Estimating wind speed

Abstract

Provided is a method of estimating a value of wind speed a wind turbine is subjected to, the wind turbine having a rotor with rotor blades at least one having an adaptable flow regulating device installed, the method including: obtaining values for power output of the wind turbine, rotor speed of the rotor, and pitch angle of the rotor blades; obtaining state information of the adaptable flow regulating device; and estimating the value of the wind speed based on the values for power output, rotor speed, pitch angle and the state information of the adaptable flow regulating device.

Claims

1. A method of estimating a value of wind speed a wind turbine is subjected to, the wind turbine having a rotor with rotor blades at least one having an adaptable flow regulating device installed, the method comprising: obtaining values for power output of the wind turbine, rotor speed of the rotor, and pitch angle of the rotor blades; obtaining state information of the adaptable flow regulating device; and estimating the value of the wind speed based on the values for power output, rotor speed, pitch angle and the state information of the adaptable flow regulating device.

2. The method according to claim 1, wherein the state information of the adaptable flow regulating device comprises information regarding an activation level of the adaptable flow regulating device.

3. The method according to claim 1, wherein the adaptable flow regulating device or at least one portion of several adaptable flow regulating portions is adjustable to be in at least two states, representing different activation levels, the state information being indicative of the respective activation level.

4. A wind turbine, comprising: a rotor having mounted thereon plural rotor blades, at least one rotor blade having an adaptable flow regulating device installed; and the arrangement according to claim 3, the input module being connected to receive the state information relating to the adaptable flow regulating device.

5. The method to claim 1, wherein the adaptable flow regulating device comprises several adaptable flow regulating portions installed along the rotor blade, wherein the state information of the adaptable flow regulating device comprises state information of at least one, portion(s) of the several adaptable flow regulating portions.

6. The method according to claim 1, wherein the adaptable flow regulating device comprises: at least one adaptable spoiler installed at at least one of the rotor blades; and/or at least one adaptable flap installed at at least one of the rotor blades.

7. The method according to claim 1, wherein the adaptable flow regulating device comprises an inflatable bag or hose which is inflatable using a fluid thereby adjusting a protrusion height and/or a tilt angle of an airfoil portion of the flow regulating device from a surrounding surface of the rotor blade, wherein the state information of the adaptable flow regulating device comprises information about a degree of filling or pressure of the bag or hose.

8. The method according to claim 1, wherein estimating the value of the wind speed includes: deriving a relationship, between wind speed and the values for power output, rotor speed, pitch angle and the state information of the adaptable flow regulating device.

9. The method according to claim 8, wherein deriving the relationship includes performing a simulation of the dynamics and/or aerodynamics and/or electrical behaviour of the wind turbine.

10. A method of estimating a value power output of a wind turbine, the method comprising: performing the method of estimating a value of wind speed according to claim 1; and estimating the value of the power output based on the estimated value of the wind speed.

11. A method of controlling a wind turbine, the method comprising: performing the method of estimating a value of wind speed according to claim 1; and controlling the wind turbine based on the estimated value of the wind speed.

12. The method according to claim 1, the controlling including at least one of: calibrating at least one wind sensor; scheduling at least one controller gain; and setting a reference value of at least one of: a rotor speed of the rotor, pitch angle of the rotor blades.

13. The method of correcting at least one measurement value of a wind characteristic, related to a wind turbine, having a rotor with plural rotor blades, the method comprising: estimating a value of the wind speed according to claim 1; measuring a value of the wind characteristic; and determining a corrected value of the wind characteristic based on the measured value of the wind characteristic and the estimated value of the wind speed.

14. An arrangement for estimating a value of wind speed a wind turbine subjected to, the wind turbine having a rotor with rotor blades at least one having an adaptable flow regulating device installed, the arrangement comprising: an input module adapted to: obtain values for power output of the wind turbine, rotor speed of the rotor, and pitch angle of the rotor blades; obtain state information of the adaptable flow regulating device; and a processor adapted to estimate the value of the wind speed based on the values for power output, rotor speed, pitch angle and the state information of the adaptable flow regulating device.

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 schematically illustrates a wind turbine according to an embodiment of the present invention comprising an arrangement for estimating a value of a wind speed, a wind turbine is subjected to according to an embodiment of the present invention;

(3) FIG. 2 schematically illustrated a block diagram of a method of estimating a value of wind speed a wind turbine is subjected to according to an embodiment of the present invention; and

(4) FIG. 3 schematically illustrated a block diagram of a method of estimating a value of wind speed a wind turbine is subjected to according to another embodiment of the present invention.

DETAILED DESCRIPTION

(5) The wind turbine 1 schematically illustrated in FIG. 1 comprises a rotor 3 having mounted thereon plural rotor blades 5, at least one rotor blade 5 having an adaptable flow regulating device (collectively labeled as) 7 installed. Further, the wind turbine 1 comprises an arrangement 9 for estimating a value of a wind speed the wind turbine 1 is subjected to. In particular, the arrangement 9 is adapted to estimate the value of the wind 11 upstream the rotor blades 5 thereby utilizing state information 13 of the state of the flow regulating device 7. The value of the wind speed estimated relating to the wind 11 may comprise the value of the wind speed which is unaffected by the operation of the wind turbine. In particular, the wind characteristic, in particular wind speed of the wind 14 as may be present downstream the plane of the rotor blades 5 may be different from the wind 11 upstream of the rotor blade plane spanned by the rotor blades 5.

