METHOD AND SYSTEM FOR CONTROLLING A WIND TURBINE

Abstract

A method for controlling a wind turbine having a rotor with at least two rotor blades, a 1P individual blade controller for individually adjusting the rotor blades in cycles about the respective longitudinal axis of the rotor blades using a first rotor assembly, and partial and full load ranges which adjoin each other in a nominal operating point. The method includes activating the controller, in particular by gradually increasing the controller, if the value of a first operating variable of the wind turbine exceeds a specified lower threshold which the operating variable has at a first operating point of the wind turbine, the first operating point lying in the partial or full load range or being the nominal operating point; and/or deactivating the controller, in particular by gradually reducing the controller, if the value of the first or a second operating variable of the wind turbine exceeds a specified upper threshold which the operating variable has below a switch-off wind speed of the wind turbine, in particular at a second wind turbine operating point which lies in the full load range.

Claims

1-9. (canceled)

10. A method for controlling a wind turbine, the wind turbine comprising a rotor having at least two rotor blades and a 1P individual blade control configured for individual cyclical adjustment of the rotor blades about their respective longitudinal axes with a first rotor order, the wind turbine operable over a partial load range and a full load range adjoining one another at a nominal operating point, the method comprising at least one of: activating the 1P individual blade control in response to a value of a first operating variable of the wind turbine exceeding a specified lower threshold value that the operating variable has at a first operating point of the wind turbine which is in the partial load range, the full load range, or is the nominal operating point; or deactivating the 1P individual blade control in response to a value of the first operating variable or of a second operating variable of the wind turbine exceeding a specified upper threshold value that the first or second operating variable has below a switch-off wind velocity of the wind turbine.

11. The method of claim 10, wherein at least one of: activating the 1P individual blade control comprises gradually increasing the 1P individual blade control; deactivating the 1P individual blade control comprises gradually reducing the 1P individual blade control; or deactivating the 1P individual blade control in response to a value of the first operating variable or of a second operating variable of the wind turbine exceeding a specified upper threshold value that the first or second operating variable has below a switch-off wind velocity of the wind turbine comprises deactivating the 1P individual blade control in response to a value of the first operating variable or the second operating variable of the wind turbine exceeding a specified upper threshold value that the first or second operating variable has at a second operating point of the wind turbine which is in the full load range.

12. The method of claim 10, wherein at least one of the first operating variable or the second operating variable depends on at least one of a generator torque, a rotational velocity, an electrical power produced by the wind turbine, a collective adjustment of the rotor blades about their respective longitudinal axes, a wind velocity, a blade bending torque, a rotor thrust, or a setpoint value.

13. The method of claim 12, wherein the wind velocity is averaged over a specified period of time.

14. The method of claim 10, wherein the first operating point is within a load range in which the wind turbine is at least one of: at at least 65 percent of a nominal rotational velocity of the wind turbine; at at most 110 percent of a nominal rotational velocity of the wind turbine; at at least 35 percent of a nominal torque of the wind turbine; at at most 65 percent of a nominal torque of the wind turbine; at at least 55 percent of a thrust of the wind turbine when a nominal power of the wind turbine is reached; or at at most 85 percent of a thrust of the wind turbine when a nominal power of the wind turbine is reached.

15. The method of claim 14, wherein the first operating point is within a load range in which the wind turbine is at at most 99 percent of the nominal rotational velocity of the wind turbine.

16. The method of claim 10, wherein the second operating point is within a load range in which at least one of: the rotor blades are at a blade pitch of between 0 degrees and 10 degrees, or between 13 degrees and 37 degrees, inclusive; the wind turbine is at at least 45 percent of its thrust when a nominal power of the wind turbine is reached; or the wind turbine is at at most 75 percent of its thrust when a nominal power of the wind turbine is reached.

17. The method of claim 11, wherein at least one of the gradual increase or the gradual reduction of the 1P individual blade control is effected over an interval of at least one of: at least 5 percent of a nominal torque of the wind turbine; at most 45 percent of a nominal torque of the wind turbine; or at least 2 percent of a blade pitch.

