Determining an orientation of a rotor plane of a wind turbine

Abstract

A method is provided for determining an orientation of a rotor plane of a wind turbine, including the following steps: determining direction information of a moving part of a wind turbine on basis of at least one signal of a positioning system received at the moving part, determining the orientation of the rotor plane on basis of the determined direction information. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are suggested for performing the method.

Claims

1. A method comprising: determining a direction information of a moving part of a wind turbine on a basis of at least one signal of a positioning system received at the moving part; and determining a speed information of the moving part of the wind turbine on a basis of the at least one signal of the positioning system, wherein the speed information corresponds to the respective direction information; wherein an orientation of the rotor plane is determined on the basis of the determined direction information and the corresponding speed information; and calibrating a yaw system of the wind turbine based on the determining the direction information, the determining the speed information, and the determining the orientation; and operating the yaw system based on the calibrating of the yaw system.

2. The method according to claim 1, wherein the orientation of the rotor plane being determined on the basis of the determined direction information and the corresponding speed information includes: determining a speed information in relation to a north-south direction and a speed information in relation to an east-west direction on the basis of the determined direction information and the corresponding speed information.

3. The method according to claim 1, wherein a yaw direction of the wind turbine is provided, and wherein the orientation of the rotor plane being determined on the basis of the determined direction information and the corresponding speed information includes: determining a speed information in relation to a side-side orientation of the wind turbine and a speed information in relation to a fore-after orientation of the wind turbine on the basis of the determined direction information, the corresponding speed information, and the provided yaw direction.

4. The method according to claim 1, wherein the moving part of the wind turbine is a rotating part of a rotor of the wind turbine, or is a nacelle and/or a tower.

5. The method according to claim 1, wherein the at least one signal is a satellite signal of a satellite-based Global Positioning System.

6. The method according to claim 5, wherein the direction information is determined on a basis of an analysis of Doppler Shifts of the at least one signal received at the moving part.

7. The method according to claim 1, wherein the corresponding speed information is above a defined threshold.

8. The method according to claim 1, wherein movement information of a tower and/or a nacelle is determined on basis of at least one signal provided by at least one accelerator sensor being fixed to the tower and/or the nacelle, wherein the orientation of the rotor plane being determined on the basis of the determined direction information and the corresponding speed information includes the determined movement information.

9. At least one device comprising at least one processor and/or hard-wired circuit and/or a logic device executes the method according to claim 1.

10. At least one computer program product, comprising at least one computer readable hardware storage device having at least one computer readable program code stored therein, said at least one computer readable program code executed by at least one processor of a computer system that implements the method according to claim 1.

11. At least one computer readable medium, having computer-executable instructions that causes at least one computer system to perform the method according to claim 1.

12. A wind turbine, comprising: at least one moving part; and one or more processors that are arranged for: determining direction information of the moving part on a basis of at least one received signal of a positioning system, and determining a speed information of the moving part of the wind turbine on a basis of the at least one signal of the positioning system, wherein the speed information corresponds to the respective direction information; wherein an orientation of the rotor plane is determined on the basis of the determined direction information and the corresponding speed information; and calibrating a yaw system of the wind turbine based on the determining the direction information, the determining the speed information, and the determining the orientation; and operating the yaw system based on the calibrating of the yaw system.

Description

BRIEF DESCRIPTION

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

(2) FIG. 1 shows an overview illustration of a wind turbine for use of the method according to embodiments of the invention;

(3) FIG. 2 shows in an exemplary flowchart a first possible functional embodiment of the proposed solution;

(4) FIG. 3 shows in a further exemplary flowchart a second possible functional embodiment of the proposed solution based on a calculated velocity vector;

(5) FIG. 4 shows in a third exemplary flowchart a further possible functional embodiment of the proposed solution based on a calculated velocity vector; and

(6) FIG. 5 exemplarily illustrates in a graph one resulting orientation of a rotor plane as derived according to the suggested solution.

DETAILED DESCRIPTION

(7) FIG. 1 shows in an exemplary schematic view a rotor 100 of a wind turbine comprising a rotor hub 110 together with three rotor blades 120, 121, 122 extracting out of the rotor hub 110 in radial direction. A GPS-sensor (highlighted by a dotted line 130) is assigned to the rotor 100 comprising a GPS antenna 131 being fixed to the rotor blade 120 in a radial distance (represented by an arrow 134) from a center 111 of the rotor hub 110. The GPS-antenna 131 is connected via a connection line 132 to a GPS module 133 of the GPS-sensor 130 located, e.g., inside the rotor hub 110. Alternatively the GPS module 133 may be also located in the rotor blade 120. According to a further possible embodiment, the GPS antenna 131 may be located in the radial outer section of a spinner of the rotor hub 110. As a further alternative the GPS module 133 together with the GPS antenna 131 and the connection line 132 may be also part of a nacelle of the wind turbine.

