Systems and methods for controlling wind turbines in response to blade shedding events.

Abstract

A system and method are provided for controlling a wind turbine in response to a blade detachment event. The method involves determining an estimated response characteristic for the wind turbine. Sensor data indicative of at least two actual response characteristics of the wind turbine components to rotor load are collected. The actual response characteristics are compared with the estimated response characteristics. Two or more actual response characteristics matching or exceeding the estimated response characteristics indicate a blade detachment event. In response to the detection of the blade detachment event, fast shutdown control logic is initiated to decelerate the rotor at a rate exceeding the rotor's nominal deceleration rate.

Description

Technical Field

[0001] This disclosure generally relates to wind turbines, and more particularly to systems and methods for controlling wind turbines in the event of blade detachment. Background Technology

[0002] Wind power is considered one of the cleanest and most environmentally friendly energy sources available today, and wind turbines have received increasing attention in this regard. A modern wind turbine typically comprises a tower, generator, gearbox, nacelle, and one or more rotor blades. The nacelle contains the rotor assembly, which is connected to the gearbox and then to the generator. The rotor assembly and gearbox are mounted on a base support frame located within the nacelle. One or more rotor blades harvest the kinetic energy of the wind using the known airfoil principle. The rotor blades transfer this kinetic energy as rotational energy to rotate the shaft that connects the rotor blades to the gearbox, or, without a gearbox, directly to the generator shaft. The generator then converts this mechanical energy into electrical energy, which can be transmitted to a converter and / or transformer housed within the tower and subsequently deployed to the public power grid. Modern wind power systems typically take the form of wind farms with multiple such wind turbine generators, which are operable to supply power to the transmission system, thereby providing power to the grid.

[0003] In some instances, portions of the rotor blades (or the blades themselves) may detach from the wind turbine. Such blade detachment events can cause the rotor to become unbalanced, leading to damage or destruction of the wind turbine.

[0004] Damage caused by an unbalanced rotor can be exacerbated by continued operation of the wind turbine after the initial imbalance has occurred. For existing wind turbines, controllers typically use turbine-operated components to decelerate the rotor within nominal design limits. However, in some instances, such a deceleration rate may be insufficient to prevent or mitigate damage to the wind turbine. Therefore, in some cases, it might be ideal to decelerate the rotor more rapidly following a blade detachment event. However, such rapid deceleration of the rotor can be costly. Therefore, it is important to exclude instances of false alarms (i.e., decelerate the rotor only when a blade detachment event has actually occurred).

[0005] Therefore, the art is constantly seeking new and improved systems and methods to solve the aforementioned problems. Accordingly, this disclosure relates to systems and methods for controlling wind turbines in response to blade detachment events. Summary of the Invention

[0006] Aspects and advantages of the invention will be set forth in part in the description which follows, or will be obvious from the description, or may be learned by practice of the invention.

[0007] In one aspect, this disclosure relates to a method for controlling a wind turbine in response to a blade detachment event. The wind turbine may include a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub. The method may include determining a plurality of estimated response signatures for the wind turbine corresponding to a plurality of different blade detachment events. The method may also include collecting sensor data via a plurality of sensors during operation of the wind turbine. The sensor data may indicate the response of at least one component of the wind turbine to an actual rotor load. The method may include identifying at least two actual response signatures within the sensor data. Additionally, the method may include determining whether the at least two actual response signatures are equal to or exceed two or more corresponding estimated response signatures of the plurality of estimated response signatures to determine the presence of a blade detachment event. In response to detecting a blade detachment event, the method may utilize a controller to initiate fast shutdown control logic to protect the wind turbine.

[0008] In an embodiment, the multiple response characteristics may include at least one and / or a combination thereof, load amplitude, load along the pitch axis and acceleration vector of at least one component, first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, bending moment affecting the rotor shaft or tower of the wind turbine.

[0009] In an additional embodiment, the acceleration vector of at least one component may include the horizontal and vertical displacements of the rotor in response to loads on the rotor.

[0010] In an embodiment, the acceleration vector of at least one component may include the acceleration of the wind turbine nacelle in response to wind load. The nacelle acceleration may include the nacelle's oscillation direction, oscillation frequency, and oscillation amplitude.

[0011] In another embodiment, the acceleration vector of at least one component may include the rotor speed response. The rotor speed response may indicate the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

[0012] In an embodiment, the method may further include determining the type of blade shedding event based on at least two actual response characteristics. The type of blade shedding event may include at least a partial deviation of one of a plurality of rotor blades.

[0013] In an additional embodiment, the fast shutdown control logic may include slowing the rotor down over a shortened time interval relative to the nominal shutdown control logic.

[0014] In another embodiment, the fast shutdown control logic may include exceeding the nominal operating limits of at least one component of the wind turbine. The fast shutdown control logic may also include establishing fast shutdown setpoints for the component(s). The fast shutdown setpoints may have values ​​greater than the nominal operating limits, such that excessive load or damage to the component(s) is permissible.

[0015] In another aspect, this disclosure relates to a method for controlling a wind turbine in response to a blade detachment event. The wind turbine may have a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub. The method may include using a controller to receive data from a plurality of sensors indicating a blade detachment event during operation of the wind turbine. In response to detecting a blade detachment event, the method may further include using the controller to activate fast shutdown control logic to protect the wind turbine. The fast shutdown control logic may include exceeding the nominal operating limits of at least one component of the wind turbine. The fast shutdown control logic may also include establishing a fast shutdown setpoint for the component(s). The fast shutdown setpoint may have a value greater than the nominal operating limits such that excessive load or damage to the component(s) is permissible. Additionally, the fast shutdown control logic may include establishing a rotor deceleration rate exceeding the nominal deceleration rate of the rotor.

[0016] In an embodiment, establishing a fast shut-off setpoint includes at least one of the following: using a controller to generate a pitch setpoint command for a plurality of rotor blades, wherein the pitch setpoint command instructs a pitch control mechanism to pitch the plurality of rotor blades into feather at a pitch rate exceeding a nominal pitch rate threshold; and using a controller to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs a converter controller to generate generator torque exceeding a nominal generator torque limit.

[0017] In an additional embodiment, the fast shutdown control logic may also include using the controller to trigger a gearbox braking system operatively coupled to the gearbox of the wind turbine.

[0018] In another embodiment, the wind turbine may further include a high-speed shaft that operatively connects the rotor to a generator via a gearbox. The gearbox may be operatively connected to the generator via a sliding coupling of the high-speed shaft. The method may further include monitoring the torque level of the sliding coupling. The method may further include reducing the generator setpoint when the torque level of the sliding coupling approaches a release threshold of the sliding coupling.

[0019] In an embodiment, the method may further include, following the detection of a blade shedding event, establishing a reduction of one-third of the rotor speed within 720 degrees of rotor rotation.

[0020] In another aspect, this disclosure relates to a wind turbine. The wind turbine may include a tower, a nacelle mounted on top of the tower, and a rotor mounted to the nacelle. The rotor may include a rotatable hub having a plurality of rotor blades fastened to the rotatable hub via a pitch drive mechanism. The wind turbine may also include a generator disposed within the nacelle and operatively coupled to the rotor via a gearbox and a high-speed shaft. Additionally, the wind turbine may include a controller communicatively coupled to the pitch drive mechanism, the generator, and a plurality of sensors. The controller may include at least one processor configured to perform a plurality of operations. The plurality of operations may include any of the operations and / or features described herein.

[0021] Technical Solution 1. A method for controlling a wind turbine in response to a blade shedding event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising:

[0022] Determine multiple estimated response characteristics for the wind turbine corresponding to multiple different blade shedding events;

[0023] During operation of the wind turbine, sensor data is collected via multiple sensors, the sensor data indicating the response of at least one component of the wind turbine to actual rotor load;

[0024] Identify at least two actual response characteristics within the sensor data;

[0025] Determine whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics among the plurality of estimated response characteristics, in order to determine the existence of the blade shedding event; and

[0026] In response to the detection of the blade detachment event, the controller is used to initiate fast shutdown control logic to protect the wind turbine.

