Method for controlling a wind energy installation, wind energy installation and wind farm

Abstract

The invention relates to a method for controlling a wind energy installation (100), a wind energy installation (100) and a wind farm (112) having a plurality of wind energy installations (100).

Description

Technical Field

[0001] The invention relates to a method for controlling a wind energy installation and also to a corresponding wind energy installation. Background Art

[0002] Wind energy installations are known, which obtain electrical power from the wind. To this end, the wind energy installations usually have a rotor with rotor blades, which are moved by the wind. Therefore, the rotor rotates at a rotor speed, which is also related to the wind speed driving the generator.

[0003] In order to control the power generation, the rotor blades can adjust their angle of attack, which is called pitch. In addition, the generator torque or output power of the generator can be influenced to control the wind energy installation. This also results in a variable rotor speed and thus a variable generator speed. In the case of a wind energy installation without a transmission, the rotor speed corresponds to the generator speed.

[0004] The control of a wind power plant has in particular the aim of ensuring the most power-optimized operation possible at low rotational speeds, in which as much power as possible is generated. At high wind speeds, the wind power plant is controlled in such a way that rotational speed limits and power limits are observed.

[0005] In the case of low wind speeds, part-load operation or a part-load range can also be mentioned, and in the case of high wind speeds, full-load operation or a full-load range can be mentioned. Therefore, in part-load operation, as much power as possible should be generated, and in full-load operation, the wind energy installation should be controlled so that it is protected from overload. Corresponding control plans are known. Accordingly, a characteristic curve open-loop control is usually used for part-load operation, wherein the operating characteristic curve predetermines the correlation between the rotational speed and the power to be set for this. The blade angle is usually constant here. In full-load operation, a speed closed-loop control is usually used, which tries to keep the speed constant by adjusting the rotor blades when the power is constant.

[0006] Additional specificities can be added to the basic requirements. It often happens that the speed range in partial load operation also includes speed ranges in which resonance points of the wind energy installation are present. To solve the problem, it can be provided that such resonance points are bypassed by avoiding speeds that are in this resonance range. However, bypassing the speed in this way can be problematic because it results in discontinuities in the operating characteristic curve. This can cause problems when implementing such bypass control in practice.

[0007] Further problems can arise in the transition region from partial load operation to full load operation. It is particularly critical here that the operating characteristic curve is relatively steep, so that small changes in speed lead to high power changes, which can be challenging in terms of control and can lead to problems such as discontinuities. In addition, for such discontinuities or almost discontinuous regions, fluctuations in wind speed can lead to high, possibly excessive, controller activity. Summary of the invention

[0008] The invention is based on the object of solving at least one of the above-mentioned problems. In particular, a solution should be proposed in which a control is described which also works well in the speed range in the range of the resonant frequency and / or in the range from partial load operation to full load operation. At least an alternative solution to the previously known solutions should be proposed.

[0009] According to the invention, a method for controlling a wind energy installation is proposed. The method for controlling a wind energy installation is based on a wind energy installation having an aerodynamic rotor that is operated at a variable speed and has rotor blades with adjustable blade angles. The wind energy installation can be operated in a partial load region and in a full load region. In the partial load region, there are wind speeds within the rated wind speed, and in the full load region, there are wind speeds starting from the rated wind speed. The regions may overlap slightly, primarily because the wind speed may fluctuate and cannot be determined with any accuracy.

[0010] In this case, the wind power plant is controlled in the partial load region by an operating characteristic curve open-loop control, which uses an operating characteristic curve. The operating characteristic curve predefines the correlation between the rotational speed, i.e. the rotor speed, and the generator state variable to be set. The generator state variable to be set can be the generator power or the generator torque. In this case, the operating characteristic curve open-loop control is performed so that the value of the generator state variable predetermined by the operating characteristic curve is set as a function of the detected rotational speed. The operating characteristic curve can also be predetermined by a functional specification, such as a formula or a function. The operating characteristic curve can also be stored as a table.

[0011] Thus, if the generator state variable is the generator power, the rotational speed is detected and the operating characteristic curve describes the associated value of the generator power to be set for the detected rotational speed. The generator power is then set. Usually, the blade angle cannot be changed in this case. The set generator power then also results in a generator torque dependent on the rotational speed, which counteracts the rotor torque generated in the rotor by the wind.

[0012] If the two torques are the same, a stable operating point is obtained. If the two torques are different, the rotor is accelerated or decelerated. Therefore, the rotor speed changes and a new value for the generator power is determined and set from the operating characteristic curve until a stable operating point is obtained.

[0013] In the full load range, the wind energy installation is controlled by pitch control, wherein the rotational speed is controlled to a desired rotational speed value by adjusting the blade angle. In particular, the rotational speed is controlled to a rated rotational speed value. This serves in particular to protect the wind energy installation from overload. Therefore, if the rotational speed increases above the rotational speed value to which the wind energy installation should be controlled, the rotor blades adjust their blade angle, i.e. turn out of the wind, at least by one or a few degrees. As a result, less power is extracted from the wind and the rotational speed can be reduced or maintained at the desired value.

[0014] Furthermore, it is proposed that in at least one predeterminable speed range in the partial load region and / or in the transition region from the partial load region to the full load region, the wind energy installation is controlled by speed power control, wherein the speed is controlled to a speed target value by adjusting the generator state variable, and within this range there are deviations from the operating characteristic curve open-loop control provided for the partial load region.

[0015] This can be provided in particular for a speed range in the partial load region, which thus forms a small part of the partial load region in which a resonant frequency can occur or in which a resonant position is present. In particular, the predeterminable speed range in the partial load region can be referred to as an avoidance range, i.e., within the avoidance range there are speeds that are to be avoided. By means of the speed power control provided, the speed can then be regulated to a speed at the start or end of the predeterminable speed range in the partial load region. This allows speeds that are particularly in the middle of such a speed range, i.e., in the middle of the avoidance range, to be skipped.

[0016] Here, two control cascades are provided for the speed power control. The speed power is thus implemented such that in the outer cascade, a first acceleration target value of the rotor is determined by a first controller from a comparison of a preset desired speed with a detected actual speed. In this regard, the control error of the speed is transferred to the acceleration target value. As a result, the acceleration target value of the rotor can be understood as the acceleration value by which the rotor should be accelerated. The acceleration target value can also assume negative values ​​and in this regard indicates how the speed should be reduced.

[0017] It is then further proposed that in the inner cascade, a generator setpoint value is determined as a setpoint value for the generator state variable by a second controller from a comparison of a first acceleration setpoint value of the rotor with a detected acceleration actual value. The second controller thus converts the control error of the rotor acceleration into a generator power setpoint value or a generator torque setpoint value, depending on which of the two variants is provided for the generator state variable.

[0018] Therefore, for the open-loop control of the operating characteristic curve in the partial load range, a change to speed control is proposed for special ranges. That is, a change from open-loop control to closed-loop control. For the control, that is, the speed control, a special cascade structure is proposed here, which controls the speed in the outer cascade and controls the torque in the inner cascade for this purpose.

[0019] In particular, it has been found that by means of such a speed control, the torque and thus also the power can be well controlled at discontinuities or at locations with very large slopes in the speed-power characteristic curve. In particular, it has been found that, in the case of small speed changes, large power changes can occur, which can be controlled thereby. Large rotor accelerations can be avoided. In addition, the interaction between the speed controller and the power controller can be achieved or simplified thereby. This is also explained in at least one exemplary embodiment below.

[0020] According to one aspect, it is proposed that the speed-power control has an integral part, in particular the second controller has an integral part. In particular, it has been recognized that in the case of discontinuities or speed-power curves with very steep slopes it is useful to keep the speed at a value, for which purpose the integral part can be used. The integral part can be used to maintain the output power even without remaining control errors.

[0021] In particular, it has been recognized that the integral part does not need to be provided in the outer control cascade. This prevents the deviation between the desired speed and the actual speed from causing an increased value of the desired torque. Instead, the integral part can be used in the inner cascade. The inner cascade generates a generator power or generator torque from the desired value-actual value comparison of the acceleration value, which can be regarded as a control variable in this respect. The increase of the control variable by the integral part is thus immediately realized in the generator and can immediately act, so that the integral part is introduced in the inner cascade.

[0022] According to one aspect, in the speed power control, the first acceleration desired value and the acceleration actual value are respectively formed as acceleration power. The acceleration power is associated with the rotor acceleration and describes the power required to cause the speed acceleration. It is thus also possible to express the difference between the desired acceleration and the actual acceleration as power and evaluate it. This power can also be associated in particular with the power that can be provided for control. It is particularly advantageous that the balance with the control in the full load range is simplified through it. The two controls are comparable by considering the power in the corresponding control variable or control variable.

[0023] According to one aspect, in the speed power control, the external cascade has at least one acceleration limit value for determining the first acceleration desired value. If the acceleration power is taken into account for the acceleration, a corresponding power limit value can be provided. The speed control can thus be kept within important limits. In particular, it is possible to consider how much power is available for implementing the speed control. The advantages are not only achievable when the acceleration power is taken into account for the acceleration. The power that can be provided from the wind and the settable generator power can be considered as the available power.

[0024] In particular, it can be considered that the maximum power for driving the rotor is derived from the wind speed. At a specific operating point, most of the available power from the wind is already allowed to be used. Then, the differential power can be reserved until the maximum extractable power that can be provided for speed control. This can be considered in the case of at least one acceleration limit value. In the case of a generator, similarly, the generator cannot be adjusted arbitrarily from its current operating point and can only provide power for speed control up to a specific value. This can be considered. In addition, when the power extracted from the wind at an operating point is reduced, a low value (Unterwert) can also be considered. This low value may - to exaggerate for the sake of intuitiveness - be a value at which the wind energy facility is facing a shutdown.

[0025] Accordingly, it is preferably provided that at least one acceleration limit value can be set, which can thus be adapted to the specified conditions.