(8) During operation of the wind turbine, i.e. during rotation of the rotor 110 the GPS-antenna is rotating in the plane of the rotor 100. In FIG. 1 a current velocity of the GPS-antenna 131 representing the corresponding speed and direction of the rotating GPS-antenna 131 is illustrated by a velocity vector 170 comprising a horizontal velocity 171 in relation to a horizontal plane and a vertical velocity 172 in relation to a vertical plane. The current rotor azimuth position 135 of the rotating GPS antenna 131 is represented by an azimuth angle α.

(9) During operation of the wind turbine GPS-signals 150 of a satellite-based Global Positioning System are received by the rotating GPS antenna 131 and being forwarded via the connection line 132 to the GPS module 133. By evaluating Doppler Shifts of the received GPS-signals 150 by a suitable processing unit (not shown) of the GPS module 133 a direction information d is determined which is provided via a first output 161 of the GPS module 133. Thereby, the direction information d is representing the current direction of the horizontal velocity 171 in [deg] in relation to true north.

(10) Further, a corresponding speed information s is determined by the processing unit which is provided via a second output 162 of the GPS module 133. Thereby, the speed information s is representing an absolute speed of the rotating GPS antenna 131 in [m/s] in the current direction represented by the horizontal velocity 171 (i.e. the “length” of the horizontal velocity 171).

(11) Further below, several possible embodiments of the suggested solution are now explained in more detail:

(12) FIG. 2 shows in an exemplary flowchart 200 a first possible functional embodiment of the proposed solution based on several functional blocks each representing a functional step according to the proposed solution.

(13) A direction information d 201 provided by the first output 161 and a corresponding speed information s 202 provided by the second output 162 of the GPS module 133 is relayed to a filter block 210. A speed threshold value thr 203 is further provided to the filter block 210. The filter block 210 is configured according to the following rule:
s>thr
wherein only direction information d 201 with a corresponding speed information s 202 above the threshold value thr 203 is passing the filter block 210. Resulting filtered direction information df 215 is transferred to a block 220 implementing the following “modulus of angle” functionality:
dfm=mod(df,180°)

(14) According to one aspect of the suggested solution, only those direction information d 201 is passing the filter block 210 having a sufficient high corresponding speed information s 202 wherein s>thr. As can be recognized by the exemplary scenario of FIG. 1 the rotating GPS-antenna 131 has the highest absolute speed in horizontal direction at a rotor azimuth position 135 of α=0° and α=180°. Consequently, the threshold value thr is configured in a way wherein only “filtered” direction information df 215 at a preferred rotor azimuth position 135 of α=0° and α=180° is passing the filter block 210. It should be noted that the rotor azimuth position 135 of the presented solution is not limited to the aforementioned values of α=0° and α=180°. According to the claimed solution an interval or an area of azimuth positions 135 around the aforementioned values of α=0° and α=180° may be also applicable.

(15) As the “filtered” direction information df 215 at the rotor azimuth position α=0° and α=180° is pointing into opposite directions (but being in line with the rotor plane) a modulus functionality is applied being implemented in a block 220 to eliminate or compensate the opposite directions:
dfm=mod(df,180°)

(16) The resulting direction information dfm 225 is forwarded to an averaging block 230 deriving a mean direction od 235 of the provided direction information dfm 225:
od=mean.Math.angle(dfm)

(17) The mean direction od 235 may be determined by an average calculation of the respective angles represented by the individual direction information dfm 225.

(18) The resulting direction information od 235 is representing a current orientation [in deg] of the rotor plane in relation to the horizontal plane and in relation to true north.

(19) According to a further optional step 240 a yaw direction ϕ 245 being rectangular to the determined orientation od 235 of the rotor plane can be derived based on the following rules:
ϕ=od+90°
or
ϕ=od−90° (both rules may be applied because there are two directions existing being orthogonal to the direction od)

(20) FIG. 3 shows in a further exemplary flowchart 300 a second possible functional embodiment of the proposed solution based on a calculated velocity vector.

