Patent Description:
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a nacelle mounted on the tower, a generator positioned in the nacelle, and one or more rotor blades. The one or more rotor blades convert kinetic energy of wind into mechanical energy using known airfoil principles. A drivetrain transmits the mechanical energy from the rotor blades to the generator. The generator then converts the mechanical energy to electrical energy that may be supplied to a utility grid.

The drivetrain may include a gearbox, a rotor shaft, and a generator shaft. More specifically, the rotor shaft may couple the rotor blades to the gearbox. The generator shaft may, in turn, couple the gearbox to the generator. As such, the drivetrain and, in particular, the gearbox may allow the generator to rotate at a different speed than the rotor blades.

In general, the gearbox must be periodically replaced. It is typically necessary to schedule the replacement of gearbox well in advance of the actual replacement operation to minimize wind turbine down time and ensure availability of a replacement gearbox and necessary equipment (e.g., a crane). In this respect, various systems and methods have been developed to monitor or otherwise predict when replacement of the gearbox is necessary. Such systems and methods are based on predetermined profiles of the operating conditions that the gearbox is expected to experience. However, the actual operating conditions experienced by the gearbox may vary greatly. For example, if the actual operating conditions are more severe than the expected operating conditions, gearbox replacement may be required before the conventional systems and method indicate such replacement is necessary. In this respect, when the gearbox wears out before a planned replacement operation, extensive wind turbine down time may occur if the replacement gearbox and necessary repair equipment are unavailable. <CIT> relates to a method for determining fatigue damage in a power train of a wind turbine. <CIT> relates to fatigue in wind turbines.

Accordingly, an improved system and method for monitoring wear on a gearbox of a wind turbine would be welcomed in the art.

Various aspects and advantages of the technology will be set forth in part in the following description, or may be clear from the description, or may be learned through practice of the technology.

In one aspect, the present disclosure is directed to a system for monitoring wear on a gearbox of a wind turbine according to claim <NUM>.

In another aspect, the present disclosure is directed to a method for monitoring wear on a gearbox of a wind turbine according to the independent method claim <NUM>.

Various features, aspects and advantages of the present technology will become better understood with reference to the following description and appended claims.

Reference will now be made in detail to present embodiments of the technology, one or more examples of which are illustrated in the accompanying drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the technology.

Each example is provided by way of explanation of the technology, not limitation of the technology. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present technology without departing from the scope thereof as defined by the appended claims.

For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present technology covers such modifications and variations as come within the scope of the appended claims.

Referring now to the drawings, <FIG> is a perspective view of one embodiment of an exemplary wind turbine <NUM>. As shown, the wind turbine <NUM> generally includes a tower <NUM> extending from a support surface <NUM>, a nacelle <NUM> mounted on the tower <NUM>, and a rotor <NUM> rotatably coupled to the nacelle <NUM>. The rotor <NUM> includes a rotor hub <NUM> and at least one rotor blade <NUM> coupled to and extending outwardly from the hub <NUM>. For example, in the embodiment shown in <FIG>, the rotor <NUM> includes three rotor blades <NUM>. In alternative embodiments, however, the rotor <NUM> may include more or less than three rotor blades <NUM>. Each rotor blade <NUM> may be spaced about the hub <NUM> to facilitate rotation of the rotor <NUM> to convert kinetic energy from the wind into usable rotational, mechanical energy. A generator <NUM> positioned within the nacelle <NUM> may generate electrical power from the rotational energy of the rotor <NUM>.

Referring now to <FIG>, a drivetrain <NUM> couples the rotor <NUM> to the electric generator <NUM>. As shown, the drivetrain <NUM> may include a rotor shaft <NUM>, which couples the rotor hub <NUM> to a gearbox <NUM>. The gearbox <NUM> may be supported by and coupled to a bedplate <NUM> in the nacelle <NUM>. The drivetrain <NUM> also include a generator shaft <NUM>, which couples the gearbox <NUM> to the generator <NUM>. In this respect, rotation of the rotor <NUM> drives the generator <NUM>. More specifically, the rotor shaft <NUM> may provide a low speed, high torque input to the gearbox <NUM> in response to rotation of the rotor blades <NUM> and the hub <NUM>. The gearbox <NUM> may then convert the low speed, high torque input into a high speed, low torque output to drive the generator shaft <NUM> and, thus, the generator <NUM>. In addition, the drivetrain <NUM> may also include a braking system <NUM> configured to stop or slow the rotation of one or more components the drivetrain <NUM>. For example, as shown in the illustrated embodiment, the braking system <NUM> may frictionally engage the generator shaft <NUM> to stop or slow the rotation thereof. Nevertheless, in alternative embodiments, the braking system <NUM> may frictionally engage the rotor shaft <NUM> or any other suitable component of the drivetrain <NUM>.

The wind turbine <NUM> may also include one or more pitch adjustment mechanisms <NUM>. Although <FIG> only illustrates one pitch adjustment mechanism <NUM>, the wind turbine <NUM> may include three pitch adjustment mechanisms <NUM>. In this respect, the wind turbine <NUM> may include one pitch adjustment mechanism <NUM> corresponding to each rotor blade <NUM>. In alternate embodiments, however, the wind turbine <NUM> may include more or fewer pitch adjustment mechanisms <NUM>.

