Controlling wind turbine pitch based on position data from a position location sensor

Abstract

The invention relates to a method for controlling a pitch of at least one rotor blade of a wind turbine, comprising receiving, via one or more position location sensors, position data relating to the at least one rotor blade of the wind turbine. Further, the method comprises determining, via a controller, a blade pitch angle signal of the at least one rotor blade based on the position data. Moreover, the method comprises determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and an azimuth angle of the at least one rotor blade.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to wind turbines, and more particularly to systems and methods for controlling pitch and / or pitch deviation of a wind turbine using position data from a position location sensor, such as a Real Time Kinematic (RTK) sensor. BACKGROUND

[0002] Wind is considered one of the cleanest and most environmentally friendly energy sources currently available, and in this regard, wind turbines have gained increased attention. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades use known airfoil principles to capture kinetic energy from wind and transfer the kinetic energy through rotational energy to turn a shaft that is coupled to the gearbox or, in the case of direct drive systems, directly to the generator. The generator then converts the mechanical energy into electrical energy that can be deployed to a utility grid. Such a configuration can also include a power converter for converting the frequency of the generated electrical power to a frequency substantially similar to that of the utility grid.

[0003] In modern wind turbines, various sensor systems are employed to monitor various conditions of the rotor blades. For example, such conditions can include load and / or pitch alignment, which can negatively impact the annual energy production (AEP) of the wind turbine. Typically, for onshore wind turbines, a plurality of proximity sensors are installed on the main shaft to measure various moments of the rotor blades. For offshore wind turbines, a plurality of strain sensors are installed on the rotor blades to measure individual blade root moments. More particularly, strain signals from the strain sensors are converted to bending moments. However, such sensors tend to experience performance degradation and drift over time and require continuous calibration.

[0004] With respect to conventional methods for determining pitch alignment, there are several methods and / or tools available for onshore wind turbines. For example, certain wind turbines use image processing techniques in combination with lasers and / or airfoil templates of the rotor blades to correct for pitch deviation. However, these tools / methods cannot be used in offshore wind turbines due to physical constraints (e.g., offshore wind turbines are installed at sea where there is no surrounding assembly location).

[0005] In view of the foregoing, there is an ongoing need in the art for new and improved systems and methods for controlling pitch and / or pitch deviation of a wind turbine. Accordingly, the present disclosure relates to systems and methods for controlling pitch and / or pitch deviation of a wind turbine using position data from a position location sensor, such as a Real Time Kinematic (RTK) sensor. SUMMARY

[0006] Aspects and advantages of the application will be set forth in part in the following description, or can be obvious from the description, or can be learned through practice of the application.

[0007] In one aspect, the present disclosure relates to a method for controlling a pitch of at least one rotor blade of a wind turbine. The method includes receiving, via one or more position location sensors, position data related to the at least one rotor blade of the wind turbine. Also, the method includes determining, via a controller, a blade pitch angle signal for the at least one rotor blade based on the position data. Further, the method includes determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and an azimuth angle for the at least one rotor blade.

[0008] In embodiments, the position location sensor(s) can include one or more of: one or more real-time kinematic (RTK) sensors, one or more inertial navigation system (INS) sensors, one or more global positioning system (GPS) sensors, or a combination thereof.

[0009] In particular embodiments, the position location sensor(s) can include RTK sensor(s). As such, in such embodiments, the RTK sensor(s) can include a base station and a plurality of mobile stations communicatively coupled to the base station, wherein the plurality of mobile stations are mounted on the rotor blade.

[0010] In another embodiment, receiving the position data related to the rotor blade of the wind turbine can include receiving, via the controller, three-dimensional or two-dimensional position data related to a location of the base station and receiving, via the controller, three-dimensional or two-dimensional position data related to a location of each of the plurality of mobile stations.

[0011] In further embodiments, determining, via the computer-implemented model stored in the controller, the pitch command for the at least one rotor blade as a function of the blade pitch angle signal and the azimuth angle can include applying, via the controller, a direct-quadrature (d-q) transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates, filtering the d-q coordinates, and reversing the d-q transformation to transform the d-q coordinates into the pitch command for the at least one rotor blade.

[0012] In such embodiments, applying the d-q transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates can include determining a blade bending moment for the at least one rotor blade using the blade pitch angle and calculating the d-q coordinates as a function of the blade bending moment and the azimuth angle.

[0013] In additional embodiments, the method can include adding the collective pitch angle demand to a pitch command for the rotor blade(s).

[0014] In another embodiment, the wind turbine can be part of a wind farm having a farm level controller and a plurality of wind turbines. In such an embodiment, the position location sensor(s) can communicate directly with the farm level controller using a wireless communication system or an existing network of the wind farm.

[0015] In yet another additional embodiment, the method can include adjusting the pitch command of the rotor blade(s) by a pitch angle offset to correct for a pitch deviation of at least one rotor blade.

