades, the axial force of the rotor changes simultaneously. The axial force of the rotor (wind direction thrust) can therefore have a large change. These force changes result in large fatigue loads on the blade and tower structures, which can often be sized as required for these structural elements.

To illustrate this, the effect of the prior art pitch adjustment can be seen. The instantaneous maximum wind speed increases from the nominal wind speed (eg 13 m / s) to twice that (26 m / s), while the rotor power and speed remain constant, the blade pitch The change will be about 20 ° to prevent the rotor power from increasing to higher wind speeds. The result of this pitch change of the blades is that the axial force of the rotor (wind direction thrust) is simultaneously halved, causing fatigue loads on the blade and tower structure.

For example, when the weather condition is an average wind speed of 19 m / s in 10 minutes, such fluctuations in wind speed are generally high in the overall axial force of the blades and rotor if the output is kept constant. It happens with change. Similar variations in axial force occur at all average wind speeds up to a range greater or less than the nominal wind speed when prior art pitch adjustment is used. There is always a specific delay between the rotor aerodynamic momentary torque and the generator torque. This is primarily due to the inertial forces of the rotor, drive gear and generator.

Since prior art pitch adjustments use measurements of rotational speed or generator output, pitch adjustments are inaccurate with respect to instantaneous forces acting on the rotor, including instantaneous rotor axial forces. And delay. This means that due to the unexpected reduction of the instantaneous maximum wind speed, the rotor blade has an excessively large blade pitch angle and the axial force of the rotor decreases rapidly and even becomes negative. In the case of an unexpected reduction in wind speed from 26 m / s to 13 m / s for the above example, if the pitch adjustment does not change quickly enough, this is the nominal wind speed at 26 m / s of 50% From the axial force, it may lead to a result of a nominal axial force at 13 m / s of -30%, i.e. a reduction of the instantaneous aerodynamic axial force of the rotor to the opposite direction of the wind. is there. Together, this means a nominal rotor axial force change of 80%. Such large variations in axial force due to delayed pitch control are particularly problematic at higher average wind speeds. This also means that rotor blades sized for low annual average wind speed cannot be used for locations with high annual average wind speed. Due to the increased fatigue load that occurs due to large changes in the thrust of the blades in the wind direction, the rotor blades intended for areas with high average wind speeds must be more strongly sized. This can mean more expensive and heavier blades. The fact that a position with a high average wind speed has more operating time also increases the fatigue strength requirement for the rotor blades.

For floating wind farms, the increased wind speed reduces the axial force of the rotor caused by pitch adjustment (for wind speeds above the nominal wind speed), and the above effect also reduces wind power May have a negative effect on the movement pattern. As the tower and rotor move to the wind, the relative wind speed to the rotor increases and the pitch adjustment attempts to maintain a constant output, thus increasing the tower motion in alternation to the wind and increasing the rotor thrust. Cause a decrease. Conversely, if the tower and rotor return in the same direction as the wind, the relative wind speed to the rotor is reduced, and in the prior art, the blades are automatically tilted to maintain a nominal output to the generator. (Turned). This in turn causes an increase in rotor thrust, which turns increase tower movement in the wind direction. When prior art pitch adjustment is used, the result is an extra excitation and increase in tower motion. This was found to lead to a large increase in the fatigue load of the floating wind tower.

U.S. Pat. 4, 201, 514 describe a method of adjusting the pitch angle of individual rotor blades with respect to changes in wind speed. The adjustment describes how a constant torque is automatically maintained when changing the wind speed of individual blades around the rotor axis. This has the same effect as for other prior art as described above. That is, the direction of rotation of the blade, in other words, the force acting perpendicularly to the wind direction and rotating the blade is kept constant. The side effect of this is that the thrust of the blades in the wind direction is similarly different as described above in other prior art. This prior art therefore has the same effect as blade and tower fatigue, as the thrust on the rotor blades changes when an attempt is made to keep the rotor torque constant.

The object of the present invention is to overcome the disadvantages of the prior art.

In the methods described below, the disadvantages of the prior art have been improved or eliminated.

In one embodiment of the present invention, a method is provided for controlling the output of a wind power plant comprised of converter units, where the pitch of the rotor blades if the output power of the converter unit is in a given range. The angle changes individually or collectively to minimize the change in rotor blade thrust in the wind direction, and if the output power of the converter unit is outside this range, the pitch angle of the rotor blade is Change to guide the output power in.

