System and method for protecting a wind turbine from overload due to pitch system failure

Abstract

The subject of the present invention is "System and method for protecting a wind turbine from overload due to a pitch system fault". A method for protecting a wind turbine from overload caused by a fault during operation includes receiving, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes. In addition, the method includes determining a common pitch rate of the pitch system as a function of the plurality of pitch signals. The method also includes defining a minimum pitch rate threshold value that varies with a speed parameter of the wind turbine. In addition, the method includes receiving a first speed parameter of the wind turbine. In addition, the method includes comparing the common pitch rate with a minimum pitch rate threshold value for the first speed parameter. Thus, the method includes controlling the wind turbine based on the comparison.

Description

Technical Field

[0001] The present disclosure relates generally to wind turbines, and more particularly to systems and methods for operating a wind turbine to protect the wind turbine from overloads caused by a fault in its pitch system. Background Art

[0002] Wind power is considered to be one of the cleanest and most environmentally friendly energy sources currently available, and wind turbines have gained increasing attention in this regard. Modern wind turbines typically include a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The nacelle includes a rotor assembly coupled to the gearbox and coupled to the generator. The rotor assembly and the gearbox are mounted to a base support frame located within the nacelle. The one or more rotor blades utilize the known airfoil principle to capture the kinetic energy of the wind. The rotor blades transmit kinetic energy in the form of rotational energy so as to rotate a shaft that couples the rotor blades to the gearbox, or if a gearbox is not used, to rotate a shaft that couples the rotor blades directly to the generator. The generator then converts the mechanical energy into electrical energy, which can be transmitted to a converter and / or transformer housed in the tower and subsequently deployed to the utility grid.

[0003] During operation, the speed of the wind powering a wind turbine can change. A wind turbine may therefore include a pitch system having multiple pitch adjustment mechanisms (i.e., one pitch adjustment mechanism per rotor blade) to adjust the pitch of individual rotor blades about a pitch axis. During normal operation, the pitch adjustment mechanisms receive pitch commands from a turbine controller. For wind speeds below a rated threshold for the wind turbine, the turbine controller may calculate the desired pitch of the individual rotor blades to maximize the power generated at a given wind speed. For wind speeds above the rated threshold for the wind turbine, the turbine controller may calculate the desired pitch of the individual rotor blades to reduce thrust generation below a specified design limit.

[0004] However, if one or more of the pitch adjustment mechanisms experiences a fault or software malfunction, the pitch system may continue to pitch the rotor blades in a manner that could overload the wind turbine. Alternatively, a fault in other turbine components may cause the controller to send a pitch command to fine pitch while the rotor speed is considered high.

[0005] Therefore, the art is continually seeking new and improved systems and methods for addressing the aforementioned problems. Accordingly, the present disclosure is directed to systems and methods for operating a wind turbine to protect the wind turbine from overloads caused by faults in its pitch system. In particular, the present disclosure is directed to systems and methods for collective pitch rate supervision that allow for flexibility in defining pitch rate thresholds. Summary of the Invention

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

[0007] In one aspect, the present disclosure is directed to a method for protecting a wind turbine from an overload caused by a fault during operation. The method includes receiving, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes. Furthermore, the method includes determining, by means of the controller, a common pitch rate of the pitch system as a function of the plurality of pitch signals. The method also includes defining, by means of the controller, a minimum pitch rate threshold that varies with a speed parameter of the wind turbine. Furthermore, the method includes receiving, by means of the controller, a first speed parameter of the wind turbine. Furthermore, the method includes comparing, by means of the controller, the common pitch rate with a minimum pitch rate threshold for the first speed parameter. Thus, the method includes controlling the wind turbine based on the comparison, by means of the controller.

[0008] In an embodiment, the method comprises measuring a plurality of pitch signals by means of a plurality of sensors. In an embodiment, the plurality of pitch signals may comprise a plurality of pitch speed signals.

[0009] In an alternative embodiment, the plurality of pitch signals may include a plurality of pitch position signals. In such an embodiment, the method may include determining a derivative of each of the plurality of pitch position signals to obtain a plurality of pitch velocity signals. Additionally, the method may include filtering the plurality of pitch position derivatives to reduce noise.

[0010] In further embodiments, determining the collective pitch rate as a function of the plurality of pitch signals may include averaging the plurality of pitch signals to obtain the collective pitch rate.

[0011] In additional embodiments, the speed parameter of the wind turbine may include rotor speed, generator speed, or derivatives thereof, and any other suitable speed parameter of the wind turbine.

[0012] In certain embodiments, comparing the collective pitch rate to a minimum pitch rate threshold for the first speed parameter may include utilizing a lookup table.