Each pitch adjustment mechanism <NUM> may adjust a pitch angle of the corresponding rotor blade <NUM> (i.e., the angular orientation of the rotor blade <NUM> with respect to a direction <NUM> (<FIG>) of the wind). In particular, each rotor blade <NUM> may be rotatably coupled to the hub <NUM> by a pitch bearing (not shown). As such, each pitch adjustment mechanism <NUM> may rotate the corresponding rotor blade <NUM> about a corresponding pitch axis <NUM> (<FIG>) relative to the hub <NUM>, thereby adjusting the pitch angle of the rotor blade <NUM>.

<FIG> illustrates an exemplary embodiment of one of the pitch adjustment mechanisms <NUM>. More specifically, the pitch adjustment mechanism <NUM> may include an electric motor <NUM> having a pinion gear <NUM> coupled thereto. The pinion gear <NUM> may engage a ring gear <NUM> formed on or coupled to an inner surface of the rotor blade <NUM>. During operation of the pitch adjustment mechanism <NUM>, the electric motor <NUM> rotates the pinion gear <NUM>. The pinion gear <NUM>, in turn, rotates the ring gear <NUM>, thereby rotating the rotor blade <NUM> about the corresponding pitch axis <NUM>. In alternate embodiments, the pitch adjustment mechanism <NUM> may include any suitable type of actuator and/or any suitable structure or mechanism for transmitting the movement of the actuator to the corresponding rotor blade <NUM>.

Furthermore, the wind turbine <NUM> may include a yaw drive <NUM> for adjusting a yaw angle of the nacelle <NUM> (i.e., the angular orientation of the nacelle <NUM> relative to the tower <NUM>). In particular, the nacelle <NUM> may be rotatably coupled to the tower <NUM> by a yaw bearing (not shown). As such, the yaw drive <NUM> may include one or more yaw adjustment mechanisms <NUM>, which rotate the nacelle <NUM> about a yaw axis <NUM> (<FIG>) relative to the tower <NUM> to adjust the yaw angle of the nacelle <NUM>. Although <FIG> illustrates two yaw adjustment mechanisms <NUM>, the wind turbine <NUM> may include any suitable number of yaw adjustment mechanisms <NUM>, such as a single yaw adjustment mechanism <NUM> or more than two yaw adjustment mechanisms <NUM>. For example, certain embodiments of the yaw drive <NUM> may include four yaw adjustment mechanisms <NUM>.

<FIG> illustrates an exemplary embodiment of the yaw adjustment mechanisms <NUM>. More specifically, each yaw adjustment mechanism <NUM> may include an electric motor <NUM> mounted to and/or through the bedplate <NUM>. Each electric motor <NUM> may include a pinion gear <NUM> coupled thereto, which engages a tower ring gear <NUM> coupled to the tower <NUM>. During operation of the yaw adjustment mechanisms <NUM>, the electric motors <NUM> rotate the corresponding pinion gears <NUM>, which rotate the tower ring gear <NUM>. The rotation of the pinion gears <NUM> relative to the tower ring gear <NUM> causes the nacelle <NUM> to rotate about the yaw axis <NUM> (<FIG>). In alternate embodiments, the yaw adjustment mechanisms <NUM> may include any suitable type of actuator and/or any suitable structure or mechanism for transmitting movement between the tower <NUM> and the nacelle <NUM>.

The yaw drive <NUM> may also include one or more brake assemblies <NUM> for controlling the rotation of the nacelle <NUM> about the yaw axis <NUM> (<FIG>). For example, as shown in the illustrated embodiment, the brake assemblies <NUM> may be mounted to and/or through the bedplate <NUM>. As such, each brake assembly <NUM> may frictionally engage the tower ring gear <NUM> or another suitable friction surface of the wind turbine <NUM> to stop, slow, and/or otherwise control the rotation of the nacelle <NUM> about the yaw axis <NUM>. The wind turbine <NUM> may include any suitable number of brake assemblies <NUM>. For instance, in an exemplary embodiment, the wind turbine <NUM> may include between twelve and twenty brake assemblies <NUM>. In other embodiments, however, the wind turbine <NUM> may include less than twelve brake assemblies <NUM> or more than twenty brake assemblies <NUM>.

<FIG> illustrates one embodiment of a system <NUM> for monitoring wear on a gearbox of a wind turbine. In general, the system <NUM> will be described herein with reference to the wind turbine <NUM> described above and shown in <FIG> and <FIG>. Nevertheless, the disclosed system <NUM> may generally be used with wind turbines having any other suitable configuration.