In another embodiment of the present invention, the change in thrust of the wind direction rotor blade is minimized by adjusting towards the target value calculated for the thrust of the wind direction rotor blade. Target values for differ for different average wind speeds.

In yet another embodiment of the invention, the target value for the thrust of the rotor blades in the wind direction is adjusted with respect to the average converter unit output or rotor speed over a given period of time.
In yet another embodiment of the invention, the predetermined target value for the thrust of the rotor blades in the wind direction is predefined and related to a given average wind speed.

In one embodiment of the invention, the thrust of the rotor blades in the wind direction is further adjusted by changing the rotor speed / min by adjusting the generator rotational resistance moment and / or the rotor braking device.

In yet another aspect, the instantaneous thrust of the rotor blades in the wind direction is combined with a measurement of blade geometric refraction, a measurement of generator torque, and / or a simultaneous measurement of the pitch angle of the blade or blades. By measuring the generator output and / or measuring or using the pitch moment of the blade around the axis of rotation of the pitch bearing, either by mounting the blade tilting backwards in the pitch bearing or by shaping the blade, As determined directly or indirectly by strain gauges, wind speed measurements, the wind impingement position on the blade is after the axis of rotation of the pitch bearing with respect to the direction of rotor rotation.

In one embodiment, the rotor blade pitch angle is additionally varied to minimize directional errors for the wind farm.

In one embodiment, the directional error is corrected if it is outside the given range.

In another embodiment of the invention, the pitch angle of the rotor blade is adjusted differently for different rotational positions.

In one embodiment, the pitch angles of the rotor blades are individually adjusted and / or independent of each other.

In an embodiment, the wind field in a plane essentially perpendicular to the wind direction is a direct or indirect measured value of the wind speed acting on the previous rotor blade or blades with respect to the direction of rotor rotation. Predicted.

In one embodiment, wind direction rotor blade thrust is actively used to impede wind turbine tower motion by adjusting the rotor blade pitch angle.

In one embodiment of the invention, one or more anemometers / anemometers are placed at the appropriate location or location on the wind farm so that the spatial distribution of wind speed can be recorded, Interpolation between different anemometers can be created to form an image of wind distribution across the sweep region of the rotor. This is done by placing the anemometer at essentially different heights and at essentially different horizontal postures. This spatial distribution of instantaneous maximum wind speed can then be used to individually adjust the pitch of the rotor blades, and optionally all the blades may be pitched collectively.

A plane wind field that is essentially perpendicular to the wind direction is predicted using directly or indirectly measured values of wind force acting on the previous rotor blade or blades with respect to the direction of rotor rotation. Can.

The rotor may be conveniently located leeward of the tower, so the anemometer records the wind speed before it affects the rotor. In addition, the directly or indirectly measured value of the thrust on the previous blade with respect to the direction of rotation of the rotor in a given blade is used to predict the wind in the field in which the given blade moves. In this way, the optimum pitch angle of the blade can be calculated in advance, so there is little delay between the aerodynamic and pitch response of the rotor blade. Thus, unexpected changes in the instantaneous maximum wind speed can be predicted. Using the horizontal distance between the anemometer mounted on the wind and the rotor and the vertical plane of the wind speed, the time delay when the measurement is performed until the actual wind speed occurs in the rotor is calculated. Can do. The controller that controls the pitch adjustment is provided with access to all these measurements and can use this information at any given time to optimize the pitch angle of the blade. It is therefore possible to avoid the particularly large rotor axial force reductions that occur in connection with the sudden instantaneous reduction of the instantaneous maximum wind speed, since the prior art pitch adjustment does not occur sufficiently rapidly.

Due to the instantaneous maximum wind speed above the nominal wind speed of the wind farm, the blades initially rotate, so the axial force on the rotor decreases. This is addressed by increasing the rotational speed of the rotor with no reduction or pitch response, while at the same time the generator torque is optionally reduced by input from the controller which helps to increase the rotational speed of the rotor. To do. The axial force of the rotor and the output of the generator are then kept approximately constant at an optimum pitch angle within a small wind speed increase. With a wind increase of about 10%, the rotational speed by this method must increase by about 10% in order to obtain both a constant rotor axial force and a constant output to the generator. The pitch angle must also change at the same time. If there is a decrease in the instantaneous maximum wind speed, a similar method is used, in which case the rotational speed of the rotor is reduced, while the generator torque is optionally increased simultaneously according to the input from the controller.