[0016] In another aspect, the present disclosure relates to a method for correcting a pitch deviation of at least one rotor blade of a wind turbine, such as an offshore wind turbine. The method includes receiving, via a controller, a reference pitch angle of the at least one rotor blade. Also, the method includes rotating the rotor blade(s) to a first pitch angle. Further, the method includes receiving, via one or more position location sensors, position data related to the rotor blade(s) of the wind turbine in the first pitch angle. Additionally, the method includes determining, via the controller, a pitch angle offset of the rotor blade(s) based on a difference between the reference pitch angle and the first pitch angle. As such, the method includes adjusting the first pitch angle of the rotor blade(s) by the pitch angle offset to correct for the pitch deviation.

[0017] In embodiments, the reference pitch angle and the first pitch angle can be a reference pitch zero position and a first pitch zero position, respectively. As such, in another embodiment, the position data can include a zero twist angle of the rotor blade(s). It should be appreciated that the method can further include any of the additional features and / or steps as described herein.

[0018] In one aspect, the present disclosure relates to a system for controlling the pitch of at least one rotor blade of a wind turbine. The system includes one or more position location sensors for generating position data related to the rotor blade(s) of the wind turbine and a controller communicatively coupled to the position location sensor(s). The controller is configured to perform a plurality of operations including, but not limited to, receiving the position data related to the rotor blade(s) of the wind turbine, determining a blade deflection degree signal of the rotor blade(s) based on the position data, and determining a pitch command for the rotor blade(s) as a function of the blade deflection degree signal and an azimuth angle of the rotor blade(s). It should be appreciated that the wind farm can further include any of the additional features as described herein.

[0019] These and other features, aspects, and advantages of the invention will become more readily understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0020] The invention is fully disclosed and can be practiced by one of ordinary skill in the art (including its best mode) in the description with reference to the accompanying drawings, in which:

[0021] Figure 1 The figure is a perspective view of one embodiment of a wind turbine according to the present disclosure;

[0022] Figure 2 Illustration provided Figure 1 A schematic diagram of one embodiment of a controller used in conjunction with a wind turbine is shown.

[0023] Figure 3 The illustration is a schematic diagram of one embodiment of a wind field according to the present disclosure;

[0024] Figure 4 The figure shows a flowchart of an embodiment of a method for controlling pitch of at least one rotor blade of a wind turbine according to the present disclosure;

[0025] Figure 5 The figure is a front view of an embodiment of a wind turbine according to the present disclosure, and in particular illustrates a plurality of position positioning sensors mounted to the rotor blades;

[0026] Figure 6 The figure shows a block diagram of an embodiment of a system for controlling the pitch of at least one rotor blade of a wind turbine according to the present disclosure; and

[0027] Figure 7 The illustration is a flowchart of an embodiment of a method for correcting pitch deviation of at least one rotor blade of a wind turbine according to the present disclosure.

[0028] The accompanying drawings are not necessarily drawn to scale, and in all drawings, for illustrative purposes, elements of similar structure or function are generally indicated by the same reference numerals. The drawings are intended only to facilitate the description of the various embodiments described herein. The drawings do not depict every aspect of the teachings disclosed herein and do not limit the scope of the claims. Detailed Implementation

[0029] Reference will now be made in detail to embodiments of the application, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the application and is not meant as a limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that this application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0030] Reference will now be made to the drawings, in which Figure 1 A perspective view of one embodiment of a wind turbine 10 configured to implement control techniques in accordance with the present disclosure is illustrated. As shown, the wind turbine 10 generally includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in alternative embodiments, the rotor 18 can include more or less than three rotor blades 22. Each rotor blade 22 can be spaced about the hub 20 to facilitate rotating the rotor 18 to enable kinetic energy to be transformed from the wind into useful mechanical energy, and subsequently into electrical energy.

[0031] For example, the hub 20 can be rotatably coupled to an electric generator (not shown) positioned within the nacelle 16 to allow electrical energy to be generated. The generator is sometimes, but not always, rotationally coupled to the rotor 18 through a gearbox. Thus, the gearbox is configured to step up the inherently low rotational speed of the rotor for the generator to efficiently convert rotational mechanical energy into electrical energy. There also exist direct drive wind turbines without a gearbox. The generated electrical power is transmitted to an electrical power grid via at least one electrical connection. Such known wind turbines can be coupled to the electrical power grid via a known full power conversion assembly. More specifically, the full power conversion assembly can include a rectifier portion that converts alternating current (AC) generated by the generator into direct current (DC) and an inverter that converts the DC into AC of a predetermined frequency and voltage amplitude.