[0013] In another embodiment, controlling the wind turbine based on the comparison may include pitching the plurality of pitch control mechanisms at a constrained pitch rate if the speed parameter is below a speed threshold for a certain period of time, and performing a control action if the speed parameter is above the speed threshold for a certain period of time. In such an embodiment, the control action may include shutting down the wind turbine, pitching the plurality of pitch control mechanisms at a maximum pitch rate, de-rating the wind turbine, or any other suitable corrective action.

[0014] In yet another embodiment, the controller may be a turbine controller or a separate controller module communicatively coupled to the turbine controller.

[0015] In another aspect, the present disclosure is directed to a pitch system for a wind turbine. The pitch system includes a plurality of pitch control mechanisms for generating a plurality of pitch signals associated with a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine, and a controller communicatively coupled to the plurality of pitch control mechanisms. The controller includes at least one processor configured to perform a plurality of operations including, but not limited to, determining a collective pitch rate for the pitch system as a function of the plurality of pitch signals, defining a minimum pitch rate threshold that varies with a speed parameter of the wind turbine, receiving a first speed parameter of the wind turbine, comparing the collective pitch rate with the minimum pitch rate threshold for the first speed parameter, and controlling the wind turbine based on the comparison. It should be understood that the pitch system may further include any of the additional steps and / or features described herein.

[0016] Technical Solution 1 is provided: a method for protecting a wind turbine from overload caused by a fault during operation, the method comprising:

[0017] receiving, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes;

[0018] determining, by means of the controller, a collective pitch rate for the pitch system as a function of the plurality of pitch signals;

[0019] defining, by means of the controller, a minimum pitch rate threshold value that varies as a function of a speed parameter of the wind turbine;

[0020] receiving, by means of the controller, a first speed parameter of the wind turbine;

[0021] comparing, by means of the controller, the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; and,

[0022] The wind turbine is controlled by means of the controller based on the comparison.

[0023] Technical solution 2 is provided: the method according to technical solution 1 further includes measuring the multiple pitch signals with the aid of multiple sensors.

[0024] Technical solution 3 is provided: a method according to technical solution 1, wherein the multiple pitch signals include multiple pitch speed signals.

[0025] Technical solution 4 is provided: a method according to technical solution 1, wherein the multiple pitch signals include multiple pitch position signals.

[0026] Technical solution 5 is provided: the method according to technical solution 4 further includes determining the derivative of each pitch position signal in the multiple pitch position signals to obtain multiple pitch speed signals.

[0027] Technical solution 6 is provided: the method according to technical solution 5 further includes filtering the derivatives of the multiple pitch positions to reduce noise.

[0028] Technical solution 7 is provided: the method according to technical solution 1, wherein determining the common pitch rate as a function of the multiple pitch signals further includes averaging the multiple pitch signals to obtain the common pitch rate.

[0029] Technical solution 8 is provided: the method according to technical solution 1, wherein the speed parameter of the wind turbine includes at least one of a rotor speed or a generator speed.

[0030] Technical solution 9 is provided: the method according to technical solution 1, wherein comparing the common pitch rate with the minimum pitch rate threshold for the first speed parameter further includes utilizing a lookup table.

[0031] Technical solution 10 is provided: a method according to technical solution 1, wherein controlling the wind turbine based on the comparison further includes: if the speed parameter is lower than a speed threshold for a certain time period, pitching the multiple pitch control mechanisms at a constrained pitch rate, and if the speed parameter is higher than the speed threshold for a certain time period, performing a control action.

[0032] Technical solution 11 is provided: a method according to technical solution 1, wherein the control action further includes at least one of shutting down the wind turbine, pitching the multiple pitch control mechanisms at a maximum pitch rate, or reducing the rating of the wind turbine.

[0033] Technical solution 12 is provided: a method according to technical solution 1, wherein the controller includes at least one of a turbine controller or a separate controller module communicatively coupled to the turbine controller.

[0034] Technical Solution 13 is provided: a pitch system for a wind turbine, the pitch system comprising:

[0035] a plurality of pitch control mechanisms for generating a plurality of pitch signals associated with a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine;

[0036] a controller communicatively coupled to the plurality of pitch control mechanisms, the controller comprising at least one processor configured to perform a plurality of operations comprising:

[0037] determining a collective pitch rate for the pitch system as a function of the plurality of pitch signals;

[0038] defining a minimum pitch rate threshold value that varies with a speed parameter of the wind turbine;

[0039] receiving a first speed parameter of the wind turbine;

[0040] comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; and,

[0041] The wind turbine is controlled based on the comparison.

[0042] Technical solution 14 is provided: the pitch system according to technical solution 13 further includes multiple sensors for measuring the multiple pitch signals.

[0043] Technical solution 15 is provided: a pitch system according to technical solution 14, wherein the multiple pitch signals include multiple pitch speed signals.

