System and method for detecting and responsing to fault in drivetrain of wind

Abstract

The invention relates to a system and method for detecting and responding to a fault in a power train of a wind turbine. Specifically, a method for detecting and responding to a fault in a drive train of a wind turbine includes estimating, via one or more rate gyroscopes mounted in a hub, a first rotational speed signal at a first location along the drive train, the first rotational speed signal being representative of a rotor speed of a rotor. The method further includes processing the first rotational speed signal to address deviations in the first rotational speed signal due to the use of the rate gyroscope. Further, the method includes receiving a second rotational speed signal at a second location along the driveline, the second location being leeward of the first location, the first and second locations being on opposite sides of the potential slip location of the driveline. Further, the method includes determining a speed error based on a comparison of the first and second rotational speed signals. In addition, the method includes comparing the speed error to a threshold and implementing a control action when the speed error exceeds the threshold.

Description

Technical Field

[0001] The present disclosure relates generally to wind turbines, and more particularly to systems and methods for detecting and responding to faults in a drive train of a wind turbine, such as slip events in the drive train. Background Art

[0002] Wind power is considered one of the cleanest and most environmentally friendly energy sources currently available, and wind turbines have received increasing attention in this regard. A modern wind turbine typically includes a tower, a nacelle mounted atop the tower, a rotor with one or more rotor blades mounted to the nacelle, and a drive train within the nacelle. The drive train typically includes various drive train components, such as a generator and a gearbox. In addition, the drive train may include one or more friction connections, such as couplings or shrink fits in an HSS section or LSS section. The nacelle includes a rotor assembly coupled to a gearbox and a generator. In many wind turbines, the generator and gearbox are mounted to a bedplate within the nacelle via one or more torque arms. Thus, one or more rotor blades capture the kinetic energy of the wind using the known airfoil principle. The rotor blades transmit the kinetic energy in the form of rotational energy to rotate a shaft that couples the rotor blades to a gearbox or, if a gearbox is not used, directly to a generator. The generator then converts the mechanical energy into electrical energy that can be deployed to a utility grid.

[0003] Typically, wind turbines are equipped with various sensors for determining drivetrain speed conditions, such as generator speed. However, if any drivetrain connection slips / decouples (or becomes disconnected), the measured generator speed is no longer a good proxy for rotor speed (when scaled by the gearbox ratio). Since generator speed is typically the primary speed measurement used by the turbine controller for rotor speed control, wind turbine damage can occur if the generator speed is not a good proxy for rotor speed. For example, if the LSS shrink fit slips, the generator speed decreases while the rotor speed does not. In this case, the turbine controller switches power to increase the generator speed, which can result in excessive rotor speed and thrust drive loads.

[0004] Thus, the present disclosure is directed to systems and methods of detecting deviations between speed measurements at locations along the drive train from the rotor to the generator and, in the event of significant deviations, implementing control actions to avoid the problems described above. Summary of the Invention

[0005] Aspects and advantages of the disclosure will be set forth in part in the description which follows, or may be obvious from the description, or may be learned through practice of the disclosure.

[0006] In one aspect, the present disclosure relates to a method for detecting and responding to a fault in a drive train of a wind turbine. The drive train has at least a rotor and a generator. The method includes estimating, via a controller, a first speed signal at a first location along the drive train via one or more rate gyroscopes mounted in the wind turbine, the first speed signal being representative of a rotor speed of a rotor of the wind turbine. The method also includes processing, via the controller, the first speed signal to account for a bias in the first speed signal resulting from the use of the one or more rate gyroscopes. Furthermore, the method includes receiving, via the controller, a second speed signal at a second location along the drive train, the second location being downwind of the first location, the first and second locations being on opposite sides of a potential slip position of the drive train. Furthermore, the method includes determining, via the controller, a speed error based on a comparison of the first and second speed signals. Furthermore, the method includes comparing, via the controller, the speed error to a threshold value and implementing, via the controller, a control action on the wind turbine when the speed error exceeds the threshold value.