Due to the greater change in the instantaneous maximum wind speed, the following is performed: if there is a decrease in the instantaneous maximum wind speed compared to the average wind speed measured over a period longer than the pitch adjustment update frequency, eg 10 minutes The blade pitch angle changes less than when a powerful power-control pitch adjustment is used. The result of this is that the axial force of the rotor remains unchanged, but the output to the generator is slightly less than the nominal output. A 10% reduction in wind speed will reduce the output by about 10% while the axial force of the rotor remains unchanged.

Similarly, a 10% increase in wind speed results in a smaller change in blade pitch angle than when pure power-control pitch adjustment is used. The result of this is that the axial force of the rotor remains unchanged, but the output to the generator is slightly larger than the nominal output. A 10% increase in the instantaneous maximum wind speed increases the output power by about 10% while the axial force of the rotor remains unchanged.

By combining the two outputs described above, the overall result is that the instantaneous maximum wind speed can generally vary +/− 20% without changing the axial force of the rotor. is there. Since the accompanying generator output changes are short-term and fluctuate around the rated power of the generator, the average generator power is almost unchanged, in other words, equivalent to the nominal power (rated power). On the other hand, the axial force of a given average wind speed is kept constant or nearly constant and is generally kept at a +/− 20% change in the instantaneous maximum wind speed.

For a given average wind speed, the axial force (target value) of the rotor corresponding to the nominal output of the generator can be calculated. The allowable maximum and minimum values for the generator output change around the mean value can be programmed in advance and the pitch control unit will then calculate the optimal instantaneous pitch angle so that the rotor axis The direction force is kept as constant as possible around the calculated target value, while the generator output is kept within a pre-programmed bandwidth.

The calculated target value for the axial force of the rotor will therefore vary at different average wind speeds. Within each average wind speed range, an attempt is made to make the axial force substantially constant using pitch adjustment. The average wind speed is, for example, an average over the last 10 minutes. Optionally, a pre-calculated value may be used for a target value of axial force that is divided into a given average wind speed interval, eg, a difference interval of 0.1 m / s.

Due to the change in instantaneous maximum wind speed exceeding +/− 20%, the pitch adjustment can be performed in preference to not changing the generator output typically above +/− 10% as described above. With such large changes in the instantaneous maximum wind speed, the axial force of the rotor begins to change, but in these cases this change is essentially small due to the prior art pitch adjustment.

Since the average wind speed over a long period of time, for example an average of 10 minutes, is a much smaller change than the instantaneous maximum wind speed change, the described method reduces the rotor axial force change considerably, which And has a positive effect on the fatigue load on the rotor.

If the axial force of the rotor is thus actively controlled by different values, this can be used, for example, to apply forces to the tower in antiphase with its movement, so that the movement of the tower Is weakened.

Tower motion can be recorded, for example, using an accelerometer.

This can be done by controlling the individual forces of the rotor blades in the wind direction, so that the individual pitch angle of the blades according to the physical position of each individual blade at a given time. By periodically changing, any torque that attempts to rotate the rotor and / or nacelle and / or tower from the wind is addressed, reduced or eliminated, so that the axial force on the rotor is required Depending on the larger of one or the other of the vertical axes of the rotor. If a given rotor blade passes through one side of the vertical axis of the tower, the pitch angle increases, for example by 0.5 °, and if the same blade passes through the opposite side, the pitch angle decreases correspondingly. . Therefore, this need not have any effect on the overall rotor power or the axial force of the entire rotor. The extra periodic adjacent pitch error is placed only on the pitch angle calculated by the above method to control the axial force of the entire rotor. This described periodic pitch adjustment can also be used to actively control the rotor, so that in the case of floating installations, some or optionally the entire wind farm is associated with the wind direction. And can be kept in a desired position. Thus, according to the prior art, when the mill housing is non-rotatably mounted on a floating equipment tower at a desired location associated with the wind, the mill housing or optionally the entire tower is rotated. It is possible to remove the motor or reduce the size or number.

Further, wind direction thrust changes on each individual blade can be reduced by changing the pitch angle in the manner described above to control the instantaneous thrust of the blade in the wind direction. The blade can then be individually controlled with respect to its position in its trajectory, and wind speed measurements at different positions or around the sweep region of the rotor.

The measured axial force is recorded and included in the pitch control unit for calculation of the optimum pitch angle at the time given by the described method.

