System and method for optimizing control of a wind turbine

Abstract

To provide a system and a method for optimizing control of a wind turbine.SOLUTION: The present disclosure relates to a method of optimizing control of a wind turbine comprising receiving, via a control system, a state of the wind turbine. The method also includes estimating a current condition of the wind turbine using the state. The method also includes computing, via a model implemented by the control system, a linearized representation of the operation of the wind turbine for a future time interval following the current condition. The method also includes defining an optimization problem to be solved. The method also includes determining a pitch adjustment factor for modifying a current state of the wind turbine. The method also includes calculating, via an optimization solver, an optimized pitch parameter of a rotor blade of the wind turbine. The method also includes adjusting a pitch parameter of the rotor blade to an optimized pitch parameter to improve control.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to wind turbines, and more particularly to systems and methods for optimizing control of wind turbines. [Background technology]

[0002] Wind power is considered one of the cleanest and most environmentally friendly energy sources currently available, and wind turbines have become a popular choice. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades are the primary components for converting wind energy into electrical energy. The blades typically have an airfoil cross-sectional profile such that, during operation, air flows over the blade, creating a pressure difference between the blade sides. As a result, a lift force acts on the blade from the pressure side to the suction side. The lift force generates a torque on the main rotor shaft, which is connected to a generator for generating electricity.

[0003] The amount of power that can be generated by a wind turbine is typically limited by the structural limitations (i.e., design loads) of the individual wind turbine components. For example, wind turbine blades may be subjected to loads associated with both average loads due to turbine operation and dynamically fluctuating loads due to environmental conditions. These loads may be affected by the blade pitch angle and other factors. Such loads may damage turbine components, such as pitch or yaw bearings, thereby causing turbine component failure. The fluctuating loads may change daily or seasonally and may be affected by wind speed, wind peaks, wind turbulence, wind shear, changes in wind direction, air density, bearing misalignment, updrafts, or similar conditions.

[0004] Therefore, it is an objective of wind turbine design to ensure that the loads acting on the turbine components do not exceed their design loads. Accordingly, many wind turbines utilize one or more sensors configured to measure the loads acting on various wind turbine components. Additionally, wind turbines may utilize control systems configured to estimate the loads acting on the wind turbine based on various factors.

[0005] Thus, the control system may operate in conjunction with sensors to estimate loads acting on wind turbine components and adjust operation of the wind turbine in response to the estimated loads. For example, the control system may command the wind turbine to adjust the pitch angle of the rotor blades or the rotor position of the wind turbine. These adjustments may be made to improve one or more conditions associated with the operation of the wind turbine. However, improving a first condition associated with the wind turbine may adversely affect another, second condition associated with the wind turbine. Furthermore, the control system may overcorrect or undercorrect operation of the wind turbine when attempting to optimize conditions associated with the operation of the wind turbine.

[0006] In view of the above, the art is continually seeking new and improved systems for optimizing wind turbine control, such as pitch control. Summary of the Invention

[0007] Aspects and advantages of the present invention will be set forth in part in the description that follows, or will be obvious from the description, or may be learned by practice of the invention.

[0008] In one aspect, the present disclosure relates to a method for optimizing control of a wind turbine. The method includes receiving, via a control system, at least one state of the wind turbine. The method also includes, via the control system, estimating a current situation of the wind turbine using the at least one state. The method also includes, via a model implemented by the control system, calculating a linearized representation of the operation of the wind turbine for a future time interval following the current situation. The method also includes, via the control system, defining an optimization problem to be solved, the optimization problem including a cost function and a pitch constraint. The method also includes, via the control system, determining a pitch adjustment factor to modify the current situation of the wind turbine, the pitch adjustment factor including at least one weight in the cost function that, when implemented, increases or decreases a behavior exhibited by the wind turbine, the cost function being implemented in an optimization solver implemented by the control system. The method also includes calculating, via an optimization solver implemented in the control system, an optimized pitch parameter of at least one rotor blade of the wind turbine from the linearized representation using the pitch adjustment factor and the pitch constraint, the optimized pitch parameter being a solution to the optimization problem. The method also includes adjusting the pitch parameter of the at least one rotor blade to the optimized pitch parameter such that the wind turbine exhibits increased or reduced behavior and improved control of the wind turbine.

[0009] In one embodiment of the method, the at least one condition includes a measurement of at least one of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural force or moment, structural displacement, structural velocity, or structural acceleration.

[0010] In one embodiment of the method, the current condition of the wind turbine includes instantaneous aerodynamic effects distributed over a portion of the wind turbine, the instantaneous aerodynamic effects including at least one of forces or moments acting on the portion of the wind turbine, or the current condition of the wind turbine includes instantaneous structural effects over the portion of the wind turbine, the instantaneous structural effects including at least one of structural displacements, structural velocities, or structural accelerations of any structural components of the wind turbine.

[0011] In one embodiment of the method, improving control of the wind turbine comprises reducing wind turbine load, improving bearing life, improving energy production, improving power quality, improving power tracking performance, or improving speed tracking performance.

[0012] In one embodiment of the method, the optimized pitch parameters include a pitch angle, a pitch rate, or a pitch acceleration trajectory of at least one rotor blade of the wind turbine.

[0013] In one embodiment of the method, the weight corresponds to a symmetric pitch motion of at least one rotor blade of the wind turbine.

[0014] In one embodiment of the method, the weight corresponds to an asymmetric pitch motion of at least one rotor blade of the wind turbine.

[0015] In one embodiment of the method, the weight corresponds to an amplitude of a harmonic higher than a fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade.

[0016] In one embodiment of the method, the at least one rotor blade includes a first rotor blade and a second rotor blade, and the pitch angle, pitch rate, or pitch acceleration of the first rotor blade includes a higher frequency than the pitch angle, pitch rate, or pitch acceleration of the second rotor blade, and a weight is applied to the pitch angle, pitch rate, or pitch acceleration of the first rotor blade such that amplitudes of harmonics higher than a fundamental frequency of the pitch angle, pitch rate, or pitch acceleration are reduced.

[0017] In one embodiment of the method, the pitch adjustment factor includes one of a linear term or a quadratic term at a future time interval, the pitch constraint includes a linear constraint or a quadratic constraint at a future time interval, or the pitch adjustment factor includes a variance or tracking of a pitch angle, pitch rate, or pitch acceleration of at least one rotor blade.

[0018] In one embodiment of the method, the pitch constraint corresponds to a maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, or the pitch constraint corresponds to a maximum or minimum allowable pitch motor torque, current, voltage, or power.

[0019] In one embodiment of the method, the pitch constraint further comprises an increase or decrease in a maximum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, or a decrease or increase in a minimum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, wherein the increase or decrease in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at a future time interval in response to the received at least one condition; or the pitch constraint further comprises an increase or decrease in a maximum allowable pitch motor torque, current, voltage, or power, or a decrease or increase in a minimum allowable pitch motor torque, current, voltage, or power, wherein the decrease or increase in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at a future time interval in response to the received at least one condition.

[0020] In one embodiment of the method, the pitch adjust factors include two or more pitch adjust factors, and an optimized pitch parameter of the at least one rotor blade is calculated using the two or more pitch adjust factors and the pitch constraint.

[0021] In one embodiment of the method, the pitch adjustment factor includes one or more penalties for a total pitch angle change of the at least one rotor blade or a penalty for a product of the pitch movement of the at least one rotor blade and a magnitude of a load on the at least one rotor blade.

[0022] In one embodiment, the method further comprises calculating, via an optimization solver implemented in the control system, an optimized torque of the rotor of the wind turbine from the linearized representation using the pitch adjustment factor and the pitch constraint, and adjusting the torque of the rotor to the optimized torque such that the wind turbine exhibits increased or reduced behavior and improves control of the wind turbine.

[0023] In another aspect, the present disclosure relates to a system for optimizing control of a wind turbine. The system includes at least one sensor configured to monitor at least one state of the wind turbine. The system also includes a control system configured to receive the at least one state of the wind turbine. The control system is also configured, via the control system, to estimate a current situation of the wind turbine using the at least one state. The control system is also configured, via a model implemented by the control system, to calculate a linearized representation of the operation of the wind turbine for a future time interval following the current situation. The control system is also configured, via the control system, to define an optimization problem to be solved, the optimization problem including a cost function and a pitch constraint. The control system is also configured, via the control system, to determine a pitch adjustment factor to modify the current situation of the wind turbine, the pitch adjustment factor including at least one weight in a cost function that, when implemented, increases or decreases a behavior exhibited by the wind turbine, the cost function being implemented in an optimization solver implemented by the control system. The control system is also configured to calculate, via an optimization solver implemented in the control system, an optimized pitch parameter of at least one rotor blade of the wind turbine from the linearized representation using the pitch adjustment factor and the pitch constraint, the optimized pitch parameter being a solution to the optimization problem, and adjust the pitch parameter of the at least one rotor blade to the optimized pitch parameter such that the behavior exhibited by the wind turbine is increased or reduced, resulting in improved control of the wind turbine.