[0044] Technical solution 16 is provided: a pitch system according to technical solution 13, wherein the multiple pitch signals include multiple pitch position signals, and the multiple operations further include:

[0045] determining a derivative of each of the plurality of pitch position signals to obtain a plurality of pitch speed signals; and

[0046] The derivatives of the plurality of pitch positions are filtered to reduce noise.

[0047] Technical solution 17 is provided: a pitch system according to technical solution 13, wherein determining the common pitch rate as a function of the multiple pitch signals further includes averaging the multiple pitch signals to obtain the common pitch rate.

[0048] Technical solution 18 is provided: a pitch system according to technical solution 13, wherein the speed parameter of the wind turbine includes at least one of a rotor speed or a generator speed.

[0049] Technical Solution 19 is provided: a pitch system according to Technical Solution 13, wherein comparing the common pitch rate with the minimum pitch rate threshold for the first speed parameter further includes utilizing a lookup table.

[0050] Technical solution 20 is provided: a pitch system according to technical solution 13, wherein controlling the wind turbine based on the comparison further includes: if the speed parameter is lower than a speed threshold for a certain time period, pitching the multiple pitch control mechanisms at a constrained pitch rate and if the speed parameter is higher than the speed threshold for a certain time period, performing a control action, the control action further including at least one of shutting down the wind turbine, pitching the multiple pitch control mechanisms at a maximum pitch rate, or reducing the rating of the wind turbine.

[0051] These and other features, aspects and advantages of the present invention will become better 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] A complete and enabling disclosure of the present invention, including the best mode thereof, intended for one skilled in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0053] Figure 1 illustrates a perspective view of one embodiment of a wind turbine according to the present disclosure;

[0054] Figure 2 illustrates a perspective view of an interior of a nacelle of a wind turbine according to one embodiment of the present disclosure;

[0055] Figure 3 A schematic diagram illustrating one embodiment of a system for controlling a wind turbine according to the present disclosure is illustrated;

[0056] Figure 4A flow chart illustrating one embodiment of a method for protecting a wind turbine from overload caused by a fault during operation according to the present disclosure; and

[0057] Figure 5 A schematic diagram of one embodiment of a system for operating a wind turbine to protect the wind turbine from an overload caused by a fault in its pitch system according to the present disclosure is illustrated.

[0058] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. DETAILED DESCRIPTION

[0059] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, not limitation, of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations may 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 together with another embodiment to produce yet another embodiment. Therefore, it is intended that the present invention covers such modifications and variations as included within the scope of the appended claims and their equivalents.

[0060] As used herein, as used throughout the specification and claims herein, approximating language is applicable to modify any quantitative representation that can be permissibly varied without causing a change in the basic function associated therewith. Thus, a value modified by one or more terms such as "approximately," "approximately," and "substantially" will not be limited to the specified precise value. In at least some instances, approximate language may correspond to the precision of an instrument for measuring the value, or the precision of a method or machine for constructing or manufacturing a component and / or system. For example, approximate language may refer to being within a 10% margin.

[0061] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, such ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0062] In general, the present disclosure is directed to systems and methods for operating a wind turbine to protect it from overloads caused by faults in its pitch system. Specifically, the present disclosure may include systems and methods for monitoring pitch rate feedback from a wind turbine's pitch system and converting individual pitch rates into a collective pitch rate. The collective pitch rate can then be compared to a minimum pitch rate threshold defined as a function of rotor speed. If the collective pitch rate falls below the threshold for a defined period of time, the turbine controller can trigger a turbine shutdown. Furthermore, one aspect of the present disclosure is the definition of hazardous pitch events. Specifically, the systems and methods of the present disclosure introduce the concept of defining a minimum pitch rate threshold as a function of rotor speed. At low rotor speeds, the wind turbine can continue to pitch at its full speed to provide power. However, at higher rotor speeds, pitching at full speed to provide power may be hazardous. Therefore, defining the threshold as a function of rotor speed provides maximum flexibility for this monitoring. Thus, the present disclosure addresses previous issues associated with defining a constant threshold with a large protection margin that can delay triggering a shutdown when necessary. Additionally, the present disclosure addresses the problem associated with defining a constant threshold to minimize the time to trigger a shutdown, which can result in shutting down the wind turbine too quickly, causing nuisance trips or limitations during maintenance operations. Still further advantages of the present disclosure include protecting the wind turbine from failures / malfunctions of pitching that overload the wind turbine.

[0063] Referring now to the accompanying drawings, Figure 1 A perspective view of one embodiment of a wind turbine 100 according to the present disclosure is illustrated. As shown, the wind turbine 100 generally includes a tower 102 extending from a support surface 104, a nacelle 106 including a housing 160 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 outwardly 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 less than three rotor blades 112. Each rotor blade 112 may be spaced about the hub 110 to facilitate rotating the rotor 108 so that kinetic energy from the wind can be converted into usable mechanical energy and subsequently electrical energy. For example, the hub 110 may be rotatably coupled to a generator 118 ( Figure 2 ) to allow electrical energy to be generated.