(21) Thereby, direction information d 301 provided by the first output 161 and a corresponding speed information s 302 provided by the second output 162 of the GPS module 133 is transferred to a velocity vector calculation block 310. Based on the provided information 301, 302 a velocity vector 315 is calculated according to the following rule:
vns=cos(d)*s
vew=sin(d)*s
wherein
vns is representing the velocity in the horizontal plane in north-south direction
vew is representing the velocity in the horizontal plane in east-west direction

(22) In a subsequent “line fitting” box 320 appropriate line parameters 325 a (slope) and b (offset) are derived based on the provided velocity vector 315 according to the following rule:
vew=a*vns+b

(23) It should be notated that the line parameters 325 may be determined based on alternative methods like, e.g., statistical analysis like modeling on basis of linear or polynomial regression.

(24) Based on the determined line parameter 325, in particular based on the derived slope “a” a corresponding yaw direction θ (in [deg]) 335 is calculated in a successive “find yaw direction” box 330 implementing the following rule:
θ=a tan(a)

(25) Thereby, the resulting angle 335 is representing the yaw direction in relation to the horizontal plane and in relation to true north.

(26) FIG. 4 shows in a third exemplary flowchart 400 a further possible functional embodiment of the proposed solution based on a calculated velocity vector.

(27) Thereby, direction information d 401 provided by the first output 161, a corresponding speed information s 402 provided by the second output 162 of the GPS module 133 and a current yaw direction information ϕ 403 provided by a yaw controller (not shown) of the wind turbine is passed to a velocity vector calculation block 410. Based on the provided information 401 . . . 403 a velocity vector 415 is calculated according to the following rule:
vss=cos(d−ϕ+90°)*s
vfa=sin(d−ϕ+90°)*s
wherein vss is representing the velocity in a side-side direction in the wind turbine coordinate system, vfa is representing the velocity in a for-after direction in the wind turbine coordinate system

(28) In a subsequent “line fitting” box 420 appropriate line parameter 425 comprising “a” (slope) and “b” (offset) are derived based on the provided velocity vector 415 according to the following rule:
vfa=a*vss+b

(29) Again, it should be notated that the line parameter 425 may be determined based on alternative methods like, e.g., statistical analysis like modeling on basis of linear or polynomial regression.

(30) Based on the determined line parameter 425, in particular based on the derived slope “a” a corresponding yaw direction θ (in [deg]) 435 is calculated in a successive “find yaw direction” box 430 implementing the following rule:
θ=a tan(a)

(31) Thereby, the resulting angle ϕ 435 is representing a direction in relation to the yaw direction information 403 provided by the yaw controller.

(32) FIG. 5 exemplarily illustrates in a graph 500 one resulting orientation of a rotor plane as derived according to the suggested solution based on a calculated velocity vector.

(33) Thereby an abscissa 501 is representing the velocity vew in [m/s] in the horizontal plane in east-west direction and an ordinate 502 is representing the velocity vns in [m/s] in the horizontal plane in north-south direction.

(34) Each data point (some of them are exemplarily highlighted by a reference number 510) is representing a resulting velocity vector 315 provided by the velocity vector calculation box 310. The position of each data point in the graph 500 is determined according to its respective velocity in the horizontal plane in east-west direction and velocity in the horizontal plane in north-south direction.

(35) As an outcome of the line fitting algorithm implemented in box 320 a line 520 with the respective slope a and offset b is representing the best fitting line along the data points 510. According to the proposed solution, the line 520 is representing the current orientation or plane of the rotor of the wind turbine.

(36) Based on the identified rotor plane 520 a corresponding yaw direction 530 of the rotor can be optionally determined usually being rectangular to the rotor plane 520.

(37) According to a further embodiment of the proposed solution, the GPS-sensor may be also located in or at the nacelle thereby measuring the velocity of the whole nacelle moving back and forth with a tower frequency. Thereby, the tower oscillates in a slightly different direction than the yaw direction wherein the difference can be corrected or compensated by using an accelerator-sensor like, e.g. a Gyroscope-sensor (G-sensor) which might be a fixed part of the nacelle measuring accelerations in the back-forth and side-side direction of the nacelle.

(38) The resulting velocity information of the nacelle-based approach comprises “lower” speed values than the rotor-based approach. As a negative consequence, the accuracy of the nacelle-based approach is worse but, as an advantage, no additional sensors at the blades or spinner are necessary to implement the suggested solution. As a further advantage, the proposed solution may be easily implemented in existing wind turbine installations. Thus, when the nacelle-based approach reaches the desired precision in the near future it may be the preferred approach.

(39) 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 intention.

(40) 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. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.