[0024] These and other features, aspects, and advantages of the present invention will be best understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0025] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in this specification, which references the accompanying drawings, in which: [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view of an embodiment of a wind turbine according to the present disclosure; FIG. [Figure 2] 1 is a simplified internal view of an embodiment of a nacelle of a wind turbine according to the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of one embodiment of a controller according to the present disclosure. [Figure 4] 1 is a simplified diagram of one embodiment of a control system for a wind turbine according to the present disclosure. [Figure 5] 1 is a perspective view of one embodiment of a wind turbine according to the present disclosure, particularly illustrating various axes of rotation and corresponding structural forces and moments acting on the wind turbine; FIG. [Figure 6] FIG. 1 illustrates a flowchart of an embodiment of a method for optimizing control of a wind turbine according to the present disclosure. [Figure 7] FIG. 1 illustrates a graph of one embodiment of a current situation being estimated from the state of a wind turbine and a linearized representation of the wind turbine's operation being calculated for a future time interval following the current situation, in accordance with the present disclosure. [Figure 8] FIG. 1 illustrates a graph of one embodiment of a multi-objective model for determining optimized pitch parameters of a wind turbine according to the present disclosure. [Figure 9A] FIG. 10 illustrates a graph of the effect of adjusting pitch parameters of a wind turbine rotor blade to optimized pitch parameters using weights corresponding to symmetric or asymmetric pitch motion in accordance with the present disclosure. [Figure 9B] FIG. 10 illustrates a graph of the effect of adjusting pitch parameters of a wind turbine rotor blade to optimized pitch parameters using weights corresponding to symmetric or asymmetric pitch motion in accordance with the present disclosure. [Figure 10A] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters using weights corresponding to amplitudes of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of rotor blades of a wind turbine in accordance with the present disclosure. [Figure 10B] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters using weights corresponding to amplitudes of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of rotor blades of a wind turbine in accordance with the present disclosure. [Figure 10C] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters using weights corresponding to amplitudes of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of rotor blades of a wind turbine in accordance with the present disclosure. [Figure 10D] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters using weights corresponding to amplitudes of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of rotor blades of a wind turbine in accordance with the present disclosure. [Figure 11A] FIG. 10 illustrates a graph of a pitch adjustment factor being applied in response to a peak load interval in accordance with the present disclosure. [Figure 11B] FIG. 10 illustrates a graph of a pitch adjustment factor being applied in response to a peak load interval in accordance with the present disclosure. [Figure 12A] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters in accordance with the present disclosure. [Figure 12B] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters in accordance with the present disclosure. [Figure 12C] FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters in accordance with the present disclosure. [Figure 12D]FIG. 10 illustrates a graph of the effect of adjusting rotor blade pitch parameters to optimized pitch parameters in accordance with the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0027] Reference will now be made in detail to the embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is presented as an illustration of the invention, not as a limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used in another embodiment to yield yet a further embodiment. It is therefore intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0028] Generally, the present disclosure relates to improved systems and methods for optimizing control of a wind turbine, such as pitch control. More specifically, the systems and methods of the present disclosure use a control system that receives one or more states of a wind turbine. These states may be received at various time intervals. These states may also be related to the pitch of the wind turbine. The control system then uses the states to estimate a current condition of the wind turbine. The control system then implements a model that uses the current condition of the wind turbine to calculate a predicted condition of the wind turbine for a future time interval. The control system then defines an optimization problem to be solved, including a pitch adjustment factor and a pitch constraint. Through solving the optimization problem, optimized pitch parameters may be determined that, when implemented by the control system of the wind turbine, may improve control of the wind turbine and increase or decrease the behavior exhibited by the wind turbine.

[0029] Once the optimization problem is defined, the control system determines pitch adjustment factors to modify the current state of the wind turbine by finding weights for a cost function that is implemented in an optimization solver programmed within the control system. The optimization solver is then implemented to calculate optimized pitch parameters for the wind turbine's rotor blades from the linearized representation using the pitch adjustment factors and the pitch constraints, the optimized pitch parameters being the solution to the optimization problem. The control system is then utilized to adjust the rotor blade pitch parameters to the optimized pitch parameters such that the behavior exhibited by the wind turbine is increased or decreased, resulting in improved control of the wind turbine. As a result, improved control of the wind turbine may be achieved, as evidenced by the realization of various objectives.

[0030] Thus, the systems and methods of the present disclosure provide a framework through which control of a wind turbine may be periodically updated and optimized to be consistent with operator-determined goals, which may include at least one or more of reducing loads acting on the wind turbine, improving pitch bearing life, and / or improving energy production.

[0031] Referring now to FIG. 1 , a perspective view of one embodiment of a wind turbine 10 is shown that may implement control techniques according to the present disclosure. As shown, the wind turbine 10 generally includes a tower 12 extending from a support surface 14, a nacelle 16 mounted to 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 outward 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 may include more or fewer than three rotor blades 22. Each rotor blade 22 may be spaced about the hub 20 to facilitate rotation of the rotor 18, such that kinetic energy may be converted from the wind into usable mechanical energy and, subsequently, electrical energy. For example, the hub 20 may be rotatably coupled to a generator 24 ( FIG. 2 ) disposed within the nacelle 16 to enable the generation of electrical energy.

[0032] The wind turbine 10 may also include a wind turbine control system 26 centralized within the nacelle 16. However, in other embodiments, the control system 26 may be located within any other component of the wind turbine 10 or at a location external to the wind turbine 10. Furthermore, the control system 26 may be communicatively coupled to any number of components of the wind turbine 10 to control the operation of such components and / or implement corrective actions. Accordingly, the control system 26 may include a computer or other suitable processing unit. Accordingly, in some embodiments, the control system 26 may include suitable computer-readable instructions that, when implemented, configure the control system 26 to perform various functions, such as receiving, transmitting, and / or executing wind turbine control signals. Accordingly, the control system 26 may be generally configured to control various operating modes (e.g., a start-up sequence or a shutdown sequence), slow down the wind turbine, and / or control various components of the wind turbine 10, as described in more detail below.

[0033] Referring now to FIG. 2 , a simplified internal view of one embodiment of the nacelle 16 of the wind turbine 10 shown in FIG. 1 is shown. As shown, a generator 24 may be coupled to the rotor 18 to generate electrical power from the rotational energy generated by the rotor 18. For example, as shown in the illustrated embodiment, the rotor 18 may include a rotor shaft 34 coupled to the hub 20 for rotation therewith. The rotor shaft 34 may in turn be rotatably coupled to a generator shaft 36 of the generator 24 through a gearbox 38. As commonly understood, the rotor shaft 34 may provide a low-speed, high-torque input to the gearbox 38 in response to rotation of the rotor blades 22 and the hub 20. The gearbox 38 may then be configured to convert the low-speed, high-torque input to a high-speed, low-torque output to drive the generator shaft 36 and, therefore, the generator 24.

[0034] Each rotor blade 22 may also include a pitch adjustment mechanism 32 configured to rotate each rotor blade 22 about its pitch axis 28. Further, each pitch adjustment mechanism 32 may include a pitch drive motor 40 (e.g., any suitable electric, hydraulic, or pneumatic motor), a pitch drive gearbox 42, and a pitch drive pinion 44. The pitch drive motor 40 is coupled to the pitch drive gearbox 42 such that the pitch drive motor 40 provides mechanical power to the pitch drive gearbox 42. Similarly, the pitch drive gearbox 42 may be coupled to the pitch drive pinion 44 for rotation therewith. The pitch drive pinion 44 may then be rotationally engaged with a pitch bearing 46 coupled between the hub 20 and the corresponding rotor blade 22 such that rotation of the pitch drive pinion 44 causes rotation of the pitch bearing 46. Thus, in such an embodiment, rotation of pitch drive motor 40 drives pitch drive gearbox 42 and pitch drive pinion 44, thereby rotating pitch bearing 46 and rotor blades 22 about pitch axis 28. Similarly, wind turbine 10 may include one or more yaw drive mechanisms 66 communicatively coupled to control system 26, each yaw drive mechanism 66 configured to change the angle of nacelle 16 relative to the wind (e.g., by engaging a yaw bearing 68 of wind turbine 10).

[0035] 2 , wind turbine 10 may also include one or more sensors 48, 50 for measuring various operating conditions that may be used to determine the operating status of wind turbine 10, as described in detail below. For example, in various embodiments, the sensors may include a blade sensor 48 for measuring the pitch angle, pitch rate, or pitch acceleration of one of the rotor blades 22, for measuring loads acting on one of the rotor blades 22, or for measuring the rotor speed of rotor 18. The sensors may also include a generator sensor (not shown) for monitoring generator 24 (e.g., torque, rotational speed, acceleration, and / or power output), a sensor (not shown) for measuring unbalanced loads in the rotor (e.g., main shaft bending sensor), various wind sensors 50 for measuring various wind conditions such as wind speed, wind peak, wind turbulence, wind shear, wind direction changes, or air density, and / or sensors (not shown) for measuring structural forces or moments, structural displacements, structural velocities, or structural accelerations experienced by or exerted on wind turbine 10.