[0064] Wind turbine 100 may also include a controller 202 ( Figure 3). In an embodiment, controller 202 may be a wind turbine controller 204 centrally located within nacelle 106. However, in other embodiments, controller 202 may be located within any other component of wind turbine 100 or at a location external to the wind turbine. Furthermore, controller 202 may be communicatively coupled to any number of components of wind turbine 100 to control the components. Similarly, controller 202 may include a computer or other suitable processing unit. Accordingly, in several embodiments, controller 202 may include suitable computer-readable instructions that, when executed, configure controller 202 to perform various functions, such as receiving, transmitting, and / or executing wind turbine control signals.

[0065] Now refer to Figure 2 , which explains Figure 1 A simplified internal view of one embodiment of a nacelle 106 of a wind turbine 100 is shown. As shown, a generator 118 may be coupled to the rotor 108 for generating 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 the hub 110 for rotation therewith. The rotor shaft 122 may be rotatably supported by main bearings 144. The rotor shaft 122 may, in turn, be rotatably coupled to a generator shaft 124 of the generator 118 via a gearbox 126, which is connected to a base support frame 136 via one or more torque arms 142. As is generally understood, the rotor shaft 122 may provide a low-speed, high-torque input to the gearbox 126 in response to the rotation of the rotor blades 112 and the hub 110. The gearbox 126 may then be configured to convert the low-speed, high-torque input into a high-speed, low-torque output to drive the generator shaft 124 and, therefore, the generator 118.

[0066] Wind turbine 100 may also include a pitch system 150 for controlling the pitch angle of each of rotor blades 112. In particular, as Figure 2 and Figure 3As shown, pitch system 150 may include multiple pitch control mechanisms 120, for example, one pitch control mechanism for controlling the rotation of each rotor blade 112 about its pitch axis 116. Pitch control mechanism(s) 120 may include a pitch controller 152 configured to receive at least one pitch setpoint command from controller 202. Furthermore, each pitch control mechanism(s) 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, pitch drive motor 128 may be coupled to pitch drive gearbox 130 such that pitch drive motor 128 transmits mechanical force to pitch drive gearbox 130. Similarly, pitch drive gearbox 130 may be coupled to pitch drive pinion 132 for rotation therewith. Pitch drive pinion 132 may, in turn, rotationally engage a pitch bearing 134 coupled between hub 110 and a corresponding rotor blade 112, such that rotation of pitch drive pinion 132 causes rotation of pitch bearing 134. Thus, in such an embodiment, rotation of pitch drive motor 128 drives pitch drive gearbox 130 and pitch drive pinion 132, thereby rotating pitch bearing 134 and rotor blade(s) 112 about pitch axis 116. Similarly, wind turbine 100 may include one or more yaw drive mechanisms 138 communicatively coupled to controller 202, wherein each yaw drive mechanism(s) 138 is configured to change the angle of nacelle 106 relative to the wind (e.g., by engaging a yaw bearing 140 of wind turbine 100).

[0067] Rotation of each rotor blade 112 about its pitch axis 116 by its corresponding pitch control mechanism 120 may establish a pitch angle for each of the rotor blades 112. In an embodiment, the pitch angle may be an angular deviation from a zero-pitch position. The zero-pitch position may be established, for example, during blade installation by relying on a mechanical reference at the blade root or nose that triggers a limit switch to automate the calibration process. The controller 202 may track the pitch angle of the rotor blade(s) 112 based on the accumulated deviation from the zero-pitch position. The controller 202 may therefore transmit a pitch setpoint command(s) to the pitch control mechanism 120, instructing the rotor blade(s) 112 to rotate a specified number of degrees relative to the sensed pitch angle of the rotor blade(s) 112 as interpreted by a motor-mounted encoder.

[0068] Still refer to Figure 2One or more sensors 214, 216, 218 may be provided on wind turbine 100 to monitor the performance of wind turbine 100 and / or environmental conditions affecting wind turbine 100. It should also be appreciated that, as used herein, the term "monitoring" and variations thereof indicate that the various sensors of wind turbine 100 may be configured to provide direct measurements of the parameters being monitored or indirect measurements of such parameters. Thus, the sensors described herein may, for example, be used to generate signals related to the parameters being monitored, which signals may then be used by controller 202 to determine conditions.