[0026] In addition or alternatively, it is proposed that an upper acceleration limit value and a lower acceleration limit value with different values ​​are provided as at least one acceleration limit value. In particular, it is also considered that for aerodynamic reasons, there may be a different amount of power available for increasing the speed than for reducing the speed.

[0027] In addition or alternatively, it is proposed that the inner cascade has an integrating element with an integrator limit for determining the control variable for setting the generator state variable. Optionally, such an integrator limit can be set and in addition or alternatively, different upper and lower limit values ​​are provided for the integrator limit. The advantages of using an integrating element in the inner cascade and thus in the second controller have already been explained above.

[0028] In addition, it is proposed that integrator limits are set for the corresponding integral elements. This can prevent, in particular, the integral part from increasing or decreasing in the negative direction when the control deviation remains. It is also taken into account that only a limited power is available as adjustment energy for implementing the speed control. By limiting the integral element, this is taken into account and it can be avoided that the integral element predetermines a control variable that cannot be implemented at all, in particular the corresponding desired power. In order to take this into account particularly well, it is proposed that the integrator limits can be preset and / or that the corresponding power limitation by different upper and lower limit values ​​is taken into account.

[0029] According to one aspect, it is proposed that at least one predeterminable speed range is provided as a speed avoidance range, characterized by a lower avoidance speed and an upper avoidance speed. It is proposed that a speed power control is used if the lower avoidance speed is reached when the speed increases or the upper avoidance speed is reached when the speed decreases. In particular, it is proposed that such a avoidance speed range is formed around a speed that forms a resonance frequency or contributes to the excitation of a resonance in the wind energy installation.

[0030] To this end, it is also proposed that when using speed power control, the wind energy installation can be operated at a lower operating point within a lower speed range including a lower avoidance speed depending on the existing wind speed, and can be operated at an upper operating point within an upper speed range including an upper avoidance speed, and the change between the lower and upper operating points is performed based on an aerodynamic evaluation of the lower and upper operating points.

[0031] The basis of this aspect is therefore that when using speed and power control, the wind energy installation can be operated at one of the two operating points, which, to put it in a straightforward manner, is basically below or above the resonance situation to be avoided. If the wind speed changes, a change from the upper operating point to the lower operating point or vice versa can then be considered. For such a change, it is proposed to carry out an aerodynamic evaluation of the lower and upper operating points.

[0032] In particular, the idea is based on the fact that by using a speed control, the speed is essentially constant despite the variable wind speed, which speed control is implemented here by the proposed speed power control. The speed is therefore not very suitable as a criterion for whether a switch between two operating points is sensible. It is therefore proposed to evaluate the two operating points aerodynamically and to switch, in particular, when the other operating point is aerodynamically better or more suitable.

[0033] In particular, it has also been recognized here that a pure assessment of the generator power set in the speed power control may not be appropriate.

[0034] According to one aspect, it is proposed that at least two levels of checks are performed for the change between the lower and upper operating points. In this case, in the first level, it is checked whether the operating point to which the change is to be made has a higher aerodynamic efficiency than the operating point to which the change is to be made. In the second level, it is checked whether the generator state variable determined by means of the partial load speed control reaches an upper generator state limit or a lower generator state limit. Such a generator state limit can be, in particular, a predefined maximum power value. If the generator power reaches this value, i.e., the generator power increases to this value when operating at the lower operating point, this results in a change from the lower operating point to the upper operating point. Accordingly, a lower power value can be predefined, which results in a change from the upper operating point to the lower operating point when the generator power drops to this lower power limit.

[0035] In particular, it is proposed that the change is permitted according to the check in the first stage and that the change is prescribed according to the check in the second stage. Therefore, if the current operating point is more unfavorable than other operating points, that is, the current operating point has a lower aerodynamic efficiency than the operating point to which it is to be changed, then a change is considered. However, the change does not necessarily have to be carried out and can be related to other conditions. Such other conditions can be, for example, how strongly the wind fluctuates. If the wind fluctuates strongly, then the change between the operating points is carried out more cautiously. However, if the wind speed hardly fluctuates, then it can be more meaningful to change to an operating point with higher aerodynamic efficiency, because it is assumed that the operating point with higher aerodynamic efficiency is still maintained for a period of time.

[0036] However, if it is determined in the second stage that a limit has been reached, a change must be made. This is based in particular on the knowledge that a non-optimal operating point can be accepted for a period of time. The disadvantages can be weighed against other criteria.

[0037] For example, an operating point with a higher aerodynamic efficiency guarantees a greater gain. However, this can be compared with the loss of gain due to the changeover, and it can also be considered whether frequent changes can be expected.

[0038] However, it has also been recognized that an operating point that is too unfavorable can endanger the operation of the wind energy installation as a whole. For example, if a wind energy installation is operated in the lower speed range, in particular at the lower avoidance speed with increasing power, this can lead to an aerodynamically unfavorable operating point, so that the wind energy installation stops, as just one example.

[0039] According to one aspect, it is proposed that if the operating point to be changed to has a higher aerodynamic efficiency than the operating point to be changed away from within a predeterminable check time period, a change is made between the lower operating point and the upper operating point. This can avoid a rash change despite the higher aerodynamic efficiency of the other operating point. In particular, the predeterminable check time period is in the range of 5 seconds to 10 minutes, in particular in the range of 10 seconds to 5 minutes. The time slice has a lower value, which can be suitable for checking for a sufficiently long time whether the operating point or the wind conditions on which it is based is stable. The two upper values ​​of 5 minutes or 10 minutes give the following time, within which the change losses no longer prevail. The specific selection can be related in particular to how much the two operating points differ. This can also be related to how large the speed avoidance range must be selected.

[0040] According to one aspect, it is proposed that for the speed power control, a speed target value is predefined as a constant or via at least one speed characteristic curve, wherein the speed characteristic curves each have speed values ​​that are dependent on the generator state variable to be set. In particular, it is proposed that the speed characteristic curve is designed such that it has a negative slope at least in sections, so that the speed value decreases as the value of the generator state variable increases.

[0041] This results in a branch with a higher slope, in particular a vertical one, according to the speed / power diagram. When using a speed / torque diagram, the above explanation applies in a reasonable manner to the generator torque as the generator state variable. The fact that the speed target value is preset as a constant means that the speed increases due to a corresponding increase in power when the wind increases. In particular, a controller with an integral part can be used to achieve a fixed accuracy for the preset constant speed target value, i.e., by using a correspondingly high generator power as the control variable. Therefore, as the wind increases, the power increases, while the speed does not increase. In a reasonable manner, when the wind decreases, the speed can remain constant, while the generator power as the control variable decreases.

[0042] It has been recognized that a negative slope can even have advantages over a vertical slope. A negative slope is therefore a situation in which the rotational speed does not increase and even decreases slightly when the wind speed increases, while the generator power as a controlled variable increases significantly. For example, the generator power can increase by 10% while the rotational speed decreases again by 1%. This control can avoid the generation of multi-meaning rotational speed-power branches in the rotational speed-power diagram. In other words, each rotational speed on this branch can be associated with a single power value.

[0043] It is appropriate that, when the wind speed decreases, when the wind energy installation reaches the upper operating point, the generator power as a control variable can continue to decrease, but the rotational speed can even increase slightly. Here, as an example, it is also considered that the generator power is reduced by 10% while the rotational speed is only reduced by 1%. From this, a corresponding straight line or linear correlation can be determined. In other words, a 5% power reduction is associated with a 0.5% increase in rotational speed, etc. The same situation is also appropriate for an increase in wind speed and thus for an increase in power from the lower operating point.

[0044] According to one aspect, a switching time is preset for switching between a lower operating point and an upper operating point, which is preferably less than 20 seconds, in particular less than 10 seconds. In addition or alternatively, a time profile is preset for the generator state variable to be set, in order to control the switching accordingly.

[0045] By speed power control, the wind energy plant is operated and maintained at the operating point, i.e., at a predetermined speed, for example. For this purpose, the generator power is set accordingly as a generator state variable and is continuously readjusted. Of course, all of this can also be performed with the aid of the generator torque as the generator state variable.

[0046] If the operating point is now to be changed, for example from a lower operating point to an upper operating point, the generator state variable is withdrawn, i.e. the generator state variable forms the control variable for the speed power control. This allows the rotor to be accelerated. The greater the generator state variable is withdrawn for the change from the lower operating point to the upper operating point, the faster the change can be carried out. Thus, the changeover time can be achieved in this way.

[0047] When selecting the switching time, boundary conditions are preferably also taken into account, so that an arbitrarily fast switching is not necessarily the only sensible goal. Limit values ​​can also be taken into account. In particular, it is necessary to consider which value is calculated for the generator state variable after the switching. Thus, for example, the value of the generator state variable to be expected in the switching process can also be set for the switching process. After the switching, the operating point is then controlled directly with the aid of the associated generator state variable.

[0048] However, this can result in a change that is too slow. Therefore, the generator state variable must be set correspondingly smaller when changing from a lower operating point to an upper operating point. If it is set too small for a change that is too fast, an overshoot may result, so that when the desired speed is reached after the change, the generator state variable does not reach the desired value quickly enough. Accordingly, it is proposed to predetermine the change time and to determine the generator state variable to be set, for example, in a simulation or from empirical values ​​or targeted tests.

[0049] It is appropriate that the same process is followed when changing from an upper operating point to a lower operating point, wherein the value of the generator state variable increases accordingly, but not too much. For this purpose, suitable values ​​for the generator state variable can also be determined via the proposed presetting of the changeover time.

[0050] In addition or alternatively, it is thus provided that a time profile is predefined for the generator state variable to be set. Such a time profile can be seen in particular for a change from a lower operating point to an upper operating point as a continuous decrease of the generator state variable within a certain time, in particular within half the change time, and a continuous increase within the remaining time, i.e. in particular to a value determined to be meaningful for the controlled upper operating point, which value has been calculated or determined by simulation, for example.

[0051] It is appropriate for the generator state variable to first increase in each case and then decrease when the change is to be made from an upper operating point to a lower operating point.