Instead of just using the measured wind speed and pitch angle, several other direct or indirect methods can be used to calculate the rotor axial force.

In other words, the blade's longitudinal axis crosses the rotor's axis of rotation because the blade's longitudinal axis deviates slightly from the pitch bearing's axis because the blade is mounted tilted rearward at the pitch bearing. Without this, the subsequent pitch moment can be measured via oil pressure through the blade pitch control system and the axial force can be calculated therefrom;
Alternatively, it is calculated using the strain gauges of the blade and / or rotor spindle and / or other parts of the wind farm.

Or calculated indirectly by measuring the pitch angle of the blades and measuring the rotor torque directly, or recording other parameters such as generator torque, power, etc., and the corresponding rotor axial force Can be calculated by measuring the refraction of the blade using a mechanical or electronic measurement system.

A description of non-limiting examples of preferred methods illustrated in the accompanying drawings follows.

A wind farm 1 having a horizontal and substantially horizontal rotor shaft 11 is composed of one or more rotor blades 1 which together form a rotor 2. Here, the adjusted or individually rotor blades essentially control their own longitudinal direction around their own longitudinal axis or to control the output of the rotor 2 to the generator (not shown). First, it is rotated (tilted) about its axis 14. Here, the rotor shaft is fixed in the mill housing 3, and the rotor shaft is optionally connected to the generator via a power transmission device (gear). The pitch adjustment of the rotor blade is based on different recorded operational information such as wind measurements that signal the pitch motor indicating the amount of change required in the pitch angle at a given time, etc. Executed by.

The mill housing may optionally be one or more of a tower 4 that is fixedly mounted on land 9, or a seabed 8, a part of a floating device, or itself an anchor 7 on the seabed 8. There is a possibility of being mounted on what constitutes a floating device having the anchor connection 6. The design of the anchor systems 6, 7 is not important for the described method.

One of the objectives of the method described below is to reduce the change in the axial force of the rotor compared to the prior art, while the resulting output of the generator is hardly affected or the drive To maintain within acceptable limits due to gear, generator and power grid limitations. It is also an object of the invention to use the axial force of the rotor to actively cope with the movement of a floating wind farm. In addition, to control and deal with the rotational force around the vertical axis 12 of the tower, different heights (vertical wind shear) and rotor planes (horizontal) on each individual blade throughout the entire rotational cycle. The method described to reduce the aerodynamic change resulting from different wind speeds in a parallel direction parallel to (wind shear) is the object of the present invention.

Since one or more anemometers 5 are arranged at a suitable position or positions on the wind farm 1, the spatial distribution of the wind speed is conveniently recorded and the interpolation between the different anemometers is It can be created to form an image of wind distribution across the sweep area of the rotor. This can be done by placing the anemometer in an essentially different horizontal position at an essentially different height. This spatial distribution of instantaneous maximum wind speed can then be used to individually adjust the pitch of the rotor blades, optionally all blades are collectively pitch adjusted.

Since the rotor 2 may be conveniently located leeward of the tower 4, the anemometer records the wind speed before it affects the rotor. In this way, the optimum pitch angle of the blade can be calculated in advance, so there is little delay between the aerodynamics and the pitch response of the rotor blades. Thus, unexpected changes in the instantaneous maximum wind speed can be predicted. The anemometer and rotor vertical plane mounted on the windward, and the horizontal distance between the wind speeds, delays the time from when the measurement was made until the actual measured wind speed effect occurred in the rotor. Can be calculated. A controller (not shown) that controls the pitch adjustment is given access to all these measurements and uses this information to optimize the pitch angle of the blade 13 at any given time. can do. Thus, since the prior art pitch adjustment has a time lag, it is possible to avoid a particularly large axial force reduction of the rotor which causes an unexpected instantaneous reduction of the instantaneous maximum wind speed.

In the case where the average speed is above the nominal wind speed for the wind farm 1 and the instantaneous wind speed then increases beyond the given average wind speed, the rotational speed of the rotor 2 by this method is conventionally The generator torque is increased by a decreasing pitch response compared to the technology, while at the same time optionally decreasing according to the input from the controller, which also serves to increase the rotational speed of the rotor 2. Since the rotor axial force generally increases the number of revolutions / min for an increased given rotor output, the reduced rotor axial force resulting from the pitch rotating in the blades increases In response to the instantaneous wind speed to be compensated. The result is that at small wind speed increases, both the axial force of the rotor and the output of the generator can be kept approximately constant by increasing the rotational speed of the rotor. With a wind increase of about 10%, the rotational speed by this method should increase by 10% to obtain a constant rotor axial force and a constant output to the generator. The pitch angle must change at the same time. If there is a reduction in the instantaneous maximum wind speed, a similar method is used, in which case the generator torque is optionally increased simultaneously with the input from the controller, while the rotational speed of the rotor is reduced.