[0032] The wind turbine 10 can also include a wind turbine controller 26 centralized within the nacelle 16. In other embodiments, however, the controller 26 can be located within any other component of the wind turbine 10 or at a location external to the wind turbine. Moreover, the controller 26 can be communicatively coupled to any number of components of the wind turbine 10 in order to control operation of such components and / or implement control actions. As such, the controller 26 can comprise a computer or other suitable processing unit. Thus, in several embodiments, the controller 26 can include suitable computer-readable instructions that, when implemented, configure the controller 26 to perform a variety of different functions, such as receiving, transmitting, and / or executing wind turbine control signals. Thus, the controller 26 can be generally configured to control various operational modes of the wind turbine 10 (e.g., start-up or shut-down sequences), derate or upgrade the wind turbine 10, control various components of the wind turbine 10, and / or implement various method steps as described herein.

[0033] For example, in certain embodiments, the methods described herein can be implemented at least in part by a processor. Performance of some of the operations can be distributed among one or more processors not only within a single machine, but also deployed across a number of machines. One or more processors can also operate to support performance of the relevant operations in a "cloud computing" environment or as a "software as a service" (SaaS). For example, at least some of the operations can be performed by a group of computers (as examples of machines including processors), these operations being accessible via a network (e.g., the Internet) and via one or more appropriate interfaces (e.g., an application program interface (API)).

[0034] In additional embodiments, the controller 26 can be configured to control a blade pitch or pitch angle of each of the rotor blades 22 (i.e., an angle that determines a viewing angle of the rotor blades 22 relative to a wind direction) to control a power output generated by the wind turbine 10. For example, the controller 26 can control the pitch angle of the rotor blades 22 by causing the rotor blades 22 to individually or simultaneously rotate about a pitch axis 28, by transmitting suitable control signals to a pitch drive or pitch adjustment mechanism (not shown) of the wind turbine 10.

[0035] Reference is now made to Figure 2, a block diagram of one embodiment of suitable components that can be included within controller 26 (or field controller 122) is illustrated in accordance with aspects of the present disclosure. Controller(s) 26, 122 can operate as standalone devices or can be coupled (e.g., networked) to other machines. In a networked deployment, controller 26 can operate in the capacity of a server machine or a client machine in server-client network environments or as a peer machine in peer-to-peer (or distributed) network environments. By way of non-limiting example, controller 26 can include or correspond to a server computer, a client computer, a personal computer (PC), a tablet computer, a laptop computer, a netbook, a mobile device, or any machine capable of sequentially or otherwise executing instructions that specify actions to be taken by controller 26.

[0036] As shown, controller 26 can include one or more processors 58 and associated memory device(s) 60 (and / or input / output (I / O) components not shown) configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, computations and / or the like disclosed herein). As used herein, the term "processor" refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, a dedicated processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) and / or any other programmable circuit. Additionally, memory device(s) 60 can generally include memory element(s) including, without limitation, computer readable medium (e.g., random access memory (RAM)), computer readable nonvolatile memory (e.g., flash memory), one or more hard drives, floppy disks, compact disks- read only memory (CD-ROM), compact disks - read / write (CD-R / W), magneto-optical disks (MOD), digital versatile disks (DVD), flash drives, optical drives, solid state storage devices, and / or other suitable memory elements. In one embodiment, controller 26 can include a plurality of processors 58 and / or memory devices 60. For example, controller 26 can include a first processor 58a and a second processor 58b. In this embodiment, first processor 58a can be configured to perform the functions of controller 26, while second processor 58b can be configured to perform the functions of field controller 122. In another embodiment, controller 26 can include a single processor 58 that is configured to perform the functions of controller 26 and field controller 122.

[0037] Additionally, controller 26 can also include a communication module 62 to facilitate communication between various components of wind turbine 10 and controller 26. For example, communication module 62 can include a sensor interface 64 (e.g., one or more analog-to-digital converters) to allow signals transmitted by one or more sensors 65, 66, 67, 116, 118 to be converted into signals that can be understood and processed by controller 26. Moreover, it should be appreciated that sensors 65, 66, 67, 116, 118 can be communicatively coupled to communication module 62 using any suitable means. For example, as shown, sensors 65, 66, 67, 116, 118 can be communicatively coupled to communication module 62 via a wired connection 68. In another embodiment, sensors 65, 66, 67, 116, 118 can be communicatively coupled to communication module 62 via a wireless connection 69. Figure 2As shown in FIG. 1, sensors 65, 66, 67, 116, 118 are coupled to sensor interface 64 via wired connections. However, in alternative embodiments, sensors 65, 66, 67, 116, 118 can be coupled to sensor interface 64 via wireless connections, such as by using any suitable wireless communication protocol known in the art. For example, communication module 62 can include the Internet, a local area network (LAN), a wireless local area network (WLAN), a wide area network (WAN) such as a Worldwide Interoperability Microwave Access (WiMax) network, a satellite network, a cellular network, a sensor network, an ad hoc network, and / or a short-range wireless network. As such, processor 58 can be configured to receive one or more signals from sensors 65, 66, 67, 116, 118.