[0052] According to one aspect, the transition region is located in the partial load region in an upper speed range, which is characterized by a speed starting from the transition speed. If a speed avoidance range exists, the upper speed range is located in particular in this speed avoidance range.

[0053] For this purpose, it is also proposed that the wind energy facility is characterized by a rated speed and a transition speed of at least 80%, in particular at least 85%, of the rated speed and / or the desired speed of the pitch control. In this regard, it is proposed that the speed power control is used in the transition region so that the speed power control is used for such a high speed from 80% or 85% of the rated speed to the full load region, that is, until 100% of the rated speed. The pitch control, as long as it is activated, attempts to control the speed to the desired speed, that is, by means of pitch adjustment. The desired speed basically corresponds to the rated speed, but it may be better considered in the specific implementation, especially in the control structure. In addition, this involves a transition region from the partial load region to the full load region, in which a speed desired value is preset for the pitch control, so that the speed desired value gives a meaningful orientation. The following explanation for the rated speed is also applicable to the desired speed in a meaningful way.

[0054] It has been recognized in particular that in the speed range from 80% or 85% to 100% of the rated speed, the operating characteristic curve is very steep. Therefore, a small speed change leads to a very large change in the generator state variable. For example, a 1% increase in the speed leads to a 3% or more increase in the generator state variable. In particular, for a range of 95% to 100% of the rated speed, a 1% speed change leads to a 5% to 10% change in the generator state variable. Small fluctuations in wind speed thus lead to small changes in the speed and these lead to strong changes in the generator state variable. In order to solve these problems in the specific range, the application of speed power control is proposed here.

[0055] Therefore, a speed control is performed, which is different from the speed control in the full load range because it uses the generator state variable, that is, the generator power or the generator torque, as the control variable. By the proposed cascade control, the rotor acceleration and thus the dynamics can be additionally taken into account here. In particular, this is impossible by using the operating characteristic curve open-loop control, because the operating characteristic curve open-loop control only sets the generator state variable, that is, the generator power or the generator torque, for the detected speed. How fast the speed changes here is not considered. This can be a good and proven strategy for small speeds that are also usually based on small wind speeds with small fluctuations. In the described steep area where stronger wind fluctuations are also considered, improvements can be achieved by using speed power control.

[0056] According to one aspect, a speed desired value is preset for speed power control via a transition speed characteristic curve, wherein the transition speed characteristic curve forms the speed characteristic curve or a speed characteristic curve, wherein the transition speed characteristic curve extends vertically for a speed whose speed value corresponds to the transition speed, so that as the generator state variable increases, the speed is constant until the generator state variable reaches a predetermined first generator reference value that is lower than the rated value of the generator state variable.

[0057] Therefore, for the transition region, it is not only proposed to use speed-power control instead of the operating characteristic curve open-loop control, but also to save another speed-power characteristic curve - or speed-torque characteristic curve, which runs vertically from the transition speed. This also means that when the wind speed increases, the speed does not increase further after reaching the transition speed. Therefore, the system is operated at a lower speed compared to the operating characteristic curve.

[0058] This makes it possible, in particular, to not reach the rated speed too early, from which full-load operation and thus corresponding regulation can be started. In particular, with an operating characteristic curve open-loop control having a very steep operating characteristic curve, the speed can often reach the rated speed due to wind fluctuations. It is then necessary to check how to react to this, i.e. whether the speed regulation proposed for full-load operation is activated. Frequent changes between the operating characteristic curve open-loop control and the pitch regulation can result, which is avoided by the solution proposed here.

[0059] In addition or alternatively, it can be provided that the transition speed characteristic curve still has a positive slope from the transition speed and / or that the transition speed characteristic curve has a positive slope from the first generator reference value, so that the value of the generator state variable increases with increasing speed until the rated value of the generator state variable is reached. The transition speed characteristic curve is designed so that it has a positive slope from the transition speed and extends to the rated speed, which is not a preferred solution, but can be provided. It can then be provided that the transition speed characteristic curve differs from the operating characteristic curve in this area. In particular, the transition speed characteristic curve can be linear and thus higher than the operating characteristic curve in this area. The speed is then regulated along the transition speed characteristic curve, i.e. by means of the proposed speed power controller.

[0060] However, it is particularly proposed that the transition speed characteristic curve extends vertically from the transition speed until the generator reference value is reached, wherein the transition speed characteristic curve has a positive slope from this point on. However, it is preferred that the transition speed characteristic curve reaches the rated value of the generator state variable, i.e. the rated power or the rated torque, before the speed reaches the rated speed. As a result, the rated value of the generator state variable is already reached in the partial load range and the speed is then increased to the rated speed in order to then or at this point transition to the full load range and corresponding control in the full load range.

[0061] According to one aspect, it is proposed that the control reserve is determined based on the difference between the set generator state variable and the generator state upper limit. The difference can also directly form the control reserve. This is particularly relevant whether the generator state variable has the same physical unit as the control reserve. The control reserve can be designed in particular as power. If the generator state variable is designed as a torque, then the corresponding difference in torque is considered to be converted into the control reserve. It is particularly advantageous if, in the inner cascade, the first acceleration target value and the detected acceleration actual value are provided with the same unit as the control reserve.

[0062] It is also proposed that the control reserve is transferred from the speed power control to the pitch control. Pitch control is a speed control in which the blade angle forms the controlled variable. In this respect, there are two speed controls with the speed power control and the pitch control, which can thus be coordinated with each other.

[0063] It is also proposed that the speed power control and the pitch control operate at least partially in parallel and coordinate with each other via the control reserve. The control reserve is an indicator of how much control power or control energy is still available overall. If the control reserve provides a lot of control energy, the value of the control reserve is large. This can signal the pitch control that the speed power control is therefore not yet at its limit and can still be controlled.

[0064] In particular, it has been recognized that it is advantageous to first hand over the control to the speed power control when transitioning from the partial load range to the full load range, as long as this is possible. In this case, that is, if the pitch control is not activated until the wind speed is exceeded, the rotor blades are still in the aerodynamically optimal state, that is, they are not yet away from the wind. If the pitch control is activated in this case, this only means that it moves the blades away from the wind. As a result, less power is extracted from the wind. If this is necessary for the limitations and loads of the facility, it should also be implemented; however, it is not yet necessary and can be reset. This can be detected precisely by the control reserve so that this can be signaled to the pitch control.

[0065] In this case, the pitch control not only receives the information that the speed power control still has adjustment energy, but also receives information about the height. This allows the transition to be continuous. That is, if there is still a lot of adjustment energy, that is, the value of the control reserve is still large, the pitch control can still remain inactive. However, if the control reserve is small but still exists, the pitch control can already be activated, while the speed power control is also still active. Therefore, the two speed controls are active and cooperate with each other via the control reserve.

[0066] In particular, it has been recognized that the transition is meaningful but not expected until the speed-power control is no longer completely controllable in the absence of control energy. This avoids hard switching and also allows the rapid control capability of the speed-power control to be utilized.

[0067] At reduced wind speeds, the transition from pitch control to speed and power control works in the same way. Thus, operation then passes from the full-load range to the partial-load range and the transition can begin as soon as it is recognized that there is a control reserve, i.e., the generator power or generator torque can be reduced.

[0068] In principle, a switchover can also be provided, which, however, can be carried out at least by taking into account the control reserve for the most suitable state or the most suitable situation.

[0069] According to one aspect, it is proposed that the speed-power control is prioritized over the pitch control, in particular so that the pitch control is completely or partially suppressed as long as the speed-power control has not reached the controlled variable limit.

[0070] Additionally or alternatively, it is proposed that the pitch control additionally controls the speed as a function of the actual acceleration value of the rotor and that the speed control by the pitch control is suppressed the more the generator setpoint falls below a generator setpoint limit in the speed power control.

[0071] It is therefore proposed that the speed power control is started completely or partially, as long as it can also be effective. This has been explained above. It can also be checked whether the speed power control reaches the control variable limit. If the speed power control reaches the control variable limit, the pitch control can be switched in or its share can be increased.

[0072] According to one aspect, the pitch control can additionally control the speed as a function of the actual value of the acceleration of the rotor. This can be used to detect, in particular, whether or to what extent an excessively high speed is taken into account for a short period of time, which should then offset the pitch control. This offset can additionally be related to the extent to which the speed power control can also offset it.

[0073] In particular, it is proposed to take into account the specific design of the proposed speed power control and in this case in particular an inner cascade which determines the generator setpoint value via a second controller as a function of a comparison between a first acceleration setpoint value and a detected acceleration actual value.

[0074] The generator desired value thus forms a control variable, which can act directly or indirectly on the generator. How far the control variable is from a limit, i.e. the generator desired value limit, is taken into account here, so that the pitch control can be taken into account more or less accordingly. If the generator desired value is still far from the generator desired value limit, the pitch control can be strongly suppressed. If the generator desired value is close to the generator desired value limit, the pitch control can be used for control accordingly more strongly. This can be used to determine the control reserve and to supply it to the pitch control via it.

[0075] According to one aspect, it is proposed that the speed power control uses the generator state variable as the control variable for controlling the speed, which is hereby referred to as the generator control variable, and the pitch control uses the blade angle as the control variable for controlling the speed, which is hereby referred to as the pitch control variable, wherein the blade angle increases, in particular as the wind speed increases, from the part-load blade angle set in the part-load range toward the final angle, wherein the speed power control is coordinated with the pitch control, and in particular, in order to coordinate the speed power control with the pitch control, the generator control variable and the pitch control variable are coordinated with each other.

[0076] This coordination can be manifested in particular by the control variable used in one controller being subtracted from the other controller, if necessary with a corresponding conversion of the relevant units. However, it is also conceivable that the two controllers are coordinated with one another in such a way that the value of the control variable of one controller can be directly subtracted from the other controller. To this end, the two control variables must be coordinated with one another, for example, via normalization. As a result, the two controllers can perform speed control, but without compensating for each other or causing overcontrol, wherein the control variables of the two controllers are actually added in an uncoordinated manner.