[0036] Additionally, sensors may be located near the ground of the wind turbine, on the nacelle, or on the wind turbine's weather mast. It should also be understood that any other number or type of sensors may be utilized at any location. For example, the sensors may be micro inertial measurement units (MIMUs), strain gauges, accelerometers, pressure sensors, angle-of-attack sensors, vibration sensors, proximity sensors, light detection and ranging (LIDAR) sensors, camera systems, fiber optic systems, anemometers, wind vanes, sound detection and ranging (SODAR) sensors, infrared lasers, radiometers, pitot tubes, radiosondes, other optical sensors, and / or any other suitable sensors. As used herein, it should also be understood that the term "monitor" and variations thereof indicate that various sensors may be configured to provide direct measurements of the condition being monitored or indirect measurements of such condition. Thus, the sensors may be used, for example, to generate signals related to the condition being monitored, which may then be utilized by control system 26 to determine the actual condition.

[0037] Referring now to FIG. 3 , a block diagram of one embodiment of various components of the control system 26 according to the present disclosure is shown. For example, as shown, the control system 26 may include one or more processors 58 and associated memory devices 60 configured to perform various computer-implemented functions (e.g., performing methods, steps, calculations, etc., and storing associated data as disclosed herein). Additionally, the control system 26 may also include a communications module 62 to facilitate communication between the control system 26 and the various components of the wind turbine 10. Furthermore, the communications module 62 may include a sensor interface 64 (e.g., one or more analog-to-digital converters) that enable signals transmitted from the sensors 48, 50 to be converted into signals that can be understood and processed by the processor 58. It should be understood that the sensors 48, 50, or any other sensors monitoring the wind turbine 10, may be communicatively coupled to the communications module 62 using any suitable means. For example, as shown in FIG. 3 , the sensors 48, 50 are coupled to the sensor interface 64 via a wired connection. However, in other embodiments, the sensors 48, 50 may be coupled to the sensor interface 64 via a wireless connection, such as by using any suitable wireless communication protocol known in the art.

[0038] 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 to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuitry. Furthermore, memory device 60 may generally include memory elements including, but not limited to, computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disk read-only memories (CD-ROMs), magneto-optical disks (MODs), digital versatile disks (DVDs), and / or other suitable memory elements. Such memory device 60 may generally be configured to store suitable computer-readable instructions that, when executed by processor 58, configure control system 26 to perform various functions, including, but not limited to, determining one or more current wind turbine conditions of wind turbine 10 based on a plurality of operational data, determining maximum wind turbine conditions, and transmitting appropriate control signals to implement control actions to reduce loads acting on the wind turbine, as well as various other suitable computer-implemented functions.

[0039] As described, control system 26 may be capable of implementing various methods of processing and control. For example, with particular reference to FIG. 4 , control system 26 may be a model predictive control (MPC) system that may implement an MPC framework 70. The MPC framework may be any MPC system understood in the art. MPC framework 70 may also utilize any algorithm, rule, or code, such as machine learning or artificial intelligence.

[0040] As shown, the MPC framework 70 may generally include an estimation module 72, a simulation module 74, an optimization module 76, and an adjustment module 78. The estimation module 72 is configured to receive at least one state of the wind turbine 10 and estimate a current situation of the wind turbine 10 using the state. The simulation module 74 is configured to implement a model for calculating a predicted situation of the wind turbine 10, the model defining a future time interval following the current situation. As described, the "future time interval" may be any time in the future that the control system 26 may predict, i.e., a prediction period. For example, the future time interval may be approximately 0.001 to 11 seconds, such as approximately 0.01 to 10 seconds, or approximately 1 to 9 seconds.

[0041] The optimization module 76 is configured to define an optimization problem to be solved, including a pitch adjustment factor and a pitch constraint. The optimization module 76 is also configured to determine a pitch adjustment factor to modify a current state of the wind turbine. The optimization module is also configured to implement an optimization solver to solve the optimization problem and calculate optimized pitch parameters of the wind turbine 10. As described further herein, the pitch parameters are any state associated with a pitch system, such as the pitch drive mechanism 32 of the wind turbine 10. For example, in one embodiment, the pitch parameters may be a pitch trajectory, a pitch angle of at least one rotor blade 22, a pitch rate of at least one rotor blade 22, and / or a pitch acceleration of at least one rotor blade 22.

[0042] Once the optimized pitch parameter is determined, control system 26 may adjust the pitch parameter of at least one rotor blade 22 to the optimized pitch parameter to optimize control of wind turbine 10 and / or increase or decrease the behavior exhibited by wind turbine 10. Either before or after the pitch parameter is adjusted, adjustment module 78 is configured to further calculate a predicted state of wind turbine 10 that takes into account the adjustment of the pitch parameter and is representative of the operation of wind turbine 10 in a future time interval.

[0043] Thus, as described, the MPC framework 70 is configured to handle multiple factors within a predictive framework. Specifically, as relevant to this disclosure, the MPC framework 70 can manage input constraints, structural loads, and / or operability constraints while optimizing the operation of the wind turbine 10, as described in detail herein. Furthermore, the MPC framework 70 is configured to provide a single multiple-input, multiple-output (MIMO) formulation that can unify performance and constraint objectives. Thus, the MPC framework 70 can avoid the need for complex interactions of multiple single-input, single-output (SISO) control functions traditionally used to address wind turbine control design when multiple objectives are considered.

[0044] 5, an exploded view of one embodiment of wind turbine 10 is shown, particularly illustrating the various axes of rotation and the corresponding structural forces and moments acting on wind turbine 10. The forces acting on wind turbine 10 may vary between wind turbines, but generally include the following: distributed forces from the wind, which are traditionally decomposed into lift and drag components; gravity; and blade root resultant forces (e.g., F rB ), pitch force and hub force (F xB , F yb , F zb ), main shaft force (e.g., F yr , F zr ), main bearing force (e.g., F xr , F yr ), yaw driving force (e.g., F xk), yaw bolt / bearing / flange force (e.g., F yk , F zk ), or tower bending force (e.g., F xt , F yt , and F zt ) Moment loads may also be exerted on the wind turbine 10 as a result of forces acting on the wind turbine 10 at various locations and various structural components throughout the profile of the wind turbine 10.

[0045] Similar to the forces acting on the wind turbine 10, the moment loads acting on the wind turbine 10 may vary from turbine to turbine, but generally include the following: moments generated by distributed aerodynamic forces and gravity, blade root resultant moment loads (e.g., M rB ), pitch and hub moment load (M xB , M yb , and M zb ), main shaft moment load (e.g., M yr , M zr ), main bearing moment load (e.g., M xr , M yr ), yaw drive moment load (e.g., M xk ), yaw bolt / bearing / flange moment load (e.g., M yk , M zk ), or tower bending moment load (e.g., M xt , M yt , and M zt ) It should be understood that the force and moment loads described herein may include any additional force or moment loads experienced by the wind turbine 10, and that the force and moment loads shown in FIG. 4 are provided for illustrative purposes only.

[0046] Referring now to FIG. 6 , a flow diagram of one embodiment of a method 100 for optimizing pitch control of a wind turbine according to the present disclosure is shown. In one embodiment, for example, pitch control may be optimized by using, for example, the control system 26 with one or more of the rotor blades 22, pitch bearings 46, and / or hub 20 of the wind turbine 10. The method 100 is described herein as being implemented using, for example, the wind turbine 10 described above. However, it should be understood that the disclosed method 100 may be implemented using any other suitable wind turbine now known in the art or later developed. In addition, while FIG. 6 depicts steps performed in a particular order for purposes of illustration and description, the methods discussed herein are not limited to any particular order or arrangement. Those skilled in the art will understand, using the disclosure provided herein, that various steps of the method may be omitted, rearranged, combined, and / or adapted in various ways.

[0047] As shown at (102), method 100 includes receiving at least one condition of wind turbine 10 via control system 26. For example, in one embodiment, the condition may be one or more of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural forces or moments, structural displacements, structural velocities, structural accelerations, etc. Such conditions may be detected by sensors 48, 50 with wind turbine 10 or any other sensors communicatively coupled to wind turbine 10. The conditions may also be detected using sensors (not shown) external to wind turbine 10.

[0048] As shown at (104), method 100 includes estimating, via control system 26, a current condition of wind turbine 10 using the state. For example, in one embodiment, the current condition of wind turbine 10 may include instantaneous aerodynamic effects distributed across a portion of wind turbine 10, such as at least one of rotor blades 22. Specifically, the instantaneous aerodynamic effects may include a blade root resultant force (e.g., F rB ), pitch and hub force (FxB , F yb , and F zb ), blade root resultant moment load (e.g., M rB ), or pitch and hub moment loads (M xB , M yb , and M zb ), and the aforementioned force and moment loads. The instantaneous aerodynamic effect may be calculated from the pitch of each of the rotor blades 22 of the wind turbine 10 and the torque exerted on the rotor blades 22, as well as wind forces acting on the wind turbine 10, such as wind speed, wind direction, vertical shear, horizontal shear, wind deviation, or turbulence. However, if the wind forces cannot be determined (e.g., due to a lack of sensors), the wind forces may be estimated for purposes of calculating the instantaneous aerodynamic effect.