[0038] The various components (e.g., I / O components) of controller 26 can include a wide variety of components to receive input, provide output, produce output, communicate

[0039] Referring now to the drawings Figure 3 At least some of the wind turbines are physically located in remote geographic areas or in areas that are difficult to physically access, such as offshore installations. These wind turbines can be physically nested together in a common geographic area to form a wind farm and can be electrically coupled to a common AC collector system. For example, as shown in FIG. 1, wind turbines 10, 12, 14, 16, 18, 20, 22, 24 are physically located in a common geographic area and are electrically coupled to AC collector system 28. Figure 3An embodiment of a wind farm 100 that can be controlled in accordance with the present disclosure is illustrated. More specifically, as illustrated, the wind farm 100 can include a plurality of wind turbines 102 (including the wind turbine 10 described above) communicatively coupled to a farm controller 122 via a network 126. For example, as illustrated in the illustrated embodiment, the wind farm 100 includes twelve wind turbines (including the wind turbine 10). However, in other embodiments, the wind farm 100 can include any other number of wind turbines, such as fewer than twelve wind turbines or more than twelve wind turbines. In one embodiment, the controller 26 of the wind turbine 10 can be communicatively coupled to the farm controller 122 by a wired connection, such as by connecting the controller 26 via a suitable communication link (e.g., a suitable cable). Alternatively, the controller 26 can be communicatively coupled to the farm controller 122 by a wireless connection, such as by using any suitable wireless communication protocol known in the art. Additionally, the farm controller 122 can be similarly configured to the controller 26 substantially for each of the individual wind turbines 102 within the wind farm 100.

[0040] In several embodiments, one or more of the wind turbines 102 in the wind farm 100 can include a plurality of sensors for monitoring various operational data points or control settings of the individual wind turbines 102 and / or one or more wind parameters of the wind farm 100. For example, as illustrated, each of the wind turbines 102 includes a wind sensor 116, such as an anemometer or any other suitable device, configured to measure a wind speed or any other wind parameter.

[0041] Accordingly, it should be appreciated that the various sensors 65, 66, 67, 116, 118 described herein can be any suitable sensor configured to measure any operational data point of the wind turbine 10 and / or a wind parameter of the wind farm 100 (e.g., a wind speed, a wind direction, a wind turbulence intensity, a wind shear, a wind veer, a wind gust, a wind lull, a wind speed threshold, a wind direction threshold, a wind turbulence intensity threshold, a wind shear threshold, a wind veer threshold, a wind gust threshold, a wind lull threshold, etc.). Figure 3 ) of the wind farm 100. For example, in embodiments, one or more of the sensors can be a position location sensor, such as a real-time kinematic sensor or sensor system 124 installed at least partially locally to one or more of the wind turbines 10 and / or integrated with the wind farm controller 122, one or more global positioning system (GPS) sensors, or a combination thereof.

[0042] As used herein, a position location sensor, and more particularly a Real Time Kinematic (RTK) sensor, generally refers to a sensor that uses RTK positioning, which is a satellite navigation technique for improving the precision of position data derived from satellite-based positioning systems (Global Navigation Satellite System GNSS). Thus, RTK position systems enable improvements in aspects of satellite positioning within a frequency range classified at approximately 1.164-1.610 Mhz, which is a frequency range that is different from other RF-based devices operating at higher frequencies, such as cellular 3G, Bluetooth, UWB, etc.

[0043] Thus, the sensor system 124 of the present disclosure is configured to use measurements of the phase of the carrier of the signal in addition to the information content of the signal, and relies on a single reference station or an interpolated virtual station to provide real-time corrections, thereby providing up to centimeter-level accuracy. More specifically, in certain embodiments, as shown in Figure 3 and Figure 4 the sensor system 124 can use a single base station receiver 125 and multiple mobile units 128 (e.g., flow station(s)). For example, as shown in particular in Figure 4 one or more of the mobile units 128 can be locally mounted to each of the rotor blades 22 of the wind turbine 10. As such, the base station 125 again broadcasts the phase of the carrier it observes, and the mobile units 128 compare their own phase measurements to the one received from the base station 125. The most common way to transfer the correction signal from the base station 125 to one or more of the mobile stations 128 to enable real-time low-cost signal transmission is using a radio modem (not shown). However, in certain embodiments, as shown in Figure 3 the present disclosure can also implement the communication between the base station 125 and the flow station(s) 128 using the existing network 126 of the wind farm 100, rather than using a wireless RF modem. It should also be understood that the position location sensor(s) can also include an inertial navigation system (INS) sensor, a global positioning system (GPS) sensor, or a combination of any of the sensors described herein.

[0044] In the present disclosure, for a wind turbine, the position measurements are used as inputs to be incorporated into a wind turbine model and / or algorithm to derive parameters / variables related to the turbine as described herein, such as model-based estimations. Thus, the present disclosure includes a new system architecture that excludes the additional processor and radio modem of an RTK system, while also providing a more reliable and cost-effective solution. More specifically, in embodiments, the system of the present disclosure can only require a GPS module, where the position calculations and subsequent estimations and controls are implemented in the existing wind turbine controller.