[0077] In particular, it is proposed to take into account the control variable limits of the generator control variable and to coordinate the speed power control and the pitch control in such a way that the speed power control has a greater influence on the speed than the pitch control, as long as the speed power control does not reach the control variable limits. Therefore, the speed power control is adopted as long as it can achieve a sufficient control variable.

[0078] In addition or alternatively, it is proposed that the pitch control variable is set as a function of the control variable limit of the generator control variable. In particular, it is proposed that the difference between the generator control variable and the control variable limit defines the adjustment range of the speed power control and that the pitch control variable is changed such that the larger the adjustment range of the speed power control, the smaller the influence of the pitch control on the speed. This makes it possible to achieve coordination of the two controllers in a simple manner. In particular, the adjustment range can be determined in a simple manner and taken into account during the coordination.

[0079] According to one aspect, pitch control is performed such that in an outer cascade, a second acceleration expected value is determined via a third controller from a comparison between a preset expected rotational speed and a detected actual rotational speed, and in an inner cascade, a control variable, in particular a pitch control variable, is determined via a fourth controller from a comparison between the second acceleration expected value and the detected acceleration expected value to adjust the blade angle, and the comparison between the second acceleration expected value and the detected acceleration value forms a control error and the control error is modified with the aid of a control reserve, and the control error modified in this way forms an input variable of the fourth controller.

[0080] The fourth controller is therefore an inner cascade of the pitch control. The inner cascade takes into account the acceleration desired value / actual value comparison. The inner cascade therefore takes into account whether the detected acceleration of the rotor corresponds to the desired acceleration of the rotor. If this is not the case, a difference is obtained which can be referred to as a control error. The difference then causes a corresponding reaction via the fourth controller, namely an adjustment of the blade angle. The deviation between the desired and detected acceleration is thus offset.

[0081] In order to coordinate the pitch control with the speed power controller, it is now proposed that the control error indicating the acceleration deviation is modified. Intuitively speaking, the control error of the inner cascade of the pitch control does not need to be corrected via the pitch control, when instead this can be achieved via the generator. When there is a corresponding control reserve, the speed power control can then be achieved via the generator. Preferably, the control reserve is adapted in its size to the acceleration deviation in the pitch control. The control reserve is then simply subtracted from the acceleration control error in the pitch control. In extreme cases, when the speed power control has sufficient control reserve, a value of zero is obtained and the pitch control can be inactive.

[0082] However, it is also conceivable that only the control error of the acceleration in the pitch control is reduced thereby. This then results in the fourth controller generating or changing the pitch control variable, i.e. in such a way that the pitch should be adjusted, but only by a reduced amount. In this way, the pitch control can be coordinated with the speed-power control, i.e. in such a way that the pitch control takes into account how well or how strongly the speed-power control can still work overall. For this purpose, a control reserve exists.

[0083] Preferably, the acceleration target value, the acceleration actual value and the resulting control error of the inner cascade of the pitch control are each formed as a power value, thereby simplifying the coordination with the speed power control.

[0084] It is therefore also proposed that the modification is carried out in particular in such a way that the adjustment of the blade angle is reduced or suppressed compared to when the control error had not been modified.

[0085] Additionally or alternatively, it is provided that the modification is carried out in particular in that a control reserve or a variable equivalent thereto, in particular proportional thereto, is effectively combined with the comparison of the second acceleration target value with the detected acceleration value.

[0086] This combination is particularly useful if the pitch control takes into account the acceleration target value and the corresponding acceleration actual value and the resulting control error as acceleration power, as has already been described above for the speed power controller. The acceleration power therefore also indicates the power required to achieve the corresponding acceleration. In this case, the control reserve can form a power value, that is, the power value indicates how much control power is still available for the speed power control. This power value is then subtracted from the acceleration control error of the pitch control, which is also a power.

[0087] This results in a simple control structure, in which only a control reserve needs to be generated in the speed power control and fed forward to the pitch control, ie with a negative sign, in order to be subtracted therefrom. Of course, other, thus possibly more complex, implementations are also possible.

[0088] According to one aspect, it is proposed that in the speed power control, a first acceleration target value is additionally changed as a function of the blade angle, the first acceleration target value being determined as a function of a comparison of a predefined target speed with a detected actual speed. This is done in particular in that the first acceleration target value is increased by a feedforward value, wherein the feedforward value is determined as a function of an angle difference as a difference between the current blade angle and the partial load blade angle, in particular in proportion thereto.

[0089] First of all, it should be noted that a constant partial load blade angle should be set in the partial load range. However, in the transition range to the full load range, deviations can occur, namely due to the pitch control. This also means that the pitch control is already at least partially active. This is now taken into account by taking into account the angle difference that has been set by the pitch control.

[0090] The consideration is carried out in the speed power control when determining the acceleration target value. In particular, it is proposed that when such an angle difference is determined, the acceleration target value is increased. In particular, the greater the angle difference, ie the greater its value, the greater the acceleration target value is increased.

[0091] The increase in the acceleration target value causes the speed power control to attempt to correct the increased acceleration target value, i.e. the speed power control attempts to reach the acceleration target value by correspondingly setting the generator state variable, i.e. the generator power or the generator torque. However, the speed power control can then reach a limit. This can also be referred to as saturation. This can then also mean that a smaller control reserve is identified or that no control reserve is identified at all. The control reserve or a correspondingly smaller control reserve or a non-existent control reserve can react to the pitch control in a corresponding embodiment so that the pitch control is activated or its influence is increased, if necessary up to 100%, so that the speed power control then no longer has an effect. It is thus possible to return to the speed power control in a simple manner when the pitch control is activated.

[0092] According to one aspect, it is proposed to carry out a characteristic curve shift, wherein the operating characteristic curve is shifted as a function of the operating point, in particular as a function of the behavior of the pitch control, in particular as a function of the set blade angle, so that a higher value of the generator state variable is set at the same speed. When the operating characteristic curve is shown with the speed plotted on the abscissa and the generator state variable, i.e. the generator power or the generator torque, plotted on the ordinate, the operating characteristic curve is thereby shifted to the left.

[0093] The operating characteristic curve is provided for controlling the wind power plant in the partial load range, but in the transition to the full load range and in gusty winds, pitch control can be effective, while the operating characteristic curve open-loop control is also active. In such operating points, a shift of the operating characteristic curve is proposed.

[0094] In particular, it has been recognized that in the case of such gusts, the wind speed can quickly fluctuate around the average wind speed. Pitch control is usually not able to correct rapid fluctuations, so that rotational speed fluctuations can occur. In this case, the rotational speed can also be reduced below the rated rotational speed, which can cause a reaction of the operating characteristic curve open-loop control, which reduces the power as the rotational speed decreases. Since the operating characteristic curve is particularly steep at high rotational speeds, even small rotational speed changes can cause strong power changes. If the rotational speed is reduced below the rated rotational speed, this will cause a strong reduction in power, i.e. to a value below the rated power, although the average rotational speed does not have to be below the rated rotational speed at all.

[0095] This is avoided by shifting the operating characteristic curve. It has been found that the described situation can be recognized in particular from the behavior of the pitch control. The situation can be derived in particular from the blade angle, which is predetermined by the pitch control.

[0096] It is therefore particularly proposed that the operating characteristic curve is moved at a predetermined or adjustable movement speed, which is particularly in the range of 0.3 rpm to 1.5 rpm, preferably in the range of 0.5 rpm to 1 rpm. Thus, during movement at 1.5 rpm, the speed can be reduced by up to 1.5 rpm below the rated speed without the operating characteristic curve causing a reduction in power.

[0097] Thus, at low speeds, this shift has less effect, but at high speeds, if the operating characteristic curve is very steep, it has a stronger effect. This also has the effect that at high speeds close to the rated speed, the rated value of the generator state variable, i.e. the rated power or the rated torque, is reached already at a speed slightly lower than the rated speed. This can prevent, when the wind speed fluctuates and the speed fluctuates accordingly, a power lower than the rated power or a torque lower than the rated torque from being repeatedly set despite a sufficiently high wind speed, i.e. within the range of the rated wind speed.

[0098] In particular, it is provided that a characteristic curve shift is carried out as a function of the excess part-load blade angle, in particular as a function of the excess value of the blade angle over the part-load angle.

[0099] As long as the blade angle has the part-load angle, the pitch control is not yet active. If the blade angle is exceeded, the pitch control becomes active and the characteristic curve shift is taken into account. However, when the part-load angle is exceeded by a small amount, for example by only 1°, strong gusts cannot yet be assumed. Therefore, the characteristic curve shift is dependent on the exceeded value.

[0100] In particular, a characteristic curve shift is only carried out when the excess reaches an excess minimum value, which lies in particular in the range of 2° to 5°.

[0101] Additionally or alternatively, it is provided that the excess value is quantitatively evaluated and the displacement speed is set as a function of the excess value.

[0102] The excess value thus enables an assessment of the gust of wind and the movement speed can be selected accordingly as a function of this, ie the greater the excess value, the greater the movement speed.

[0103] According to the invention, a wind power plant is also proposed. Such a wind power plant has an aerodynamic rotor, which is operated at a variable speed and has rotor blades with adjustable blade angles. In addition, the wind power plant has a control device for controlling the wind power plant. The control device is configured to control the wind power plant by means of a method for controlling a wind power plant according to at least one of the above-described embodiments.

[0104] This means in particular that the control device can have at least one process computer on which the method is implemented. In particular, for this purpose one or more operating characteristic curves are stored and an operating characteristic curve open-loop control is implemented, which extracts the corresponding generator state variables of the relevant operating characteristic curve as a function of the detected rotational speed and adjusts the wind energy installation accordingly.

[0105] In particular, the control device has access to the generator of the wind energy plant and can set its power output and / or its generator torque. In addition, the control device has access to an adjustment device for adjusting the blade angle of the rotor blades.

[0106] Furthermore, the speed and power control is implemented in the control device and the control device can receive actual values ​​and simultaneously actuate the generator and the blade adjustment device.