[0007] In another aspect, the present disclosure relates to a drive train assembly for a wind turbine. The drive train assembly includes a rotor shaft for coupling to a rotor of the wind turbine, a gearbox coupled to the rotor shaft, a generator coupled to the gearbox via a generator shaft, and a controller for controlling operation of the wind turbine. The controller includes at least one processor configured to perform a plurality of operations, including but not limited to estimating a first rotational speed signal at a first location along the drive train via one or more rate gyroscopes mounted in the wind turbine, the first rotational speed signal being representative of a rotor speed of the rotor of the wind turbine; processing the first rotational speed signal to account for deviations in the first rotational speed signal resulting from the use of the one or more rate gyroscopes; receiving a second rotational speed signal from a second location along the drive train assembly, the second location being downwind of the first location, the first and second locations being on opposite sides of a potential slip position of the drive train assembly; determining a speed error based on a comparison of the first and second rotational speed signals; comparing the speed error to a threshold; and implementing a control action on the wind turbine when the speed error exceeds the threshold.

[0008] These and other features, aspects and advantages of the present disclosure will be 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 present disclosure and, together with the description, serve to explain the principles of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A complete and enabling disclosure of the present disclosure, including the best mode thereof, is set forth in this specification for those skilled in the art, and the specification refers to the accompanying drawings, in which:

[0010] Figure 1A perspective view illustrating a wind turbine according to an embodiment of the present disclosure;

[0011] Figure 2 a perspective interior view of a nacelle of a wind turbine illustrating an embodiment of the present disclosure;

[0012] Figure 3 A schematic diagram illustrating an embodiment of suitable components that may be included in a wind turbine controller according to the present disclosure;

[0013] Figure 4 A flow chart illustrating an embodiment of a method for detecting and responding to a fault in a drive train of a wind turbine according to the present disclosure;

[0014] Figure 5 a schematic diagram illustrating an embodiment of a controller configured to detect and respond to faults in a drive train of a wind turbine according to the present disclosure; and

[0015] Figure 6 1. Illustrated is a graph of a generator-based rotor speed measurement, a rotor speed measurement, and the output of a complementary filter of a controller plotted together as a function of time, in accordance with the present disclosure. DETAILED DESCRIPTION

[0016] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided in a manner to explain the present disclosure, rather than to limit the present disclosure. In fact, it will be understood by those skilled in the art that various modifications and variations may be made in the present disclosure without departing from the scope of the present disclosure. For example, a feature illustrated or described as a part of an embodiment may be used together with another embodiment to produce another further embodiment. Therefore, the present disclosure is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0017] Generally, the present disclosure relates to systems and methods for detecting drivetrain speed excursions (e.g., those that can be caused by a slip or decoupling event) and responding to such events in a manner that limits the impact on the turbine. At the generator end, a high-fidelity encoder can be used to detect the generator speed. However, the encoder solution is more difficult for the LSS due to the lower speeds. Thus, in one embodiment, the speed measurement for the LSS can be based on a rate gyroscope. Additionally, since rate gyroscopes typically have temperature dependent drift and thus contain low frequency bias, the present disclosure is also configured to address this bias. Also, there is some variation in the gear box ratios from component to component. Thus, the present disclosure provides a method for detecting drivetrain problems despite such DC / low frequency measurement errors. More specifically, in one embodiment, the systems and methods of the present disclosure are configured to compare speed measurements on opposite sides of a potential slip location (e.g., a drivetrain connection) to detect a fault. Additionally, using filtering and / or operational calibration enables one or more speed measurements to be taken using a rate gyroscope despite their susceptibility to sensor drift and / or bias errors.

[0018] Reference is now made to the drawings, Figure 1 A perspective view of an embodiment of a wind turbine 10 in accordance with the present disclosure is illustrated. As shown, the wind turbine 10 includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outward from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in alternative embodiments, the rotor 18 can include more or less than three rotor blades 22. Each rotor blade 22 can be spaced about the hub 20 to facilitate rotating the rotor 18 such that kinetic energy from the wind can be converted into useful mechanical energy and subsequently into electrical energy. For example, the hub 20 can be rotatably coupled to a generator 24 Figure 2 ) positioned within the nacelle 16 to permit electrical energy to be generated.