As shown, the system <NUM> may include various sensors. In the embodiment shown in <FIG>, for example, the system <NUM> includes a torque sensor <NUM>, a rotational speed sensor <NUM>, a vibration sensor <NUM>, and an acoustic sensor <NUM>. In alternate embodiments, however, the system <NUM> may include only some of the sensors <NUM>, <NUM> or none of the sensors <NUM>, <NUM>. Furthermore, the system <NUM> may include other sensors (e.g., one or more bearing temperature sensors, oil temperature sensors, etc.) in addition to or lieu of the sensors <NUM>, <NUM>.

The torque sensor <NUM> is configured to detect a parameter indicative of a torque exerted on the rotor shaft <NUM> or the generator shaft <NUM>, such as by the rotor <NUM>. In this respect, in one embodiment, the torque sensor <NUM> may be operative association with the rotor shaft <NUM> such that the torque sensor <NUM> detects a parameter indicative of the torque exerted on the rotor shaft <NUM> as illustrated in <FIG>. In another embodiment, as shown in <FIG>, the torque sensor <NUM> may be operative association with the generator shaft <NUM> such that the torque sensor <NUM> detects a parameter indicative of the torque exerted on the generator shaft <NUM>. The torque sensor <NUM> may be a contact torque sensor, such as a slip ring torque sensor, or a non-contact torque sensor, such as a rotary transformer or an infrared torque sensor. Furthermore, the torque sensor <NUM> may be a wired sensor or a wireless/telemetry sensor. Nevertheless, the torque sensor <NUM> may be any suitable sensor for detecting torque.

The rotational speed sensor <NUM> is configured to detect a parameter indicative of a rotational speed of one of the rotor shaft <NUM> or the generator shaft <NUM>. In this respect, in one embodiment, the rotational speed sensor <NUM> may be operative association with the rotor shaft <NUM> such that the rotational speed sensor <NUM> detects a parameter indicative of the rotational speed of the rotor shaft <NUM> as illustrated in <FIG>. In another embodiment, as shown in <FIG>, the rotational speed sensor <NUM> may be operative association with the generator shaft <NUM> such that the rotational speed sensor <NUM> detects a parameter indicative of the rotational speed of the generator shaft <NUM>. The rotational speed sensor <NUM> may be a Hall Effect sensor or any other suitable type of sensor for detecting rotational speed or rotational position.

The vibration sensor <NUM> is configured to detect a parameter indicative of vibrations occurring within or being emitted from the gearbox <NUM>. In this respect, the vibration sensor <NUM> may be in operative association with the gearbox <NUM> as illustrated in <FIG> and <FIG>. The vibration sensor <NUM> may be an accelerometer, an eddy current sensor probe, a capacitance proximity sensor, or any other suitable type of sensor for detecting vibrations occurring within or being emitted from the gearbox <NUM>.

The acoustic sensor <NUM> is configured to detect a parameter indicative of sounds or other acoustic signals occurring within or being emitted by the gearbox <NUM>. In this respect, the acoustic sensor <NUM> may be in operative association with the gearbox <NUM> as illustrated in <FIG> and <FIG>. The acoustic sensor <NUM> may be a microphone or any other suitable type of sensor for detecting sounds or other acoustic signals occurring within or being emitted by the gearbox <NUM>.

The system <NUM> also includes a controller <NUM> communicatively coupled to one or more components of the system <NUM> and/or the wind turbine <NUM>, such as the sensors <NUM>, <NUM>, <NUM>, <NUM>, the pitch adjustment mechanisms <NUM>, and the yaw drive <NUM>. In the embodiment shown in <FIG>, for example, the controller <NUM> is disposed within a control cabinet <NUM> mounted within the nacelle <NUM>. In alternate embodiments, however, the controller <NUM> may be disposed at any location on or in the wind turbine <NUM>, at any location on the support surface <NUM> (<FIG>), or any other suitable location.

In general, the controller <NUM> may correspond to any suitable processor-based device, including one or more computing devices. As shown in <FIG>, for example, the controller <NUM> may include one or more processors <NUM> and one or more associated memory devices <NUM> configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations, and the like disclosed herein). As used herein, the term "processor" refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), a Field Programmable Gate Array (FPGA), and other programmable circuits. Additionally, the memory device(s) <NUM> may generally include memory element(s) including, but not limited to, a computer readable medium (e.g., random access memory (RAM)), a computer readable nonvolatile medium (e.g., flash memory), a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD), and/or other suitable memory elements or combinations thereof. The memory device(s) <NUM> may store instructions that, when executed by the processor <NUM>, cause the processor <NUM> to perform functions (e.g., method <NUM> described below).

The controller <NUM> may also include a communications module <NUM> to facilitate communications between the controller <NUM> and the various components of the system <NUM> and/or the wind turbine <NUM>. For example, the communications module <NUM> may permit the controller <NUM> to receive data from the sensors <NUM>, <NUM>, <NUM>, <NUM>. As such, the communications module <NUM> may include a sensor interface <NUM> (e.g., one or more analog-to-digital converters) that converts measurement signals <NUM>, <NUM>, <NUM>, <NUM> received from the sensors <NUM>, <NUM>, <NUM>, <NUM> into signals that can be understood and processed by the processor(s) <NUM>. Furthermore, the communications module <NUM> may permit the controller <NUM> to transmit control signals <NUM> to each pitch adjustment mechanism <NUM> for controlling the pitch angle of the rotor blades <NUM>. Additionally, the communications module <NUM> may permit the controller <NUM> to transmit control signals <NUM> to the yaw drive <NUM> for controlling the yaw angle of the nacelle <NUM>. In this respect, the communications module <NUM> may be any combination of suitable wired and/or wireless communication interfaces that communicatively couple the sensors <NUM>, <NUM>, <NUM>, <NUM>, the pitch adjustment mechanisms <NUM>, and the yaw drive <NUM> to the controller <NUM>.