[0045] The sensors 65, 66, 67, 116, 118 described herein can also include blade sensors for measuring a pitch angle of one of the rotor blades 22 or for measuring a load acting on one of the rotor blades 22, generator sensors for monitoring a generator (e.g., torque, rotational speed, acceleration, and / or power output), and / or various wind sensors for measuring various wind parameters (e.g., wind speed, wind direction, etc.). Also, the sensors 65, 66, 67, 116, 118 can be located near the ground of the wind turbine 10, on the nacelle 16, on a meteorological mast of the wind turbine 10, or at any other location in the wind farm 100.

[0046] It should also be appreciated, therefore, that any other number or type of sensor can be employed and located at any location. For example, the sensors can be accelerometers, pressure sensors, strain gauges, angle of attack sensors, vibration sensors, MIMU sensors, camera systems, fiber optic systems, anemometers, wind vanes, SODAR sensors, infrared lasers, LIDAR sensors, radiometers, Pitot tubes, radiosondes, other optical sensors, and / or any other suitable sensor. It should be appreciated that, as used herein, the term "monitoring" and variations thereof indicate that the various sensors of the wind turbine 10 can be configured to provide a direct measurement of the parameter being monitored or an indirect measurement of such parameter. Thus, the sensors 65, 66, 67, 116, 118 may, for example, be used to generate a signal related to the parameter being monitored, which can then be utilized by the controller 26 to determine the actual condition.

[0047] Certain embodiments are described herein as including logic or a number of components, modules, or mechanisms. Modules can constitute either software modules (e.g., code embodied on a machine-readable medium or in a transmission signal) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and can be configured or arranged in a certain manner. In example embodiments, one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware modules of a computer system (e.g., a processor or a group of processors) can be configured by software (e.g., an application or application portion) as a hardware module that operates to perform certain operations as described herein.

[0048] In various embodiments, the hardware module may be implemented mechanically or electronically. For example, the hardware module may include a specialized circuitry or logic permanently configured (e.g., as a dedicated processor, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC)) to perform certain operations. The hardware module may also include programmable logic or circuitry temporarily configured by software to perform certain operations (e.g., as contained within a general-purpose processor or other programmable processor). It will be appreciated that the decision to implement the hardware module in a specially and permanently configured circuitry or in a temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0049] Now for reference Figure 5 The diagram illustrates a flowchart of one embodiment of a method 200 for controlling pitch control of one or more rotor blades (such as one or more rotor blades 22 of a wind turbine 10). Generally, reference is made herein to... Figures 1-3 Method 200 is described in connection with controllers 26, 122 and (one or more) wind turbines 10, 102. However, it should be appreciated that the disclosed method 200 can be implemented with wind turbines having any other suitable configuration. Additionally, although... Figure 5 The steps are depicted in a specific order for illustration and discussion purposes, but the methods discussed herein are not limited to any particular order or arrangement. Those skilled in the art using the disclosure provided herein will recognize that the various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or adapted in various ways without departing from the scope of this disclosure.

[0050] As shown in (202), method 200 includes receiving position data relating to one or more rotor blades(s) of wind turbine 10 via one or more location sensors (such as any one of sensors 65, 66, 67, 116, 118). More specifically, in embodiments, the position data may be three-dimensional or two-dimensional position data relating to the position of base station 125 and / or three-dimensional or two-dimensional position data relating to the position of each of a plurality of mobile stations 128.

[0051] Still referencing Figure 5 As shown in (204), method 200 includes determining the blade deflection signal of one or more rotor blades 22 based on position data via a controller. As shown in (206), method 200 includes determining a pitch command for one or more rotor blades 22 based on the blade deflection signal of one or more rotor blades 22 and the azimuth angle via a computer-implemented model stored in the controller.

[0052] Figure 5 The method 200 of Figure 6 may be better understood with reference to Figure 6 FIGURE 1 1 is a block diagram illustrating one embodiment of a system 300 for controlling the pitch of the rotor blade(s) 22 in accordance with the present disclosure. Thus, as shown, the system 300 includes a controller 302 (such as the controller 26) and a computer-implemented model 304 stored therein. Accordingly, as shown, position data 306 from the position location sensors can be used by the computer-implemented model 304 to determine the pitch command(s) 318 for the rotor blade(s) 22 as a function of the blade pitch angle signal 308 and the azimuth angle. More specifically, as shown, the controller 302 can derive the blade pitch angle 308 for each of the rotor blades 22 of the wind turbine 10.