[0027] Technical Solution 2. The method according to Technical Solution 1, wherein the plurality of response characteristics include at least one or a combination thereof, load amplitude, the direction of the load along the pitch axis, the acceleration vector of the at least one component, a first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

[0028] Technical Solution 3. The method according to Technical Solution 2, wherein the acceleration vector of the at least one component includes:

[0029] The rotor responds to the horizontal and vertical displacements of the load on the rotor.

[0030] Technical Solution 4. The method according to Technical Solution 2, wherein the acceleration vector of the at least one component includes:

[0031] The nacelle of the wind turbine responds to the acceleration of the wind load, wherein the nacelle acceleration includes the oscillation direction, oscillation frequency, and oscillation amplitude of the nacelle.

[0032] Technical Solution 5. The method according to Technical Solution 2, wherein the acceleration vector of the at least one component includes:

[0033] Rotor speed response, wherein the rotor speed response indicates the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

[0034] Technical Solution 6. The method according to Technical Solution 1 further includes:

[0035] The type of blade shedding event is determined based on the at least two actual response characteristics, wherein the type of blade shedding event includes at least a partial deviation of one of the plurality of rotor blades.

[0036] Technical Solution 7. The method according to Technical Solution 1, wherein the fast shutdown control logic includes decelerating the rotor within a shortened time interval relative to the nominal shutdown control logic.

[0037] Technical Solution 8. The method according to Technical Solution 1, wherein the fast shutdown control logic includes:

[0038] Exceeding the nominal operating limit of at least one component of the wind turbine; and

[0039] Establish a quick-close setpoint for the at least one component, wherein the quick-close setpoint has a value greater than the nominal operating limit, such that excessive load or damage to the at least one component is permissible.

[0040] Technical Solution 9. A method for controlling a wind turbine in response to a blade shedding event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising:

[0041] During operation of the wind turbine, a controller is used to receive data from multiple sensors indicating blade detachment events; and

[0042] In response to the detection of the blade detachment event, the controller is used to initiate fast shutdown control logic to protect the wind turbine, the fast shutdown control logic including:

[0043] Exceeding the nominal operating limit of at least one component of the wind turbine,

[0044] Establish a quick-closing setpoint for the at least one component, wherein the quick-closing setpoint has a value greater than the nominal operating limit, such that excessive load or damage to the at least one component is permissible, and

[0045] Establish a reduction rate for the rotor that exceeds its nominal reduction rate.

[0046] Technical Solution 10. The method according to Technical Solution 9, wherein establishing the fast-closing setpoint includes at least one of the following:

[0047] The controller is used to generate pitch setpoint commands for the plurality of rotor blades, wherein the pitch setpoint commands instruct the pitch control mechanism to pitch the plurality of rotor blades into feathering at a pitch rate exceeding a nominal pitch rate threshold; and

[0048] The controller is used to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs the converter controller to generate generator torque exceeding the nominal generator torque limit.

[0049] Technical Solution 11. The method according to Technical Solution 9, wherein the fast shutdown control logic further includes:

[0050] The controller is used to trigger a gearbox braking system operably connected to the gearbox of the wind turbine.

[0051] Technical Solution 12. The method according to Technical Solution 10, wherein the wind turbine further includes a high-speed shaft of the generator operably connected to the rotor via a gearbox, the gearbox being operably connected to the generator via a sliding coupling of the high-speed shaft, the method further comprising:

[0052] Monitor the torque level of the sliding coupling; and

[0053] When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the generator set point is reduced.

[0054] Technical Solution 13. The method according to Technical Solution 10 further includes:

[0055] Following the detection of the blade shedding event, a reduction of one-third of the rotor's rotational speed is established within 720 degrees of rotor rotation.

[0056] Technical Solution 14. A wind turbine, comprising:

[0057] Tower;

[0058] The nacelle is mounted on top of the tower.

[0059] A rotor, which is mounted to the nacelle, the rotor including a rotatable hub having a plurality of rotor blades fastened to the rotatable hub via a pitch drive mechanism;

[0060] A generator, disposed within the nacelle and operably coupled to the rotor via a gearbox and a high-speed shaft; and

[0061] A controller communicatively coupled to multiple sensors, the generator, and the pitch drive mechanism, the controller including at least one processor configured to perform multiple operations, the multiple operations including:

[0062] During operation of the wind turbine, sensor data is collected via the plurality of sensors, the sensor data indicating the response of the wind turbine's components to rotor loads.

[0063] Identify at least two actual response characteristics within the sensor data.

[0064] To determine the existence of the leaf abscission event, it is necessary to determine whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics of a plurality of estimated response characteristics, wherein the plurality of estimated response characteristics correspond to a plurality of different leaf abscission events.

[0065] In response to the detection of the blade detachment event, the controller is used to initiate fast shutdown control logic to protect the wind turbine.

[0066] Technical Solution 15. The wind turbine according to Technical Solution 14, wherein the plurality of response characteristics include at least one or a combination thereof, load amplitude, the direction of the load along the pitch axis, the acceleration vector of the at least one component, a first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

[0067] Technical Solution 16. The wind turbine according to Technical Solution 15, wherein the plurality of response characteristics includes a plurality of acceleration vectors, the plurality of acceleration vectors including:

[0068] The nacelle responds to the acceleration of the wind load, wherein the nacelle acceleration includes the oscillation direction, oscillation frequency, and oscillation amplitude of the nacelle;

[0069] The rotor responds to the horizontal and vertical displacements of the load on the rotor; and

[0070] Rotor speed response, wherein the rotor speed response indicates the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

[0071] Technical Solution 17. The wind turbine according to Technical Solution 14, wherein the plurality of operations further includes:

[0072] The type of blade shedding event is determined based on the at least two actual response characteristics, wherein the type of blade shedding event includes at least a partial deviation of one of the plurality of rotor blades.

[0073] Technical Solution 18. The wind turbine according to Technical Solution 14, wherein the fast shutdown control logic includes decelerating the rotor within a shortened time interval relative to the nominal shutdown control logic.

[0074] Technical Solution 19. The wind turbine according to Technical Solution 18, wherein the time interval for decelerating and shortening the rotor includes:

[0075] The controller is used to generate pitch setpoint commands for the plurality of rotor blades, wherein the pitch setpoint commands instruct the pitch control mechanism to pitch the plurality of rotor blades into feathering at a pitch rate exceeding a nominal pitch rate threshold; and

[0076] The controller is used to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs the converter controller to generate generator torque exceeding a nominal generator torque threshold; and

[0077] Exceeding the operating limits of at least one component of the wind turbine, wherein the operating limits are higher than the nominal operating limits, such that excessive load or damage to the at least one component is permissible.

[0078] Technical Solution 20. The wind turbine according to Technical Solution 19, wherein the high-speed shaft further includes a sliding coupling, and the plurality of operations further include:

[0079] Monitor the torque level of the sliding coupling; and

[0080] When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the generator set point is reduced.

[0081] These and other features, aspects, and advantages of the invention will become more readily understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0082] The invention (including its preferred mode) is fully disclosed and can be practiced by one of ordinary skill in the art in the description with reference to the accompanying drawings, in which:

[0083] Figure 1 The figure is a perspective view of one embodiment of a wind turbine according to the present disclosure;

[0084] Figure 2 The figure shows a perspective interior view of an embodiment of a wind turbine nacelle according to the present disclosure.

[0085] Figure 3 The figure shows a schematic diagram of one embodiment of the transmission system of a wind turbine according to the present disclosure;

[0086] Figure 4 The figure is a schematic diagram of one embodiment of a controller for use with a wind turbine, according to the present disclosure;

[0087] Figure 5 The figure is a schematic diagram of an embodiment of the control logic of a system for controlling a wind turbine according to the present disclosure;

[0088] Figure 6 The illustration is based on this disclosure. Figure 5 A schematic diagram of one embodiment of the control logic portion;

[0089] Figure 7 The illustration is based on this disclosure. Figure 5 A schematic diagram of one embodiment of the control logic portion; and

[0090] Figure 8 The illustration is a schematic representation of one embodiment of the wind turbine's response to a blade detachment event according to the present disclosure.