[0019] Reference is now made to Figure 2, illustrated is a simplified interior view of an embodiment of a nacelle 16 of a wind turbine 10. As shown, wind turbine 10 includes a generator 24 disposed within nacelle 16. Generally, generator 24 may be coupled to rotor 18 of wind turbine 10 for generating electrical power from the rotational energy generated by rotor 18. For example, rotor 18 may include a rotor shaft 40 coupled to hub 20 for rotation therewith. Generator 24 may then be coupled to rotor shaft 40 such that rotation of rotor shaft 40 drives generator 24. For example, in the illustrated embodiment, generator 24 includes a generator shaft 42 rotatably coupled to rotor shaft 40 via a gearbox 44. However, in other embodiments, it should be understood that generator shaft 42 may be directly rotatably coupled to rotor shaft 40. Alternatively, generator 24 may be directly rotatably coupled to rotor shaft 40. Such components may generally be referred to herein as a drive train 50 or drive train assembly.

[0020] It should be appreciated that the rotor shaft 40 may generally be supported within the nacelle 16 by a support frame or bedplate 46 positioned atop the wind turbine tower 12. For example, the rotor shaft 40 may be supported by the bedplate 46 via a pair of pillow blocks mounted thereto.

[0021] like Figure 1 and Figure 2 As shown in FIG, the wind turbine 10 may also include a turbine control system or turbine controller 26 within the nacelle 16. For example, Figure 2 1 , the turbine controller 26 is disposed within a control cabinet 27 mounted to a portion of the nacelle 16. However, it should be understood that the turbine controller 26 may be disposed anywhere on or in the wind turbine 10, the support surface 14 ( Figure 1 ) or generally disposed at any other location. The turbine controller 26 generally may be configured to control various operating modes (eg, startup or shutdown sequences) and / or components of the wind turbine 10.

[0022] like Figure 2As shown in FIG, wind turbine 10 may also include at least one pitch adjustment mechanism 32 for each rotor blade 22, the pitch adjustment mechanism 32 being configured to rotate each rotor blade 22 about its pitch axis 34. In one embodiment, each pitch adjustment mechanism 32 may include a pitch drive motor 33 (e.g., any suitable electric, hydraulic, or pneumatic motor), a pitch drive gearbox 35, and a pitch drive pinion 37. In such an embodiment, pitch drive motor 33 may be coupled to pitch drive gearbox 35 such that pitch drive motor 33 applies mechanical force to pitch drive gearbox 35. Similarly, pitch drive gearbox 35 may be coupled to pitch drive pinion 37 for rotation therewith. Pitch drive pinion 37, in turn, may rotationally engage a pitch bearing 36 coupled between hub 20 and the corresponding rotor blade 22, such that rotation of pitch drive pinion 37 causes rotation of pitch bearing 36. Thus, in such embodiments, rotation of pitch drive motor 33 drives pitch drive gearbox 35 and pitch drive pinion 37, thereby rotating pitch bearing 36 and rotor blades 22 about pitch axis 34. Similarly, wind turbine 10 may include one or more yaw drive mechanisms 38 communicatively coupled to controller 26, wherein each yaw drive mechanism 38 is configured to change the angle of nacelle 16 relative to the wind (e.g., by engaging yaw bearing 56 of wind turbine 10 and rotating nacelle 16 about yaw axis 39).

[0023] Additionally, as shown, the turbine controller 26 may also be configured to operate via a separate or integrated pitch controller 30 ( Figure 1 ) is communicatively coupled to each pitch adjustment mechanism 32 of wind turbine 10 for controlling and / or changing the pitch angle of each corresponding rotor blade 22 (ie, the angle that determines the viewing angle of rotor blade 22 relative to wind direction 28).

[0024] In addition, if Figure 2 As shown in FIG, one or more sensors 51, 52, 57, 59 may be provided on wind turbine 10. More specifically, as shown, shaft sensor 51 may be communicatively coupled to rotor shaft 40 and / or rotor 18 to monitor their speed. Furthermore, as shown, generator sensor 52 may be communicatively coupled to generator 24 to monitor its speed. Additionally, tower sensor 57 may be provided on tower 12 and / or hub sensor 59 may be provided on hub 20. Further embodiments may include any other suitable type of sensor, such as a wind vane, accelerometer, or the like. Thus, sensors 51, 52 may further communicate with controller 26 and may provide relevant information to controller 26.