Referring again to <FIG>, in some embodiments, the system <NUM> may include a user interface <NUM> configured to allow interaction between a user and the controller <NUM>. More specifically, the user interface <NUM> may be communicatively coupled to the controller <NUM> to permit feedback signals (e.g., as indicated by arrow <NUM> in <FIG>) to be transmitted from the controller <NUM> to the user interface <NUM>. In this respect, the user interface <NUM> may include one or more feedback devices (not shown), such as display screens, speakers, warning lights, etc., which communicate the feedback from the controller <NUM> to the user. In one embodiment, the user interface <NUM> may be located at a remote location (e.g., a control center for a wind farm) from the wind turbine <NUM>. In such embodiment, the controller <NUM> and the user interface <NUM> may be communicatively coupled via the Internet or another suitable network. In alternate embodiments, however, the system <NUM> may not include the user interface <NUM>.

In general, the controller <NUM> may be configured to monitor the wear on the gearbox <NUM> by executing various logic stored on the memory device(s) <NUM>. In particular, the controller <NUM> (e.g., via the processor(s) <NUM>) executes the logic to determine an accumulated wear value for the gearbox <NUM> based on the data received from the sensors <NUM>, <NUM>, <NUM>, <NUM> and/or data stored in the memory device(s) <NUM>. When the accumulated wear value exceeds a wear threshold, the controller <NUM> may initiate various control actions associated with reducing the rate at which the gearbox <NUM> incurs additional wear.

The controller <NUM> may be configured to determine or estimate a torque exerted on the rotor shaft <NUM> or the generator shaft <NUM> associated with the torque sensor <NUM>. More specifically, as mentioned above, the controller <NUM> is communicatively coupled to the torque sensor <NUM>. In this respect, the controller <NUM> receives the torque measurement signals <NUM> from the torque sensor <NUM>. In the embodiment shown in <FIG>, the torque sensor <NUM> is operatively associated with the generator shaft <NUM>. In such embodiments, the torque measurement signals <NUM> are indicative of the torque exerted on the generator shaft <NUM>. The controller <NUM> may include torque measurement logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the torque measurement logic <NUM>, the controller <NUM> may determine a measured torque (e.g., as indicated by arrow <NUM> in <FIG>) exerted on the generator shaft <NUM> based on the received torque measurement signals <NUM>. Nevertheless, in embodiments where the torque sensor <NUM> is operatively associated with the rotor shaft <NUM>, the controller <NUM> may execute the torque measurement logic <NUM> to determine a measured torque exerted on the rotor shaft <NUM>.

In several embodiments, the controller <NUM> may be configured to determine or calculate a torque exerted on the other of the rotor shaft <NUM> or the generator shaft <NUM> based on the determined torque <NUM>. As such, the controller <NUM> may include gearbox torque efficiency logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the gearbox torque efficiency logic <NUM>, the controller <NUM> may determine a calculated torque (e.g., as indicated by arrow <NUM> in <FIG>) exerted on the rotor shaft <NUM> based on the determined torque <NUM> exerted on the generator shaft <NUM>. Nevertheless, in embodiments where the torque sensor <NUM> is operatively associated with the rotor shaft <NUM>, the controller <NUM> may execute the gearbox torque efficiency logic <NUM> to determine a calculated torque exerted on the generator shaft <NUM>. In alternative embodiments, the system <NUM> may include one torque sensor <NUM> in operative association with the rotor shaft <NUM> and another torque sensor <NUM> in operative association with the generator shaft <NUM>. In such embodiments, the controller <NUM> may be configured to determine (e.g., by executing the torque measurement logic <NUM>) the torque exerted on both shafts <NUM>, <NUM> based on the torque measurement signals <NUM> received from the torque sensors <NUM>.

The controller <NUM> may also be configured to determine or estimate a rotational speed of the rotor shaft <NUM> or the generator shaft <NUM> associated with the rotational speed sensor <NUM>. More specifically, as mentioned above, the controller <NUM> is communicatively coupled to the rotational speed sensor <NUM>. In this respect, the controller <NUM> receives the rotational speed measurement signals <NUM> from the torque sensor <NUM>. In the embodiment shown in <FIG>, the rotational speed sensor <NUM> is operatively associated with the generator shaft <NUM>. In such embodiments, the rotational speed measurement signals <NUM> are indicative of the rotational speed of the generator shaft <NUM>. The controller <NUM> may include rotational speed measurement logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the rotational speed measurement logic <NUM>, the controller <NUM> may determine a measured rotational speed (e.g., as indicated by arrow <NUM> in <FIG>) of the generator shaft <NUM> based on the received rotational speed measurement signals <NUM>. Nevertheless, in embodiments where the rotational speed sensor <NUM> is operatively associated with the rotor shaft <NUM>, the controller <NUM> may execute the rotational speed measurement logic <NUM> to determine a measured rotational speed of the rotor shaft <NUM>.