Due to the greater change in the instantaneous maximum wind speed, the following is performed: Rather than updating the frequency of pitch adjustment compared to the average wind speed measured over a longer period of time, for example 10 minutes When there is a reduction in the instantaneous maximum wind speed, the pitch angle of the blade changes less than when purely controlled pitch adjustment is used. The result is that the axial force of the rotor remains unchanged, but the output to the generator is slightly less than the nominal output. While the rotor axial force remains unchanged, a 10% reduction in wind speed reduces the output by about 10%.

Similarly, due to the 10% increase in instantaneous maximum wind speed, smaller changes in the pitch angle of the blade will occur more than if purely power controlled pitch adjustment is used. The result of this is that the axial force of the rotor remains unchanged, but the output to the generator is slightly greater than the nominal output. A 10% increase in the instantaneous maximum wind speed provides an increase in power of about 10% while the axial force of the rotor remains unchanged. By combining the two outputs described above, the overall result is that the instantaneous maximum wind speed can generally vary by +/− 20% without changing the axial force of the rotor. become. Since the accompanying generator output changes are short-term and fluctuate around the nominal output of the wind farm or around the rated power of the generator, the average generator output is almost unchanged, in other words, the nominal output (rated On the other hand, the axial force of a given average wind speed can be kept constant or nearly constant, generally with a +/− 20% change in the instantaneous maximum wind speed.

At a given average wind speed and rotor rotational speed, the axial force (target value) of the rotor corresponding to the nominal output of the generator can be calculated. The allowable maximum and minimum values for the generator output change around the mean value can be programmed in advance and the pitch control unit can then select the optimal instantaneous pitch angle (in response to the instantaneous maximum wind speed) So that the axial force of the rotor is kept as constant as possible around the calculated target value, while the generator output is maintained within a pre-programmed bandwidth.

The target value calculated for the axial force of the rotor varies with different average wind speeds. Within each average wind speed range, an attempt is then made to keep the axial force approximately constant around the target value using pitch adjustment. The average wind speed is, for example, an average over the last 10 minutes. Optionally, a pre-calculated value may be used for the axial force target value for a given average wind speed interval (eg, divided into 0.1 m / s difference intervals). .

Due to the instantaneous maximum wind speed change of about +/− 20% excess as described above, the pitch adjustment prioritizes not changing the generator output from a typical bandwidth of +/− 10% as described. Can be executed. With such large changes in the instantaneous maximum wind speed, the axial force of the rotor also begins to change, but in these cases this change is essentially less than the prior art pitch adjustment.

Since the average wind speed over a longer period of time, for example an average of 10 minutes, changes less than the change in the instantaneous maximum wind speed, the described method significantly reduces the axial force change of the rotor and And has a positive effect on the fatigue load on the rotor.

The same method as above can also be used to actively adjust the axial force of the rotor around a given mean value. If the rotor axial force is actively controlled in this way with different values, this can be used, for example, the force is applied to the antiphase tower 1 in its motion, so that the motion of the tower is weakened. It is done. This is particularly convenient for floating wind farms.

The control device also has access to the movement of the tower in this case. Tower motion can be recorded using, for example, an accelerometer or other suitable measurement method.

In addition, axial forces can be used actively in a similar manner to cope with any force that attempts to rotate the rotor from the wind. This can be done by controlling the individual forces of the rotor blades in the wind direction, so that the torque is at a given time to rotate the rotor and / or mill housing and / or tower from the wind. According to the physical position of each individual blade, it is dealt with, reduced or eliminated by periodically changing the individual pitch angle of the blade so that the axial force on the rotor is , Larger on one side or the other side of the vertical axis of the rotor, if desired. If a given rotor blade passes through one side of the vertical axis of the tower, the pitch angle increases, for example by 0.5 °, and if the same blade passes through the opposite side, the pitch angle decreases correspondingly. Therefore, this need not have any effect on the overall rotor output or the axial force of the entire rotor. The extra periodic adjacent pitch error is placed above the pitch angle calculated by the above method to control the axial force of the entire rotor. This described periodic pitch adjustment can also be used to actively control the rotor 2 so that in the case of floating installations, part or optionally the whole of the wind farm is associated with the wind direction. And can be kept in a desired position. Thus, according to the prior art, it is possible to eliminate or reduce the size or number of motors that rotate the mill housing 3 or optionally the entire tower 5, resulting in a desired location associated with the wind. The housing is mounted on a tower of non-rotatable equipment.