[0091] The repeated use of reference characters in this specification and drawings is intended to indicate the same or similar features or elements of the invention. Detailed Implementation

[0092] Reference will now be made in detail to embodiments of the invention, one or more of which are illustrated in the accompanying drawings. Each example is provided by way of explanation rather than limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope or spirit thereof. For example, features illustrated or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Thus, it is intended that the invention cover such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0093] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish components from one another and are not intended to indicate the location or importance of any individual component.

[0094] Unless otherwise specified herein, the terms “connection,” “fixation,” “attachment,” etc., refer to both direct connection, fixation, or attachment and indirect connection, fixation, or attachment through one or more intermediate components or features.

[0095] As used throughout the specification and claims herein, approximate language applies to any modification of a quantitative representation that can be permitted to be changed without altering the relevant essential function. Therefore, values ​​modified with terms such as "approximately," "approximately," and "substantially" are not limited to the specified precise value. In at least some instances, approximate language may correspond to the precision of the instrument used to measure the value or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to a margin of 10%.

[0096] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scope is indicated and includes all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be independently combined with each other.

[0097] Generally, this disclosure relates to systems and methods for controlling wind turbines in response to blade detachment events that can be considered anomalous operational events. In particular, this disclosure includes systems and methods for facilitating the detection of partial or complete blade misalignment and rapid braking of the wind turbine rotor to protect the entire wind turbine. According to this disclosure, various estimated response characteristics of the wind turbine can be modeled for various blade misalignment scenarios. These estimated response characteristics can be compared with numerous data inputs from numerous sensors measuring the response of the wind turbine components to rotor loads. A blade detachment event can be indicated when at least two of the measured actual response characteristics match or exceed the corresponding estimated response characteristics. In other words, under one of the various blade misalignment scenarios, at least partial loss of the rotor blades can be detected when the measured response of the wind turbine matches the estimated response of the wind turbine. It should be appreciated that any single response characteristic can correspond to an estimated response characteristic without indicating a blade detachment event. Therefore, detecting a blade detachment event when multiple actual response characteristics match or exceed the corresponding estimated response characteristics can rule out false alarms.

[0098] Rotor blade losses (complete or partial) can cause the rotor to become unbalanced and generate unbalanced loads acting on the wind turbine. Continued operation of an unbalanced rotor can lead to deterioration of the wind turbine and / or its various components. Therefore, it is ideal to rapidly slow down the wind turbine rotor in response to the detection of a detachment event. Accordingly, the system can activate fast shutdown control logic as soon as a detachment event is detected to protect the wind turbine. The fast shutdown control logic can exceed the nominal operating limits of the wind turbine components and establish setpoints for component(s) with values ​​greater than the nominal operating limits. As a result of operating component(s) above the nominal operating limits, excessive loads or damage to component(s) can be tolerated to generate forces that slow the rotor. For example, the turbine's generator can be operated at a generator setpoint that allows the generator to produce generator torque exceeding the nominal generator torque limit. It should be appreciated that generating torque exceeding the torque limit may, for example, cause an increase in the operating temperature of various components of the electrical system that could deteriorate the components of the electrical system.

[0099] Now refer to the attached diagram, Figure 1The figure shows a perspective view of one embodiment of a wind turbine 100 according to the present disclosure. As shown, the wind turbine 100 generally includes: a tower 102 extending from a support surface 104; a nacelle 106 mounted on the tower 102; and a rotor 108 coupled to the nacelle 106. The rotor 108 includes a rotatable hub 110 and at least one rotor blade 112 coupled to and extending outward from the hub 110. For example, in the illustrated embodiment, the rotor 108 includes three rotor blades 112. However, in alternative embodiments, the rotor 108 may include more or fewer than three rotor blades 112. Each rotor blade 112 may be spaced apart around the hub 110 to facilitate rotation of the rotor 108 so that kinetic energy from the wind can be converted into usable mechanical energy, and subsequently into electrical energy. For example, the hub 110 may be rotatably coupled to an electric generator 118 located within the nacelle 106. Figure 2 ), to allow the generation of electrical energy.

[0100] The wind turbine 100 may also include a controller 200 centralized within the nacelle 106. However, in other embodiments, the controller 200 may be located within any other component of the wind turbine 100 or at a location external to the wind turbine. Furthermore, the controller 200 may be communicatively coupled to any number of components of the wind turbine 100 to control those components. Accordingly, the controller 200 may include a computer or other suitable processing unit. Thus, in several embodiments, the controller 200 may include suitable computer-readable instructions that, when executed, configure the controller 200 to perform various functions, such as receiving, transmitting, and / or executing wind turbine control signals.

[0101] Now for reference Figure 3 and Figure 2 Illustration Figure 1The diagram shows a schematic of one embodiment of the drivetrain 146 of the wind turbine 100 and a simplified internal view of one embodiment of the nacelle 106. As shown, a generator 118 can be coupled to a rotor 108 to generate electrical power from the rotational energy generated by the rotor 108. For example, as shown in the illustrated embodiment, the rotor 108 may include a rotor shaft 122 coupled to a hub 110 for rotation with the hub 110. The rotor shaft 122 may be rotatably supported by a main bearing 144. The rotor shaft 122 can, in turn, be rotatably coupled to a high-speed shaft 124 of the generator 118 via an optional gearbox 126, which is connected to a base support frame 136 via one or more torque arms 142. As generally understood, the rotor shaft 122 can provide a low-speed, high-torque input to the gearbox 126 in response to rotation of the rotor blades 112 and the hub 110. Therefore, gearbox 126 can be configured with a plurality of gears 148 for converting a low-speed, high-torque input into a high-speed, low-torque output to drive the high-speed shaft 124 and thus the generator 118. In embodiments, gearbox 126 can be configured with a plurality of gear ratios to produce varying rotational speeds of the high-speed shaft for a given low-speed input or vice versa.

[0102] In one embodiment, the wind turbine 100 may include a brake 152 positioned to prevent rotation of the rotor 108. In at least one embodiment, the brake 152 may be oriented to engage the high-speed shaft 124. The brake 152 may be configured to further slow down an already slowed rotor 108 and / or temporarily keep the rotor 108 stationary.

[0103] In additional embodiments, brake 152 may be combined with or used as an accessory to other components that slow down rotor 108. For example, in one embodiment, rotor 108 may be slowed down via torque generated by generator 118. Since generator 118 can generate torque in the opposite direction to the rotation of rotor 108, high-speed shaft 124 may be equipped with sliding coupling 154. Sliding coupling 154 can prevent damage to components of transmission system 146 due to overload of transmission system 146. Accordingly, sliding coupling 154 may have a release threshold above which allows the first portion 162 and the second portion 164 of high-speed shaft 124 to have different rotational speeds. It should be appreciated that if the torsional torque at sliding coupling 154 exceeds the release threshold, generator 118 may be communicatively decoupled from rotor 108. In such an event, the torque generated by generator 118 may not be available to slow down rotor 108.