18. The method of claim 17, wherein the interval of at least 2 percent of a blade pitch is a collective blade pitch.

19. The method of claim 10, wherein the wind turbine additionally comprises an nP single blade control configured for the individual cyclical adjustment of the rotor blades about their respective longitudinal axis with an nth rotor order, and the method further comprises at least one of: activating the nP individual blade control in response to a value of an operating variable of the wind turbine exceeding a specified lower limit value; or deactivating the nP individual blade control in response to a value of an operating variable of the wind turbine exceeding a specified upper limit value.

20. The method of claim 19, wherein at least one of: activating the nP individual blade control comprises gradually increasing the nP individual blade control; or deactivating the nP individual blade control comprises gradually reducing the nP individual blade control.

21. The method of claim 19, wherein at least one of: the lower limit value corresponds to a lower wind velocity than the lower threshold value; the upper limit value corresponds to a lower wind velocity than the upper threshold value; or an operating range interval of the wind turbine between the lower and upper limit values is smaller than an operating range interval of the wind turbine between the lower and upper threshold values.

22. The method of claim 21, wherein at least one of: the operating range interval of the wind turbine is a wind velocity interval; or the operating range interval of the wind turbine between the lower and upper limit values is smaller than an operating range interval of the wind turbine between the lower and upper threshold values by at least 20 percent.

23. A system for controlling a wind turbine, the wind turbine comprising a rotor having at least two rotor blades and a 1P individual blade control configured for individual cyclical adjustment of the rotor blades about their respective longitudinal axes with a first rotor order, the wind turbine operable over a partial load range and a full load range adjoining one another at a nominal operating point, the system comprising at least one of: means for activating the 1P individual blade control in response to a value of a first operating variable of the wind turbine exceeding a specified lower threshold value that the operating variable has at a first operating point of the wind turbine which is in the partial load range, the full load range, or is the nominal operating point; or means for deactivating the 1P individual blade control in response to a value of the first operating variable or of a second operating variable of the wind turbine exceeding a specified upper threshold value that the first or second operating variable has below a switch-off wind velocity of the wind turbine.

24. The system of claim 23, wherein at least one of: the means for activating the 1P individual blade control is configured to gradually increase the 1P individual blade control; the means for deactivating the 1P individual blade control is configured to gradually reduce the 1P individual blade control; or the switch-off wind velocity of the wind turbine is at a second operating point of the wind turbine which is in the full load range.

25. A computer program product for controlling a wind turbine, the wind turbine comprising a rotor having at least two rotor blades, a 1P individual blade control configured for individual cyclical adjustment of the rotor blades about their respective longitudinal axis with a first rotor order, the wind turbine operable over a partial load range and a full load range adjoining one another at a nominal operating point, the computer program product having a program code stored on a non-transitory, computer-readable medium, the program code configured, when executed by a computer, to cause the computer to at least one of: activate the 1P individual blade control in response to a value of a first operating variable of the wind turbine exceeding a specified lower threshold value that the operating variable has at a first operating point of the wind turbine which is in the partial load range, the full load range, or is the nominal operating point; or deactivate the 1P individual blade control in response to a value of the first operating variable or of a second operating variable of the wind turbine exceeding a specified upper threshold value that the first or second operating variable has below a switch-off wind velocity of the wind turbine.

26. The computer program product of claim 25, wherein at least one of: activating the 1P individual blade control comprises gradually increasing the 1P individual blade control; deactivating the 1P individual blade control comprises gradually reducing the 1P individual blade control; or the switch-off wind velocity of the wind turbine is at a second operating point of the wind turbine which is in the full load range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention.

[0075] FIG. 1 depicts an exemplary system for controlling a wind turbine according to one embodiment of the present invention;

[0076] FIG. 2 illustrates a method for controlling the wind turbine according to one embodiment of the present invention;

[0077] FIG. 3 depicts a blade pitch adjustment signal of a 1P and 2P individual blade control; and

[0078] FIG. 4 shows graphs depicting a partial load range, full load range, and nominal operating point of the wind turbine.

DETAILED DESCRIPTION

[0079] FIG. 1 shows a wind turbine with a tower 110 on which a nacelle 120 can be rotated, and thus track the wind, about a vertical yaw axis G by an actuator 20. In the nacelle 120, a rotor 130 is rotatably mounted about a horizontal axis of rotation R.

[0080] The rotor 130 has three rotor blades distributed equidistantly over the circumference, two rotor blades 30, 31 of which can be seen in the side view of FIG. 1. It is coupled to a generator 40, which supplies electric power to a power grid 150.