[0025] It should also be understood that, as used herein, the term "monitor" and variations thereof indicate that the various sensors of wind turbine 10 may be configured to provide direct measurements of monitored parameters and / or indirect measurements of such parameters. Thus, the sensors described herein may be used, for example, to generate signals related to the monitored parameters, which signals may then be utilized by controller 26 to determine a condition.

[0026] Now refer to Figure 3 , which illustrates a block diagram of an embodiment of suitable components according to the present disclosure that may be included within the controller 26. As shown, the controller 26 may include one or more processors 60 and associated memory devices 62 configured to perform various computer-implemented functions (e.g., execute the methods, steps, calculations, etc. as disclosed herein and store related data).

[0027] In addition, the controller 26 may also include a communication module 64 to facilitate communication between the controller 26 and various components of the wind turbine 10. In addition, the communication module 64 may include a sensor interface 66 (e.g., one or more analog-to-digital converters) to allow signals transmitted from one or more sensors 51, 52 to be converted into signals that can be understood and processed by the processor 60. It should be understood that the sensors 51 and 52 can be communicatively coupled to the communication module 64 using any suitable means. For example, Figure 3 , the sensors 51 and 52 are coupled to the sensor interface 66 via a wired connection. However, in other embodiments, the sensors 51, 52 may be coupled to the sensor interface 66 via a wireless connection, such as by using any suitable wireless communication protocol known in the art.

[0028] As used herein, the term "processor" refers not only to integrated circuits included in computers as is known in the art, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuits. Additionally, the memory device 62 may generally include memory elements including, but not limited to, computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disk read-only memory (CD-ROMs), magneto-optical disks (MODs), digital versatile disks (DVDs), and / or other suitable memory elements. Such memory device 62 may generally be configured to store suitable computer-readable instructions that, when executed by the processor 60, configure the controller 26 to perform various functions, including, but not limited to, transmitting suitable control signals to implement corrective actions in response to a distance signal exceeding a predetermined threshold as described herein, as well as various other suitable computer-implemented functions.

[0029] Now refer to Figure 4, illustrates a flow chart of an embodiment of a method 100 for detecting and responding to a fault in a drive train of a wind turbine. The method 100 may be implemented using, for example, the method described above with reference to Figure 1-3 The wind turbine 10 and controller 26 discussed are implemented. Figure 4 The steps are depicted as being performed in a particular order for ease of illustration and discussion. One of ordinary skill in the art, using the disclosure provided herein, will appreciate that the various steps of method 100 or any other method disclosed herein may be adjusted, modified, rearranged, performed simultaneously, or modified in various ways without departing from the scope of the present disclosure.

[0030] As shown at (102), method 100 includes estimating, via a controller (such as controller 26), via one or more rate gyroscopes mounted in wind turbine 10 (such as in hub 20 or anywhere along drive train 50), a first rotational speed signal at a first location along the drive train, the first rotational speed signal being representative of a rotor speed for rotor 18 of wind turbine 10.

[0031] Furthermore, in one embodiment, the first position may correspond to a position on or within the hub 20 and / or on the rotor shaft 40. In other words, the method 100 may include estimating the first rotational speed signal via one or more rate gyroscopes (also referred to as velocity gyroscopes) mounted in the hub 20 of the wind turbine 10 or at a point rigidly connected to the hub 20. As used herein, a rate gyroscope generally refers to a type of gyroscope that represents the rate of change of an angle with respect to time. If a gyroscope has only one gimbaled ring and therefore only one free plane, it may be suitable for use as a rate gyroscope to measure the rate of angular motion. In addition, the rate gyroscopes described herein may also encompass microelectromechanical system (MEMS) gyroscopes.

