Wind turbine control method and system

Abstract

A method of controlling a wind turbine including a plurality of rotor blades, a first controller for controlling an adaptive flow regulating system having a plurality of individually controllable adaptive flow regulating devices arranged on the rotor blades, and a second controller for controlling a pitch regulating system for regulating a pitch angle of each rotor blade. The method includes (a) determining a diagnostic value indicative of an operational efficiency of the adaptive flow regulating system, (b) determining a first gain value for the first controller and a second gain value for the second controller based on the diagnostic value, (c) applying the first gain value to control signals for the adaptive flow regulating system generated by the first controller, and (d) applying the second gain value to control signals for the pitch regulating system generated by the second controller, is provided.

Claims

1. A method of controlling a wind turbine, the wind turbine comprising a plurality of rotor blades, a first controller for controlling an adaptive flow regulating system having a plurality of individually controllable adaptive flow regulating devices arranged on the rotor blades, and a second controller for controlling a pitch regulating system for regulating a pitch angle of each rotor blade, the method comprising: determining a diagnostic value indicative of an operational efficiency of the adaptive flow regulating system; determining a first gain value for the first controller and a second gain value for the second controller based on the diagnostic value; applying the first gain value to control signals for the adaptive flow regulating system generated by the first controller; and applying the second gain value to control signals for the pitch regulating system generated by the second controller.

2. The method according to claim 1, wherein the first gain value is set to a first maximum gain value and the second gain value is set to a second minimum gain value when the diagnostic value is equal to a maximum diagnostic value, and wherein the first gain value is set to a first minimum gain value and the second gain value is set to a second maximum gain value when the diagnostic value is equal to a minimum diagnostic value.

3. The method according to claim 1, wherein the first gain value is decreased and the second gain value is increased when the diagnostic value decreases.

4. The method according to claim 1, wherein the first gain value is increased and the second gain value is decreased when the diagnostic value increases.

5. The method according to claim 1, wherein the wind turbine further comprises a third controller for controlling an output power regulating system of the wind turbine, the method further comprising: determining a third gain value for the third controller based on the diagnostic value; and applying the third gain value to a control signal for the output power regulating system generated by the third controller.

6. The method according to claim 5, wherein the third gain value is set to a third minimum gain value when the diagnostic value is equal to the maximum diagnostic value, and wherein the third gain value is set to a third maximum gain value when the diagnostic value is equal to the minimum diagnostic value.

7. The method according to claim 5, wherein the third gain value is increased when the diagnostic value decreases, and/or wherein the third gain value is decreased when the diagnostic value increases.

8. The method according to claim 2, wherein the maximum diagnostic value corresponds to 100% operational efficiency of the adaptive flow regulating system, and wherein the minimum diagnostic value corresponds to 0% operational efficiency of the adaptive flow regulating system.

9. The method according to claim 2, wherein the first maximum gain value, the second maximum gain value, and the third maximum gain value are equal to one, and wherein the first minimum gain value, the second minimum gain value, and the third minimum gain value are equal to zero.

10. The method according to claim 1, further comprising: determining a further diagnostic value indicative of an operational efficiency of the pitch regulating system; and wherein the first gain value and the second gain value are further based on the further diagnostic value.

11. A control system for a wind turbine, the wind turbine comprising a plurality of rotor blades, an adaptive flow regulating system having a plurality of individually controllable adaptive flow regulating devices arranged on the rotor blades, and a pitch regulating system for regulating a pitch angle of each rotor blade, the control system comprising: a first controller for controlling the adaptive flow regulating system; a second controller for controlling the pitch regulating system; a diagnostic unit for determining a diagnostic value indicative of an operational efficiency of the adaptive flow regulating system; and a controller gain unit configured to determine a first gain value for the first controller and a second gain value for the second controller based on the diagnostic value; wherein the first controller is configured to apply the first gain value to control signals for the adaptive flow regulating system; and wherein the second controller is configured to apply the second gain value to control signals for the pitch regulating system.

12. A wind turbine comprising the control system according to claim 11.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 depicts a block diagram of a control system according to an embodiment of the present invention; and

(3) FIG. 2 depicts a flow diagram of a method of controlling a wind turbine according to an embodiment of the present invention.

DETAILED DESCRIPTION

(4) The illustration in the drawing is schematic. It is noted that in different figures, similar or identical elements are provided with the same reference numerals or with reference numerals which differ only within the first digit.