[0081] An operating guidance system 200 determines a wind velocity by means of an anemometer 10 combined with a wind vane 11 and controls the actuator 20 to track the nacelle 120 to the wind. A controller integrated into the operating system controls a generator torque of the generator 40 as well as blade pitch actuators 131 of the rotor 130 in order to adjust the blade pitches β of the rotor blades about their respective longitudinal axis, as shown in FIG. 1 by β.sub.30 and β.sub.31. The operating management system or controller controls or regulates the wind tracking, blade pitch adjustment, or generator torque in one embodiment on the basis of a detected rotor and/or generator rotational velocity, of the detected wind velocity—in particular, its magnitude and/or direction—and/or of other input variables, e.g., detected loads—in particular, blade loads, accelerations or the like.

[0082] FIG. 3 shows a blade pitch adjustment signal β.sub.1P of a 1P individual blade control (in bold in FIG. 3) and a blade pitch adjustment signal β.sub.2P of a 2P individual blade control (thin dashed lines in FIG. 3) over a full rotation of the rotor or a rotor pitch ρ of 0 degrees to 360 degrees.

[0083] Both blade pitch adjustment signals β.sub.1P, β.sub.2P are sinusoidal, phase shifted with respect to one another, and comprise different (maximum) amplitudes, wherein, in a modification (not shown), the blade pitch adjustment signal of the 1P individual blade control and the 2P individual blade control may also comprise the same phase and/or (maximum) amplitudes, or even a non-sinusoidal profile.

[0084] The blade pitch adjustment signal β.sub.1P is determined by a 1P individual blade control 210 of the operating management system 200, and the blade pitch adjustment signal β.sub.2P is determined by a 2P individual blade control 220 of the operating management system 200. In addition, a collective blade control 230 of the operating control system 200 determines a collective blade pitch, which is constant in FIG. 3 or over one rotation of the rotor.

[0085] The operating management system 200 superimposes this and the two blade pitch adjustment signals β.sub.1P, β.sub.2P, and controls the individual rotor blades or their blade pitch actuators 131 accordingly.

[0086] In this way, the rotor blade 30, in its position shown in FIG. 1, comprises, for example, the collective blade pitch plus the corresponding blade pitch adjustment signals β.sub.1P(p=0 degrees) and β.sub.2P (ρ=0 degrees). When rotated further (ρ.fwdarw.ρ>0 degrees), this (total) blade pitch of the rotor blade 30 is initially reduced. Conversely, the (total) blade pitch of the other rotor blade 31 changes accordingly, so that the rotor blades each (then) (would) have the same (total) blade pitch if they (were to) assume the same pitch position relative to the nacelle (successively) about the axis of rotation R. In this case, the individual blade controls 210, 220 change the amplitude and/or phase of the respective blade pitch adjustment signal β.sub.1P or β.sub.2P, e.g., according to measured wind and/or blade loads or the like.

[0087] FIG. 4 shows a thrust F on or in the rotor (“rotor thrust”), the collective blade pitch β.sub.koll, the torque M of the rotor or generator, its rotational velocity ω, and the electrical power P.sub.el over a wind velocity, wherein their values are specified only by way of example.

[0088] In FIG. 4, v.sub.nenn designates a nominal operating point of the wind turbine or a corresponding nominal wind velocity and a partial load range T, which extends from a switch-on wind velocity v.sub.on to the nominal operating point or to the nominal wind velocity v.sub.nenn, as well as a full load range, which extends from the nominal operating point or the nominal wind velocity v.sub.nenn up to a switch-off wind velocity v.sub.off.

[0089] In particular, it can be seen that, in a manner known per se, the collective blade pitch β.sub.koll is increased once the nominal operating point is reached or the nominal wind velocity is increased, in order to keep the electric power as constant as possible and not overload the installation. It can also be clearly seen that the thrust on the rotor comprises a maximum in the range of the nominal operating point or the nominal wind velocity.

[0090] FIG. 2 shows a method for controlling the wind turbine according to one embodiment of the present invention.

[0091] In a step S10, a current value of a first operating variable, e.g., a current torque, is determined.