[0032] Rate gyros, as described herein, are generally effective at detecting rapid velocity changes, but may drift (e.g., due to temperature and / or various other factors) and, therefore, may contain biases, such as low-frequency biases or DC biases. Bias may also exist because rate gyros may be difficult to calibrate after power is applied to them because rate gyros are rarely truly stationary. Thus, despite the presence of such measurement errors, the method 100 of the present disclosure can detect drive train problems. Specifically, as shown at (104), the method 100 includes processing the first rotational speed signal, via the controller 26, to account for biases in the first rotational speed signal resulting from the use of one or more rate gyros.

[0033] As shown at (106), the method 100 includes receiving, via the controller 26, a second rotational speed signal from a second location along the drivetrain 50, the second location being downwind of the first location, the first and second locations being on opposite sides of the potential slip locations 54, 58 of the drivetrain 50. In an embodiment, the second rotational speed signal can be measured using any suitable sensor, such as a bolt counter, a slip ring sensor, a tachometer sensor, and / or another rate gyro. Further, in an embodiment, the second location can correspond to a location on the generator 24. In such embodiments, for example, the second rotational speed signal can be representative of a generator speed for the generator 24 of the wind turbine 10. Thus, in an embodiment, the first and second rotational speed signals can be collected at the extremes of the drivetrain 50 (e.g., at the rotor 18 and at the generator 24). In other embodiments, the first and second rotational speed signals can be collected from either side of each slip element, such that the controller 26 can determine which member is actually slipping. In still further embodiments, any number of speed signals can be collected and analyzed in accordance with the present disclosure, for example, to estimate the presence of slip and the location of slip.

[0034] Further, as shown in (108), the method 100 includes determining, via the controller 26, a speed error based on a comparison of the first and second rotational speed signals. For example, in an embodiment, determining a speed error based on a comparison of the first and second rotational speed signals can include determining a difference between the first rotational speed signal and the second rotational speed signal. Figure 2

[0035] Further, as shown at (108), the method 100 includes determining, via the controller 26, a speed error based on a comparison of the first and second rotational speed signals. For example, in an embodiment, determining a speed error based on a comparison of the first and second rotational speed signals can include determining a difference between the first rotational speed signal and the second rotational speed signal.

[0036] ​In additional embodiments, processing the first rotational rate signal to account for bias in the first rotational rate signal due to use of one or more rate gyros can include correcting the first rotational rate signal for at least one of a low frequency bias or a DC bias using the second rotational rate signal prior to determining the speed error. In such embodiments, for example, correcting the first rotational rate signal for the low frequency bias or the DC bias using the second rotational rate signal can include low pass filtering the second rotational rate signal to determine a bias offset, and then adding the bias offset to the first rotational rate signal. In alternative embodiments, the method 100 can include high pass filtering the speed error prior to comparing the speed error to the threshold.

[0037] More specifically, in an embodiment, the method 100 can include estimating the first rotational rate signal (e.g., rotor speed) using a rate gyro mounted in the hub 20 or at a location rigidly connected to the hub 20, wherein the rate gyro is periodically calibrated (e.g., for bias offset) using a high fidelity speed measurement of another location in the drivetrain (e.g., generator speed) while spinning. In such embodiments, the speed measurement of the other location in the drivetrain 50 can be used as a reasonableness check for the rate gyro based speed measurement.

[0038] Accordingly, and still referring to Figure 4 As shown at (110), the method 100 includes comparing, via the controller 26, the speed error to a threshold. In an embodiment, the threshold can be a variable threshold dependent on at least one of rotor speed, torque, wind speed, or a function thereof. In another embodiment, the threshold can be a fixed threshold. Additionally, as shown at (112), the method 100 includes implementing, via the controller 26, a control action on the wind turbine 10 when the speed error exceeds the threshold. For example, in an embodiment, implementing a control action on the wind turbine 10 can include shutting down the wind turbine 10, derating the wind turbine 10, yawing the nacelle 16 of the wind turbine 10, or pitching one or more rotor blades 22 of the wind turbine 10.