[0069] Now refer to Figure 3 , presents a schematic diagram of one embodiment of a system 200 for controlling a wind turbine 100 according to the present disclosure. As shown, suitable components may be included within a controller 202 according to the present disclosure. As shown, the controller 202 may include one or more processors 206 and associated memory devices 208 configured to perform various computer-implemented functions (e.g., perform methods, steps, calculations, etc. and store relevant data as disclosed herein). Additionally, the controller 202 may also include a communication module 210 to facilitate communication between the controller 202 and various components of the wind turbine 100. Furthermore, the communication module 210 may include a sensor interface 212 (e.g., one or more analog-to-digital converters) to allow signals transmitted from one or more sensors 214, 216, 218 to be converted into signals that can be understood and processed by the processor 206. It should be appreciated that the sensors 214, 216, 218 may be communicatively coupled to the communication module 210 using any suitable means. For example, Figure 3 As shown, sensors 214, 216, 218 are coupled to sensor interface 212 via a wired connection. However, in other embodiments, sensors 214, 216, 218 may be coupled to sensor interface 212 via a wireless connection, such as by using any suitable wireless communication protocol known in the art.

[0070] As used herein, the term "processor" refers not only to what are known in the art as integrated circuits included in computers, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuits. Additionally, 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 memories (CD-ROMs), magneto-optical disks (MODs), digital versatile discs (DVDs), and / or other suitable memory elements. Such memory device(s) 208 may generally be configured to store suitable computer-readable instructions that, when executed by processor(s) 206, configure controller 202 to perform various functions, including, but not limited to, calculating collective pitch offsets and using the collective pitch offsets in the control of turbine 100 as described herein, as well as various other suitable computer-implemented functions.

[0071] Usually as Figure 1-3 As shown, system 200 may include at least one first sensor 214 configured to monitor wind conditions at the wind turbine or acting on rotor 108. The first sensor(s) 214 may be, for example, a wind vane, anemometer, lidar sensor, or other suitable sensor. Wind conditions may include wind speed, wind direction, wind shear, gusts, and / or wind veering, and the first sensor(s) 214 may be configured to measure wind speed, wind direction, wind shear, gusts, and / or wind veering. In at least one embodiment, the first sensor(s) 214 may be mounted to nacelle 106 at a location downwind of rotor 108. In alternative embodiments, the first sensor(s) 214 may be coupled to or integrated with rotor 108. It should be appreciated that the first sensor(s) 214 may comprise a network of sensors and may be located remotely from wind turbine 100. In an embodiment, the system 200 may include at least one second sensor 216 configured to monitor a load condition of the wind turbine 100, such as a load of one of the rotor blades 112. Figure 2 and Figure 3 As shown, system 200 may further include at least one third sensor 218 configured to monitor operating conditions or environmental conditions of wind turbine 100. For example, third sensor(s) 218 ​​may be power sensors configured to monitor power output of generator 118.

[0072] In an embodiment, the sensors 214, 216, 218 may be any suitable sensor, such as a proximity sensor, an inductive sensor, a micro inertial measurement unit (MIMU), a pressure sensor, an accelerometer, a SODAR sensor, a LIDAR sensor, an optical sensor, or the like. The sensors 214, 216, 218 may, for example, be configured to provide the controller 202 with measurements related to air temperature, component temperature, air pressure, and / or the rotational speed of the rotor blade(s) 112. Furthermore, the sensors 214, 216, 218 may comprise a network of sensors or a single sensor.

[0073] According to the present disclosure, such as Figure 3 , controller 202 of system 200 may include a common pitch rate module 220 for determining a common pitch rate as described herein. Alternatively, common pitch rate module 220 may be a component of wind turbine controller 204 or may be a component of a separate controller 202. In such an embodiment, utilizing separate controller 202 may facilitate determining a common pitch rate without requiring access to software and / or hardware of wind turbine controller 204.

[0074] Additionally, in an embodiment, collective pitch rate module 220 may be configured to execute one or more suitable data processing techniques or algorithms. The techniques or algorithms may allow controller 202 or wind turbine controller 204 to accurately and efficiently analyze sensor data from sensors 214, 216, 218. Furthermore, collective pitch rate module 220 may apply corrections or adjustments to the received data based on sensor type, sensor resolution, and / or other parameters associated with wind conditions or wind turbine 100 operation. In one example, collective pitch rate module 220 may filter the data to remove outliers by executing subroutines or intermediate calculations required to calculate the collective pitch angle and / or by executing any other desired data processing-related techniques or algorithms.

[0075] Now refer to Figure 4 and Figure 5 , respectively, describe a method 250 and a system 300 for protecting a wind turbine from overloads during operation caused by, for example, a fault from a pitch system. In particular, Figure 4 A flow chart illustrating one embodiment of a method 250 for operating a wind turbine to protect the wind turbine from an overload caused by a fault in its pitch system may be used, for example, with reference to Figure 4 The system 300 discussed implements the method 250. Furthermore, for purposes of illustration and discussion, Figure 4The steps are depicted as being performed in a particular order. One of ordinary skill in the art, using the disclosure provided herein, will appreciate that the various steps of method 250, or any of the methods disclosed herein, may be modified, altered, rearranged, performed concurrently, or otherwise altered in various ways without departing from the scope of the present disclosure.