In some embodiments, the controller <NUM> may be configured to determine or calculate a rotational speed of the other of the rotor shaft <NUM> or the generator shaft <NUM> based on the measured rotational speed <NUM>. As such, the controller <NUM> may include gearbox rotational speed efficiency logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the gearbox rotational speed efficiency logic <NUM>, the controller <NUM> may determine a calculated rotational speed (e.g., as indicated by arrow <NUM> in <FIG>) of the rotor shaft <NUM> based on the measured rotational speed <NUM> of the generator shaft <NUM>. Nevertheless, in embodiments where the rotational speed sensor <NUM> is operatively associated with the rotor shaft <NUM>, the controller <NUM> may execute the gearbox rotational speed efficiency logic <NUM> to determine the rotational speed of the generator shaft <NUM>. In alternative embodiments, the system <NUM> may include one rotational speed sensor <NUM> in operative association with the rotor shaft <NUM> and/or another rotational speed sensor <NUM> in operative association with the generator shaft <NUM>. In such embodiments, the controller <NUM> may be configured to determine (e.g., by executing the rotational speed measurement logic <NUM>) the rotational speed of both shafts <NUM>, <NUM> based on the rotational speed measurement signals <NUM> received from the rotational speed sensors <NUM>.

Furthermore, the controller <NUM> is configured to determine or calculate a stress value for the gearbox <NUM> based on the torques <NUM>, <NUM> and the rotational speeds <NUM>, <NUM>. In general, the stress value may be indicative of a magnitude or a level of stress experienced by one or more components (e.g., bearings, gears, etc.) of the gearbox <NUM>. This stress may be caused by the torques <NUM>, <NUM> exerted on the corresponding shafts <NUM>, <NUM>. As shown in <FIG>, the controller <NUM> may include stress logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the stress logic <NUM>, the controller <NUM> may determine or calculate the stress value (e.g., as indicated by arrow <NUM> in <FIG>) of the gearbox <NUM> or one or more components of the gearbox <NUM> based on the respective torques <NUM>, <NUM> and rotational speeds <NUM>, <NUM> of the rotor shaft <NUM> and the generator shaft <NUM>.

According to the invention, the controller <NUM> is configured to assign a positive value to one of the torque <NUM> exerted on the rotor shaft <NUM> or the torque <NUM> exerted on the generator shaft <NUM> and a negative value to the other of the torque <NUM> exerted on the rotor shaft <NUM> or the torque <NUM> exerted on the generator shaft <NUM>. For example, in one embodiment, the controller <NUM> may be configured to assign the torque <NUM> exerted on the rotor shaft <NUM> a positive value and the torque <NUM> exerted on the generator shaft <NUM> a negative value. As such, the controller <NUM> is able to account for torque reversals in the gearbox <NUM> when determining the stress value <NUM>. For example, in one embodiment, a torque reversal may occur when the rotor <NUM> changes its direction of rotation. By accounting for torque reversals, the system <NUM> provides a more accurate determination of the stress value.

In the embodiment shown in <FIG>, the controller <NUM> includes an internal clock <NUM> configured to monitor a time duration (e.g., as indicated by arrow <NUM> in <FIG>) over which the gearbox <NUM> experiences the stress value <NUM>. In alternative embodiment, the controller <NUM> may receive a signal (not shown) from an external time keeping device (not shown) indicative of the duration of time over which the gearbox <NUM> experiences the stress value <NUM>.

Moreover, the controller <NUM> is configured to determine an accumulated wear value for the gearbox <NUM> based on the stress value <NUM> and the time duration <NUM>. In general, the accumulated wear value may be indicative the remaining life of the gearbox <NUM> or certain components of the gearbox <NUM> based on the magnitude and duration of the stress experienced by the gearbox <NUM> throughout its operational life. For example, in one embodiment, the accumulated wear value may be a percentage or ratio of the remaining life of the gearbox <NUM>. As shown in <FIG>, the controller <NUM> may include accumulated wear logic <NUM> having one or more mathematical functions and/or one or more look-up tables. In certain embodiments, the mathematical equations may include Miner's Rule method or any other suitable cumulative damage equations/functions. By executing the accumulated wear logic <NUM>, the controller <NUM> may determine or calculate the accumulated wear value (e.g., as indicated by arrow <NUM> in <FIG>) of the gearbox <NUM> or one or more components of the gearbox <NUM> based on the stress value <NUM> and the time duration <NUM>. As described above, the stress value <NUM> is based on the torques <NUM>, <NUM> and the rotational speeds <NUM>, <NUM> of the rotor and generator shafts <NUM>, <NUM>. In this respect, the accumulated wear value <NUM> may also be based on the torques <NUM>, <NUM> and the rotational speeds <NUM>, <NUM>.