[0107] In particular, the speed power control is implemented in such a way that it can receive a speed actual value as well as a speed target value and it can also receive or calculate an acceleration actual value from the received speed.

[0108] According to the invention, a wind farm is also proposed, which has a plurality of wind energy installations. One, a plurality of or all of the wind energy installations are configured as wind energy installations according to at least one of the above-mentioned embodiments. In particular, by using at least one of the above-mentioned methods for controlling wind energy installations by a plurality of or even all of the wind energy installations of the wind farm, their operation can be coordinated with each other. It should be noted in particular that possible oscillating behavior of the wind energy installations can also act on the wind energy installations. Thus, a better suppression of such oscillations by the proposed method and a more continuous behavior of the wind energy installations by at least one of the above-mentioned methods generally lead to a more favorable behavior of the wind farm. In particular, a wind farm is an arrangement of wind energy installations that feed into the power supply network via the same grid connection point. The proposed method can also be used to feed in the feed-in more uniformly and with less oscillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Now, the present invention is described in detail hereinafter by way of example with reference to the accompanying drawings.

[0110] Figure 1 A perspective view of a wind energy installation is shown.

[0111] Figure 2 A schematic diagram of a wind farm is shown.

[0112] Figure 3 Speed ​​power control and pitch control are each shown in a simplified schematic diagram.

[0113] Figure 4 A speed-power diagram is shown for illustrating the proposed control method.

[0114] Figure 5 A time-power diagram is shown to illustrate the transition between an upper operating point and a lower operating point.

[0115] Figure 6 Shows the speed-power control relative to Figure 3 Extended structure. DETAILED DESCRIPTION

[0116] Figure 1The schematic diagram of a wind power plant according to the invention is shown. The wind power plant 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 is arranged on the nacelle 104, which has three rotor blades 108 and a fairing 110. The aerodynamic rotor 106 is set into rotational motion by the wind during the operation of the wind power plant, thereby also rotating the electric rotor or rotating part of the generator, which is directly or indirectly coupled to the aerodynamic rotor 106. The generator is arranged in the nacelle 104 and generates electrical energy. The pitch angle of the rotor blades 108 can be changed by a pitch motor on the rotor blade root 108b of the corresponding rotor blade 108.

[0117] The wind energy facility 100 has a generator 101, which is shown in a pod 104. Electric power can be generated by means of the generator 101. In order to feed in the electric power, a feed-in unit 105 is provided, which can be designed in particular as an inverter. Thereby, a three-phase feed-in current and / or a three-phase feed-in voltage can be generated according to the amplitude, frequency and phase to be fed in at the grid connection point PCC. This can be done directly or together with other wind energy facilities in the wind farm. In order to control the wind energy facility 100, a facility control device 103 is also provided with the feed-in unit 105. The facility control device 103 can also obtain preset values ​​from the outside, in particular from a central power plant computer.

[0118] Figure 2 A wind farm 112 is shown by way of example with three wind energy installations 100, which can be identical or different. These three wind energy installations 100 therefore represent in principle any number of wind energy installations of a wind farm 112. The wind energy installations 100 provide their power, i.e., in particular the generated current, via a power plant grid 114. In this case, the respectively generated currents or powers of the individual wind energy installations 100 are added together and in most cases a transformer 116 is provided, which steps up the voltage in the power plant so that it can then be fed into a power supply grid 120 at a feed-in point 118, which is also usually referred to as a PCC. Figure 2 This is only a simplified diagram of a wind farm 112, which does not show a control device, although it is of course present. The power plant grid 114 can also be designed differently, for example, by having a transformer at the output of each wind energy installation 100, just to cite another exemplary embodiment.

[0119] The wind farm 112 also has a central power plant computer 122 which can be connected to the wind power plant 100 via a data line 124 or wirelessly in order to exchange data with the wind power plant and in particular to acquire measured values ​​of the wind power plant 100 and transmit control values ​​to the wind power plant 100 .

[0120] Figure 3 A simplified control structure 300 is shown. The control structure has a speed power control 302 in its upper part. In the lower part, the control structure has a pitch control 304. The speed power control 302 and the pitch control 304 can be coupled via a coupling connection 306 shown with a dashed line, which is explained in more detail below. In principle, however, the two regulators can work independently of each other, so that the coupling connection 306 is only shown with a dashed line. The coupling connection is provided at least according to one embodiment.

[0121] The speed power control 302 has a first summing point 308 at which a control is performed at the desired speed n. s and actual speed n i The control error e is obtained by comparing the expected value with the actual value. n Provided to the first controller 310. The actual speed n i The signal is detected at the wind energy installation and fed back via an external feedback 312 and provided to the first summing point 308. The first summing point 308, the first controller 310 and the external feedback 312 can be regarded as the main components of the outer cascade of the speed power controller.

[0122] The first controller 310 is based on the control error e n Determine the first acceleration expected value a s The first acceleration expected value is obtained at the second summing point 314 from the acceleration actual value a i Subtract, so that the internal control error e is obtained a . Thus, a desired value-actual value comparison with a negative sign is performed at the second summing point. In principle, this is only a question of nomenclature and is intuitively due to the fact that in the generator a generator torque is controlled which brakes, ie counteracts acceleration. This is the reason for the sign selected at the second summing point 314.

[0123] The internal control error e a is provided to a second controller 316, which determines therefrom a generator desired value, which can be in the form of a generator desired torque or, as in Figure 3 In the variant shown in FIG. 1 , the power desired value P can be formed s . Actual value of acceleration a i The second summing junction 314 is fed back via the internal feedback 318. The second summing junction 314, the second regulator 316 and the internal feedback 318 can be regarded as the main elements of the inner cascade of the speed power regulation 302.

[0124] The observed acceleration value, that is, the detected acceleration value a i and the preset acceleration value a sThe acceleration power used as the value of the corresponding acceleration value describes how much power must be applied in order to achieve the corresponding acceleration or how much power is output by the corresponding brake.

[0125] It is nevertheless necessary to be able to obtain the internal control deviation e even if the physical unit of the internal control deviation is already based on power. a The second controller 316 is converted into the expected value P of the power rate s The details of this are described further below.

[0126] In any case, the power desired value Ps determined in this way is provided to the generator 320 and thus acts on the wind power plant described in the wind power plant frame 322. The illustration of the generator 320 as its own frame is essentially used for explanation. In practice, the generator 320 is of course part of the wind power plant. However, in particular, the limitations of the pitch control 304 should be explained hereby.

[0127] Thus, during the operation of the wind power plant, the wind power plant can be operated in open-loop control according to an operating characteristic curve. This is further explained below for a specific speed or speed range, but the speed power closed-loop control shown is provided. Thus, if the wind power plant is activated, it receives a corresponding speed target value. This can be fixed or part of a specific characteristic curve.

[0128] In the case that is most suitable for illustration, there is a constant desired speed value n s Due to the fluctuation of wind speed, the actual rotation speed fluctuates and an external control error e is obtained at the first summing point 308. n .

[0129] The external control error then causes the acceleration target value a to be a via the first controller 310 s The acceleration target value is not, however, directly converted into a generator power or generator torque, but rather it is first checked how large the overall difference is from the existing acceleration value. The internal control error e a The power target value P is then determined from the internal control error by means of the second controller 316. s And it is provided to the generator 320. Therefore, the acceleration of the rotor is changed accordingly and the rotation speed is readjusted to the preset rotation speed.

[0130] Therefore, if a speed closed-loop control is to be performed in the partial load range, the speed power control 302 is used. The speed is thereby controlled and the corresponding output power of the generator is also obtained, which is not only used for control but also output as power generated by the wind. The speed power control can be set independently of the pitch control 304, especially when the speed power control 302 is used to control the lower or upper avoidance speed in the speed avoidance range. In particular, for speeds below the upper speed range, that is, not near the rated speed, the speed power control 302 is suitable without being combined with the pitch control 304, which is still inactive in this case.

[0131] However, a combination with pitch control 304 is conceivable in particular in the upper speed range. Pitch control 304 is designed similarly to speed power control 302. Pitch control 304 also has an outer cascade with a third summing point 324, at which a desired value-actual value comparison of the speed is carried out in order to generate an external control error e n And provided to the third controller 326. For the actual speed n i An external feedback 328 is provided.

[0132] The third controller 326 then generates the acceleration desired value a s The acceleration expected value is equal to the actual acceleration a at the fourth summing point 330. i Here, the actual acceleration a i Via internal feedback 332, it is supplied to fourth summing point 330. Here, the internal control error e is obtained. a .

[0133] The fifth summing point 334 may be inactive and is only needed to coordinate the speed power control 302 and the pitch control 304. If the fifth summing point 334 is inactive, the internal control error e a It is directly supplied to the fourth controller 336. In this respect, the structure still corresponds at least substantially to the speed-power control 302, so that some of the names are also selected to be identical.

[0134] However, the fourth regulator 336 then generates a s, which is provided to the pitch system 338 accordingly. The blades are therefore adjusted by means of the pitch system 338 in such a way that the actual acceleration value is adapted to the desired acceleration value, so as to thereby also achieve an adaptation of the actual rotational speed to the desired rotational speed. In this regard, the pitch system acts on a wind energy facility frame 340, which can correspond to the wind energy facility frame 322. Here, the pitch system 338 is of course also part of the wind energy facility and the entire control can also be regarded as part of the wind energy facility. In this regard, the wind energy facility frame 340 is used here to illustrate that the pitch system 338 acts on the wind energy facility. Thereby, the pitch control is achieved by presetting the desired angle α s Acting on wind energy facilities.

[0135] Although the speed power control 302 and the pitch control 304 have similar structures, the two controls use different control variables. The speed power control 302 uses the generator power or generator torque as the control variable, while the pitch control 304 uses the blade adjustment as the control variable. This is of course also taken into account in the corresponding controllers, especially in the second or fourth controller 316, 336.