[0104] Each rotor blade 112 may also include a pitch control mechanism 120 configured to rotate the rotor blade 112 about its pitch axis 116. The pitch control mechanism 120 may include a pitch controller 150 configured to receive at least one pitch setpoint command from the controller 200. Furthermore, each pitch control mechanism 120 may include a pitch drive motor 128 (e.g., any suitable electric, hydraulic, or pneumatic motor), a pitch drive gearbox 130, and a pitch drive pinion 132. In such an embodiment, the pitch drive motor 128 may be coupled to the pitch drive gearbox 130 to apply mechanical force to the pitch drive gearbox 130. Similarly, the pitch drive gearbox 130 may be coupled to the pitch drive pinion 132 to rotate together with the pitch drive pinion 132. The pitch drive pinion 132 can then be rotatably engaged with the pitch bearing 134, which is connected between the hub 110 and the corresponding rotor blade 112, such that rotation of the pitch drive pinion 132 causes rotation of the pitch bearing 134. Thus, in such an embodiment, rotation of the pitch drive motor 128 drives the pitch drive gearbox 130 and the pitch drive pinion 132, thereby causing the pitch bearing 134 and(one or more) rotor blades 112 to rotate about the pitch axis 116. Similarly, the wind turbine 100 may include one or more yaw drive mechanisms 138 communicatively coupled to the controller 200, wherein each of the one or more yaw drive mechanisms 138 is configured to change the angle of the nacelle 106 relative to the wind (e.g., by engaging the yaw bearing 140 of the wind turbine 100).

[0105] Still referencing Figure 2 In an embodiment, the wind turbine 100 may include an environmental sensor 156 configured to collect data indicating one or more environmental conditions. The environmental sensor 156 may be operatively coupled to the controller 200. Thus, in an embodiment, the environmental sensor(s) 156 may be, for example, a wind vane, an anemometer, lidar sensor, thermometer, barometer, or other suitable sensor. The data collected by the environmental sensor(s) 156 may include measurements of wind speed, wind direction, wind shear, gusts, wind direction, atmospheric pressure, and / or temperature. In at least one embodiment, the environmental sensor(s) 156 may be mounted to the nacelle 106 at a leeward location of the rotor 108. In an alternative embodiment, the environmental sensor(s) 156 may be coupled to or integrated with the rotor 108. It should be appreciated that the environmental sensor(s) 156 may include a network of sensors and may be positioned remotely from the turbine 100.

[0106] Additionally, the wind turbine 100 may include one or more operating sensors 158. The operating sensors 158 may be configured to detect the performance of the wind turbine 100 in response to environmental conditions. For example, the operating sensors 158 may be speed sensors operatively coupled to the controller 200. The operating sensors 158 may be directed to the rotor shaft 122 of the wind turbine 100. The operating sensors 158 may acquire data indicating the rotational speed and / or rotational position of the rotor shaft 122 and thus the rotor 108, in the form of rotor speed and / or rotor azimuth angle. In embodiments, the operating sensors 158 may be analog tachometers, DC tachometers, AC tachometers, digital tachometers, contact tachometers, non-contact tachometers, or time and frequency tachometers.

[0107] Still referencing Figure 2 The wind turbine 100 may also include a plurality of sensors 160 for collecting data indicating the response of one or more components of the wind turbine 100 to rotor loads. For example, in an embodiment, one or more sensors 160 may be configured as strain gauges to detect tensile loads on the component. In additional embodiments, one or more sensors 160 may include at least one of accelerometers, photoelectric-optical sensors, acoustic sensors, transducers, lidar systems, vibration sensors, force sensors, rate sensors, piezoelectric sensors, position sensors, inclinometers, and / or torque sensors. One or more sensors 160 may, for example, be configured to collect sensor data indicating at least one of the following: nacelle acceleration, tower 102 vibration, rotor shaft 122 flexure, acoustic characteristics of the wind turbine 100, optical sensor obstruction due to the passage of rotor blades 112, rotor blade 112 continuity, horizontal (Q) deflection and vertical (D) deflection of rotor 108, and / or rotor 108 acceleration.

[0108] It should also be recognized that, as used herein, the term "monitoring" and its variations indicate that various sensors of the wind turbine 100 can be configured to provide direct or indirect measurements of the parameter being monitored. Thus, the sensors described herein can, for example, be used to generate signals relating to the parameter being monitored, which can then be used by the controller 200 to determine the condition or response of the wind turbine 100.

[0109] Now for reference Figure 4-7 This presents schematic diagrams of several embodiments of a system 300 for controlling a wind turbine 100 according to the present disclosure. (See also...) Figure 4The diagram, specifically shown, is a schematic representation of an embodiment of suitable components that can be included within system 300. For example, as shown, system 300 may include a controller 200 communicatively coupled to one or more sensors 156, 158, 160. Furthermore, as shown, controller 200 includes one or more processors 206 and associated memory devices 208 configured to perform a variety of computer-implemented functions (e.g., performing methods, steps, operations, etc., as disclosed herein and storing related data). Additionally, controller 200 may include a communication module 210 for facilitating communication between controller 200 and various components of wind turbine 100. Moreover, communication module 210 may include a sensor interface 212 (e.g., one or more analog-to-digital converters) for allowing signals transmitted from one or more sensors 156, 158, 160 to be converted into signals that can be understood and processed by processor 206. It should be appreciated that the one or more sensors 156, 158, 160 may be communicatively coupled to communication module 210 using any suitable means. For example, as shown... Figure 4 As shown, one or more sensors 156, 158, and 160 are connected to sensor interface 212 via wired connections. However, in other embodiments, one or more sensors 156, 158, and 160 may be coupled to sensor interface 212 via wireless connections (e.g., using any suitable wireless communication protocol known in the art). Additionally, communication module 210 may also be operatively coupled to operation state control module 214 configured to change the operating state of at least one wind turbine.

[0110] As used herein, the term "processor" refers not only to an integrated circuit considered in the art to be included in a computer, but also to a controller, microcontroller, microcomputer, programmable logic controller (PLC), application-specific integrated circuit, and other programmable circuits. Additionally, the memory device(s) 208 may generally include one or more 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 disc-read-only memory (CD-ROM), magneto-optical discs (MOD), digital universal discs (DVDs), and / or other suitable memory elements. Such a memory device(s) 208 may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s) 206, configure the controller 200 to perform various functions, including but not limited to detecting blade detachment events and initiating fast shutdown control logic to protect the wind turbine 100 as described herein, and various other suitable computer-implemented functions.

[0111] Special reference Figure 5 and Figure 6 As shown in 302, system 300 can be configured to determine multiple estimated response characteristics of wind turbine 100 corresponding to multiple different blade detachment event scenarios 306. For example, in one embodiment, controller 200 may include an imbalance estimator module 216 that can estimate the response of various components of wind turbine 100 to an estimated rotor load 304 for a given blade detachment event scenario 306. Blade detachment event scenario 306 may be based on the losses of a portion of rotor blade 112 when the rotor has a specified rotor speed 308 and rotor azimuth angle 310 at a deviation time 108. Based on the rotor orientation and speed at the deviation time under a given blade detachment event scenario 306, the estimated rotor load 304 caused by the deviation can be determined for that scenario. In another embodiment, a range of possible blade detachment event scenarios 306 can be modeled, and the resulting possible rotor loads for each scenario can be compiled in a lookup table and stored within the imbalance estimator module 216.

[0112] In an additional embodiment, the imbalance estimator module 216 may include an algorithm that can calculate the estimated rotor load 304 based at least on data indicating rotor speed 308 and rotor azimuth angle 310 received from one or more operating sensors 158. In such an embodiment, the controller 200 of the system 300 may be configured to continuously calculate the estimated rotor load 304 due to possible losses of at least a portion of the rotor blades 112 based on real-time performance data of the wind turbine 100.

[0113] In one embodiment, the imbalance estimator module 216 can use the estimated rotor load 304 to determine the estimated response characteristics 302 for various components of the wind turbine 100. In other words, the imbalance estimator module 216 can predict how the responses of various components of the wind turbine 100 to unbalanced loads can be reflected by data from multiple sensors 160. For example, as depicted at 312, the system 300 can estimate the horizontal (Q) displacement and vertical (D) displacement of the rotor 108 (which can be expressed as predicted acceleration vectors) in response to the load on the rotor 108 under a blade shedding event scenario 306. In an additional embodiment, the system 300 can estimate the acceleration of the nacelle 106 of the wind turbine 100 at 314 in response to the estimated rotor load 304. This response of the nacelle 106 can include the oscillation direction, oscillation frequency, and oscillation amplitude of the nacelle 106 in response to the unbalanced load. In another embodiment, the system 300 can determine the estimated response characteristics, including the rotor speed response, at 316. In at least one embodiment, the rotor speed response can indicate the rotor 108's acceleration or deceleration in response to rotor mass balance and the rotational position of the rotor 108 at the moment of at least partial loss of the rotor blade 112 in blade shedding scenario 306.