[0049] The current condition of the wind turbine 10 may also include instantaneous structural effects across a portion of the wind turbine 10, such as the tower 12 or the nacelle 16. Specifically, the instantaneous structural effects may include at least one of structural displacements, structural velocities, or structural accelerations of any structural components of the wind turbine 10. For example, the instantaneous structural effects may include main shaft forces (e.g., F yr , F zr ), main bearing force (e.g., F xr , F yr ), yaw driving force (e.g., F xk ), yaw bolt / bearing / flange force (e.g., F yk , F zk ), tower bending force (e.g., F xt , F yt , and F zt ), main shaft moment load (e.g., M yr , M zr ), main bearing moment load (e.g., M xr , M yr ), yaw drive moment load (e.g., M xk ), yaw bolt / bearing / flange moment load (e.g., M yk , M zk ), or tower bending moment load (e.g., M xt , M yt , and M zt) The instantaneous structural effects may be calculated from the pitch of each of the rotor blades 22 of the wind turbine 10 and the torque exerted on the rotor blades 22, as well as wind forces acting on the wind turbine 10, such as wind speed, wind direction, vertical shear, horizontal shear, wind deviation, or turbulence. Also, similar to the instantaneous aerodynamic effects, if the wind forces cannot be determined (e.g., due to a lack of sensors) for purposes of calculating the instantaneous aerodynamic effects, the wind forces of the instantaneous structural effects may be estimated.

[0050] As shown in (106), method 100 includes calculating, via a model implemented by control system 26, a linearized representation of the operation of wind turbine 10 for a future time interval following a current situation. In particular, the linearized representation of the operation of wind turbine 10 for the future time interval may define a predicted situation of wind turbine 10. Furthermore, the predicted situation may be defined as a set of magnitudes that fully characterize the dynamics of wind turbine 10 (represented by the model). In particular, as shown in FIG. 7 , a current situation 200 of wind turbine 10 may be received by control system 26. Thus, control system 26 can simulate a predicted situation 202 using current situation 200 for a future time interval of wind turbine 10. For example, predicted situation 202 may be calculated from an input trajectory u* and the current situation 200. The input trajectory u* may be provided for any time interval to be simulated, such as a time interval observable by control system 26 as described above with reference to a future time interval.

[0051] The input trajectory u* may include predictions of coefficients used to calculate the instantaneous aerodynamic or structural effects acting on the wind turbine 10 (i.e., the pitch of each of the rotor blades 22 of the wind turbine 10 and the torque exerted on the rotor by the generator, as well as wind forces acting on the wind turbine 10, such as wind speed, wind direction, vertical shear, horizontal shear, wind deviation, or turbulence). However, if the wind forces cannot be determined (e.g., due to a lack of sensors), the wind forces may be estimated to set the input trajectory u* to the instantaneous aerodynamic or structural effects. However, if the wind forces are estimated, that estimate is used for each time interval for which the input trajectory u* is provided. Furthermore, as the predicted situation 202 progresses in time, one or more input trajectories u* from previous optimization instances in time are used along with the input trajectory u* for the time instance being simulated to provide an output for the predicted situation 202 at the new time instance. These sets of input trajectories u* provided with the current situation 200 can then be used to calculate further predicted situations 202, as represented by the plot shown in FIG. 7.

[0052] Additionally, as described above, one or more linearized representations of the operation of wind turbine 10 may also be provided. The linearized representation may be determined at a sample time interval, such as time interval 204. However, the linearized representation may be provided at any point in time during forecasted condition 202. The linearized representation may be one or more matrices that represent the expected behavior of wind turbine 10 for a particular period of time prior to when the linearized representation is initially determined (i.e., a future time interval), such as time interval 204. Once determined, the linearized representation may be collected and used within the model to implement subsequent functions or calculations, as described below.

[0053] In an alternative embodiment, the linearization process can be achieved without the need to simulate the model. If the optimization problem used in the predictive controller is a nonlinear programming problem (NLP), the model can be linearized not only immediately before running the optimization solver, but also during the optimization process. To accelerate convergence, the NLP solver algorithm may need to linearize the model at every solver iteration.

[0054] 6, as shown at (108), the method 100 further includes defining an optimization problem to be solved via the control system. The optimization problem may include a cost function and a pitch constraint. In one embodiment, the cost function may be Equation (1) shown below:

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[0055] The solution of the optimization problem, described in detail below, may include finding particular weights and slack variables corresponding to the pitch constraint that minimize the output J of the cost function. Furthermore, the cost function may be implemented in an optimization solver implemented by the control system 26. The optimization solver may be any type of algorithm, program, or software, such as the optimization module 76, that determines values ​​that result in minimizing the output of the cost function. The pitch constraint, described in detail below, may be any statement that, when implemented, sets maximum or minimum values ​​for the pitch of the rotor blades 22 of the wind turbine 10 when input into a model implemented by the control system 26. These maximum or minimum values ​​may be absolute values ​​or values ​​that are adapted to change based on real-time data analysis.

[0056] As shown in (110), method 100 further includes determining, via control system 26, a pitch adjustment factor for modifying the current condition of wind turbine 10. The pitch adjustment factor may be an algorithm, formula, or rule that, when input into a model implemented by control system 26, promotes or inhibits results related to pitch control of wind turbine 10. For example, the pitch adjustment factor may include one or more weights in a cost function (i.e., equation (1)) that, when implemented, increases or decreases the behavior exhibited by the wind turbine. The pitch adjustment factor may also include terms in the cost function, such as performance signals and reference signals, or results derived from the use of performance signals and reference signals; these terms may be relevant to controlling factors such as whether symmetric or asymmetric pitch is implemented, or whether harmonic activity is reduced. As related to equation (1), the pitch adjustment factor, when utilized, may result in minimizing the output J of the cost function.

[0057] Multiple pitch adjustment factors, such as two or more pitch adjustment factors, may be determined, which together may promote or inhibit a result or results related to pitch control of wind turbine 10. For example, referring now to FIG. 8 , a graph of one embodiment of a multi-objective model for determining an optimized regime 308 for wind turbine 10 is shown in accordance with the present disclosure. Operating wind turbine 10 at optimized regime 308 may be achieved by providing optimized pitch parameters, as described in more detail below. In general, the optimized regime may represent improved control of wind turbine 10 or reduced behavior exhibited by the wind turbine.

[0058] As shown in FIG. 8 , the results or outputs of the multi-objective model 300 are provided along the axes of the multi-objective model 300. Specifically, a first possible output shown on the x-axis 302 is optimizing the annual energy production (AEP) of the wind turbine 10, i.e., increasing the AEP of the wind turbine. A second possible output shown on the y-axis 304 is optimizing the load acting on the wind turbine 10, i.e., reducing the total load acting on the wind turbine 10. As explained, the load being optimized can be any load acting on the wind turbine 10, such as a fatigue load or an extreme / peak load. A third possible output shown on the z-axis 306 is optimizing the bearing life utilization (BLU), i.e., improving the bearing life of the wind turbine 10 by reducing the bearing life utilization.

[0059] Thus, as shown, the optimized pitch parameter state 308 may result in a reduction in load acting on the wind turbine 10, a reduction in bearing life utilization (such as that of the pitch bearings 46), and / or an increase in AEP. Specifically, a single output may be achieved while mitigating detrimental effects by de-emphasizing other outputs. Such outputs may be readily observed relative to a starting point 314. For example, as shown at point 316, the control system 26 may facilitate a maximum reduction in bearing life utilization while maintaining the AEP relative to point 314. At point 312, a maximum increase in AEP may be achieved while mitigating the total bearing life utilization required for such an increase relative to point 314. At point 310, the load may be minimized while maintaining the AEP relative to point 314. In addition to reducing the load, reducing the bearing life utilization, or improving energy production, the use of a pitch adjustment factor may also result in improved power quality (i.e., reduced levels of power oscillation or harmonics), improved power tracking performance, or improved speed tracking performance. Each of these improvements to the control of wind turbine 10 may be achieved through the use of the pitch adjustment factors and pitch constraints described herein.

[0060] For example, in one embodiment, the pitch adjustment factor may be a weighting for symmetric or asymmetric pitch activity. As explained, symmetric or collective pitch is defined as when all rotor blades 22 have the same pitch motion. In contrast, asymmetric or cyclic pitch is when rotor blades 22 have different pitch motions from one another. Symmetric pitch activity may be controlled through the use of the following equations (2)-(4), respectively:

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[0061] As shown, increasing the weighting factor W may reduce the symmetric pitch activity of the wind turbine 10. Conversely, decreasing the weighting factor W may increase the symmetric pitch activity of the wind turbine 10.