[0053] Further, the controller 302 can then apply a direct-quadrature (d-q) transformation 310 to the blade pitch angle signal 308 to transform the blade pitch angle signal 308 into d-q coordinates 312. In such embodiments, for example, the controller 302 can use the respective blade pitch angle signal 308 to determine or derive the blade bending moment (e.g., M 外平面1 , M 外平面2、 M 外平面3 ) of the rotor blades 22 and calculate the d-q coordinates 312 as a function of the blade bending moment and the azimuth angle 320. Generally, there is a linear relationship between the blade bending moment and the blade pitch angle, and thus the blade bending moment can be derived from the blade pitch angle. Accordingly, in one embodiment, the d-q coordinates 312 can be derived from Equations (1) and (2) below:

[0054] D = cos(azimuth angle)*M 外平面1 + cos(azimuth angle + 2 / 3 pi)*M 外平面2 + cos(azimuth angle + 4 / 3 pi)*M 外平面3 Equation (1)

[0055] Q = sin(azimuth angle)*M 外平面1 + sin(azimuth angle + 2 / 3 pi)*M 外平面2 + sin(azimuth angle + 4 / 3 pi)*M 外平面3 Equation (2)

[0056] Still referring to Figure 6As shown, controller 302 can also use one or more filters 314 to filter the dq coordinates 312. As shown in 316, controller 302 can then reverse the dq transformation to transform the dq coordinates 312 into pitch commands 318 for one or more rotor blades 22. In an additional embodiment, as shown in 326, controller 302 can also be configured to add a collective pitch angle requirement 322 to the pitch commands 318 for one or more rotor blades 22. Furthermore, in an embodiment, as shown in 326, controller 302 can be configured to adjust the pitch commands 318 for one or more rotor blades 22 by a pitch angle offset 324 to correct for pitch deviations of one or more rotor blades 22.

[0057] Now for reference Figure 7 The illustration shows a flowchart of one embodiment of a method 400 for correcting pitch deviation of at least one rotor blade (such as rotor blade 22 of a wind turbine 10). Generally, reference is made herein to... Figures 1-3 Method 400 is described in connection with controllers 26, 122 and (one or more) wind turbines 10, 102. However, it should be appreciated that the disclosed method 400 can be implemented with wind turbines having any other suitable configuration. Additionally, although... Figure 7 The steps are depicted in a specific order for illustration and discussion purposes, but the methods discussed herein are not limited to any particular order or arrangement. Those skilled in the art using the disclosure provided herein will recognize that the various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or adapted in various ways without departing from the scope of this disclosure.

[0058] As shown at (402), the method 400 includes receiving, via the controller, a reference pitch angle of the rotor blade(s) 22. As shown at (404), the method 400 includes rotating the rotor blade(s) 22 to a first pitch angle. For example, in an embodiment, the reference pitch angle and the first pitch angle can be a reference pitch zero position and a first pitch zero position, respectively. In another embodiment, the position data can include a zero twist angle of the rotor blade(s) 22. As shown at (406), the method 400 includes receiving and storing / recording position data related to the rotor blade(s) 22 at the first pitch angle via the one or more position location sensors. As shown at (408) through (412), the method 400 includes determining, via the controller, a pitch angle offset of the rotor blade(s) 22 based on a difference between the reference pitch angle and the first pitch angle. For example, as shown at (408), the method 400 includes determining a desired pitch position based on a design model. As shown at (410), the method 400 includes comparing the desired pitch position from the design model to an actual pitch position from the sensor. Thus, as shown at (412), a blade pitch deviation value can be determined by the controller. As shown at (414), the method 400 includes sending the pitch angle offset to the controller and adjusting the first pitch angle of the rotor blade(s) 22 by the pitch angle offset to correct for the pitch deviation.

[0059] While embodiments of the present application have been described with reference to particular examples, it will be apparent to those of ordinary skill in the art that various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the application. Therefore, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, although two embodiments are shown in the drawings, it will be understood that many other embodiments can be made without departing from the scope of the present application. The embodiments depicted are sufficient to convey the teachings of the present application to one of ordinary skill in the art. Other embodiments can be derived from the depicted embodiments by making appropriate variations within the scope of the present disclosure. Structural and logical substitutions can be made without departing from the scope of the present disclosure.

[0060] Various aspects and embodiments of the application are defined by the numbered clauses below:

[0061] Clause 1. A method for controlling a pitch of at least one rotor blade of a wind turbine, the method comprising:

[0062] receiving, via one or more position location sensors, position data related to the at least one rotor blade of the wind turbine;

[0063] determining, via the controller, a blade pitch degree signal for the at least one rotor blade based on the position data; and

[0064] determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch degree signal and the azimuth angle for the at least one rotor blade.

[0065] Clause 2. The method of Clause 1, wherein the one or more position location sensors comprise one or more of: one or more Real Time Kinematic (RTK) sensors, one or more Inertial Navigation System (INS) sensors, one or more Global Positioning System (GPS) sensors, or a combination thereof.

[0066] Clause 3. The method of Clause 2, wherein the one or more position location sensors comprise one or more RTK sensors.

[0067] Clause 4. The method of Clause 3, wherein the one or more RTK sensors comprise a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations being mounted on the rotor blades.

[0068] Clause 5. The method of Clause 4, wherein receiving position data related to the rotor blades of the wind turbine further comprises:

[0069] receiving, via the controller, three-dimensional or two-dimensional position data related to a position of the base station, and

[0070] receiving, via the controller, three-dimensional or two-dimensional position data related to a position of each of the plurality of mobile stations.