In some embodiments, the controller <NUM> may be configured to determine or calculate the accumulated wear value <NUM> based on a previous accumulated wear value <NUM>. More specifically, the accumulated wear value <NUM> may be determined at some regular interval or frequency. In general, during operation, the gearbox <NUM> incurs some amount of wear during between accumulated wear determinations. As such, the wear incurred by the gearbox <NUM> since the previous accumulated wear determination may be added to the previous value <NUM> such that the current accumulated wear value <NUM> reflects all wear incurred by the gearbox <NUM> at that time.

In particular embodiments, the controller <NUM> may be configured to identify one or more components of the gearbox <NUM> associated with the accumulated wear value <NUM> of the gearbox <NUM>. In general, the gearbox <NUM> may include a plurality of components, such as various gears and bearings. In certain instances, particular components of the gearbox <NUM> may attribute to or otherwise be associated with the accumulated wear value <NUM> of the gearbox <NUM>. For example, in one instance, a particular bearing within the gearbox <NUM> may have incurred the most wear on any component within the gearbox <NUM>. In such instance, this bearing may be the component that limits the life of the gearbox <NUM>. That is, this bearing is the reason for the particular accumulated wear value <NUM> of the gearbox <NUM>. As mentioned above, the controller <NUM> may be communicatively coupled to the vibration sensor <NUM> and the acoustic sensor <NUM>. In this respect, the controller <NUM> may receive the vibration measurement signals <NUM> from the vibration sensor <NUM> and/or acoustic measurement signals <NUM> from the acoustic sensor <NUM>. As such, the controller <NUM> may include component identification logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the component identification logic <NUM>, the controller <NUM> may identify or otherwise determine one or more components (e.g., as indicated by arrow <NUM> in <FIG>) of the plurality of components forming the gearbox <NUM> that attribute to the accumulated wear value <NUM> of the gearbox <NUM>. In alternative embodiments, the controller <NUM> may be configured to identify the components <NUM> based on other parameters (e.g., bearing temperature, oil temperature, etc.) in addition to or in lieu of the vibration measurement signals <NUM> and/or the acoustic measurement signals <NUM>.

Additionally, the controller <NUM> is configured to initiate various control actions based on the accumulated wear value <NUM>. As such, the controller <NUM> may include control action logic <NUM> having one or more mathematical functions and/or one or more look-up tables. By executing the control action logic <NUM>, the controller <NUM> compares the accumulated wear value <NUM> to a wear threshold and initiates a control action associated with modifying a rate at which the gearbox <NUM> incurs wear when the accumulated wear value <NUM> exceeds the wear threshold. In one embodiment, the wear threshold may correspond to a percentage of total wear that the gearbox <NUM> is capable of incurring. In another embodiment, the wear threshold may correspond to a percentage of wear that the gearbox <NUM> is expected (e.g., as determined by design data and/or predicted operating profiles) to have incurred based on the time duration <NUM> of operation. Nevertheless, the wear threshold may be based on any other suitable criteria. As will be described below, the controller <NUM> may be configured to initiate control actions by at least one of transmitting the feedback signals <NUM> to the user interface <NUM>, transmitting the control signals <NUM> to the pitch adjustment mechanisms <NUM>, or transmitting the control signals <NUM> to the yaw drive <NUM>.

In several embodiments, the controller <NUM> may be configured to initiate a control action associated with notifying an operator of the wind turbine <NUM> that the accumulated wear value <NUM> has exceeded the wear threshold. For example, when the accumulated wear value <NUM> exceeds the wear threshold, the controller <NUM> may be configured to transmit the feedback signals <NUM> to the user interface <NUM>. The feedback signals <NUM> instruct the user interface <NUM> to present a visual or audible notification or indicator to the operator of the wind turbine <NUM> indicating that the accumulated wear value <NUM> has exceeded the wear threshold. As mentioned above, in particular embodiments, the controller <NUM> may be configured to determine one or more components of the gearbox <NUM> associated with the accumulated wear value <NUM>. In such embodiments, the feedback signals <NUM> may also instruct the user interface <NUM> to provide an indication of the one or more components of the gearbox <NUM> associated with the accumulated wear value <NUM>.

Furthermore, the controller <NUM> may be configured to initiate a control action associated with changing an output of the generator <NUM> (<FIG> and <FIG>). For example, when the accumulated wear value <NUM> exceeds the wear threshold, the controller <NUM> may be configured to transmit the control signals <NUM> to the pitch adjustment mechanisms <NUM>. The control signals <NUM> instruct each pitch adjustment mechanism <NUM> to adjust the current pitch angle of the corresponding rotor blade <NUM> (<FIG>) to a new pitch angle such that the generator <NUM> produces more or less power. For example, when the wear value is higher than expected, the new pitch angle may cause the generator to produce less power. Conversely, when the wear value is lower than expected, the new pitch angle may cause the generator to produce more power. Additionally, the controller <NUM> may be configured to transmit the control signals <NUM> to the yaw drive <NUM> when the accumulated wear value <NUM> exceeds the wear threshold. The control signals <NUM> instruct yaw drive <NUM> (e.g., the yaw adjustment mechanisms <NUM> (<FIG>) and/or brake assemblies <NUM>) to adjust the current yaw angle of the nacelle <NUM> (<FIG> and <FIG>) to a new yaw angle such that the generator <NUM> produces more or less power. Nevertheless, in such embodiments, the controller <NUM> may be configured to initiate any suitable control action associated with changing the output of the generator <NUM>.