[0114] It should be appreciated that, in the embodiments, the estimated response characteristics of the components of the wind turbine 100 corresponding to different blade detachment event scenarios 306 can be modeled, and the possible rotor loads obtained for each scenario can be compiled in a lookup table and stored within the controller 200. In an additional embodiment, the imbalance estimator module 216 may include an algorithm that can calculate the estimated response characteristics of the components based on the continuously calculated estimated rotor load 304.

[0115] Still referencing Figure 5 and Figure 6 As shown in 318, system 300 can be configured to collect sensor data 320 via one or more sensors 160 during operation of wind turbine 100. Sensor data 320 can indicate the response of components of wind turbine 100 to the actual load on rotor 108 during normal operation.

[0116] In embodiments, sensor data 320 may reflect the component's response to rotor loads in the form of load amplitude and / or load direction. For example, in embodiments, the load direction may be along or reciprocal to the pitch axis 116. In such embodiments, a load reciprocal to the pitch axis 116 may indicate at least a portion of the losses in the rotor blade 112. In additional embodiments, sensor data 320 may indicate the acceleration vector of the component (such as nacelle 106, tower 102, or rotor 108). Sensor data 320 may also include vibration characteristics, which may be a first excitation frequency corresponding to a blade shedding event. In various embodiments, this vibration characteristic may indicate the vibration level / characteristics in the rotor blade 112, hub 110, nacelle 106, base and / or top of tower 102, and / or any other component of the wind turbine 100. It should be appreciated that the first excitation frequency may be a first frequency corresponding to the rotational frequency of the rotor 108.

[0117] In an additional embodiment, sensor data 320 may indicate communication loss with at least one of the sensors 160(one or more). For example, a detachment event may also sever communication coupling with one of the sensors 160(one or more) (e.g., strain gauges, temperature sensors, vibration sensors, piezoelectric sensors, etc.) coupled to the rotor blade 112. In another embodiment, sensor data 320 may include the acoustic characteristics of the wind turbine. In such an embodiment, a change in the acoustic characteristics of the wind turbine 100 may indicate a detachment event. In yet another embodiment, sensor data 320 may indicate bending moments affecting the rotor shaft 122 and / or tower 102. It should be appreciated that an increase in bending moment may indicate an unbalanced load generated by the rotor 108 in response to a blade detachment event. It should be further appreciated that sensor data 320 collected by sensors 158, 160 may include additional characteristics and / or combinations of characteristics indicating the response of components of the wind turbine 100 to actual rotor loads.

[0118] As in Figure 6 As depicted in 322, in this embodiment, the acceleration vector indicated by sensor data 320 may correspond to the actual horizontal (Q) displacement and actual vertical (D) displacement of rotor 108 in response to a load on rotor 108. Additionally, sensor data 320 may correspond to out-of-plane imbalances of rotor 108. For example, at least partial losses of rotor blades 112 may cause rotor 108 to generate off-axis loads. Off-axis loads may generate bending moments that can be transmitted to rotor shaft 122 via hub 110. These bending moments can be indicated by the vertical (D) displacement and / or horizontal (Q) displacement of rotor 108 relative to a nominal rotor position balanced about axis (A) of rotor 108.

[0119] like Figure 6 As depicted in the figure, in an additional embodiment, multiple acceleration vectors corresponding to the responses of different components of the wind turbine 100 can be indicated by sensor data 320. As depicted in 324, in an embodiment, one of the acceleration vectors may correspond to the actual acceleration of the nacelle 106 in response to the actual load on the rotor 108 in response to a blade shedding event. In an embodiment, the response of the nacelle 106 may include the oscillation direction, oscillation frequency, and oscillation amplitude of the nacelle 106 in response to an unbalanced load. For example, the shedding of a portion of a rotor blade may result in a rotor mass imbalance, wherein the center of mass of the rotor 108 may shift from the axis (A) to a point defined on an arc between the remaining(one or more) intact rotor blades 112. In response to the rotor mass imbalance, the nacelle 106 may accelerate in the direction of the shifted center of mass of the rotor 108. However, as the rotor 108 continues to rotate, the position of the shifted center of mass may traverse the arc so that the nacelle 106 accelerates in the opposite direction from the initial acceleration. In an embodiment, system 300 may be configured to correlate the frequency and amplitude of acceleration of nacelle 106 with the actual load on rotor 108. It should be appreciated that by correlating the acceleration vector of nacelle 106 with the actual load on rotor 108, system 300 can distinguish the acceleration vector caused by blade shedding events from acceleration vectors corresponding to other forces such as gusts.

[0120] As in Figure 6 As depicted in 326, in an embodiment, the acceleration vector indicated by sensor data 320 may correspond to the actual rotor speed response. In an embodiment, the rotor speed response may indicate acceleration and / or deceleration of rotor 108 in response to rotor mass imbalance and rotational position of rotor 108. For example, in the case where a detachment event causes the center of mass of rotor 108 to shift from axis (A), the resulting rotor mass imbalance may cause the rotor to accelerate when the shifted center of mass is located on the descending arc of rotor 108. Furthermore, as the shifted center of mass passes through the vertical plane and transitions to the ascending arc, gravity may act on the shifted center of mass, potentially causing the rotor 108 to slow down. Therefore, in an embodiment, system 300 may be configured to detect a detachment event based at least in part on the periodic acceleration and deceleration of rotor 108 as rotor 108 rotates through 360 degrees.

[0121] Special reference Figure 5As shown in 328, system 300 can be configured to identify at least two (e.g., three or more) actual response characteristics within sensor data 320. These actual response characteristics can indicate a blade shedding event. For example, in one embodiment, the controller can be configured to detect a blade shedding event whenever any of the inputs from one or more sensors 160 intersects with a predetermined threshold indicating the likelihood of such an event. In an additional embodiment, system 300 can be configured to filter sensor data 320 to focus on multiple filtered inputs, modeling which can predict that said multiple filtered inputs will accurately and / or rapidly indicate a shedding event. It should be appreciated that identifying at least two actual response characteristics within sensor data 320 can reduce the likelihood of false alarms by providing system 300 with multiple actual response characteristics that can indicate at least a portion of the loss of rotor blade 112.

[0122] As shown at 330, system 300 can also be configured to determine whether at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics of a plurality of estimated response characteristics in order to determine the existence of a blade detachment event. Accordingly, system 300 can compare the actual response characteristics indicated by sensor data 320 with the corresponding estimated response characteristics at 332. System 300 can be configured at 334 to determine whether at least two (if no more) of the actual response characteristics exceed the estimated response characteristics for any of the blade detachment event scenarios 306. In embodiments where at least two of the actual response characteristics of one or more components of the wind turbine 100 at least match the corresponding estimated response characteristics, system 300 can determine at 336 that a blade detachment event has occurred.

[0123] As illustrated in the embodiments, such as Figure 6 As depicted, system 300 can determine whether three actual response characteristics are equal to or exceed three or more corresponding estimated response characteristics for any one of various blade detachment event scenarios 306. For example, system 300 can compare the actual rotor horizontal (Q) displacement and vertical (D) displacement 322 with the estimated rotor horizontal (Q) displacement and vertical (D) displacement 312 at 338. Simultaneously, system 300 can compare the actual nacelle acceleration 324 with the estimated nacelle acceleration 314 at 340. Additionally, system 300 can simultaneously compare the actual rotor speed response 326 with the estimated rotor speed response 316 at 342. As depicted at 344, system 300 can then determine whether each of the actual response characteristics matches or exceeds the corresponding estimated response characteristic. In an embodiment, system 300 can be configured at 346 to detect a blade detachment event only if all actual responses match or exceed the estimated response for blade detachment event scenario 306.