[0092] In step S20, the operation management system 200 checks whether the value of the first operating variable exceeds a specified lower limit value. If this is the case (S20: “Y”), it activates the 1P individual blade control 210 in a step S25, wherein it gradually increases the blade pitch adjustment signal β.sub.1P specified by said signal up to the full amplitude. In this case, as the value of the first operating variable increases, the blade pitch adjustment signal, within an interval of the first operating variable specified for this purpose, is increased from zero, when the specified lower threshold value is reached, up to the full amplitude at the end of the interval. The operating management system then continues with step S30. By contrast, if the value of the first operating variable does not exceed the specified lower threshold value (S20: “N”), the operating control system returns to step S10 after step S20.

[0093] In step S30, a current value of a second operating variable, e.g., a current collective blade pitch, is determined.

[0094] In step S40, the operational management system 200 checks whether the value of the second operating variable exceeds a specified upper threshold value. If this is the case (S40: “Y”), it deactivates the 1P individual blade control 210 in a step S45, wherein, in an analogous manner, it gradually reduces the blade pitch adjustment signals β.sub.1P specified by said control from the full amplitude to zero, and subsequently returns to step S10; otherwise (S40: “N”), it returns to step S30.

[0095] In parallel to this, a current value of a third operating variable, e.g., a current wind velocity or rotational velocity, is determined in a step S50.

[0096] In step S60, the operating management system 200 checks whether the value of the third operating variable exceeds a specified lower limit value. If this is the case (S50: “Y”), it activates the 2P individual blade control 220 in a step S65, wherein it gradually increases the blade pitch adjustment signals β.sub.2P specified by said control up to the full amplitude in an analogous manner, and then continues with step S70; otherwise (S60: “N”), it returns to step S50.

[0097] In step S70, the value of the third operating variable is updated.

[0098] In step S80, the operating management system 200 checks whether the value of the third operating variable exceeds a specified upper limit value. If this is the case (S80: “Y”), it deactivates the 2P individual blade control 220 in a step S85, wherein, in an analogous manner, it gradually reduces the blade pitch adjustment signal β.sub.2P specified by said control from the full amplitude to zero, and subsequently returns to step S50; otherwise (S80: “N”), it returns to step S70.

[0099] As shown in FIG. 2, the activation and deactivation of the 1P individual blade control and 2P individual blade control can take place independently and/or in parallel. Similarly, both activations and deactivations can also be or become linked to one another. For example, in one embodiment in which the 2P individual blade control is activated and deactivated earlier than the 1P individual blade control when the wind picks up (v↑), whether the lower threshold value (cf. S60) has been exceeded needs to be checked only if the lower limit value is exceeded, and the upper threshold value (cf. S80) checked only if the upper limit value is exceeded.

[0100] Although exemplary embodiments have been explained in the preceding description, it should be noted that a number of modifications are possible. It should also be noted that the exemplary embodiments are merely examples that are not intended to limit the scope of protection, the applications, and the construction in any way. Rather, the preceding description provides the person skilled in the art with a guide for implementing at least one exemplary embodiment, wherein various changes—in particular, with regard to the function and arrangement of the described components—can be carried out without departing from the scope of protection as arises from the claims and these equivalent feature combinations.

[0101] While the present invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such de-tail. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit and scope of the general inventive concept.

LIST OF REFERENCE SIGNS

[0102] 10 Anemometer [0103] 11 Wind vane [0104] 20 Wind tracking actuator [0105] 30, 31 Rotor blades [0106] 40 Generator [0107] 110 Tower [0108] 120 Nacelle [0109] 130 Rotor [0110] 131 Blade pitch actuators [0111] 150 Power network [0112] 200 Operating management system with blade pitch controller [0113] 210 1P individual blade control [0114] 220 2P individual blade control [0115] 230 Collective blade control [0116] F Thrust [0117] G Yaw axis [0118] M Torque [0119] P.sub.el Electrical power [0120] R Axis of rotation [0121] T Partial load range [0122] V Full load range [0123] β.sub.30/31 Blade pitch [0124] β.sub.1P Blade pitch adjustment signal (from) of the 1P individual pitch control [0125] β.sub.2P Blade pitch adjustment signal (from) of the 2P individual pitch control [0126] β.sub.koll Collective blade pitch (from) of the collective blade control [0127] ω Rotational velocity