[0076] As shown at (252), method 250 receives, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of a wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of wind turbine 100 about respective pitch axes. For example, Figure 5 As shown, system 300 may include a controller 302 (such as turbine controller 204 or a separate controller as described herein) that receives a measured pitch signal from each of pitch controllers 152 of each pitch control mechanism (i.e., one pitch control mechanism from each rotor blade 112). Thus, in an embodiment, the pitch signals may be measured with the aid of a plurality of sensors (such as any of sensors 214, 216, 218). In another embodiment, the plurality of pitch signals may include a plurality of pitch speed signals.

[0077] Alternatively, in an embodiment, the plurality of pitch signals may include a plurality of pitch position signals. In such an embodiment, method 250 may include determining a derivative of each of the pitch position signals (e.g., with the aid of numerical derivative module 304) to obtain a plurality of pitch velocity signals. Additionally, in such an embodiment, where the pitch signal is a position signal, method 250 may also include filtering the derivative of the pitch position to reduce noise in the signal. However, if the pitch signal corresponds to a pitch velocity signal, such a signal may be directly input to controller 302 without first determining its derivative and / or without filtering.

[0078] Return Reference Figure 4 , as indicated at (254), method 250 includes determining, with the aid of controller 302, a collective pitch rate for pitch system 150 as a function of the plurality of pitch signals. For example, Figure 5 As shown, controller 302 may include a collective pitch rate module 306 for determining a collective pitch rate for pitch system 150. More specifically, in an embodiment, collective pitch rate module 306 may determine the collective pitch rate by averaging a plurality of pitch signals.

[0079] In an embodiment, controller 302 may determine the collective pitch rate continuously, at predetermined intervals, and / or in response to specified sensor inputs. In further embodiments, controller 302 may calculate the collective pitch rate at predetermined intervals (e.g., daily, weekly, monthly, etc.). In still further embodiments, receiving a fault signal from a sensor (such as an indication related to an unexpected output of the generator) may trigger controller 302 to calculate the collective pitch rate.

[0080] Return Reference Figure 4 As shown at (256), the method 250 includes defining, by means of the controller 302, a minimum pitch rate threshold value that varies as a function of a speed parameter of the wind turbine 100. For example, in an embodiment, the speed parameter of the wind turbine 100 may include a rotor speed, a generator speed, or a derivative thereof, and any other suitable speed parameter of the wind turbine 100. Furthermore, in an embodiment, the controller 302 may define the minimum pitch rate threshold value by generating a curve, a table, a graph, a table, etc., in which pitch rate values ​​correspond to speed parameters.

[0081] Furthermore, as indicated at (258), the method 250 includes receiving, by means of the controller 302, a first speed parameter of the wind turbine 100. For example, in an embodiment, as mentioned, the first speed parameter of the wind turbine 100 may include a rotor speed, a generator speed, or any other suitable speed parameter of the wind turbine 100. Thus, such a speed parameter may be determined or calculated by the controller 302 or may be measured by means of one of the sensors described herein.

[0082] Therefore, still refer to Figure 4 , as shown at (260), method 250 includes comparing, with the controller 302, the common pitch rate (e.g., from the common pitch rate module 306) to a minimum pitch rate threshold for the first speed parameter. In some embodiments, as Figure 5 As shown, the controller 302 may include a threshold comparison module 308 for comparing the collective pitch rate to a minimum pitch rate threshold for the first speed parameter. More specifically, as shown in the illustrated embodiment, the threshold comparison module 308 may receive the collective pitch rate, a lookup table (e.g., a minimum pitch rate table 310), and a rotor speed and may generate an output 314.

[0083] Return Reference Figure 4 , as shown at (262), method 250 includes controlling wind turbine 100 based on the comparison (eg, output 314) by controller 302. For example, in an embodiment, as Figure 5As shown, controller 302 is configured to execute control actions. Specifically, in an embodiment, if the speed parameter is below a speed threshold (e.g., as determined by counter 316) for a certain period of time, controller 302 may pitch the plurality of pitch control mechanisms 120 at a constrained pitch rate. Alternatively, if the speed parameter is above the speed threshold for a certain period of time, controller 302 may execute a control action to prevent wind turbine 100 from overloading. In such an embodiment, for example, the control action may include shutting down wind turbine 100, pitching the plurality of pitch control mechanisms at a maximum pitch rate, de-rating wind turbine 100, or any other suitable corrective action.