[0136] However, the two structures are selected similarly to the extent that the desired value-actual value comparison in the second summing point 314 and in the fourth summing point 330 can be identical in that they can be formed in the same physical units for the acceleration. In particular, it is provided that in both cases the acceleration value is considered as power. This makes it possible to couple or coordinate the speed power control 302 with the pitch control 304.

[0137] For this purpose, the second controller 316 determines the control reserve P R And output the control reserve. Control reserve P R It is indicated how much power of the speed power control 302 is available for control. If, for example, the wind energy facility has already output the maximum power, the reserve power is zero, only extreme cases are listed. At the fifth summing point 334, there is then the value zero, i.e. the pitch control does not change at all. The pitch control then adjusts the rotor blades accordingly to the wind in a completely normal manner to reduce the rotor acceleration. At the same time, the speed power control 302 does not cause a change, because its controlled variable, i.e. the generator power (which can also be the generator torque), is already at the limit, which can also be called saturation. In this case, in fact only the pitch control 304 is still active, and is 100%, while the speed power control 302 is no longer active. However, this may change again quickly, for example when the wind speed decreases.

[0138] However, if a control reserve exists, it is subtracted from the desired value-actual value difference at the fifth summing point 334 . The internal control error e aThis is the speed acceleration which remains after the desired value-actual value comparison and should be corrected. For this purpose, the internal control error is provided to the fourth controller 336. If, however, the speed power control 302 still provides sufficient control reserve, then this control reserve is subtracted from the acceleration to be corrected. In an extreme case, this can mean that it is reduced to zero. In this extreme case, only the speed power control 302 is active, but the pitch control 304 is not active.

[0139] Of course, it is also possible to regulate the reserve P R The output of the fifth summing point 334 then becomes negative. Due to the limitation, this still does not result in a blade angle or blade angle adjustment pointing in other directions. It should be taken into account in particular that the speed power control 302 and the pitch control 304 can work overlappingly, especially in the transition area from the partial load area to the full load area. At the beginning of the full load area, the rotor blades are still optimally positioned in the wind. However, the pitch control can rotate the rotor blades only in one direction. The negative output value at the fifth summing point 334 has no effect in this case. On the other hand, the rotor blades have already slightly rotated away from the wind, and the negative output value at the fifth summing point 334 can cause the blades to rotate completely into the wind again.

[0140] These are just some intuitive examples to illustrate the basic principle. The detailed control steps can of course be associated with further details, including especially the integral part in the second controller.

[0141] Figure 4 A speed-power diagram is shown, in which the generator power P is plotted against the speed n of the rotor. Starting at the starting speed n0, a speed-power characteristic curve is shown, which increases strictly monotonically until at the rated power P N At the rated speed n N And an operating characteristic curve 402 is formed. The operating characteristic curve is interrupted in a rotation speed avoidance range 404, which is shown there by a dotted line. It is also proposed that in an upper rotation speed range 406 the operating characteristic curve is also not used for controlling the wind energy installation, so that it is only shown there by a dashed line.

[0142] The rotation speed avoidance range 404 basically encloses the resonance point. At this resonance point, the resonant frequency of the wind power plant can be determined by the plotted resonant rotation speed n R Therefore, wind energy installations should not be operated at this speed as far as possible.

[0143] Therefore, when the wind speed increases, the rotation speed is gradually increased starting from the starting rotation speed n0 according to the operating characteristic curve 402 according to the increase in wind speed. Depending on which rotation speed occurs, the associated power is set according to the operating characteristic curve 402.

[0144] If the speed reaches the lower avoidance speed n1, the speed-power control is switched on, such as the speed-power control 302 in Figure 3 . The coupling connection 306 is not important here and can be omitted or has no effect. If the wind speed now increases further, this will lead to an increase in the rotation speed, but the rotation speed power control now offsets this. The rotation speed power control is as shown in FIG. Figure 3 The operation is as described above, wherein the lower avoidance speed n1 can be used as the desired speed n s The input is then provided to the first summing junction 308 .

[0145] As a result, the power is increased in order to thereby counteract the acceleration of the rotor. This can be achieved particularly well by the proposed cascade control, which determines the acceleration target value in the outer cascade and corrects it in the inner cascade. This results in the left branch 408 shown. The higher the wind speed, the more the vertical left branch 408 increases.

[0146] It can then be provided that at the upper avoidance speed n2, a change is made from the left branch 408 to the right branch 410. If the wind speed then continues to increase, the operating point continues to move upward on the right branch 410 until the operating characteristic curve 402 is reached. If the wind speed then continues to increase, the operating point continues to move on the operating characteristic curve 402 in the direction of a higher speed and thus a higher power.

[0147] The change from the left branch to the right branch, or vice versa when the wind speed drops, can be dependent on limit values. In particular, it is provided that a change from the left branch 408 to the right branch 410 occurs when the generator state variable, here the power P, reaches an upper limit value. Conversely, in particular when the wind speed drops, a change can be provided if the plant is operated at an operating point on the right branch 410 and a lower power limit is reached. In particular, it can be provided that a change is necessary if an upper limit is reached on the left branch or a lower limit is reached on the right branch.

[0148] However, it can be pointed out that there is also the possibility of changing before this. For this purpose, the aerodynamic efficiency of the current operating point can be determined. This is particularly related to the tip speed ratio, that is to the quotient of the blade tip speed divided by the current wind speed. In the partial load range, wind energy installations are usually designed so that the tip speed ratio is as ideal as possible. This design usually results in the operating characteristic curve used, that is to say, the operating characteristic curve 402 here. If the operating point is on the operating characteristic curve 402, then the operating point is aerodynamically optimal. Therefore, the optimal aerodynamic efficiency is obtained.

[0149] If the speed is now maintained, for example, at the lower avoidance speed n1, with the power increasing according to the left branch 408, the operating characteristic curve 402 and thus also the aerodynamically optimal operation is left behind. The aerodynamic efficiency is thus reduced. The aerodynamic efficiency can also be calculated, since the characteristic curve family of the wind energy installation and thus the efficiency of the different operating points of the wind energy installation are usually well known. The efficiency can be derived from the detected speed and the generated power and from this the wind speed can also be derived via the known characteristic curve family.

[0150] As long as the wind speed is derived, it can also be calculated which operating point the wind energy installation will adopt after the switch to the right branch 410. This can also be performed using a known family of characteristic curves, from which the aerodynamic efficiency can then be calculated and the aerodynamic efficiency of the current operating point, i.e. the aerodynamic efficiency of the current operating point on the left branch 408 according to the above example, can be compared with the efficiency of the operating point on the right branch 410, which the wind energy installation will adopt after the switch. If the efficiency of the operating point calculated after the switch is higher than the current aerodynamic efficiency, then a switch is considered. However, if, for example, the difference between the two efficiencies is small and it is not yet possible to foresee whether the wind speed will continue to increase, the switch does not have to be performed immediately, which is still the example above.

[0151] If the operating point moves somewhat from above to an upper avoidance speed n2 when the wind speed decreases, the method can be used expediently for the change from the right branch 410 to the left branch 408 .

[0152] The transformation process can be as follows Figure 5 Execute as described in . Figure 5 is an illustration of a transformation according to an example in which the wind speed decreases and thus the generated power P decreases. This is schematically illustrated by a strictly monotonically decreasing dashed line. It is assumed that at time t1 the upper avoidance speed n2 is reached from above. Subsequently, the speed power control begins and an attempt is made to keep the speed at the upper avoidance speed n2. This results in a power reduction, which is indicated by the power control branch 550. Thus, the dashed power curve 552 is higher than the power control branch 550. As a result, less power is converted, whereby the rotor is braked less or no longer. The speed can be maintained.

[0153] At the starting time t2, i.e. at the beginning of the transformation process, the power is reduced to such that the power has either reached the lower limit value or the aerodynamic efficiency of the operating point has deteriorated, making the transformation suitable. In principle, the power control branch 550 corresponds to Figure 4 The right branch 410 of the power control branch does not necessarily have to extend linearly as shown. Figure 4In , the power reduction is shown with respect to the speed n, so that the right branch extends vertically. However, in Figure 5 In FIG. 5 , the profile of power control branch 550 is shown over time such that it does not extend vertically.

[0154] If the conversion is now started, the power increases strongly, as can be seen in the rising branch 554 of the illustrated time profile. Together with the rising branch 554, the other upper branch 556 and the falling branch 558 form the time profile for the generator state variable to be set, ie, the power to be set here.

[0155] At the post-transformation time t3, the transformation is completed, so that the working point is then located on the left branch 408, but at the bottom of the left branch 408, because Figure 5 , the reduction branch 558 ends at the dashed power curve 552. Therefore, the power that can be generated optimally is then output, so that the optimal operating point has already appeared, which in turn is located on the operating characteristic curve. However, it is not necessary to reach the optimal operating point during the transformation, which can also be generally referred to as the operating point by the same meaning.

[0156] In this case, the time difference between the start time t2 and the subsequent changeover time t3 can be referred to and specified as the changeover time T w The distance between the power level of the upper branch 556 and the power reached after conversion can be referred to as the conversion power P w The rising branch 554, the upper branch 556 and the lower branch 558 approximately form a trapezoid and the conversion time T can be simplified to calculate the conversion energy. w and conversion power P w In order to take into account the inclination of the rising branch 554 and the lowering branch 558, as the transformation time T w Instead of the difference between start time t2 and post-change time t3 , the time required for one of the two edges, for example the time required for lowering branch 558 in order to lower from upper branch 556 to dashed power profile 552 , can be subtracted.

[0157] It is expedient to switch from left branch 408 to right branch 410 when the wind speed increases by reducing the power below the ideal power curve in order to thereby allow acceleration of the rotor.

[0158] exist Figure 4 It is also described in the figure that the speed power control is used for the upper speed range 406. It is proposed that the speed power control is used from the transition speed n3, as in Figure 3In particular, a coupling can also be provided here between the speed power control 302 and the pitch control 304 by means of a coupling connection 306 .