[0039] Referring to Figure 5 A better understanding of Figure 4 the method 100, Figure 5 is provided as example purposes only and is not intended to be limiting. More specifically, as shown, Figure 5 An illustration of an embodiment of a controller (such as the controller 26) implementing drivetrain speed protection for a wind turbine in accordance with the present disclosure is shown. Specifically, as shown, the drivetrain speed protection includes implementing a complementary filter (e.g., configured as a low pass filter) to offset a low frequency bias from the rate gyro described herein.

[0040] More specifically, in the illustrated embodiment, the controller 26 is configured to receive first and second speed signals, such as a rotor speed measurement 152 and a generator-based rotor speed measurement 150. Accordingly, as shown at 154, the controller 26 is configured to determine a difference 156 between the rotor speed measurement 152 and the generator-based rotor speed measurement 150. Furthermore, in one embodiment, the controller 26 may also include a low-pass filter 158.

[0041] Therefore, the controller 26 is configured to use the generator-based rotor speed measurement 150 to correct for bias in the rotor speed measurement 152. More specifically, as previously discussed, when the rotor speed measurement 152 is measured via a rate gyro (which is generally effective at detecting rapid speed changes but may contain low-frequency bias or DC bias), the controller 26 is configured to counteract such bias. Specifically, as shown, the controller 26 is configured to use the generator-based rotor speed measurement 150 to correct for bias in the rotor speed measurement 152 by determining the difference between the rotor speed measurements 152 using the generator-based rotor speed measurement 150 and filtering the difference using a low-pass filter 158. In such an embodiment, the low-pass filter 158 may have a slow timescale, such as approximately 100 seconds. Thus, as shown, the output of the low-pass filter 158 corresponds to a bias offset 160. Furthermore, as shown at 162, the controller 26 is then configured to subsequently add the bias offset 160 to the rotor speed measurement 152 to obtain a sum 164 (e.g., a complementary filter output (CompFilterOut)). Thus, as shown at 166 , the generator-based rotor speed measurement 150 , the rotor speed measurement 152 , and the complementary filter output signal 164 may be compared to determine if slip is occurring in the drive train 50 .

[0042] More specifically, if Figure 5 and Figure 6 As shown in FIG. 2 , the controller 26 may be configured to generate a graph 200 that plots the generator-based rotor speed measurement 150, the rotor speed measurement 152, and the complementary filter output signal 164 together as a function of time. Figure 6As particularly shown, the rotor speed measurement 152, the complementary filter output signal 164, and the generator-based rotor speed measurement 150 generally match or follow one another, except in instances where slip occurs (e.g., as shown at time Tl) and in instances where oscillations exist in the torsional direction of the rotor shaft 40. For example, as shown, when slip occurs in one of the drivetrain connections (such as the LSS coupling 54 or the HSS coupling 58), the generator-based rotor speed measurement 150 includes a dip 202 at time Tl. In such embodiments, the controller 26 can readily detect the presence of slip using the systems and methods described herein. For example, when oscillations exist in the torsional direction of the rotor shaft 40, the controller 26 is configured to set the threshold high enough so that the wind turbine 10 does not trip.

[0043] In additional embodiments, the present disclosure described herein can also include various diagnostic functions that monitor the health of the first and second rotational speed signals. Thus, in such embodiments, if such signals freeze, as an example, the systems and methods of the present disclosure are configured to trip the wind turbine 10 because the controller 26 is no longer able to determine whether slip (or other faults) exist.

[0044] Further, those skilled in the art will recognize that the various features of the different embodiments are interchangeable. Similarly, one of ordinary skill in the art can mix and match the various method steps and features described, as well as other known equivalents for each of such methods and features, to construct additional systems and techniques in accordance with the principles of the present disclosure. Of course, it is understood that not necessarily all such objects or advantages can be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein can be embodied or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught herein without necessarily achieving other objects or advantages as can be taught or suggested herein.