[0084] In addition, the skilled person will recognize the interchangeability of the various features from different embodiments. Similarly, the various method steps and features described and other known equivalents for each such method and feature can be mixed and matched by those of ordinary skill in the art to construct additional systems and techniques according to the principles of the present disclosure. Of course, it is to be understood that, according to any particular embodiment, it is not necessary to achieve all of the above-mentioned purposes or advantages. Thus, for example, it will be appreciated that the systems and techniques described herein can be embodied or performed in a manner that realizes or optimizes an advantage or a group of advantages as taught herein without having to achieve other purposes or advantages that may be taught or suggested herein.

[0085] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if such other examples include equivalent structural elements with insubstantial differences from the literal language of the claims, such other examples are intended to be within the scope of the claims.

[0086] Further aspects of the invention are provided by the subject matter of the following clauses:

[0087] Clause 1. A method for protecting a wind turbine from an overload caused by a fault during operation, the method comprising:

[0088] receiving, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes;

[0089] determining, by means of the controller, a collective pitch rate for the pitch system as a function of the plurality of pitch signals;

[0090] defining, by means of the controller, a minimum pitch rate threshold value that varies as a function of a speed parameter of the wind turbine;

[0091] receiving, by means of the controller, a first speed parameter of the wind turbine;

[0092] comparing, by means of the controller, the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; and

[0093] The wind turbine is controlled by means of the controller based on the comparison.

[0094] Clause 2. The method of any preceding claim, further comprising measuring the plurality of pitch signals by means of a plurality of sensors.

[0095] Clause 3. The method of any preceding claim, wherein the plurality of pitch signals comprises a plurality of pitch speed signals.

[0096] Clause 4. The method of any preceding claim, wherein the plurality of pitch signals comprises a plurality of pitch position signals.

[0097] Clause 5. The method of Clause 4, further comprising determining a derivative of each pitch position signal of the plurality of pitch position signals to obtain a plurality of pitch speed signals.

[0098] Clause 6. The method of Clause 5, further comprising filtering the derivatives of the plurality of pitch positions to reduce noise.

[0099] Clause 7. The method of any preceding claim, wherein determining the collective pitch rate as a function of the plurality of pitch signals further comprises averaging the plurality of pitch signals to obtain the collective pitch rate.

[0100] Clause 8. The method of any preceding claim, wherein the speed parameter of the wind turbine comprises at least one of rotor speed or generator speed.

[0101] Clause 9. The method of any preceding claim, wherein comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter further comprises utilizing a lookup table.

[0102] Clause 10. The method of any preceding claim, wherein controlling the wind turbine based on the comparison further comprises pitching the plurality of pitch control mechanisms at a constrained pitch rate if the speed parameter is below a speed threshold for a certain period of time and performing a control action if the speed parameter is above the speed threshold for a certain period of time.

[0103] Clause 11. The method of any preceding claim, wherein the control action further comprises at least one of shutting down the wind turbine, pitching the plurality of pitch control mechanisms at a maximum pitch rate, or de-rating the wind turbine.

[0104] Clause 12. The method of any preceding claim, wherein the controller comprises at least one of a turbine controller or a separate controller module communicatively coupled to the turbine controller.

[0105] Clause 13. A pitch system for a wind turbine, comprising:

[0106] a plurality of pitch control mechanisms for generating a plurality of pitch signals associated with a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine;

[0107] a controller communicatively coupled to the plurality of pitch control mechanisms, the controller comprising at least one processor configured to perform a plurality of operations, the plurality of operations comprising:

[0108] determining a collective pitch rate for the pitch system as a function of the plurality of pitch signals;

[0109] defining a minimum pitch rate threshold value that varies with a speed parameter of the wind turbine;

[0110] receiving a first speed parameter of the wind turbine;

[0111] comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; and

[0112] The wind turbine is controlled based on the comparison.

[0113] Clause 14. The pitch system of Clause 13, further comprising a plurality of sensors for measuring the plurality of pitch signals.

[0114] Clause 15. The pitch system of Clause 14, wherein the plurality of pitch signals comprises a plurality of pitch speed signals.

[0115] Clause 16. The pitch system of clauses 13-15, wherein the plurality of pitch signals comprises a plurality of pitch position signals, the plurality of operations further comprising:

[0116] determining a derivative of each of the plurality of pitch position signals to obtain a plurality of pitch speed signals; and

[0117] The derivatives of the plurality of pitch positions are filtered to reduce noise.

[0118] Clause 17. The pitch system of clauses 13-16, wherein determining the collective pitch rate as a function of the plurality of pitch signals further comprises averaging the plurality of pitch signals to obtain the collective pitch rate.

[0119] Clause 18. The pitch system of clauses 13-17, wherein the speed parameter of the wind turbine comprises at least one of rotor speed or generator speed.

[0120] Clause 19. The pitch system of clauses 13-18, wherein comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter further comprises utilizing a lookup table.