[0124] It should be recognized that utilizing multiple actual response characteristics from multiple sensors (one or more) of sensor(s) 160 can facilitate rapid detection of blade detachment events. Specifically, the response of wind turbine 100 to different blade detachment event scenarios 306 may vary. For example, in an embodiment, the actual response characteristics of a component of wind turbine 100 may be within normal limits at the start of one blade detachment event scenario 306, while exhibiting a readily detectable deviation from the normal limits in another blade detachment event scenario 306. Therefore, utilizing multiple sensors that collect operational data from various components of wind turbine 100 can be used to limit delays in the detection of blade detachment events.

[0125] It should also be recognized that, ideally, the reliability of any blade shedding event detection can be improved by limiting and reporting false detections. This improvement in detection reliability can be facilitated by ensuring that at least two of the actual response characteristics meet or exceed the requirements of the corresponding estimated response characteristics. Thus, by employing multiple sensors and requiring two more actual response characteristics consistent with the predicted response characteristics, the speed and reliability of blade shedding detection can be improved compared to systems requiring fewer sensors and / or fewer response characteristics.

[0126] In an embodiment, system 300 can determine the type of blade detachment event based on actual response characteristics. For example, in an embodiment, the magnitude of rotor speed response and acceleration of nacelle 106 can indicate that the entire blade 112 has detached from hub 110. However, if the magnitude of rotor speed response and acceleration is less than the magnitude predicted for a complete blade deviation, it can indicate partial blade detachment. In an embodiment, when wind turbine 100 is at rated power, actual response characteristics can correspond to a blade detachment event when the loss of blade 112 exceeds 25% of the rotor blade span. In an additional embodiment, when wind turbine 100 is operating at less than rated power, actual response characteristics can correspond to a blade detachment event when the loss of blade 112 exceeds 50% of the rotor blade span.

[0127] Refer again Figure 6 And also refer to Figure 7As depicted in 348, controller 200 may activate fast shutdown control logic to protect wind turbine 100 in response to detecting a blade detachment event. In an embodiment, the fast shutdown control logic may be configured to decelerate rotor 108 within a shortened time interval relative to the nominal shutdown control logic by establishing a deceleration rate of rotor 108 exceeding its nominal deceleration rate at 352. It should be appreciated that establishing the deceleration rate of rotor 108 may require a maximum force opposite to the rotation of rotor 108. Such drag / braking force may be generated by one or more components of wind turbine 100. Additionally, in an embodiment, activation of the fast shutdown control logic may coincide with the generation of a warning signal by system 300.

[0128] As in Figure 7 As depicted in section 350, implementing the fast shutdown control logic may include exceeding the nominal operating limits of at least one component of the wind turbine 100. The nominal operating limit may be a component design limitation calculated to maintain the longest usable life of that component. For example, the nominal operating limit may correspond to a temperature limit, torque limit, load limit, position limit, power limit, engagement limit, and / or any other relevant limit or combination of limits.

[0129] In an embodiment, system 300 may establish a rapid shut-off setpoint for one or more components at 354. In an embodiment, the rapid shut-off setpoint may have a value greater than the nominal operating limit of the component. It should be appreciated that establishing a rapid shut-off setpoint above the nominal operating limit may allow for excessive load or damage to the component. It should be further appreciated that excessive load or damage to one or more components may be acceptable to facilitate rapid deceleration of rotor 108 following a blade shedding event.

[0130] As shown in 356, in one embodiment, the controller 200 of system 300 may be configured to generate pitch setpoint commands for a plurality of rotor blades 112. The pitch setpoint commands may instruct the pitch control mechanism 120 to pitch the rotor blades 112 toward feathering about the pitch axis 116 at a pitch rate exceeding a nominal pitch rate threshold. In other words, the controller 200 may instruct the rotor blades 112 to pitch away from power deviation in a manner as rapid as the pitch control mechanism 120 could produce without regard to potential damage to the pitch control mechanism 120. It should be appreciated that pitching the rotor blades 112 into feathering can limit the amount of rotational speed applied to the rotor 108 in response to wind flow over the rotor blades 112.

[0131] Furthermore, as shown in 358, in an additional embodiment, the controller 200 of system 300 may be configured to generate a generator setpoint for the generator 118 of the wind turbine 100. The generator setpoint may instruct the converter controller 218 to generate generator torque exceeding the nominal generator torque limit. In other words, the controller 200 may instruct the converter controller 218 to generate the maximum amount of torque without considering the possibility of damage to components of the wind turbine's electrical system. For example, generating torque at the generator setpoint could result in thermal damage to at least one component of the wind turbine 100's electrical system.

[0132] In additional embodiments, the rapid shutdown control logic may include additional means for decelerating rotor 108. For example, in the embodiment depicted in 360, controller 200 may trigger a gearbox braking system 166 operatively coupled to gearbox 126. Gearbox braking system 166 may be a device configured to engage gears 148 of gearbox 126 and constrain rotation of gears 148. For example, in an embodiment, gearbox braking system 166 may include a pawl or other similar structure positioned adjacent to at least one of the gears 148. When gearbox braking system 166 is triggered by controller 200, the pawl may be driven into gear(s) 148 to engage and hold the teeth of gear(s) 148. In an embodiment, the pawl may be made of a sacrificial material that may significantly slow the rotation of gear(s) 148 and thus rotor 108. In another embodiment, gearbox braking system 166 may be configured to introduce a highly viscous fluid into gearbox 126. For example, the gearbox braking system 166 may introduce foam, mud, emulsion, resin, adhesive and / or other suitable materials with viscous properties that may significantly slow down the rotation of the gear 148.

[0133] In an embodiment, system 300 may be configured to simultaneously employ more than one of the braking paths disclosed herein. For example, in an embodiment, system 300 may simultaneously activate brake 152, generate pitch setpoint command, generate generator setpoint command, and trigger gearbox braking system.

[0134] Now for reference Figure 8 The diagram illustrates one embodiment of the response of a wind turbine 100 to a blade detachment event. Figure 8 In the first curve 362, the response of a component of the wind turbine 100 to a blade detachment event can be depicted without the implementation of the fast shutdown control logic. In contrast, a second curve 364 can depict the response when the response of one or more components is suppressed by implementing the fast shutdown control logic according to this disclosure. Figure 8As depicted, using system 300 can reduce the maximum component response 366. For example, in the embodiment where curve 364 represents the horizontal (Q) displacement of nacelle 106, the maximum component response 366 could indicate a horizontal (Q) displacement greater than 2 meters (m) in response to a blade detachment event. However, for the same blade detachment event, establishing a reduction rate of rotor 108 exceeding the nominal reduction rate at 352 could result in a maximum component response 366 of less than 1.5 m.

[0135] In an additional embodiment, system 300 may decelerate the rotor within a shortened time interval 370 at 368. The shortened time interval 370 may represent two oscillations of component(s) following a blade shedding event. For example, in an embodiment, system 300 may establish a reduction of one-third of the rotor speed 308 within two oscillations of nacelle 106 in response to at least a portion of the loss of rotor blade 112 by implementing fast shutdown control logic. The two oscillations of nacelle 106 may correspond to a 720-degree rotation of rotor 108.

[0136] Refer again Figure 7 As depicted in 372, controller 200 can detect a speed of rotor 108 less than 40% of its rated speed. In other words, from the moment a blade detachment event is detected, system 300 can apply a force, such as that used to decelerate the rotor, within the shortest possible time interval 370. However, as previously discussed, this force can be generated in a manner that results in a shortened usable lifespan of one or more components of wind turbine 100. Therefore, as shown in 374, when the speed of rotor 108 is less than 40% of its rated speed, controller 200 can reduce the generator setpoint for generator 118 to reduce generator torque. Reducing the generator setpoint can establish a generator torque level below the nominal generator torque limit.