[0062] In contrast to the symmetric pitch control afforded by equations (2)-(4), asymmetric pitch activity can be controlled through the use of the following equations (5)-(7), respectively:

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[0063] As shown, increasing the weighting factor W may reduce the asymmetric pitch activity of the wind turbine 10. Conversely, decreasing the weighting factor W may increase the asymmetric pitch activity of the wind turbine 10.

[0064] 9A and 9B, graphs illustrating the effect of pitch adjustment factors being applied to provide asymmetric and symmetric pitch are shown. As shown in FIG. 9A, a plot 400 of the pitch of each rotor blade 402, 404, and 406 is shown. As shown in FIG. 9B, a plot 450 of the loads applied to the same rotor blades 402, 404, and 406 is shown. In particular, in FIG. 9A, the pitch of each rotor blade 402, 404, and 406 is shown on the y-axis 408 and plotted along with applied time on the x-axis 410 of plot 400. In FIG. 9B, the loads applied to each rotor blade 402, 404, and 406 are shown on the y-axis 452 and plotted along the same time as in FIG. 9A, shown along the x-axis 454 of plot 450.

[0065] Further, as shown in FIG. 9B , the loads on rotor blades 402, 404, and 406 are shown as exceeding threshold value 456 in box 458. To address this, control system 26 may activate asymmetric or periodic pitching of rotor blades 402, 404, and 406, as shown in box 412 of FIG. 9A . Specifically, activating asymmetric or periodic pitching results in a reduction in weight W given by equations (5)-(7). This results in a difference in pitch angle between rotor blades 402, 404, and 406, which causes rotor blades 402, 404, and 406 to operate out of phase with one another, as shown in box 412. As a result of this difference in pitch between rotor blades 402, 404, and 406, the loads on rotor blades 402, 404, and 406 decrease below threshold value 456, as shown in box 460. Thus, loads can be reduced through the use of asymmetric or periodic pitch, which results in an increase in the difference in pitch angles between rotor blades 402, 404, and 406. Furthermore, as shown in FIGS. 9A and 9B, once the load on rotor blades 402, 404, and 406 falls below threshold 456, symmetric pitch can be utilized, as shown in box 414. Because load reduction is achieved with asymmetric pitch, this strategy results in additional power production beyond the standard approach of handling blade loads through an increase in collective pitch. In this manner, an appropriate combination of weights in symmetric and asymmetric pitch can achieve the desired behavior of utilizing periodic pitch when load reduction is important and using symmetric pitch otherwise.

[0066] Thus, through the use of weights W in equations (2)-(7), it is feasible to fine-tune the pitch parameters of the wind turbine 10 and rotor blades 22 so that an optimal trade-off between load alleviation, BLU savings, and energy production is achieved. Specifically, through the use of these increases or decreases in the cost function, optimal utilization of collective or asymmetric pitch behavior can be achieved to address any particular load constraint. Further customization can be achieved by scheduling the weighting factors according to several operating parameters, such as wind speed or wind turbulence intensity.

[0067] In another embodiment, the pitch adjustment factor may correspond to the amplitude of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration. Specifically, the pitch adjustment factor may be a weight that, when applied, reduces the amplitude of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration. For example, the harmonics may be controlled through the use of the following equation (8):

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[0068] By providing weighting that reduces the amplitude of harmonics higher than the fundamental frequency, higher harmonics exhibited by the rotor blades 22 of the wind turbine 10 may be reduced or completely eliminated. If desired, weighting may be applied to all rotor blades 22. Alternatively, if a particular rotor blade 22 operates at a higher frequency due to its pitch angle, pitch rate, or pitch acceleration when compared to a second rotor blade 22, the higher frequency may be utilized to provide a reduction for that particular rotor blade 22.

[0069] In one embodiment, when high harmonics of pitch activity are utilized that may drive excessive BLU, the weight W s and W c Appropriate selection of W allows for the penalization of specific Fourier components of the pitch trajectory, which are relevant for pitch bearing life management. Specifically, the weights W s and W c Increasing W can reduce the amplitude of higher order harmonics. Thus, pitch bearing life can be improved through the selection of a pitch adjustment factor that reduces the amplitude of harmonics higher than the fundamental frequency of the pitch angle, pitch rate, or pitch acceleration. For example, if a user wants to remove harmonic components from the pitch trajectory, the user can adjust the weight W s and W c Equation (8) may be utilized to penalize these higher order harmonics by increasing

[0070] 10A-10D, various graphs are shown illustrating the effectiveness of Equation (8) in discerning the higher harmonic content of a pitch signal. FIG. 10A shows a plot 500 illustrating the fundamental frequency of a high-frequency signal 502 and a low-frequency signal 504 for a pitch angle, pitch rate, or pitch acceleration of one or more of the rotor blades 22, while FIG. 10B-10D show plots 520, 540, and 560 illustrating the first, second, and third harmonics of the fundamental frequency of the high-frequency signal 502 and the low-frequency signal 504. Specifically, for each of the plots 500, 520, 540, and 560 shown in FIG. 10A-10D, the y-axis 506 is the pitch angle of one or more of the rotor blades 22, while the x-axis 508 is the phase of one or more of the rotor blades 22.

[0071] Furthermore, as shown, plots 520, 540, and 560 in FIGS. 10B-10D illustrate that equation (8) applies to the first, second, and third harmonics of the two signals 502 and 504. Specifically, as shown, the application of equation (8) to the first harmonic is low. Furthermore, for the first harmonic shown in plot 520 of FIG. 10B, the penalty is equal or nearly the same for the high-frequency signal 502 and the low-frequency signal 504. However, as shown in plots 540 and 560 of FIGS. 10C-10D, the second and third harmonics are substantially zero for the low-frequency signal 504, while they are high for the high-frequency signal 502. Therefore, the weight W in equation (8) s and W c It can be seen that through the selection of , the high order harmonics of the high frequency signal can be reduced or completely eliminated. Thus, the high order harmonics of the high frequency signal can be reduced, and as a result, the pitch bearing life of the wind turbine 10 can be improved.

[0072] In another embodiment, the pitch adjustment factor may be a linear or quadratic penalty term at the future time interval. For example, a linear penalty term may be provided at the future time interval through use of Equation (9) below:

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[0073] Additionally, a quadratic penalty term can be provided at future time intervals through the use of equation (10) below:

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[0074] Both linear and quadratic penalty terms may be applied at any time interval for future time intervals. For example, a penalty term may be applied at sample time 204 (FIG. 7). Furthermore, the linear and quadratic penalty terms may vary over multiple time intervals. However, although the term "penalty" is used, it should be understood that a corresponding reward may also be utilized that encourages the wind turbine 10 to exhibit more activity or increases the behavior exhibited by the wind turbine 10.

[0075] In another embodiment, the pitch constraint may be a linear or quadratic constraint in the future time interval. For example, a linear constraint may be provided in the future time interval through use of Equation (11) below:

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[0076] Furthermore, a quadratic constraint can be provided at future time intervals through the use of equation (12) below.

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[0077] Like the penalty terms, the linear and quadratic constraints may also be applied at multiple future time intervals and may vary over multiple future time intervals.

[0078] In another embodiment, the pitch adjustment factor may also include a variance or tracking of the pitch angle, pitch rate, or pitch acceleration of one or more of the rotor blades 22 .

[0079] Each of these penalties, constraints, variances, or tracking can result in fine-tuning of any of the other pitch adjustment factors provided. Specifically, by providing either penalty terms or constraints corresponding to equations (9)-(12), the utilization of the other pitch adjustment factors can be efficiently controlled.

[0080] In another embodiment, the pitch constraint may be a maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade 22. For example, the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration may be implemented through the use of equations (13)-(15), respectively. LB≦θ ik ≦UB(13)

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[0081] As described herein, physical limits or caps may be applied to the pitch activity of the rotor blades 22 through the use of maximum or minimum allowable pitch angles, pitch rates, or pitch accelerations. Specifically, the maximum or minimum allowable pitch angles, pitch rates, or pitch accelerations may be established through the use of equations (11)-(13). As described, the maximum or minimum allowable pitch angles, pitch rates, or pitch accelerations may be modified based on protection logic. For example, if conditions, such as wind conditions, require a lower maximum allowable pitch angle, pitch rate, or pitch acceleration, the control system 26 may include protection logic enacted by the control system 26 that instructs the wind turbine 10 to reduce the maximum pitch angle, pitch rate, or pitch acceleration. Thus, depending on the conditions existing around the wind turbine 10, the protection logic may increase or decrease the maximum and minimum allowable pitch angles, pitch rates, or pitch accelerations of the rotor blades 22 of the wind turbine 10. Furthermore, when the conditions that caused the protection logic to be implemented no longer exist, the control system 26 may restore the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration of the rotor blades 22 to the values ​​they had before the protection logic was implemented. It is therefore understood that the protection logic may be temporarily activated depending on conditions existing around the wind turbine 10.