(6) In the illustrated embodiment, the adaptive flow regulating device 7 comprises a spoiler 15 having spoiler portions 15a, 15b, 15c installed along the rotor blade 5 at the leading edge 17. Furthermore, the flow regulating device 7 comprises a flap 19 installed along at least a portion of the trailing edge 21 of the rotor blade 5.

(7) The state information 13 thereby comprises information regarding the state of each individual spoiler portion 15a, 15b, 15c as well as the state information of the flap 19. In other embodiments, the adaptive flow regulating device 7 may comprise other portions. For example, the spoiler 15 may be configured as an integral spoiler not comprising several spoiler portions and/or the flap 19 may be configured as comprising several flap portions arranged along the trailing edge 21 of the rotor blade 5.

(8) The arrangement 9 receives, beside the state information 13, further operational parameter information 23 comprising values for power output of the wind turbine, a rotor speed of the rotor and pitch angle of the rotor blades. Based on the values 23 for power output, rotor speed, pitch angle and based on the state information 13 of the adaptable flow regulating device 7, the arrangement 9 estimates the value 25 of the wind speed of the wind 11, in particular upstream the wind turbine 1, in particular representing a rotor mean wind speed.

(9) The value 25 of the wind speed may be utilized for one or more control processes for controlling the wind turbine 1 and may in particular be utilized by the arrangement 9 also to estimate a value 27 of a power output which is output at output terminals 29 of a converter 31 which is connected to a generator 33 which is driven by the rotor 3. Furthermore, the value 25 of the wind speed may be utilized for correcting or calibrating a wind speed sensor 35 which may be installed at the nacelle 4 harboring the rotor, the generator 33, the converter 31 and also the arrangement 9.

(10) Since the activation level of the adaptive flow regulating device 7 impacts or influences the operation of the wind turbine, in particular impacts on the rotor speed and the pitch angle and the output power, taking into account the state information 13 of the flow regulating device 7, may improve the accuracy of the estimation of the value 25 of the wind speed of the wind 11.

(11) FIG. 2 schematically illustrates a block diagram of a method 50 as may be performed by the arrangement 9 illustrated in FIG. 1 and which may be performed according to an embodiment of the present invention. In a block 51 values for the pitch angle, the rotor speed of the rotor 3 and the power output (for example at output terminals 29) are obtained, for example measured or derived using simulation. The values 23 of these parameters are then supplied to a module 53 representing an estimated wind speed table. To this module 23 also the state information 13 is supplied which is obtained by a module 55 which for example senses the state of the flow regulating device 7 or obtains setting values. In the embodiment illustrated in FIG. 2, the state information 13 may for example encode the state information in the way that the number of active segments (for example number of spoiler portions 15a, 15b, 15c), which are in an on state, is specified. According to other embodiments, the adaptive flow regulating device may only comprise a spoiler or only comprise a flap. Using the estimated wind speed table in module 53, the wind speed value 25 is estimated.

(12) FIG. 3 illustrates another embodiment of a block diagram 60 of a method as performed according to the embodiments of the present invention. In a similar module 51, the values 23 for pitch angle, rotor speed and power output are obtained and supplied to a module 63 representing an estimated wind speed table. The block diagram 60 illustrated in FIG. 3, considers the state information 13a, 13b, 13c from different portions of the adaptive flow regulating device 7, for example from the different spoiler portions 15a, 15b, 15c, respectively. The respective settings are obtained in the respective block or blocks 55a, 55b, 55c. Each of the individual state information 13a, 13b, 13c comprises either on-off information of the respective segments 15a, 15b, 15c or even information regarding a degree of activation, such as a degree of tilt and/or degree of protrusion of the respective spoiler portion.

(13) The estimated wind speed table 63 is utilized to derive the wind speed 25 from the values 23 of pitch angle, rotor speed and power output as well as using the individual state information 13a, 13b, 13c.

(14) Thereby, according to an embodiment of the present invention, the trim stall activation level (also representing the activation level of the adaptive flow regulating device) is added as a new dimension of the available wind speed estimation. The activation level can either be the number of segments activated according to FIG. 2 or it can be a function of the activation of the individual segments according to FIG. 3. Thereby, the activation level of the trim stall segment(s) (in particular the adaptive flow regulating device) is included into the calculation of the available wind speed. An advantage may be that the inclusion of the trim stall segment activation level may improve the available wind estimation independent of the state of the trim stall system. Embodiments of the present invention may be applied to one or more spoiler(s) or one or more flap(s) or in general any active add-on installed at the rotor blade.

(15) 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 invention.

(16) 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.