In addition, the change in thrust in the flap direction (usually approximately the same as the wind direction) on each individual blade (which together make up the rotor axial force) controls the instantaneous thrust of the blade in the wind direction, This is reduced by changing the pitch angle in the above manner. The blades can then be individually controlled in or around the sweep region of the rotor at different positions with respect to their trajectory position and directly or indirectly measured values of wind speed.

The measured or calculated axial force is recorded by the described method and includes a pitch control unit for the calculation of the optimum pitch angle at a given time.

Instead of just using the measured wind speed and pitch angle to calculate the rotor axial force, several other direct or indirect methods can be used.

The blade 13 is mounted tilted rearwardly on the pitch bearing 10, i.e., the blade longitudinal axis 14 slightly deviates from the pitch bearing axis so that the blade longitudinal axis 14 is the rotor rotation axis 11. The moment of pitch that does not intersect with and can be measured via oil pressure by the blade pitch control system, and the rotor blade thrust in the wind direction for each individual blade can be calculated therefrom Or
Can be calculated using strain gauges on the blade 13 and / or the main axis of the rotor and / or other parts of the wind farm; or indirectly measuring the pitch angle of the blade 13 and the torque of the rotor 2 By directly measuring or recording other parameters such as generator torque, power, etc., the corresponding rotor axial force of the rotor can be calculated.

It can be calculated by measuring the refraction of the blade using a mechanical or electronic measurement system.

An embodiment of the inventive method is illustrated in FIG. 4 by a flowchart. The method determines whether the rotor speed or any output power of the generator is within the range of +/− 10% of the nominal value, in the example the generator instantaneous / instantaneous rotor speed, or , Based on a 40 determination of whether the arbitrary output power is within the nominal value range for the wind farm.

Instantaneous / instantaneous rotor speed, optionally if generator output power is within that range, change of rotor axial force by adjusting to target value for axial force, arbitrarily An attempt is made to minimize the thrust of each blade in a separate wind direction. At 44, it is then determined that the average rotor speed or average generator output power for a given time t, for example the last 10 minutes, is above or below the nominal output of the wind farm. According to this, the target value for the axial force of the rotor is adjusted at 45,46. As previously mentioned, the new target value for the axial force will gradually increase or decrease the target value for the axial force that determines whether an increase or decrease in the average output of the generator is required, For example, it can be calculated based on the average value of the axial force in a given period t of 10 minutes. The target value for the axial force of the rotor is also an arbitrarily pre-calculated value in relation to the average wind speed. The instantaneous value of the rotor axial force is then compared at 47 with the target value for the axial force as achieved at 45/46, and the rotor blade pitch angle is then 48 and according to this comparison. At 49.

On the other hand, if the instantaneous / instantaneous rotor speed or any output power of the generator, as calculated at 40, is outside the given range, the rotor speed or any average output power of the generator is set to the desired range. For example, an attempt is made to fit within this range by adjusting the pitch angle in the same way as described in the prior art, in order to bring it within a range of +/− 10% of the nominal value. . The pitch angle is adjusted at 42/43 according to a calculation of 41 whether the instantaneous / instantaneous rotor speed or any output power of the generator is above or below the desired range. In this way, the pitch angle is first adjusted to maintain a constant rotor axial force adjusted towards the slowly changing target value, and unlike the prior art, the pitch angle is the generator output power or It is only adjusted to the range necessary to bring the rotor speed to the desired range. Therefore, if the adjustment is accompanied by a large rotor axial force change and occurs towards a constant value for the generator output, then a smaller adjustment device and a smaller rotor axial force change than the prior art Exists.

In the example of FIG. 4, the pitch angle of the rotor blades can be adjusted either collectively for all rotor blades or for each individual rotor blade. Due to the system capable of adjusting each individual rotor blade, the direction information for the wind farm is intended to keep the wind farm in a stable position, in addition to the moments mentioned above, Can be considered. This information 50 is considered in step 47 of the figure. FIG. 5 illustrates in detail the steps of providing this direction information.