Moreover, in several embodiments, the controller <NUM> may be configured to initiate a control action associated with terminating power generation of the generator <NUM> (<FIG> and <FIG>). For example, when the accumulated wear value <NUM> exceeds the wear threshold, the controller <NUM> may be configured to transmit the control signals <NUM> to the pitch adjustment mechanisms <NUM>. The control signals <NUM> instruct each pitch adjustment mechanism <NUM> to adjust the current pitch angle of the corresponding rotor blade <NUM> (<FIG>) to a feathered position such that the generator <NUM> ceases to produce power. Additionally, the controller <NUM> may be configured to transmit the control signals <NUM> to the yaw drive <NUM> when the accumulated wear value <NUM> exceeds the wear threshold. The control signals <NUM> instruct yaw drive <NUM> (e.g., the yaw adjustment mechanisms <NUM> (<FIG>)) to adjust the current yaw angle of the nacelle <NUM> (<FIG> and <FIG>) to a new yaw angle such that the generator <NUM> ceases to produce power. Nevertheless, in such embodiments, the controller <NUM> may be configured to initiate any suitable control action associated with terminating power generation of the generator <NUM>.

In several embodiments, the controller <NUM> may be configured to compare the accumulated wear value <NUM> to a plurality of wear thresholds and initiate specific control actions based on the particular wear threshold that the accumulated wear parameter <NUM> exceeds. For example, the controller <NUM> may be configured to compare the accumulated wear value <NUM> to a first wear threshold, a second wear threshold, and a third wear threshold. In general, the second wear threshold may be higher than the first wear threshold, and the third wear threshold may be higher than the second wear threshold. In one embodiment, the first, second, and third wear thresholds may respectively be ninety percent, ninety-five percent, and ninety-nine percent of the total wear that the gearbox <NUM> is able to incur. Although, in other embodiments, the first, second, and third wear thresholds may be any suitable values. As such, the controller <NUM> may be configured to initiate a control action associated with notifying an operator of the wind turbine <NUM> when the accumulated wear value <NUM> exceeds the first wear threshold. When the accumulated wear value <NUM> exceeds the second wear threshold, the controller <NUM> may be configured to initiate a control action associated with derating the generator <NUM>. Furthermore, the controller <NUM> may be configured to initiate a control action initiate a control action associated with terminating power generation of the generator <NUM> when the accumulated wear value <NUM> exceeds the third wear threshold. For example, in one embodiment, the control action may be associated with engaging the braking system <NUM> when the accumulated wear value <NUM> exceeds the third wear threshold to protect the drivetrain <NUM> and wind turbine <NUM> from damage due to excessive wear. In such embodiment, the controller <NUM> may be configured to transmit suitable control signals (e.g., as indicated by arrow <NUM> in <FIG>) to the braking system <NUM> that instruct the braking system <NUM> to frictionally engage the drivetrain <NUM>, thereby stopping rotation of the drivetrain <NUM>. Nevertheless, the controller <NUM> may be configured to initiate any suitable control action when the accumulated wear value exceeds any wear threshold.

<FIG> illustrates one embodiment of a method <NUM> for monitoring wear on a gearbox of a wind turbine in accordance with aspects of the present subject matter. Although <FIG> depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. As such, the various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

As shown in <FIG>, at (<NUM>), the method <NUM> may include receiving, with a controller, torque measurement signals from a torque sensor in operative association with one of a rotor shaft or a generator shaft. For example, in the embodiment shown in <FIG>, the torque sensor <NUM> is in operative association with the generator shaft <NUM>. Furthermore, as described above, the controller <NUM> may be communicatively coupled to the torque sensor <NUM>. As such, the controller <NUM> may be configured to receive the torque measurement signals <NUM> indicative of the torque exerted on the generator shaft <NUM> from the torque sensor <NUM>. In alternative embodiments, the torque sensor <NUM> may be in operative association with the rotor shaft <NUM> such that the controller <NUM> may be configured to receive the torque measurement signals <NUM> indicative of the torque exerted on the rotor shaft <NUM>.

At (<NUM>), the method <NUM> may include determining, with the controller, a torque exerted on the rotor shaft or the generator shaft associated with the torque sensor based on the received torque measurement signals. For example, as described above, the controller <NUM> may be configured to determine or estimate (e.g., by executing the torque measurement logic <NUM>) the torque <NUM> exerted on generator shaft <NUM> based on the received measurement signals <NUM>. Nevertheless, in alternative embodiments, the controller <NUM> may be configured to determine or estimate the torque <NUM> exerted on the rotor shaft <NUM> based on the received measurement signals <NUM> when the torque sensor <NUM> is in operative association with the rotor shaft <NUM>.