[0082] In another embodiment, the pitch constraint may correspond to a maximum or minimum allowable pitch motor torque, current, voltage, or power. Such constraints may protect electrical components, such as pitch drive motor 40 of wind turbine 10.

[0083] Additionally, if flexibility in these maximum or minimum allowable values ​​is desired, an increase or decrease in the input or output constraints may be utilized. For example, an increase or decrease in the maximum pitch angle, pitch rate, or pitch acceleration, or an increase or decrease in the minimum pitch angle, pitch rate, or pitch acceleration, may result. In another example, an increase or decrease in the maximum allowable pitch motor torque, current, voltage, or power, or an increase or decrease in the minimum allowable pitch motor torque, current, voltage, or power, may result. The increase or decrease may be applied at a future time interval or multiple future time intervals and may vary over multiple future time intervals, with the inequalities defining the constraints needing to be satisfied at each future time interval or multiple future time intervals. For example, the increase in the input and output constraints may be provided according to the following equation (16):

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[0084] Further, a reduction in input and output constraints can be provided according to equation (17) below.

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[0085] As shown, the placeholder ε U or ε L can act as slack variables for the constraints. Also, the placeholder ε U or ε L may be in absolute terms. The placeholder ε U or ε L ε may also be any other term recognized in the art to provide an upper or lower bound increase or decrease in a desired value. For example, the placeholder ε U or ε L may also be adaptive terms that change in real time based on conditions surrounding the wind turbine 10. Specifically, weights may be applied to slack variables to provide greater control over the constraints. Additionally, increases or decreases may be applied at future time intervals in response to operating conditions of the wind turbine 10, such as conditions received by sensors on the wind turbine 10.

[0086] In another embodiment, the pitch adjustment factor may be one or more variance penalties for the pitch angle, pitch rate, or pitch acceleration of at least one rotor blade 22. For example, the variance penalty may be provided according to the following equation (18):

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[0087] In yet another embodiment, the pitch adjustment factor may be one or more penalties for the total pitch angle change of at least one rotor blade 22, i.e., the total angle traveled by each rotor blade 22 or all of the rotor blades 22 collectively. For example, the total pitch angle change may be penalized according to the following equation (19):

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[0088] In one embodiment, an advantage of penalizing total pitch change, for example, through increasing the weighting factor W in equation (17), is that the control system 26 can prevent micropitching, which are small movements of blade pitch that contribute significantly to bearing life consumption but have little load relief benefit. Furthermore, equation (17) does not preclude necessary control action in the event of a gust of wind. Furthermore, equation (17) also does not significantly penalize large deviations in pitch angle, especially when compared to other conventional methods. Examples of these scenarios are a gust of wind that requires a rapid increase in pitch to relieve load, or a sudden decrease in wind speed that requires a rapid reduction in pitch to capture more energy.

[0089] In yet another embodiment, the pitch adjustment factor may be a penalty for the product of the pitch movement of the at least one rotor blade 22 and the magnitude of the load on the at least one rotor blade 22 .

[0090] Referring back to FIG. 6 , as shown in (112), method 100 includes calculating, via an optimization solver implemented in the control system, an optimized pitch parameter of at least one rotor blade 22 of wind turbine 10 from a linearized representation using a pitch adjustment factor and a pitch constraint. Specifically, the optimized pitch parameter may be a solution to an optimization problem in which a cost function is minimized. For example, the optimized pitch parameter may be an output in the form of a trajectory of at least one pitch angle, pitch rate, or pitch acceleration of rotor blade 22. The optimized pitch parameter may also be an optimized torque of rotor 18 of wind turbine 10.

[0091] In determining the optimized pitch parameters, the model may use the pitch adjustment factors to determine the pitch parameters of at least one rotor blade 22 to achieve results such as those described above with reference to Figure 8. Such results may result in the wind turbine 10 exhibiting increased or decreased behavior, for example, such that improved pitch control of the wind turbine 10 is achieved. Such behavior, described in more detail below, may include symmetric or asymmetric pitch, higher harmonics in pitch activity, or operation of the wind turbine 10 outside set constraints or boundaries.

[0092] Further, as described above, multiple pitch adjustment factors may be used to determine optimized pitch parameters to achieve one result or multiple results. Determining the optimized pitch parameters may be accomplished by using the pitch adjustment factors to modify a linearized representation of the predicted situation in the model to provide optimized pitch parameters. This determination may take the form of a simulation of the pitch parameters of wind turbine 10 being modified by control system 26, thereby causing wind turbine 10 to deviate from the predicted situation to the optimized situation.

[0093] As shown at (114), the method 100 includes adjusting the pitch parameter of at least one rotor blade 22 to an optimized pitch parameter such that the wind turbine 10 exhibits increased or decreased behavior and improved control of the wind turbine 10. By doing so, the rotor blade 22 may be adjusted such that the rotor blade 22 is modified to the optimized pitch parameter that achieves one or more results provided in the model.

[0094] In another embodiment, the torque of the rotor 18 of the wind turbine 10 may be adjusted to increase or decrease the behavior exhibited by the wind turbine, improving control of the wind turbine. By doing so, the rotor blades 22 may be adjusted so that the rotor 18 is modified to an optimized pitch parameter that achieves one or more results provided in the model.

[0095] Thus, control of wind turbine 10 can be optimized through use of the model to simulate optimized pitch parameters and through tuning wind turbine 10 with control system 26 to match the optimized pitch parameters.

[0096] Furthermore, control of wind turbine 10 may be continuously optimized. For example, by updating a simulation of anticipated conditions based on adjustments to the pitch parameters of at least one rotor blade 22, the model may simulate new anticipated conditions and use those new anticipated conditions to further determine optimized conditions to which wind turbine 10 may be aligned. Thus, the present disclosure provides systems and methods for continuously optimizing pitch control using control system 26.

[0097] For example, referring now to FIGS. 11A-11B, various graphs of pitch adjustment factors being applied in response to peak load intervals are shown, according to one embodiment of the present disclosure. As shown in either FIG. 11A or FIG. 11B, the loads may be increased or decreased. Specifically, as shown in FIGS. 11A-11B, plots 600, 650 depict loads and weighting factors applied to one or more rotor blades 22 on y-axes 602, 652, and x-axes 604, 654 depict wind speed acting on one or more rotor blades 22. Furthermore, FIG. 11A depicts a peak load interval 606 at an arbitrary location on the plot 600, while FIG. 11B depicts a peak load interval 656 at another location on the plot 650. Furthermore, the peak load intervals coincide with minimum weighting factor intervals 608, 658. Specifically, as shown in FIG. 11A, the peak load interval 606 is achieved at the minimum weighting factor interval 608. As shown in FIG. 11B, a peak load interval 656 is achieved at a minimum weighting factor interval 658. These peak load intervals 606, 656 and minimum weighting factor intervals 608, 658 may be provided at various wind speeds. Conversely, outside of the peak load intervals 606, 656 and minimum weighting factor intervals 608, 658, heavier weighting factors result in reduced loads. Therefore, as previously described, these loads may be mitigated through the use of pitch adjustment factors, including weighting factors. In one example, increasing the difference between pitch angle, pitch rate, or pitch acceleration, as shown in FIG. 9B, may help reduce loads, as demonstrated by FIG. 11A or 11B. Pitch constraints may be utilized to further enhance the control shown in FIGS. 11A-11B.

[0098] 12A-12D, various graphs are shown of the specific impact of pitch adjustment factors and pitch constraints applied to increase or maintain a difference in a pitch parameter of a wind turbine rotor blade according to one embodiment of the present disclosure. As shown, the pitch parameter may be power, pitch angle, generator torque, or pitch speed, where the solid line represents control using pitch control system 26 using a pitch adjustment factor, while the dotted line represents pitch control by conventional means.

[0099] 12A, a plot 700 of power generated using control system 26 is shown compared to a conventional method. Further, as shown, power is plotted on y-axis 702 while time is plotted on x-axis 704. Further, as shown, the conventional method is represented by line 706 while the method using control system 26 is represented by line 708. Further, as shown, line 706 representing the conventional method has a deep valley and is consistently below line 708 representing the method using control system 26. Therefore, it can be seen that the method using control system 26 results in improved power generation compared to the conventional method.

[0100] 12B , a plot 720 of the pitch angle of rotor blades 22 using control system 26 is compared to a conventional method. Further, as shown, the pitch angle of one or more rotor blades 22 is plotted on y-axis 722, while time is plotted on x-axis 724. Further, as shown, the conventional method is represented by line 726, while the method using control system 26 is represented by line 728. Further, as shown, line 726 representing the conventional method has an irregular pattern, indicated by a greater amount of peaks and troughs on line 726, as compared to line 728. Thus, it can be seen that the method described herein provides greater control over the pitch angle effect of rotor blades 22, as compared to the conventional method.