[0159] For this purpose, it is proposed that the speed power control obtains the speed as the speed target value according to the transition speed characteristic curve. This transition speed characteristic curve 412 has a vertical branch 414 and a remaining branch 416, which is connected to the vertical branch 414. A horizontal branch 418 is connected to the remaining branch 416, and the horizontal branch has a rated power P N And extend to rated speed n N The horizontal branch 418 can also be regarded as a part of the transition speed characteristic curve 412 .

[0160] As a result, the vertical branch 414 causes that when the wind speed increases, the transition speed n3 first forms the desired speed for speed power control. If the power reaches the reference power value P as the wind speed increases, ref , the reference power value is lower than the rated power P N , then the remaining branch 416 is used. When the wind speed increases, the remaining branch 416 should eventually guide the operating point to the rated power P N . Rated power P N Here, the rated speed n N Preferably reached before.

[0161] For this reason, the remaining branch 416 has a positive slope and, as in Figure 4 , is formed as a straight line. The power increases proportionally with the increase in speed according to the remaining branch 416. However, other variation curves are also conceivable, for example according to a quadratic polynomial, so that the remaining branch 416 can be curved, so as to reach the rated power P N .

[0162] In any case, this remaining branch 416 depicts the correlation between the rotational speed and the power. The correlation can be used to identify the operating point based on the output power and then input the associated rotational speed as the desired rotational speed into the rotational speed power control. Thus, the wind power plant can also be guided along the remaining branch 416 by means of the rotational speed power control.

[0163] For the vertical branch 414, a negative slope can alternatively also be preset, so that as the power increases, the speed decreases slightly. This is indicated by the alternative branch 420, which is shown as a dotted line. The value of its slope can be up to 10%, according to which if the power increases by the rated power, the speed decreases by less than 10% of the rated speed. Therefore, the maximum slope of 10%, respectively with respect to the rated speed or rated power, involves the speed change for each power change. The control of the alternative branch 420 can also be carried out in the following way, that is, the power is detected and the speed associated with the alternative branch 420 is used as the desired speed for the speed power control independently of it.

[0164] In particular, within the scope of the remaining branch 416, the speed power control, such as Figure 3 As explained above, there is no longer sufficient control reserve. Figure 3 , the coupling connection 306 transmits a correspondingly small value to the pitch control 304, which is taken into account there at the fifth summing point 334. Accordingly, the pitch control 304 can then already become active.

[0165] Figure 6 Shown corresponding to Figure 3 The speed power control of the upper part of the invention, however, has further elements, is partly more detailed and partly shown in slightly different diagrams. Figure 6 The speed power control 602 also has a first summing point 608, which in principle performs a desired value-actual value comparison for the speed and thus generates an external control error e for the speed. n The external control error is input to the first controller 610, which has other details and is therefore only shown as a dashed box. The first controller 610 also outputs the desired acceleration a s For this purpose, a desired value-actual value comparison is performed at the second summing point 614 and is input to the second controller 616. This in turn outputs the desired generator state variable, in this case the desired power P S There is also an external feedback 612 and an internal feedback 618 .

[0166] In this regard, the function also corresponds to Figure 3 The working method described for the speed power control 302. The desired power P outputted from the second controller 616 SThis is provided to the wind power plant block 622, which in this case, however, contains the generator. In addition, the wind power plant block 622 outputs the rotational speed n and provides it via the filter block 650. Thus, the filter block 650 outputs two filtered rotational speeds, wherein the filtering can be performed differently. For the internal feedback 618, the rotational speed is also converted into the detected acceleration a by derivation in the acceleration block 652 i In the case of external feedback 612 , no differentiation of this kind is provided, so that it may be expedient for filter block 650 to filter differently for internal feedback 618 than for external feedback 612 .

[0167] The first controller 610 is designed to convert the speed control error into a preliminary acceleration value a in the speed conversion block 654: v The preliminary acceleration value is converted into the acceleration expected value a via the acceleration limit block 656. s . Initial acceleration value a v has been set to power. From it the equivalent blade angle power P can be subtracted α , i.e. in the third summing point 658. The equivalent blade angle power P α The blade angle power block 660 determines the blade angle α and the minimum blade angle α. min Furthermore, information about the current pitch control Pit_C is taken into account.

[0168] In particular, the difference between the current and the minimum blade angle is critical. If the current blade angle α corresponds to the minimum blade angle α min , then the difference is zero and does not need to be considered. The output value of the blade angle power block 660, i.e., the equivalent blade angle power P α However, if the blade angle is adjusted relative to the minimum blade angle, this means that the power extraction is no longer optimal, in particular the power extraction is reduced, ie the equivalent blade angle power value P is reduced. α This is thus taken into account in the first controller 610 at the third summing point 658. This should result in a desired acceleration a s The initial acceleration a v This can be reduced.

[0169] The stronger the feedforward is chosen, the more the described rotational speed control by means of the generator power is decoupled from the pitch control.

[0170] In certain operating situations, in which the minimum blade angle is exceeded, ie approximately during the plant startup process, it is proposed to deactivate the described feedforward.

[0171] Accordingly, modify the initial acceleration value a v The result is additionally provided via the acceleration limit block 656, so that the acceleration expected value a is obtained. s .

[0172] The expected value-actual value comparison of the acceleration value then results in an internal control error e a , the internal control error is input into the acceleration conversion block 664 in the second controller 616. In the acceleration conversion block 664, in particular, the time constant is taken into account, which can be referred to as the post-adjustment time. The result is then provided to the integrator 666. The output of the integrator 666 is in principle the desired power P to be determined. s , wherein the desired power is first also output via a power limitation block 668 in order to take the limitation into account.

[0173] In order to prevent the integrator 666 from continuing to integrate despite the fact that the limit has been reached in the power limit block 668, a comparison is made between the unlimited and limited power in the fifth summing point 670. If the limit in the power limit block 668 has not been reached, the result of the difference in the fifth summing point 670 is the value zero. However, if the limit is reached, the difference is fed back to the input of the integrator 666 via the integrator limit block 672 by being subtracted from the result of the acceleration conversion block 664 at the sixth summing point 674.

[0174] In addition, Figure 6 The speed power control 602 of FIG. 60 is provided with a characteristic curve shift. The speed power characteristic curve is used here to take into account the speed shift value n in the speed power control. k To this end, the speed shift value n k The speed shift value n is added to the actual speed value at the seventh summing point 676. k For example, it can be 0.3 rpm to 1.5 rpm. This value is added to the measured or detected speed n and this has the effect that, from the perspective of the speed-power controller, the actual speed is slightly greater than it actually is. This has the effect that the operating characteristic curve, i.e. the speed-power characteristic curve, is shifted by the speed n. k The corresponding values ​​are shifted to the left.

[0175] The activation and also the magnitude of the movement can be dependent on the set blade angle and thus on the pitch control, for example Figure 3 The performance of the pitch control 304 is related to the pitch control. According to the pitch control, the expected value α for the blade angle s It can be used as a criterion for movement. It can be achieved that, in gusts, if the speed is reduced to less than the moving speed below the rated speed, the speed reduction does not cause a reduction in power.

[0176] The invention is therefore used for speed control of wind power plants in the partial load range, ie as long as the speed is controlled primarily via the plant power or the generator torque and not yet initially via the blade angle.

[0177] In particular, an improvement of the power curve of the wind power plant and a bypassing of the rotational speed can be achieved, in particular to avoid operation in the resonance region. This can achieve load and tonality avoidance, to name just two examples.

[0178] In particular, the following are proposed:

[0179] A cascaded control structure is proposed, with an outer loop for speed control and an inner loop for acceleration control. This allows an advantageous coupling of the full-load controller, ie, in particular, the pitch control.

[0180] A transition characteristic curve is proposed, via which the proposed control concept, in particular the speed-power control, can be made compatible with the pitch control.

[0181] A transition function or concept, which can also be referred to as a conversion function, is proposed for the controlled passage through a rotational speed avoidance range of the resonance region and for the selection of a switching time for the passage through the rotational speed avoidance range.

[0182] For the sections in the partial load region in which speed power control is provided, in particular in the upper speed range, at least one section with a non-vertical speed characteristic curve is provided, in particular as a linear section with a constant slope, whereby the section predetermines a power-dependent speed target value.

Claims

1. A method for controlling a wind power plant (100), wherein the wind power plant (100) has an aerodynamic rotor (106) which is operated with a variable rotational speed and has rotor blades (108) with adjustable blade angles, wherein The wind energy installation (100) is controlled in the partial load range by an operating characteristic curve open-loop control, which uses an operating characteristic curve, wherein the operating characteristic curve (402) prescribes a correlation between the rotational speed and a generator state variable to be set, wherein the generator state variable to be set is a generator power or a generator torque, and The operating characteristic curve open-loop control is performed such that a value of the generator state variable which is predetermined by the operating characteristic curve is set according to the detected rotational speed, and - the wind energy facility is regulated in the full load range by pitch control (304), wherein the rotational speed is regulated to a desired rotational speed value by adjusting the blade angle, wherein - In at least one predeterminable speed range in the partial load region and / or in the transition region from the partial load region to the full load region, the wind energy installation is controlled by speed power control (302), wherein the speed is controlled to a desired speed value by adjusting the generator state variable, wherein - The speed and power control is performed so that - In the external cascade, a first acceleration expected value (a) of the rotor is determined by comparing a preset expected speed with a detected actual speed via a first controller (310) s ), In the inner cascade, a generator setpoint value is determined as a setpoint value for the generator state variable from a comparison of the first acceleration setpoint value of the rotor with a detected acceleration actual value via a second controller (316).

2. The method according to claim 1, It is characterized in that The speed power control (302) has an integral part.

3. The method according to claim 2, It is characterized in that The second controller has an integrating part.

4. The method according to any one of claims 1 to 3, It is characterized in that - In the speed power control The first acceleration target value and the acceleration actual value are each formed as an acceleration power, wherein The acceleration power is correlated with the rotor acceleration and specifies the power required to bring about the rotor acceleration.