[0121] Clause 20. A pitch system as described in clauses 13-19, wherein controlling the wind turbine based on the comparison further includes pitching the plurality of pitch control mechanisms at a constrained pitch rate if the speed parameter is below a speed threshold for a certain period of time and performing a control action if the speed parameter is above the speed threshold for a certain period of time, the control action further including at least one of shutting down the wind turbine, pitching the plurality of pitch control mechanisms at a maximum pitch rate, or de-rating the wind turbine.

Claims

1. A method for protecting a wind turbine from an overload caused by a fault during operation, the method comprising: receiving, by means of a controller, a plurality of pitch signals from a plurality of pitch control mechanisms of a pitch system of the wind turbine, the pitch system being configured to rotate a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine about respective pitch axes; determining, by means of the controller, a collective pitch rate for the pitch system as a function of the plurality of pitch signals; defining, by means of the controller, a minimum pitch rate threshold value that varies as a function of a speed parameter of the wind turbine; receiving, by means of the controller, a first speed parameter of the wind turbine; comparing, by means of the controller, the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; as well as, The wind turbine is controlled by means of the controller based on the comparison. 2 . The method according to claim 1 , further comprising measuring the plurality of pitch signals by means of a plurality of sensors. 3 . The method of claim 1 , wherein the plurality of pitch signals comprises a plurality of pitch speed signals. The method of claim 1 , wherein the plurality of pitch signals comprises a plurality of pitch position signals. 5 . The method of claim 4 , further comprising determining a derivative of each of the plurality of pitch position signals to obtain a plurality of pitch speed signals. 6 . The method of claim 5 , further comprising filtering the derivatives of the plurality of pitch positions to reduce noise. 7 . The method of claim 1 , wherein determining the collective pitch rate as a function of the plurality of pitch signals further comprises averaging the plurality of pitch signals to obtain the collective pitch rate. 8 . The method of claim 1 , wherein the speed parameter of the wind turbine comprises at least one of a rotor speed or a generator speed.

9. The method of claim 1, wherein comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter further comprises utilizing a lookup table.

10. The method of claim 1 , wherein controlling the wind turbine based on the comparison further comprises: The plurality of pitch control mechanisms are pitched at a constrained pitch rate if the speed parameter is below a speed threshold for a period of time, and a control action is performed if the speed parameter is above the speed threshold for a period of time.

11. The method of claim 1 , wherein the control action further comprises at least one of shutting down the wind turbine, pitching the plurality of pitch control mechanisms at a maximum pitch rate, or de-rating the wind turbine. 12 . The method of claim 1 , wherein the controller comprises at least one of a turbine controller or a separate controller module communicatively coupled to the turbine controller.

13. A pitch system for a wind turbine, the pitch system comprising: a plurality of pitch control mechanisms for generating a plurality of pitch signals associated with a plurality of rotor blades mounted to a rotatable hub of a rotor of the wind turbine; a controller communicatively coupled to the plurality of pitch control mechanisms, the controller comprising at least one processor configured to perform a plurality of operations comprising: determining a collective pitch rate for the pitch system as a function of the plurality of pitch signals; defining a minimum pitch rate threshold value that varies with a speed parameter of the wind turbine; receiving a first speed parameter of the wind turbine; comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter; and, The wind turbine is controlled based on the comparison.

14. The pitch system of claim 13, further comprising a plurality of sensors for measuring the plurality of pitch signals.

15. The pitch system of claim 14, wherein the plurality of pitch signals comprises a plurality of pitch speed signals.

16. The pitch system of claim 13, wherein the plurality of pitch signals comprises a plurality of pitch position signals, the plurality of operations further comprising: determining a derivative of each of the plurality of pitch position signals to obtain a plurality of pitch speed signals; as well as The derivatives of the plurality of pitch positions are filtered to reduce noise.

17. The pitch system of claim 13, wherein determining the collective pitch rate as a function of the plurality of pitch signals further comprises averaging the plurality of pitch signals to obtain the collective pitch rate.

18. The pitch system of claim 13, wherein the speed parameter of the wind turbine comprises at least one of rotor speed or generator speed.

19. The pitch system of claim 13, wherein comparing the collective pitch rate to the minimum pitch rate threshold for the first speed parameter further comprises utilizing a lookup table.

20. The pitch system of claim 13, wherein controlling the wind turbine based on the comparison further comprises: pitching the plurality of pitch control mechanisms at a constrained pitch rate if the speed parameter is below a speed threshold for a certain period of time and performing a control action if the speed parameter is above the speed threshold for a certain period of time, the control action further comprising at least one of shutting down the wind turbine, pitching the plurality of pitch control mechanisms at a maximum pitch rate, or de-rating the wind turbine.

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