[0101] 12C, a plot 740 of generator torque using control system 26 is compared to the conventional method. Further as shown, generator torque is plotted on y-axis 742 while time is plotted on x-axis 744. Further as shown, the conventional method is represented by line 746 while the method using control system 26 is represented by line 748. Further as shown, line 746 representing the conventional method has a deep valley and is consistently below line 748 representing the method using control system 26. Thus, it can be seen that the method described herein results in improved generator torque when compared to the conventional method.

[0102] 12D , a plot 760 of the rotor speed of the wind turbine 10 using the control system 26 is shown compared to a conventional method. Further, as shown, rotor speed is plotted on the y-axis 762, while time is plotted on the x-axis 764. Further, as shown, the conventional method is represented by line 766, while the method using the control system 26 is represented by line 768. Further, as shown, line 766 representing the conventional method has larger peaks and deeper valleys compared to line 768 representing the method using the control system 26. Therefore, it can be seen that the method using the control system 26 provides improved control over the speed of the rotor of the wind turbine 10 compared to the conventional method. Thus, as shown, pitch control can be smoother and more optimal through the use of the control methods described herein compared to the conventional control methods.

[0103] Various aspects and embodiments of the present invention are defined by the following clauses. Clause 1. A method for optimizing control of a wind turbine, the method comprising: receiving, via a control system, at least one state of the wind turbine; estimating, via a control system, a current condition of the wind turbine using the at least one state; calculating, via a model implemented by the control system, a linearized representation of the operation of the wind turbine for a future time interval following the current situation; defining an optimization problem to be solved via a control system, the optimization problem including a cost function and a pitch constraint; determining, via the control system, a pitch adjustment factor for modifying a current state of the wind turbine, the pitch adjustment factor comprising at least one weight in a cost function that, when implemented, increases or decreases a behavior exhibited by the wind turbine, the cost function being implemented in an optimization solver implemented by the control system; calculating, via an optimization solver implemented in the control system, optimized pitch parameters of at least one rotor blade of the wind turbine from the linearized representation using the pitch adjustment factors and the pitch constraints, the optimized pitch parameters being a solution to the optimization problem; and adjusting a pitch parameter of at least one rotor blade to an optimized pitch parameter such that the behavior exhibited by the wind turbine is increased or reduced, thereby improving control of the wind turbine. Clause 2. The method of clause 1, wherein the at least one condition includes a measurement of at least one of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural force or moment, structural displacement, structural velocity, or structural acceleration. Clause 3. The current situation of the wind turbine includes instantaneous aerodynamic effects distributed over a portion of the wind turbine, the instantaneous aerodynamic effects including at least one of a force or a moment acting on the portion of the wind turbine; Alternatively, the method of clause 1 or 2, wherein the current condition of the wind turbine includes instantaneous structural effects across a portion of the wind turbine, the instantaneous structural effects including at least one of structural displacement, structural velocity, or structural acceleration of any structural component of the wind turbine. Clause 4. The method of any one of clauses 1 to 3, wherein improving control of the wind turbine comprises reducing wind turbine load, improving bearing life, improving energy production, improving power quality, improving power tracking performance, or improving speed tracking performance. Clause 5. The method of clause 4, wherein the optimized pitch parameters include a pitch angle, a pitch rate, or a pitch acceleration trajectory of at least one rotor blade of the wind turbine. Clause 6. The method of any one of clauses 1 to 5, wherein the weight corresponds to a symmetric pitch movement of at least one rotor blade of the wind turbine. Clause 7. The method of any one of clauses 1 to 6, wherein the weight corresponds to an asymmetric pitch movement of at least one rotor blade of the wind turbine. Clause 8. The method of any one of clauses 1 to 7, wherein the weight corresponds to an amplitude of a harmonic higher than a fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of at least one rotor blade. Clause 9. The at least one rotor blade comprises a first rotor blade and a second rotor blade; the pitch angle, pitch rate, or pitch acceleration of the first rotor blade includes a higher frequency than the pitch angle, pitch rate, or pitch acceleration of the second rotor blade; 9. The method of claim 8, wherein a weight is applied to the pitch angle, pitch rate, or pitch acceleration of the first rotor blade such that amplitudes of harmonics higher than a fundamental frequency of the pitch angle, pitch rate, or pitch acceleration are reduced. Clause 10. The pitch adjustment coefficient includes one of a linear term or a quadratic term in a future time interval; the pitch constraint comprises a linear or quadratic constraint in a future time interval, or 10. The method of any one of clauses 1-9, wherein the pitch adjustment factor comprises a variance or tracking of a pitch angle, a pitch rate, or a pitch acceleration of at least one rotor blade. Clause 11. The pitch constraint corresponds to a maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, or 11. The method of any one of clauses 1 to 10, wherein the pitch constraint corresponds to a maximum or minimum allowable pitch motor torque, current, voltage, or power. Clause 12. The pitch constraint further includes an increase or decrease in a maximum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, or a decrease or increase in a minimum allowable pitch angle, pitch rate, or pitch acceleration of at least one rotor blade, and the increase or decrease in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at a future time interval in response to the received at least one condition; or 12. The method of claim 11, wherein the pitch constraint further includes an increase or decrease in a maximum allowable pitch motor torque, current, voltage, or power, or a decrease or increase in a minimum allowable pitch motor torque, current, voltage, or power, and wherein the decrease or increase in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at a future time interval in response to the received at least one condition. Clause 13. The method of any one of clauses 1 to 12, wherein the pitch adjustment factors include two or more pitch adjustment factors, and the optimized pitch parameter of the at least one rotor blade is calculated using the two or more pitch adjustment factors and the pitch constraint. Clause 14. The method of any one of clauses 1 to 13, wherein the pitch adjustment factor comprises one or more penalties for the total pitch angle change of the at least one rotor blade, or a penalty for the product of the pitch movement of the at least one rotor blade and the magnitude of the load on the at least one rotor blade. Clause 15. Calculating an optimized torque of the rotor of the wind turbine from the linearized representation using the pitch adjustment factor and the pitch constraint via an optimization solver implemented in the control system; 15. The method of any one of clauses 1 to 14, further comprising adjusting the torque of the rotor to an optimized torque such that the behavior exhibited by the wind turbine is increased or reduced, improving control of the wind turbine. Clause 16. A system for optimizing the control of a wind turbine, the system comprising: at least one sensor configured to monitor at least one condition of the wind turbine; 1. A control system comprising: receiving at least one state of the wind turbine; estimating, via a control system, a current condition of the wind turbine using the at least one state; calculating, via a model implemented by the control system, a linearized representation of the operation of the wind turbine for a future time interval following the current situation; defining an optimization problem to be solved via a control system, the optimization problem including a cost function and a pitch constraint; determining, via the control system, a pitch adjustment factor for modifying a current state of the wind turbine, the pitch adjustment factor comprising at least one weight in a cost function that, when implemented, increases or decreases a behavior exhibited by the wind turbine, the cost function being implemented in an optimization solver implemented by the control system; calculating, via an optimization solver implemented in the control system, optimized pitch parameters of at least one rotor blade of the wind turbine from the linearized representation using the pitch adjustment factors and the pitch constraints, the optimized pitch parameters being a solution to the optimization problem; adjusting the pitch parameter of at least one rotor blade to an optimized pitch parameter such that the behavior exhibited by the wind turbine is increased or reduced and control of the wind turbine is improved; a control system configured to implement A system comprising: Clause 17. The system of clause 16, wherein the at least one condition includes a measurement of at least one of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural force or moment, structural displacement, structural velocity, or structural acceleration. Clause 18. The current situation of the wind turbine includes instantaneous aerodynamic effects distributed over a portion of the wind turbine, the instantaneous aerodynamic effects including at least one of a force or a moment acting on the portion of the wind turbine; Alternatively, the system of clause 16 or 17, wherein the current condition of the wind turbine includes an instantaneous structural effect across a portion of the wind turbine, the instantaneous structural effect including at least one of a structural displacement, a structural velocity, or a structural acceleration of any structural component of the wind turbine. Clause 19. The system of any one of clauses 16 to 18, wherein the weight corresponds to a symmetric or asymmetric pitch movement of at least one rotor blade of the wind turbine. Clause 20. The system of any one of clauses 16 to 19, wherein the weighting corresponds to an amplitude of a harmonic higher than a fundamental frequency of the pitch angle, pitch rate, or pitch acceleration of at least one rotor blade.