[0045] Various aspects and embodiments of the present disclosure are defined by the following numbered clauses:

[0046] A method for detecting and responding to a fault in a drive train of a wind turbine, the drive train having at least a rotor and a generator, the method comprising: estimating, via a controller, a first rotational speed signal at a first location along the drive train via one or more rate gyroscopes mounted in the wind turbine, the first rotational speed signal being representative of a rotor speed for a rotor of the wind turbine; processing, via the controller, the first rotational speed signal to account for deviations in the first rotational speed signal resulting from use of the one or more rate gyroscopes; receiving, via the controller, a second rotational speed signal at a second location along the drive train, the second location being downwind of the first location, the first and second locations being on opposite sides of a potential slip position of the drive train; determining, via the controller, a speed error based on a comparison of the first and second rotational speed signals; comparing, via the controller, the speed error to a threshold; and implementing, via the controller, a control action on the wind turbine when the speed error exceeds the threshold.

[0047] A method according to any preceding clause, wherein the second rotational speed signal is representative of a generator speed for a generator of the wind turbine.

[0048] A method as in any preceding clause, wherein the deviation comprises at least one of a low frequency deviation or a DC deviation, and wherein processing the first rotational speed signal to account for the deviation in the first rotational speed signal resulting from use of one or more rate gyroscopes further comprises correcting the first rotational speed signal for at least one of the low frequency deviation or the DC deviation using the second rotational speed signal before determining the velocity error.

[0049] A method according to any preceding clause, wherein correcting at least one of a low frequency deviation or a DC deviation of the first speed signal using the second speed signal before determining the speed error further comprises: low pass filtering the second speed signal to determine the deviation offset; and adding the deviation offset to the first speed signal.

[0050] A method as in any preceding clause, wherein processing the first rate of rotation signal to account for bias in the first rate of rotation signal resulting from use of one or more rate gyroscopes further comprises high pass filtering the rate error before comparing the rate error to a threshold value.

[0051] A method according to any preceding clause, wherein determining the speed error based on a comparison of the first and second rotational speed signals further comprises determining a difference between the first rotational speed signal and the second rotational speed signal.

[0052] A method according to any preceding clause, wherein the potential slip location of the driveline comprises at least one of a low speed shaft coupling, a low speed shaft shrink fit, a high speed shaft coupling, a high speed shaft shrink fit or a gearbox connection.

[0053] The method according to any preceding Clause, further comprising estimating the first rotational speed signal using information from one or more accelerometers mounted in a nacelle of the wind turbine.

[0054] The method according to any preceding Clause, wherein the threshold value is a variable threshold value dependent on at least one of a rotor speed, a torque, a wind speed, or a function thereof.

[0055] The method according to any preceding Clause, wherein the threshold value is a fixed threshold value.

[0056] The method according to any preceding Clause, wherein implementing the control action on the wind turbine further comprises at least one of shutting down the wind turbine, derating the wind turbine, yawing a nacelle of the wind turbine, or pitching one or more rotor blades of the wind turbine.

[0057] A drive train assembly of a wind turbine, the drive train assembly comprising: a rotor shaft for coupling to a rotor of the wind turbine; a gearbox coupled to the rotor shaft; a generator coupled to the gearbox via a generator shaft; and a controller for controlling operation of the wind turbine, the controller comprising at least one processor configured to perform a plurality of operations, the plurality of operations comprising: estimating, via one or more rate gyroscopes mounted in the wind turbine, a first rotational speed signal at a first location along the drive train, the first rotational speed signal being representative of a rotor speed of the rotor of the wind turbine; processing the first rotational speed signal to account for a bias in the first rotational speed signal resulting from use of the one or more rate gyroscopes; receiving a second rotational speed signal from a second location along the drive train assembly, the second location being downwind of the first location, the first and second locations being on opposite sides of a potential slip location of the drive train assembly; determining a speed error based on a comparison of the first and second rotational speed signals; comparing the speed error to a threshold value; and implementing a control action on the wind turbine when the speed error exceeds the threshold value.

[0058] The drive train assembly according to any preceding Clause, wherein the second rotational speed signal is representative of a generator speed of a generator of the wind turbine.

[0059] The drive train assembly according to any preceding Clause, wherein the bias comprises at least one of a low frequency bias or a DC bias, and wherein processing the first rotational speed signal to account for the bias in the first rotational speed signal resulting from use of the one or more rate gyroscopes further comprises correcting the first rotational speed signal for at least one of a low frequency bias or a DC bias using the second rotational speed signal prior to determining the speed error.