(5) FIG. 1 shows a functional block diagram of a control system 100 according to an embodiment of the present invention. More specifically, the control system 100 comprises a first controller 110 for generating and supplying control signal(s) 112 to an adaptive flow regulating system 101, a second controller 120 for generating and supplying control signal(s) 122 to a pitch angle regulating system 102, a diagnostic unit 130 for determining a diagnostic value 132 indicative of an operational efficiency of the adaptive flow regulating system 101 based on feedback signal 104, and a controller gain unit 140 adapted to determine a first gain value 142 for the first controller 110 and a second gain value 144 for the second controller 120 based on the diagnostic value 132. The first controller 110 applies the first gain value to control signals for the adaptive flow regulating system 101, e.g. by multiplication, in order to generate control signal(s) 112, and the second controller applies the second gain value 144 to control signals for the pitch angle regulating system 102, e.g. by multiplication, in order to generate control signal(s) 122. Optionally, the control system 100 may further comprise a third controller 150 for generating control signal(s) 152 to output power regulating system 103. In this case, the controller gain unit 140 is further adapted to determine a third gain value 146 for the third controller 150 based on the diagnostic value 132. Further optionally, the control system 100 may further comprise a further diagnostic unit 160 for determining a further diagnostic value 162 indicative of an operational efficiency of the pitch angle regulating system 102 based on feedback signal 105.

(6) Operation and functioning of the control system 100 will now be described with reference to FIG. 2 which shows a flow diagram of a method 200 of controlling a wind turbine according to an embodiment of the present invention. The method 200 begins at S1 where the diagnostic unit 130 determines a diagnostic value 132 indicative of an operation efficiency of the adaptive flow regulating system 101 based on the feedback signal 104. The feedback signal 104 may e.g. contain information on the functional state of each adaptive flow regulating device in the adaptive flow regulating system. Based on this information, the diagnostic unit 130 determines the diagnostic value 132, which may e.g. be a value between 0% and 100%, where 0% corresponds to a non-working adaptive flow regulating system while 100% corresponds to a perfectly working adaptive flow regulating system. In other words, any value between 0% and 100% indicates how many of the adaptive flow regulating devices are working and how well.

(7) The method 200 continues at S2, where the controller gain unit 140 determines a first gain value 142 for the first controller 110 and a second gain value 144 for the second controller 120 based on the diagnostic value 132. If the optional third controller 150 is present, a third gain value 146 for this third controller 150 may also be determined at this stage. When the diagnostic value 132 equals 100%, the first gain value 142 is set to its maximum value, e.g. 1 (one) and the second gain value 144 is set to its minimum value, e.g. 0 (zero). On the other hand, when the diagnostic value 132 equals 0%, the first gain value 142 is set to its minimum value, e.g. 0 and the second gain value 144 is set to its maximum value, e.g. 1. For a diagnostic value 132 between 0% and 100%, say 50%, both the first gain value 142 and the second gain value 144 are set to a value between the respective maximum and minimum values, such as both being equal to 0.5. Generally, when the diagnostic value 132 decreases, the first gain value 142 is decreased and the second gain value 144 is increased. Similarly, when the diagnostic value 132 increases, the first gain value 142 is increased and the second gain value 144 is decreased.

(8) The method 200 continues at S3, where the first gain value 142 is applied by the first controller 110 to generate control signal(s) 112, and at S4, where the second gain value 144 is applied by the second controller 120 to generate control signal(s) 122. This results in a weighting of the influence of the first 110 and second 120 controllers. More specifically, when the first gain value 142 equals 1 and the second gain value 144 equals 0, only the first controller 110 has an actual influence. Thus, in this case, the 100% functioning adaptive flow regulating system 101 is solely responsible. In the other extreme situation, where the first gain value 142 equals 0 and the second gain value 144 equals 1, only the pitch regulating system 102 is active. For first and second gain values between 0 and 1, both the adaptive flow regulating system 101 and the pitch angle regulating system 102 will be active. Thus, in this case, where the operational efficiency of the adaptive flow regulating system 101 is less than 100%, the pitch angle regulating system 102 takes over and assists the only partially working adaptive flow regulating system 101.

(9) The method 200 may now return to S1 and repeat the steps and operations discussed above. However, if the optional third controller 150 is present and a corresponding third gain value 146 has been determined at S2 as discussed above, then such third gain value 146 is applied by the third controller 150 to generate control signal(s) 152 for the output power regulating system 103, e.g. in order to apply additional curtailment in certain situations. Thereafter, the method 200 returns to S1 as discussed above.

(10) In embodiments comprising the optional further diagnostic unit 160, the further diagnostic value 162 may be used at S1 of the method 200 instead of or in addition to the diagnostic value 132. Thereby, in cases where the pitch angle regulating system 102 is not working optimally, i.e. at less than 100% operational efficiency, the adaptive flow regulating system 101 may compensate this in a similar manner as discussed above for the case where the adaptive flow regulating system 101 is not working optimally.

(11) Generally, the present invention is capable of assuring a safe and continued operation of a wind turbine in a case where either the adaptive flow regulating system 101 or the pitch angle regulating system 102 is working with less than optimal efficiency, e.g. due to one or more defective components.

(12) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the present invention.

(13) For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.