[0071] Clause 6. The method of any of the preceding claims, wherein determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch degree signal and the azimuth angle further comprises:

[0072] applying, via the controller, a direct-quadrature (d-q) transformation to the blade pitch degree signal to transform the blade pitch degree signal into d-q coordinates;

[0073] filtering the d-q coordinates; and

[0074] inversely transforming the d-q transformation to transform the filtered d-q coordinates into the pitch command for the at least one rotor blade.

[0075] Clause 7. The method of any of the preceding claims, wherein applying, via the controller, a d-q transformation to the blade pitch degree signal to transform the blade pitch degree signal into d-q coordinates further comprises:

[0076] to determine a blade bending moment of the at least one rotor blade using the blade deflection, and

[0077] to calculate d-q coordinates from the blade bending moment and the azimuth angle.

[0078] Clause 8. The method of any of the preceding claims, further comprising adding a collective pitch angle demand to the pitch command for the at least one rotor blade.

[0079] Clause 9. The method of any of the preceding claims, wherein the wind turbine is part of a wind farm comprising a farm level controller and a plurality of wind turbines, the one or more position location sensors directly communicating with the farm level controller using a wireless communication system or an existing network of the wind farm.

[0080] Clause 10. The method of any of the preceding claims, further comprising adjusting the pitch command of the at least one rotor blade by a pitch angle offset to correct for a pitch deviation of the at least one rotor blade.

[0081] Clause 11. A method for correcting a pitch deviation of at least one rotor blade of a wind turbine, the method comprising:

[0082] receiving, via a controller, a reference pitch angle of the at least one rotor blade;

[0083] rotating the at least one rotor blade to a first pitch angle;

[0084] receiving, via one or more position location sensors, position data related to the at least one rotor blade of the wind turbine in the first pitch angle;

[0085] determining, via the controller, a pitch angle offset of the at least one rotor blade based on a difference between the reference pitch angle and the first pitch angle; and

[0086] adjusting the first pitch angle of the at least one rotor blade by the pitch angle offset to correct for the pitch deviation.

[0087] Clause 12. The method of Clause 11, wherein the reference pitch angle and the first pitch angle comprise a reference pitch zero position and a first pitch zero position, respectively.

[0088] Clause 13. The method of Clauses 11-12, wherein the position data comprises a zero twist angle of the at least one rotor blade.

[0089] Clause 14. The method of Clauses 11-13, wherein the one or more position location sensors comprise one or more of: one or more Real Time Kinematic (RTK) sensors, one or more Inertial Navigation System (INS) sensors, one or more Global Positioning System (GPS) sensors, or a combination thereof.

[0090] Clause 15. The method of clause 14, wherein the one or more position location sensors comprise one or more RTK sensors, the one or more RTK sensors comprising a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations mounted on the rotor blade.

[0091] Clause 16. The method of clauses 11-15, wherein the wind turbine comprises an offshore wind turbine.

[0092] Clause 17. A system for controlling a pitch of at least one rotor blade of a wind turbine, the system comprising:

[0093] one or more position location sensors for generating position data related to the at least one rotor blade of the wind turbine;

[0094] a controller communicatively coupled to the one or more position location sensors, the controller configured to perform a plurality of operations, the plurality of operations comprising:

[0095] receiving the position data related to the at least one rotor blade of the wind turbine;

[0096] determining a blade pitch angle signal for the at least one rotor blade based on the position data; and

[0097] determining a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and the azimuth angle for the at least one rotor blade.

[0098] Clause 18. The system of clause 17, wherein the one or more position location sensors comprise one or more of: one or more Real Time Kinematic (RTK) sensors, one or more Inertial Navigation System (INS) sensors, one or more Global Positioning System (GPS) sensors, or a combination thereof.

[0099] Clause 19. The system of clauses 17-18, wherein the one or more position location sensors comprise one or more RTK sensors, the one or more RTK sensors comprising a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations mounted on the rotor blade.

[0100] Clause 20. The system of clause 19, wherein receiving the position data related to the rotor blade of the wind turbine further comprises:

[0101] receiving three-dimensional or two-dimensional position data related to a position of the base station, and

[0102] receiving three-dimensional or two-dimensional position data related to a position of each of the plurality of mobile stations.

[0103] This written description uses examples to disclose the application, including the best mode, and also to enable any person skilled in the art to practice the application, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the application is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method for controlling a pitch of at least one rotor blade of a wind turbine, the method comprising: receiving, via one or more position location sensors, position data related to at least one rotor blade of the wind turbine; determining, via a controller, a blade pitch angle signal for the at least one rotor blade based on the position data; and determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and an azimuth angle for the at least one rotor blade, wherein the one or more position location sensors comprise one or more RTK sensors, wherein the one or more RTK sensors comprise a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations mounted on the rotor blade.