[0104] Examples are used herein to disclose the invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any methods incorporated therein. The patentable scope of the invention is defined by the claims, and may 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 contain structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that have no substantial differences from the literal language of the claims. [Explanation of symbols]

[0105] 10. Wind Turbines 12. Tower 14 Support surface 16 Nacelle 18 rotors 20 Hub 22 At least one rotor blade 24 Generator 26 Wind Turbine Control System 28 Pitch axis 32 Pitch adjustment mechanism 34 rotor shaft 36 Generator shaft 38 Gearbox 40 pitch drive motor 42 pitch drive gearbox 44 pitch drive pinion 46 Pitch bearing 48 sensors 50 sensors 58 processors 60 Memory Devices 62 Communication Module 64 Sensor Interface 66 Yaw drive mechanism 68 Yaw axis 70 MPC Framework 72 Estimation Module 74 Simulation Modules 76 Optimization Module 78 Regulatory Module 100 ways 200 Current Situation 202 Forecast 204 Time Interval 300 Multipurpose Model 302 x-axis 304 y-axis 306 z-axis 308 Optimized Situation 310 points As of 312 314 Starting point 316 points 400 pitch plot 402 rotor blades 404 rotor blades 406 rotor blades 408 x-axis 410 y-axis Box 412 450 Load Plot 452 y-axis 454 x-axis 456 threshold 458 Box 500 Fundamental Frequency Plot 502 High Frequency Signal 504 Low Frequency Signal 506 y-axis 508 x-axis 520 First Harmonic Plot 540 Second Harmonic Plot 560 Third Harmonic Plot 600 Load Plot 602 y-axis 604 x-axis 606 Peak Load Interval 608 Minimum Weighting Coefficient Interval 650 Weighting Factor Plot 652 y-axis 654 x-axis 656 Peak Load Interval 658 Minimum Weighting Coefficient Interval 700 Power Plot 702 y-axis 704 x-axis 706 line 708 line 720 Pitch Angle Plot 722 y-axis 724 x-axis 726 line 728 line 740 Generator Torque Plot 742 y-axis 744 x-axis 746 line 748 line 760 Rotor Speed ​​Plot 762 y-axis 764 x-axis 766 line 768 line

Claims

1. A method (100) for optimizing control of a wind turbine (10), said method (100) comprising: receiving (102) via a control system (26) at least one state of the wind turbine (10); estimating (104) a current situation (200) of the wind turbine (10) using the at least one state via the control system (26); calculating (106) a linearized representation of the operation of the wind turbine (10) for a future time interval following the current situation (200) via a model implemented by the control system (26); a step (108) of defining an optimization problem to be solved via the control system (26), the optimization problem including a cost function and a pitch constraint; determining (110) via the control system (26) a pitch adjustment factor for modifying the current situation (200) of the wind turbine (10), the pitch adjustment factor comprising at least one weight in the cost function that, when implemented, increases or decreases the behavior exhibited by the wind turbine (10), the cost function being implemented in an optimization solver implemented by the control system (26); calculating (112) an optimized pitch parameter of at least one rotor blade (22) of the wind turbine (10) from the linearized representation using the pitch adjustment factor and the pitch constraint via the optimization solver implemented in the control system (26), wherein the optimized pitch parameter is a solution to the optimization problem; and adjusting (114) a pitch parameter of the at least one rotor blade (22) to the optimized pitch parameter such that the behavior exhibited by the wind turbine (10) is increased or reduced, thereby improving the control of the wind turbine (10).

2. 2. The method of claim 1, wherein the at least one condition comprises a measurement of at least one of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural force or moment, structural displacement, structural velocity, or structural acceleration.

3. the current situation (200) of the wind turbine (10) comprises instantaneous aerodynamic effects distributed over a portion of the wind turbine (10), the instantaneous aerodynamic effects comprising at least one of forces or moments acting on the portion of the wind turbine (10); or 2. The method of claim 1, wherein the current condition of the wind turbine includes instantaneous structural effects across a portion of the wind turbine, the instantaneous structural effects including at least one of structural displacements, structural velocities, or structural accelerations of any structural components of the wind turbine.

4. 10. The method of claim 1, wherein the improved control of the wind turbine comprises reduced load on the wind turbine, improved bearing life, improved energy production, improved power quality, improved power tracking performance, or improved speed tracking performance.

5. The method (100) of claim 4, wherein the optimized pitch parameter comprises a pitch angle, a pitch rate, or a pitch acceleration trajectory of the at least one rotor blade (22) of the wind turbine (10).

6. The method (100) of claim 1, wherein the weight corresponds to a symmetric pitch motion of the at least one rotor blade (22) of the wind turbine (10).

7. The method (100) of claim 1, wherein the weight corresponds to an asymmetric pitch motion of the at least one rotor blade (22) of the wind turbine (10).

8. The method (100) of claim 1, wherein the weight corresponds to an amplitude of a harmonic higher than a fundamental frequency of a pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade (22).

9. the at least one rotor blade (22) comprises a first rotor blade and a second rotor blade; the pitch angle, the pitch rate, or the pitch acceleration of the first rotor blade includes a higher frequency than the pitch angle, the pitch rate, or the pitch acceleration of the second rotor blade; 9. The method (100) of claim 8, wherein the weighting is applied to the pitch angle, the pitch rate, or the pitch acceleration of the first rotor blade such that the amplitude of the harmonics higher than the fundamental frequency of the pitch angle, the pitch rate, or the pitch acceleration is reduced.

10. the pitch adjustment factor includes one of a linear term or a quadratic term in the future time interval; the pitch constraint comprises a linear or quadratic constraint in the future time interval; or The method (100) of claim 1, wherein the pitch adjustment factor comprises a variance or tracking of a pitch angle, a pitch rate, or a pitch acceleration of the at least one rotor blade (22).

11. the pitch constraint corresponds to a maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade; or The method (100) of claim 1 , wherein the pitch constraint corresponds to a maximum or minimum allowable pitch motor torque, current, voltage, or power.

12. the pitch constraint further comprises an increase or decrease in the maximum allowable pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade, or a decrease or increase in the minimum allowable pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade, and the increase or decrease in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at the future time interval in response to the received at least one condition; or 12. The method (100) of claim 11, wherein the pitch constraint further comprises an increase or decrease in the maximum allowable pitch motor torque, current, voltage, or power, or a decrease or increase in the minimum allowable pitch motor torque, current, voltage, or power, and wherein the decrease or increase in the maximum or minimum allowable pitch angle, pitch rate, or pitch acceleration is applied at the future time interval in response to the received at least one condition.

13. 2. The method of claim 1, wherein the pitch adjustment factors include two or more pitch adjustment factors, and the optimized pitch parameters of the at least one rotor blade are calculated using the two or more pitch adjustment factors and the pitch constraint.

14. 2. The method of claim 1, wherein the pitch adjustment factor comprises one or more penalties for a total pitch angle change of the at least one rotor blade or a penalty for a product of a pitch movement of the at least one rotor blade and a magnitude of a load on the at least one rotor blade.

15. calculating an optimized torque for a rotor (18) of the wind turbine (10) from the linearized representation using the pitch adjustment factor and the pitch constraint via the optimization solver implemented in the control system (26); and adjusting the torque of the rotor (18) to the optimized torque such that the behavior exhibited by the wind turbine (10) is increased or reduced, thereby improving the control of the wind turbine (10).

16. 1. A system for optimizing control of a wind turbine (10), the system comprising: at least one sensor (48, 50) configured to monitor at least one condition of the wind turbine (10); A control system (26) comprising: receiving the at least one state of the wind turbine (10); estimating, via the control system (26), a current state (200) of the wind turbine (10) using the at least one state; calculating, via a model implemented by the control system (26), a linearized representation of the operation of the wind turbine (10) for a future time interval following the current situation (200); defining an optimization problem to be solved via the control system (26), the optimization problem including a cost function and a pitch constraint; determining, via the control system (26), a pitch adjustment factor for modifying the current state (200) of the wind turbine (10), the pitch adjustment factor comprising at least one weight in the cost function that, when implemented, increases or decreases a behavior exhibited by the wind turbine (10), the cost function being implemented in an optimization solver implemented by the control system (26); calculating, via the optimization solver implemented in the control system (26), optimized pitch parameters of at least one rotor blade (22) of the wind turbine (10) from the linearized representation using the pitch adjustment factor and the pitch constraint, the optimized pitch parameters being a solution to the optimization problem; adjusting a pitch parameter of the at least one rotor blade (22) to the optimized pitch parameter such that the behavior exhibited by the wind turbine (10) is increased or reduced and the control of the wind turbine (10) is improved; a control system (26) configured to implement the A system comprising:

17. 17. The system of claim 16, wherein the at least one condition comprises a measurement of at least one of rotor speed, generator speed, wind speed, wind direction, wind shear, wind veer, wind turbulence, structural force or moment, structural displacement, structural velocity, or structural acceleration.

18. the current situation (200) of the wind turbine (10) comprises instantaneous aerodynamic effects distributed over a portion of the wind turbine (10), the instantaneous aerodynamic effects comprising at least one of forces or moments acting on the portion of the wind turbine (10); or 17. The system of claim 16, wherein the current condition (200) of the wind turbine (10) includes instantaneous structural effects across a portion of the wind turbine (10), the instantaneous structural effects including at least one of structural displacements, structural velocities, or structural accelerations of any structural components of the wind turbine (10).

19. The system of claim 16, wherein the weight corresponds to a symmetric or asymmetric pitch motion of the at least one rotor blade (22) of the wind turbine (10).

20. The system of claim 16 , wherein the weight corresponds to an amplitude of a harmonic higher than a fundamental frequency of a pitch angle, pitch rate, or pitch acceleration of the at least one rotor blade (22).

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