[0137] As depicted in 376, in an embodiment, system 300 may be configured to monitor the torque level of sliding coupling 154. It should be appreciated that in embodiments where the torque level of sliding coupling 154 exceeds its nominal release threshold, sliding coupling 154 can operatively disengage generator 118 from rotor shaft 122. In such embodiments, the torque generated by generator 118 may then be unavailable to aid in the deceleration of rotor 108. Therefore, system 300 may detect at 378 that the torque level is approaching the release threshold. If the torque level is not approaching the release threshold, system 300 may maintain the generator setpoint at 380 to continue decelerating the rotor over shortened time intervals. However, in embodiments where the torque level of sliding coupling 154 is approaching the release threshold, system 300 may decrease the generator setpoint at 382 to maintain operative connection between generator 118 and rotor 108.

[0138] Furthermore, those skilled in the art will recognize the interchangeability of various features from different embodiments. Similarly, those skilled in the art can mix and match the various method steps and features described, as well as other known equivalents for each such method and feature, to construct additional systems and techniques in accordance with the principles of this disclosure. It will be understood, of course, that not all such objectives or advantages described above may necessarily be achieved according to any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or implemented in a manner that achieves or optimizes one or a set of advantages as taught herein, but not necessarily achieves other objectives or advantages as may be taught or suggested herein.

[0139] This written description uses examples to disclose the invention (including the best mode) and also enables any person skilled in the art to practice the invention (including making and using any device or system and performing any incorporated method). The patentability scope of the invention is defined by the claims and may include other examples that would occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they comprise structural elements that are not different from the literal language of the claims, or if they comprise equivalent structural elements that are not substantially different from the literal language of the claims.

[0140] Further aspects of the invention are provided by the subject matter of the following provisions:

[0141] Clause 1. A method for controlling a wind turbine in response to a blade detachment event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising: determining a plurality of estimated response characteristics of the wind turbine corresponding to a plurality of different blade detachment events; collecting sensor data via a plurality of sensors during operation of the wind turbine, the sensor data indicating the response of at least one component of the wind turbine to actual rotor loads; identifying at least two actual response characteristics within the sensor data; determining whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics of the plurality of estimated response characteristics to determine the presence of a blade detachment event; and, in response to detecting a blade detachment event, using a controller to initiate fast shutdown control logic to protect the wind turbine.

[0142] Clause 2. The method of Clause 1, wherein a plurality of response characteristics include at least one or a combination thereof, load amplitude, load direction along the pitch axis, acceleration vector of at least one component, first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

[0143] Clause 3. Any of the methods described in the preceding clauses, wherein the acceleration vector of at least one component comprises: horizontal and vertical displacements of the rotor in response to loads on the rotor.

[0144] Clause 4. Any of the methods described in the preceding clause, wherein the acceleration vector of at least one component comprises: the acceleration of the nacelle of the wind turbine in response to wind load, wherein the nacelle acceleration comprises the nacelle's oscillation direction, oscillation frequency, and oscillation amplitude.

[0145] Clause 5. Any of the methods described in the preceding clauses, wherein the acceleration vector of at least one component comprises: a rotor speed response, wherein the rotor speed response indicates acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

[0146] Clause 6. Any of the methods described in the foregoing clauses further includes: determining the type of blade detachment event based on at least two actual response characteristics, wherein the type of blade detachment event includes at least a partial deviation of one of a plurality of rotor blades.

[0147] Clause 7. Any of the methods described in the preceding clause, wherein the rapid shutdown control logic comprises causing the rotor to decelerate over a shortened time interval relative to the nominal shutdown control logic.

[0148] Clause 8. Any of the methods described in the preceding clause, wherein the fast-shutdown control logic comprises: exceeding the nominal operating limit of at least one component of the wind turbine; and establishing a fast-shutdown setpoint for at least one component, wherein the fast-shutdown setpoint has a value greater than the nominal operating limit such that excessive load or damage to at least one component is permissible.

[0149] Clause 9. A method for controlling a wind turbine in response to a blade detachment event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising: receiving data from a plurality of sensors indicating a blade detachment event during operation of the wind turbine using a controller; and, in response to detecting a blade detachment event, initiating fast shutdown control logic using the controller to protect the wind turbine, the fast shutdown control logic comprising: exceeding a nominal operating limit of at least one component of the wind turbine; establishing a fast shutdown setpoint for at least one component, wherein the fast shutdown setpoint has a value greater than the nominal operating limit such that excessive load or damage to at least one component is permissible; and establishing a rotor deceleration rate exceeding a nominal deceleration rate of the rotor.

[0150] Clause 10. Any of the methods described in the preceding clause, wherein establishing a fast-closing setpoint comprises at least one of the following: using a controller to generate a pitch setpoint command for a plurality of rotor blades, wherein the pitch setpoint command instructs a pitch control mechanism to pitch the plurality of rotor blades to feather at a pitch rate exceeding a nominal pitch rate threshold; and using a controller to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs a converter controller to generate a generator torque exceeding a nominal generator torque limit.

[0151] Clause 11. Any of the methods described in the preceding clause, wherein the rapid shutdown control logic further comprises: using a controller to trigger a gearbox braking system operatively coupled to a gearbox of a wind turbine.

[0152] Clause 12. Any of the methods described in the preceding clause, wherein the wind turbine further comprises operably coupling the rotor to a high-speed shaft of a generator via a gearbox, the gearbox being operably coupled to the generator via a sliding coupling of the high-speed shaft, the method further comprising: monitoring the torque level of the sliding coupling; and reducing the generator setpoint when the torque level of the sliding coupling approaches a release threshold of the sliding coupling.

[0153] Clause 13. Any of the methods described in the foregoing clauses further includes: following the detection of a blade shedding event, establishing a reduction of one-third of the rotor speed within 720 degrees of rotor rotation.

[0154] Clause 14. A wind turbine comprising: a tower; a nacelle mounted on top of the tower; a rotor mounted to the nacelle, the rotor including a rotatable hub having a plurality of rotor blades fastened to the rotatable hub via a pitch drive mechanism; a generator disposed within the nacelle and operatively coupled to the rotor via a gearbox and a high-speed shaft; and a controller communicatively coupled to the pitch drive mechanism, the generator, and a plurality of sensors, the controller including at least one processor configured to perform a plurality of operations, the plurality of operations including: collecting sensor data via the plurality of sensors during operation of the wind turbine, the sensor data indicating the response of components of the wind turbine to rotor loads; identifying at least two actual response characteristics within the sensor data; determining whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics of a plurality of estimated response characteristics in order to determine the existence of a blade detachment event, wherein the plurality of estimated response characteristics correspond to a plurality of different blade detachment events; and, in response to detecting a blade detachment event, using the controller to initiate fast shutdown control logic to protect the wind turbine.

[0155] Clause 15. Any wind turbine of the foregoing clauses, wherein multiple response characteristics include at least one or a combination thereof, including load amplitude, load direction along the pitch axis, acceleration vector of at least one component, first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

[0156] Clause 16. Any wind turbine of the foregoing clauses shall have multiple response characteristics including multiple acceleration vectors, the multiple acceleration vectors including: nacelle acceleration in response to wind load, wherein the nacelle acceleration includes the nacelle oscillation direction, oscillation frequency and oscillation amplitude; rotor horizontal and vertical displacements in response to loads on the rotor; and rotor speed response, wherein the rotor speed response indicates the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

[0157] Clause 17. Any wind turbine of the foregoing clauses, wherein the plurality of operations further comprises: determining the type of blade detachment event based on at least two actual response characteristics, wherein the type of blade detachment event includes at least a partial deviation of one of the plurality of rotor blades.

[0158] Clause 18. Any wind turbine of the foregoing clause, wherein the fast shutdown control logic includes causing the rotor to decelerate over a shortened time interval relative to the nominal shutdown control logic.