5. The method according to any one of claims 1 to 3, It is characterized in that - In the speed power control The outer cascade has at least one acceleration limit value for determining the first acceleration target value, and / or - The inner cascade is used to determine the control variables to set the generator state variables -Has an integrating element with integrator limitations.

6. The method according to claim 5, It is characterized in that The first controller has the at least one acceleration limit value.

7. The method according to claim 5, It is characterized in that - the at least one acceleration limit value is settable, and / or An upper acceleration limit value and a lower acceleration limit value having different values ​​are provided as the at least one acceleration limit value.

8. The method according to claim 5, It is characterized in that The second controller has the integrating element with an integrator limitation.

9. The method according to claim 5, - the integrator limits are settable, and / or -With different upper and lower limits.

10. The method according to any one of claims 1 to 3, It is characterized in that - the at least one pre-settable speed range is respectively set as a speed avoidance range, wherein the speed avoidance range is characterized by having a lower avoidance speed and an upper avoidance speed, and If the lower avoidance speed is reached when the speed increases, or the upper avoidance speed is reached when the speed decreases, the speed power control is used, wherein When the speed power control is used, the wind energy facility is controlled according to the prevailing wind speed. - can be operated at a lower operating point within a lower speed range including the lower avoidance speed, and - can be operated at an upper operating point within an upper speed range including the upper avoidance speed, and A change between the lower operating point and the upper operating point is performed as a function of an aerodynamic evaluation of the lower operating point and the upper operating point.

11. The method according to claim 10, It is characterized in that - for the change between the lower operating point and the upper operating point at least two-stage checks are carried out, wherein - in a first stage, a check is made as to whether the operating point to which a change is to be made has a higher aerodynamic efficiency than the operating point from which a change is to be made, and In the second stage, a check is carried out to determine whether the generator state variable determined by means of the partial load speed control has reached an upper generator state limit or a lower generator state limit.

12. The method according to claim 11, It is characterized in that - Based on the check in the first level, the change is allowed, and based on the check in the second level, the change is prescribed.

13. The method according to claim 10, It is characterized in that if - the operating point to which it should be transformed, - During the scheduled inspection time, - has a higher aerodynamic efficiency than the operating point it should be shifted away from, A change is then carried out between the lower operating point and the upper operating point.

14. The method according to claim 13, It is characterized in that The predeterminable examination time period lies in the range from 5 seconds to 10 minutes.

15. The method according to claim 14, It is characterized in that The predeterminable examination time period lies in the range from 10 seconds to 5 minutes.

16. The method according to any one of claims 1 to 3, It is characterized in that -For the speed power control, the speed expected value - preset to a constant, or - Predetermining via at least one speed characteristic curve, wherein the speed characteristic curves each have a speed value which is a function of a generator state variable to be set.

17. The method according to claim 16, It is characterized in that The rotational speed characteristic curve is designed in such a way that it has a negative slope at least in sections, so that the rotational speed value decreases as the value of the generator state variable increases.

18. The method according to claim 10, It is characterized in that - for switching between the lower working point and the upper working point - preset change times, and / or A time profile is predefined for the generator state variable to be set in order to control the change accordingly.

19. The method according to claim 18, It is characterized in that The conversion time is less than 20 seconds.

20. The method according to claim 19, It is characterized in that The conversion time is less than 10 seconds.

21. The method according to claim 10, It is characterized in that The transition region in the partial load region is in an upper speed range, which is characterized by a speed starting from a transition speed, wherein The wind energy installation is characterized by a rated rotational speed, and the transitional rotational speed is at least 80% of the rated rotational speed and / or the desired rotational speed for the pitch control.

22. The method according to claim 21, It is characterized in that -The upper rotation speed range is higher than the rotation speed avoidance range.

23. The method according to claim 21, It is characterized in that The transition speed is at least 85% of the rated speed and / or the desired speed for the pitch control.

24. The method according to claim 16, It is characterized in that The speed target value is predefined for the speed power control via a transition speed characteristic curve, which forms the speed characteristic curve, wherein - for a speed having a speed value corresponding to the transition speed, the transition speed characteristic curve extends vertically so that the speed is constant as the generator state variable increases until the generator state variable reaches a predetermined first generator reference value, which is lower than the rated value of the generator state variable, and / or The transition speed characteristic curve has a positive slope starting from the transition speed and / or starting from the first generator reference value, so that the value of the generator state variable increases with increasing speed until the setpoint value of the generator state variable is reached.

25. The method according to any one of claims 1 to 3, It is characterized in that - determining a control reserve based on a difference between a set generator state variable and an upper generator state limit, - transferring the control reserve from the speed power control to the pitch control, and The speed power control and the pitch control operate at least partially in parallel and coordinate with one another via the control reserve, and / or A switch or transition between the speed-power control and the pitch control is performed as a function of the control reserve.

26. The method according to claim 25, It is characterized in that - The difference is the regulation reserve.

27. The method according to any one of claims 1 to 3, It is characterized in that - the speed power control takes precedence over the pitch control, and / or The pitch control additionally controls the speed as a function of the actual acceleration value of the rotor, and the control of the speed by the pitch control is suppressed the more the generator setpoint falls below a generator setpoint limit during the speed power control.

28. The method according to claim 27, It is characterized in that The speed-power control has priority over the pitch control, so that the pitch control is completely or partially suppressed as long as the speed-power control does not reach the controlled variable limit.

29. The method according to claim 25, It is characterized in that the speed power control uses the generator state variable as a control variable for controlling the speed, which is referred to as a generator control variable, and The pitch control uses the blade angle as a controlled variable for controlling the rotational speed, which is referred to as a pitch controlled variable, wherein the blade angle is increased in each case from a partial load blade angle which is set in the partial load range to a final angle, wherein - The speed power control is coordinated with the pitch control.

30. The method according to claim 29, It is characterized in that The blade angle increases with increasing wind speed from a partial load blade angle which is set in the partial load range to a final angle.

31. The method according to claim 29, It is characterized in that In order to coordinate the speed power control with the pitch control, the generator control variable and the pitch control variable are coordinated with each other.

32. The method according to claim 29, It is characterized in that - taking into account control variable limits of the generator control variables, and - the speed power control and the pitch control are coordinated in such a way that the speed power control, as long as it does not reach the controlled variable limit, has a greater influence on the speed than the pitch control, and / or - Setting the pitch control variable according to a control variable limit of the generator control variable.

33. The method according to claim 32, It is characterized in that - the difference between the generator control variable and the control variable limit defines the adjustment range of the speed power regulation, and - Changing the pitch control variable so that the larger the adjustment range of the speed power regulation is, the smaller the effect of the pitch regulation on the speed is.

34. The method according to claim 29, It is characterized in that - The pitch control is performed such that - in the outer cascade, a second acceleration target value is determined by a third controller from a comparison of a preset target speed with a detected actual speed, - in an inner cascade, determining a control variable from a comparison of the second acceleration desired value with the detected acceleration actual value via a fourth controller for adjusting the blade angle, and The comparison of the second acceleration target value with the detected acceleration actual value forms a control error and the control error is modified by means of the control reserve, and the control error modified in this way forms an input variable of the fourth controller.

35. The method according to claim 34, It is characterized in that - In the inner cascade, the pitch control variable is determined via the fourth controller from a comparison of the second acceleration desired value with a detected acceleration actual value for adjusting the blade angle.

36. The method according to claim 34, It is characterized in that - the acceleration expected value, the acceleration actual value and the generated control error are respectively constituted as power values, and / or The modification is performed such that the adjustment of the blade angle is reduced or suppressed compared to when the control error is not modified, and / or wherein The modification is carried out in such a way that the control reserve or a variable equivalent thereto is effectively fed forward into the comparison of the second acceleration target value with the detected acceleration actual value.

37. The method according to claim 36, It is characterized in that - said variable is proportional to said regulatory reserve.

38. The method according to claim 29, It is characterized in that In the speed-power control, the first acceleration target value determined as a function of a comparison of a predefined target speed with a detected actual speed is additionally varied as a function of the blade angle.

39. The method according to claim 38, It is characterized in that The first acceleration target value is increased by a feedforward value, wherein the feedforward value is determined as a function of a differential angle as a difference between a current blade angle and the part-load blade angle.

40. The method according to claim 39, It is characterized in that - The feedforward value is determined proportionally to the difference angle.

41. The method according to claim 29, It is characterized in that A characteristic curve shift is performed, wherein the operating characteristic curve is shifted as a function of the operating point, so that a higher value of the generator state variable is set at the same rotational speed.

42. The method according to claim 41, It is characterized in that The operating characteristic curve is shifted as a function of the behavior of the pitch control, so that at the same rotational speed a higher value for the generator state variable is set.

43. The method according to claim 41, It is characterized in that The operating characteristic curve is shifted as a function of the set blade angle, so that at the same rotational speed a higher value for the generator state variable is set.

44. The method according to claim 41, It is characterized in that The operating characteristic curve is moved at a predetermined or adjustable movement speed.

45. The method according to claim 44, It is characterized in that The predetermined or adjustable movement speed is in the range of 0.3 rpm to 1.5 rpm.

46. ​​The method according to claim 44, It is characterized in that The predetermined or adjustable movement speed is in the range of 0.5 rpm to 1 rpm.

47. The method according to claim 41, It is characterized in that - The characteristic curve shifts - Executed according to the part load blade angle exceeded.

48. The method according to claim 47, It is characterized in that The characteristic curve shift is performed as a function of the excess of the blade angle over the part-load blade angle.

49. A wind energy facility (100) having an aerodynamic rotor (106) which is operated at a variable rotational speed and has rotor blades (108) with adjustable blade angles, and - a control device for controlling the wind energy installation (100), wherein The control device is configured to control the wind energy installation by means of a method according to any one of claims 1 to 48.

50. A wind farm (112) having a plurality of wind energy installations (100), wherein one, a plurality or all of the wind energy installations are designed as wind energy installations according to claim 49.

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