[0060] A transmission system component according to any preceding clause, wherein correcting at least one of a low frequency deviation or a DC deviation of the first speed signal using the second speed signal before determining the speed error further comprises: low pass filtering the second speed signal to determine the deviation offset; and adding the deviation offset to the first speed signal.

[0061] A powertrain assembly as described in any preceding clause, wherein processing the first rotational speed signal to account for bias in the first rotational speed signal resulting from use of one or more rate gyroscopes further comprises high pass filtering the speed error before comparing the speed error to a threshold value.

[0062] A powertrain assembly as described in any preceding clause, wherein determining the speed error based on a comparison of the first and second speed signals further comprises determining a difference between the first speed signal and the second speed signal.

[0063] A drive train assembly according to any preceding clause, wherein the potential slip location of the drive train comprises at least one of a low speed shaft coupling, a low speed shaft shrink fit, a high speed shaft coupling, a high speed shaft shrink fit or a gearbox connection.

[0064] The drive train assembly of any preceding clause, wherein the plurality of operations further comprises estimating the first rotational speed signal using information from one or more accelerometers mounted in a nacelle of the wind turbine.

[0065] The drive train assembly of any preceding clause, wherein performing a control action on the wind turbine further comprises at least one of shutting down the wind turbine, de-rating the wind turbine, yawing a nacelle of the wind turbine, or pitching one or more rotor blades of the wind turbine.

[0066] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A method for detecting and responding to a fault in a drive train of a wind turbine, the drive train having at least a rotor and a generator, the method comprising: estimating, via a controller, a first rotational speed signal at a first location along the drive train via one or more rate gyroscopes mounted in the wind turbine, the first rotational speed signal being representative of a rotor speed for the rotor of the wind turbine; processing, via the controller, the first rotational speed signal to account for bias in the first rotational speed signal resulting from use of the one or more rate gyroscopes; receiving, via the controller, a second speed signal at a second location along the powertrain, the second location being downwind of the first location, the first and second locations being on opposite sides of a potential slip position of the powertrain; determining, via the controller, a speed error based on a comparison of the first speed signal and the second speed signal; comparing, via the controller, the speed error with a threshold; as well as When the speed error exceeds the threshold, a control action is implemented on the wind turbine via the controller.

2. The method according to claim 1, wherein The second rotational speed signal is representative of a generator speed of the generator of the wind turbine.

3. The method according to claim 1, wherein The deviation includes at least one of a low-frequency deviation or a DC deviation, and wherein processing the first rotational speed signal to account for the deviation in the first rotational speed signal caused by use of the one or more rate gyroscopes further includes correcting at least one of the low-frequency deviation or the DC deviation of the first rotational speed signal using the second rotational speed signal before determining the velocity error.

4. The method according to claim 3, wherein: Correcting at least one of the low-frequency offset or the DC offset of the first rotational speed signal using the second rotational speed signal before determining the speed error further comprises: low-pass filtering the second speed signal to determine a deviation offset; and The deviation offset is added to the first rotational speed signal.

5. The method according to claim 3, wherein Processing the first rotational speed signal to account for the bias in the first rotational speed signal resulting from use of the one or more rate gyroscopes further comprises: The speed error is high-pass filtered before being compared with the threshold.

6. The method according to claim 1, wherein Determining the speed error based on the comparison between the first speed signal and the second speed signal further includes: A difference between the first speed signal and the second speed signal is determined.

7. The method according to claim 1, wherein The potential slip location of the driveline includes at least one of a low speed shaft coupling, a low speed shaft shrink fit, a high speed shaft coupling, a high speed shaft shrink fit, or a gearbox connection. 8 . The method of claim 1 , further comprising estimating the first rotational speed signal using information from one or more accelerometers mounted in a nacelle of the wind turbine.

9. The method according to claim 1, wherein The threshold is a variable threshold that depends on at least one of rotor speed, torque, wind speed or a function thereof.

10. The method according to claim 1, wherein The threshold is a fixed threshold.

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