2. The method of claim 1, wherein, The one or more position location sensors further comprise one or more INS sensors, one or more GPS sensors, or a combination thereof.

3. The method of claim 1, wherein, Receiving position data related to a rotor blade of the wind turbine further comprises: receiving, via the controller, three-dimensional or two-dimensional position data related to a location of the base station, and receiving, via the controller, three-dimensional or two-dimensional position data related to a location of each of the plurality of mobile stations.

4. The method of claim 1, wherein, Determining, via the computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and the azimuth angle further comprises: applying, via the controller, a d-q transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates; filtering the d-q coordinates; and reversing the d-q transformation to transform the filtered d-q coordinates into a pitch command for the at least one rotor blade.

5. The method of claim 4, wherein, Applying the d-q transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates further comprises: determining a blade bending moment for the at least one rotor blade using the blade pitch angle, and calculating the d-q coordinates as a function of the blade bending moment and the azimuth angle.

6. The method of claim 1, wherein, The method further comprises adding a collective pitch angle demand to the pitch command for the at least one rotor blade.

7. The method of claim 1, wherein, The wind turbine is part of a wind farm comprising a farm level controller and a plurality of wind turbines, the one or more position location sensors directly communicating with the farm level controller using a wireless communication system or an existing network of the wind farm.

8. The method of claim 1, wherein, The method further comprises adjusting the pitch command for the at least one rotor blade by a pitch angle offset to correct for a pitch deviation for the at least one rotor blade.

9. A method for correcting a pitch deviation of at least one rotor blade of a wind turbine, the method comprising: receiving, via a controller, a reference pitch angle for the at least one rotor blade; rotating the at least one rotor blade to a first pitch angle; receiving, via one or more position location sensors, position data related to the at least one rotor blade of the wind turbine at the first pitch angle; receiving, via the controller, three-dimensional or two-dimensional position data related to a location of the base station, and receiving, via the controller, three-dimensional or two-dimensional position data related to a location of each of the plurality of mobile stations. Determining, via the computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade pitch angle signal and the azimuth angle further comprises: applying, via the controller, a d-q transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates; filtering the d-q coordinates; and reversing the d-q transformation to transform the filtered d-q coordinates into a pitch command for the at least one rotor blade. Applying the d-q transformation to the blade pitch angle signal to transform the blade pitch angle signal into d-q coordinates further comprises: determining a blade bending moment for the at least one rotor blade using the blade pitch angle, and calculating the d-q coordinates as a function of the blade bending moment and the azimuth angle. The method further comprises adding a collective pitch angle demand to the pitch command for the at least one rotor blade. The wind turbine is part of a wind farm comprising a farm level controller and a plurality of wind turbines, the one or more position location sensors directly communicating with the farm level controller using a wireless communication system or an existing network of the wind farm. The method further comprises adjusting the pitch command for the at least one rotor blade by a pitch angle offset to correct for a pitch deviation for the at least one rotor blade. determining, via the controller, a pitch angle offset for the at least one rotor blade based on a difference between the reference pitch angle and the first pitch angle; and adjusting the first pitch angle of the at least one rotor blade by the pitch angle offset to correct for the pitch deviation.

10. The method of claim 9, wherein, The reference pitch angle and the first pitch angle include a reference pitch zero position and a first pitch zero position, respectively.

11. The method of claim 9, wherein, The position data includes a zero twist angle for the at least one rotor blade.

12. The method of claim 9, wherein, The one or more position location sensors include one or more RTK sensors, one or more INS sensors, one or more GPS sensors, or a combination thereof.

13. The method of claim 12, wherein, The one or more position location sensors include the one or more RTK sensors, the one or more RTK sensors including a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations mounted to the rotor blade.

14. The method of claim 9, wherein, The wind turbine includes an offshore wind turbine.

15. A system for controlling the pitch of at least one rotor blade of a wind turbine, the system comprising: one or more position location sensors for generating position data related to at least one rotor blade of the wind turbine; a controller communicatively coupled to the one or more position location sensors, the controller configured to perform a plurality of operations, the plurality of operations comprising: receiving position data related to at least one rotor blade of the wind turbine; determining a blade deflection signal for the at least one rotor blade based on the position data; and determining a pitch command for the at least one rotor blade as a function of the blade deflection signal and an azimuth angle for the at least one rotor blade, wherein the one or more position location sensors include one or more RTK sensors, wherein the one or more RTK sensors include a base station and a plurality of mobile stations communicatively coupled to the base station, the plurality of mobile stations mounted to the rotor blade.

16. The system of claim 15, wherein, The one or more position location sensors further include one or more INS sensors, one or more GPS sensors, or a combination thereof.

17. The system of claim 15, wherein, Receiving position data related to a rotor blade of the wind turbine further includes: receiving three-dimensional or two-dimensional position data related to a location of the base station, and receiving three-dimensional or two-dimensional position data related to a location of each of the plurality of mobile stations.

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