In step 51, the recess (α) is calculated or recorded, where α is the rotational position of the blade, in other words it describes where each individual rotor blade rotates. In step 52, it is determined whether the direction error of the wind farm direction relative to the wind direction is outside the given range, in this case +/− 5 °. If the directional error is in range, no action is taken, but if the directional error is out of range, the rotation mechanism for the tower is activated arbitrarily, and on which side the directional error is in range Therefore, the signal is calculated at 55,56. The information provided at 55 or 56 is placed on the control signal provided to adjust the thrust of each individual blade in the pitch angle, and optionally the wind direction, with respect to the rotor axial force change. The direction error information is composed of information about the rotational position, in other words, the pitch angle is individually adjusted for each blade according to its instantaneous rotational position. This means that the thrust of each individual blade in the wind direction is adjusted differently for different rotational positions, so that a force effect is obtained that addresses directional errors for the wind farm.

1 shows a floating wind farm 1 having a rotor 2 which may have a rotor shaft 11 mounted horizontally or nearly horizontally attached to the lee of the tower 4. This figure also shows the mill housing 3, anemometer 5, anchor connection 6 and anchor 7. 1 shows a wind farm 1 having a rotor 2 with a rotor shaft 11 mounted horizontally or nearly horizontally mounted on the wind in a tower 4 located on land or in shallow water. This figure also shows the mill housing 3 and the anemometer 5. Located on land or in shallow water, or floats on water and can rotate about their longitudinal axis or essentially about their longitudinal axis 14 with pitch bearing 10 1 shows a wind farm 1 having a rotor blade 13 attached to 2 is a process flow diagram illustrating the method of the present invention. FIG. FIG. 4 is a process flow diagram for any portion of the method of the present invention.

Claims (11)

A method for controlling the output of a wind power plant consisting of converter units, wherein the output power of the converter unit is within a given range, the pitch angles of the plurality of rotor blades are singly or jointly. When the change in thrust of the rotor blade due to the wind direction is changed to be minimal and the output power of the converter unit is outside the range, the pitch angle of the rotor blade is the output power. The method is characterized in that it changes so as to bring it into the range. The method of claim 1, wherein the rotor blades according to the wind direction are adjusted by adjusting the pitch angle of the rotor blades toward a target value calculated for the thrust of the rotor blades in the wind direction. The method wherein the change in thrust is minimized and the target value for the thrust in the wind direction is different when the average wind speed is different. 3. A method according to claim 2, wherein the target value for the thrust of the rotor blade in the wind direction is related to the average output power of the converter unit or the speed of the rotor blade over a given period of time. A method characterized by being adjusted. 3. The method of claim 2, wherein the target value for the thrust of the rotor blade in the wind direction is predefined and related to a given average wind speed. The method according to claim 1, wherein the converter unit is a generator, and the thrust of the rotor blade in the wind direction is adjusted by adjusting a rotational resistance moment of the generator and / or a rotor braking device. A method characterized in that it is adjusted by changing the number of revolutions per minute. The method of claim 1, wherein the converter unit is a generator and the instantaneous thrust of the rotor blade in the wind direction is:
Measuring the geometric refraction of the rotor blade, measuring the torque of the generator, and / or measuring the output power of the generator simultaneously with measuring the pitch angle of the rotor blade, and / or pitch bearings Measuring or using the pitch moment of the rotor blade about the axis of rotation of the pitch bearing, either by attaching the rotor blade tilted rearward at or shaping the rotor blade,
Since the rotor blade can be determined directly or indirectly by a strain gauge or a wind speed measuring device, the rotor blade collision position is behind the rotational axis of the pitch bearing with respect to the rotational direction of the rotor. Feature method. 2. The method of claim 1, wherein the pitch angle of the rotor blade is varied to minimize directional errors between the wind direction and the direction of the rotor axis of rotation. . The method of claim 7, wherein the directional error is corrected if it is outside a given range. The method of claim 1, wherein the pitch angle of the rotor blades is adjusted differently for different rotational positions of the rotor blades. The method according to claim 1, wherein the pitch angle of the rotor blades is adjusted independently for each of the rotor blades. The method of claim 1, wherein the thrust of the rotor blades in the wind direction is actively controlled to prevent movement of the wind power tower by external forces by adjusting the pitch angle of the rotor blades. A method characterized in that it is used.