Furthermore, at (<NUM>), the method <NUM> may include determining, with the controller, an accumulated wear value for the gearbox based on the determined torque. For example, as described above, the controller <NUM> may be configured to determine or calculate (e.g., by executing the stress logic <NUM>) a stress value <NUM> based at least in part on the determined torque <NUM>. The controller <NUM> may then be configured to determine or calculate (e.g., by executing the accumulated wear logic <NUM>) an accumulated wear value <NUM> based at least in part on the stress value <NUM>.

Moreover, at (<NUM>), the method <NUM> may include comparing, with the controller, the accumulated wear value to a wear threshold. For example, as described above, the controller <NUM> may be configured to compare (e.g., by executing the control action logic <NUM>) the determined accumulated wear value <NUM> to a wear threshold.

Additionally, at (<NUM>), the method <NUM> may include initiating, with the controller, a control action associated with modifying a rate at which the gearbox incurs wear when the accumulated wear value exceeds the wear threshold. For example, as described above, the controller <NUM> may be configured to initiate (e.g., by executing the control action logic <NUM>) a control action associated with modifying a rate at which the gearbox <NUM> incurs wear when the accumulated wear value <NUM> exceeds the wear threshold. Such control actions may include notifying an operator of the wind turbine <NUM>, changing the output of the generator <NUM> of the wind turbine <NUM>, and/or terminating power generation of the wind turbine <NUM>.

The disclosed system <NUM> and method <NUM> for monitoring wear on a gearbox of a wind turbine provide advantages over conventional wear monitoring systems and methods. For example, as described above, the system <NUM> and method <NUM> determine the wear on the gearbox (i.e., the accumulated wear value <NUM>) based the torque exerted on the rotor and/or the generator shafts coupled to the gearbox. In this respect, and unlike with conventional systems and methods, the system <NUM> and the method <NUM> account for the actual conditions experienced by the gearbox, which, as mentioned above, may vary greatly from the predicted conditions, during wear determinations. Furthermore, in some embodiments, and unlike with conventional systems and methods, the system <NUM> and the method <NUM> may account for torque reversals when determining wear on gearbox. Such torque reversals may greatly impact the wear incurred by the gearbox. As such, the system <NUM> and the method <NUM> provide more accurate determination of the wear incurred by the gearbox than conventional systems and methods, thereby reducing unplanned downtime of the wind turbine.

Claim 1:
A system (<NUM>) for monitoring wear on a gearbox (<NUM>) of a wind turbine (<NUM>), the system (<NUM>) comprising:
a wind turbine (<NUM>) including a rotor (<NUM>), a gearbox (<NUM>), a rotor shaft (<NUM>) coupling the rotor (<NUM>) and the gearbox (<NUM>), a generator (<NUM>), and a generator shaft (<NUM>) coupling the gearbox (<NUM>) and the generator (<NUM>);
a first sensor (<NUM>) configured to detect a parameter indicative of a torque (<NUM>, <NUM>) exerted on the rotor shaft (<NUM>) or the generator shaft (<NUM>); and
a controller (<NUM>) communicatively coupled to the first sensor (<NUM>), the controller (<NUM>) being configured to determine the torque (<NUM>, <NUM>) exerted on the rotor shaft (<NUM>) or the generator shaft (<NUM>) based on measurement signals (<NUM>) received from the first sensor (<NUM>);
wherein the controller (<NUM>) is further configured to determine a torque (<NUM>) exerted on the other of the rotor shaft (<NUM>) or the generator shaft (<NUM>) based on the determined torque (<NUM>) exerted on the rotor shaft (<NUM>) or the generator shaft (<NUM>);
wherein the controller (<NUM>) is further configured to determine a stress value (<NUM>) for the gearbox (<NUM>) based on the respective torques (<NUM>, <NUM>) and rotational speeds (<NUM>, <NUM>) of the rotor shaft (<NUM>) and the generator shaft (<NUM>);
wherein the controller (<NUM>) is further configured to assign a positive value to one of the torque (<NUM>) exerted on the rotor shaft (<NUM>) or the torque (<NUM>) exerted on the generator shaft (<NUM>) and a negative value to the other of the torque (<NUM>) exerted on the rotor shaft (<NUM>) or the torque (<NUM>) exerted on the generator shaft (<NUM>) to account for torque reversals in the gearbox (<NUM>) when determining the stress value (<NUM>);
wherein the controller (<NUM>) is further configured to determine an accumulated wear value (<NUM>) based on the stress value (<NUM>); wherein the controller (<NUM>) is further configured to monitor a duration (<NUM>) during which the gearbox (<NUM>) experiences the stress value (<NUM>) and determine the accumulated wear value (<NUM>) based on the duration (<NUM>) of the stress value (<NUM>).