[0159] Clause 19. Any wind turbine of the foregoing clauses, wherein the time interval for decelerating and shortening the rotor comprises: using a controller to generate a pitch setpoint command for a plurality of rotor blades, wherein the pitch setpoint command instructs a pitch control mechanism to pitch the plurality of rotor blades to feather at a pitch rate exceeding a nominal pitch rate threshold; and using a controller to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs a converter controller to generate a generator torque exceeding a nominal generator torque threshold; and exceeding the operating limits of at least one component of the wind turbine, wherein the operating limits are higher than nominal operating limits such that excessive load or damage to at least one component is permissible.

[0160] Clause 20. Any wind turbine of the foregoing clauses, wherein the high-speed shaft further includes a sliding coupling, and the plurality of operations further include: monitoring the torque level of the sliding coupling; and reducing the generator setpoint when the torque level of the sliding coupling approaches the release threshold of the sliding coupling.

Claims

1. A method for controlling a wind turbine in response to a blade shedding event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising: Determine multiple estimated response characteristics for the wind turbine corresponding to multiple different blade shedding events; During operation of the wind turbine, sensor data is collected via multiple sensors, the sensor data indicating the response of at least one component of the wind turbine to actual rotor load; Identify at least two actual response characteristics within the sensor data; To determine whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics among the plurality of estimated response characteristics, in order to determine the existence of the leaf drop event; as well as In response to the detection of the blade detachment event, the controller initiates a fast shutdown control logic to protect the wind turbine. The fast shutdown control logic includes: Exceeding the nominal operating limit of at least one component of the wind turbine; and Establish a quick-close setpoint for the at least one component, wherein the quick-close setpoint has a value greater than the nominal operating limit, such that excessive load or damage to the at least one component is permissible.

2. The method according to claim 1, wherein, The plurality of response characteristics include at least one or a combination thereof, load amplitude, the load along the pitch axis, the acceleration vector of the at least one component, a first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

3. The method according to claim 2, wherein, The acceleration vector of the at least one component includes: The rotor responds to the horizontal and vertical displacements of the load on the rotor.

4. The method according to claim 2, wherein, The acceleration vector of the at least one component includes: The nacelle of the wind turbine responds to the acceleration of the wind load, wherein the nacelle acceleration includes the oscillation direction, oscillation frequency, and oscillation amplitude of the nacelle.

5. The method according to claim 2, wherein, The acceleration vector of the at least one component includes: Rotor speed response, wherein the rotor speed response indicates the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

6. The method of claim 1, further comprising: The type of blade shedding event is determined based on the at least two actual response characteristics, wherein the type of blade shedding event includes at least a partial deviation of one of the plurality of rotor blades.

7. The method according to claim 1, wherein, The fast shutdown control logic includes decelerating the rotor within a shortened time interval relative to the nominal shutdown control logic.

8. A method for controlling a wind turbine in response to a blade shedding event, the wind turbine having a rotor having a rotatable hub and a plurality of rotor blades mounted to the rotatable hub, the method comprising: During the operation of the wind turbine, a controller is used to receive data from multiple sensors indicating blade detachment events; as well as In response to the detection of the blade detachment event, the controller is used to initiate fast shutdown control logic to protect the wind turbine, the fast shutdown control logic including: Exceeding the nominal operating limit of at least one component of the wind turbine, Establish a quick-closing setpoint for the at least one component, wherein the quick-closing setpoint has a value greater than the nominal operating limit, such that excessive load or damage to the at least one component is permissible, and Establish a reduction rate for the rotor that exceeds its nominal reduction rate.

9. The method according to claim 8, wherein, Establishing the fast-closing setpoint includes at least one of the following: The controller is used to generate pitch setpoint commands for the plurality of rotor blades, wherein the pitch setpoint commands instruct the pitch control mechanism to pitch the plurality of rotor blades into feathering at a pitch rate exceeding a nominal pitch rate threshold; and The controller is used to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs the converter controller to generate generator torque exceeding the nominal generator torque limit.

10. The method according to claim 8, wherein, The fast shutdown control logic further includes: The controller is used to trigger a gearbox braking system operably connected to the gearbox of the wind turbine.

11. The method according to claim 9, wherein, The wind turbine further includes a high-speed shaft of the generator operably connected to the rotor via a gearbox, the gearbox being operably connected to the generator via a sliding coupling of the high-speed shaft, and the method further includes: Monitor the torque level of the sliding coupling; and When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the generator set point is reduced.

12. The method of claim 9, further comprising: Following the detection of the blade shedding event, a reduction of one-third of the rotor's rotational speed is established within 720 degrees of rotor rotation.

13. A wind turbine, comprising: Tower; The nacelle is mounted on top of the tower. A rotor, which is mounted to the nacelle, the rotor including a rotatable hub having a plurality of rotor blades fastened to the rotatable hub via a pitch drive mechanism; A generator, which is located in the nacelle and is operatively connected to the rotor via a gearbox and a high-speed shaft; as well as A controller communicatively coupled to multiple sensors, the generator, and the pitch drive mechanism, the controller including at least one processor configured to perform multiple operations, the multiple operations including: During operation of the wind turbine, sensor data is collected via the plurality of sensors, the sensor data indicating the response of the wind turbine's components to rotor loads. Identify at least two actual response characteristics within the sensor data. To determine the existence of the leaf abscission event, it is necessary to determine whether the at least two actual response characteristics are equal to or exceed two or more corresponding estimated response characteristics of a plurality of estimated response characteristics, wherein the plurality of estimated response characteristics correspond to a plurality of different leaf abscission events. In response to the detection of the blade detachment event, a controller is used to activate a fast shutdown control logic to protect the wind turbine, wherein the fast shutdown control logic includes: exceeding the nominal operating limit of at least one component of the wind turbine; and establishing a fast shutdown setpoint for the at least one component, wherein the fast shutdown setpoint has a value greater than the nominal operating limit, such that excessive load or damage to the at least one component is permissible.

14. The wind turbine according to claim 13, wherein, The plurality of response characteristics include at least one or a combination thereof, load amplitude, the load along the pitch axis, the acceleration vector of the at least one component, a first excitation frequency, sensor communication loss, acoustic characteristics corresponding to blade detachment, vibration characteristics corresponding to blade detachment, and bending moment affecting the rotor shaft or tower of the wind turbine.

15. The wind turbine of claim 14, wherein the plurality of response characteristics includes a plurality of acceleration vectors, the plurality of acceleration vectors comprising: The nacelle responds to the acceleration of the wind load, wherein the nacelle acceleration includes the nacelle's oscillation direction, oscillation frequency, and oscillation amplitude; The rotor responds to the horizontal and vertical displacements of the load on the rotor; and Rotor speed response, wherein the rotor speed response indicates the acceleration or deceleration of the rotor in response to rotor mass balance and rotational position.

16. The wind turbine according to claim 13, wherein, The plurality of operations further include: The type of blade shedding event is determined based on the at least two actual response characteristics, wherein the type of blade shedding event includes at least a partial deviation of one of the plurality of rotor blades.

17. The wind turbine according to claim 13, wherein, The fast shutdown control logic includes decelerating the rotor within a shortened time interval relative to the nominal shutdown control logic.

18. The wind turbine according to claim 17, wherein, The time intervals for slowing down and shortening the rotor include: The controller is used to generate pitch setpoint commands for the plurality of rotor blades, wherein the pitch setpoint commands instruct the pitch control mechanism to pitch the plurality of rotor blades into feathering at a pitch rate exceeding a nominal pitch rate threshold; and The controller is used to generate a generator setpoint for the generator of the wind turbine, wherein the generator setpoint instructs the converter controller to generate generator torque exceeding a nominal generator torque threshold; and Exceeding the operating limits of at least one component of the wind turbine, wherein the operating limits are higher than the nominal operating limits, such that excessive load or damage to the at least one component is permissible.

19. The wind turbine according to claim 18, wherein, The high-speed shaft further includes a sliding coupling, and the plurality of operations further include: Monitor the torque level of the sliding coupling; and When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the generator set point is reduced.

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