System and method for controlling a wind turbine to protect the wind turbine from abnormal operation

Abstract

The present invention relates to a system and method of controlling a wind turbine to protect the wind turbine from abnormal operation, and in particular provides a system and method for controlling a wind turbine to protect the wind turbine from abnormal operation. Thus, in response to receiving data indicative of an abnormal operation event of the wind turbine, a controller initiates an enhanced braking mode for the wind turbine. The enhanced braking mode is characterized by operating the generator at a torque setpoint that generates the maximum available torque for a given set of operating conditions. Additionally, the torque setpoint exceeds the nominal torque limit for the generator.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to wind turbines, and more particularly to systems and methods for controlling a wind turbine to protect the wind turbine from abnormal operation. BACKGROUND

[0002] Wind power is considered one of the cleanest, environmentally friendly energy sources currently available, and, in this regard, wind turbines have gained increased attention. A modern wind turbine typically includes 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 to the generator. The rotor assembly and the gearbox are mounted on a bedplate support frame located within the nacelle. The one or more rotor blades use known airfoil principles to capture kinetic energy of wind. The rotor blades transfer the kinetic energy in the form of rotational energy to a shaft that couples the rotor blades to the gearbox or, if no gearbox is used, directly to the generator. The generator then converts the mechanical energy into electrical energy, which can be transferred to a transformer and / or converter housed within the tower and subsequently deployed to a utility grid. Modern wind power systems typically take the form of a wind farm having a plurality of such wind turbine generators operable to supply power to a power transmission system, thereby providing power to a grid.

[0003] In certain instances, a wind turbine can experience an abnormal operating event, such as an overspeed condition, a portion of a rotor blade (or the rotor blade in its entirety) separating from the wind turbine, and / or other significant deviation from a normal operating state of the wind turbine. Such events can cause significant damage to the wind turbine.

[0004] Damage caused by an abnormal operating event can be exacerbated by continuing to operate the wind turbine. With existing wind turbines, a controller typically uses components of the wind turbine operating within nominal design limits to slow the rotor. Nominal design limits can typically be established at a level that allows the components of the wind turbine to operate under all conditions without causing an impact to the nominal life expectancy of the components. However, the rate of deceleration that can be achieved when operating at the nominal design limits can not be sufficient to prevent or mitigate damage to the wind turbine caused by the abnormal operating event. Thus, in certain instances, it can be desirable to slow the rotor in a more accelerated manner than can be achieved at the nominal design limits in response to the abnormal operating event.

[0005] Accordingly, there is a continuing desire in the art for new and improved systems and methods that address the foregoing concerns. With this in mind, the present disclosure relates to systems and methods for controlling a wind turbine to protect the wind turbine from abnormal operation. SUMMARY

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

[0007] In one aspect, the present disclosure relates to a method for protecting a wind turbine from abnormal operation. The method can include receiving, with a controller of the wind turbine, data indicative of an abnormal operation event of the wind turbine. In response to receiving the data indicative of the abnormal operation event of the wind turbine, the method can include initiating, with the controller, an enhanced braking mode for the wind turbine. The enhanced braking mode can feature operating a generator at a torque setpoint that generates a maximum available torque for a given set of operating conditions and exceeds a nominal torque limit for the generator. Additionally, the method can include operating, with the controller, the wind turbine in the enhanced braking mode.

[0008] In embodiments, the enhanced braking mode can include a first enhanced braking mode. The method can further include determining, with a converter controller of the wind turbine, an actual operating parameter for each of a plurality of electrical system components. The method can also include determining, with the converter controller, an actual operating limit for each of the electrical system components based on the determined actual operating parameter. The actual operating limit can indicate an operating parameter value below which the electrical system component maintains a nominal life expectancy. Operating the electrical system component below the actual operating limit can prevent a trip of the electrical system component. Additionally, the method can include determining, with the converter controller, an enhanced torque limit for the generator relative to the actual operating limit for each of the electrical system components and at least one mechanical limit of a drivetrain of the wind turbine. Moreover, the method can include establishing, with the converter controller, the torque setpoint relative to the enhanced torque limit.

[0009] In additional embodiments, the actual operating parameter can include a voltage, current, and / or temperature level of the electrical system component and / or a rotational speed of the generator.

[0010] In further embodiments, the actual operating limit for each of the electrical system components can be a value corresponding to a bridge switch device temperature, a coolant temperature, a generator temperature, and / or a modeled converter component temperature. The method can also include detecting, with the converter controller, a proximity of the actual operating parameter to the corresponding actual operating limit. Additionally, the method can include reducing, with the converter controller, the torque setpoint in order to prevent damage to or tripping of the electrical system component during application of the maximum available torque in the first enhanced braking mode.

[0011] In embodiments, the method can further include increasing, with the converter controller, an actual operating limit for the electrical system component in order to extend a duration of a maximum available torque in the first enhanced braking mode. Increasing the actual operating limit can decrease a life expectancy of the electrical system component relative to a nominal life expectancy of the electrical system component.

[0012] In additional embodiments, the enhanced braking mode can include a second enhanced braking mode, and the abnormal operating event can indicate a failure of a blade or a tower of the wind turbine. The method can include overriding, with a converter controller of the wind turbine, a plurality of nominal operating thresholds corresponding to a plurality of electrical system components. Overriding the plurality of nominal operating thresholds can increase a maximum value of a torque of a generator produced by the electrical system relative to a nominal torque limit. Additionally, the method can include permitting an increased wear rate relative to a nominal wear rate of the electrical system component(s) to facilitate generating the maximum generator torque.

[0013] In further embodiments, overriding the plurality of nominal operating thresholds can include increasing a thermal protection limit, an overvoltage limit, an undervoltage limit, and / or a current limit of the electrical system.

[0014] In embodiments, permitting the increased wear rate of at least one of the plurality of electrical system components can include permitting a remaining useful life of the electrical system component to be consumed in order to generate the maximum available torque in the enhanced braking mode for a longest duration.

[0015] In additional embodiments, the wind turbine can further include a slip coupling operably coupling the generator to a gearbox of the wind turbine. The method can further include monitoring, with the converter controller, a torque level of the slip coupling. Additionally, the method can include reducing, with the converter controller, the torque of the generator when the torque level of the slip coupling approaches a release threshold of the slip coupling.

[0016] In further embodiments, the abnormal operation of the wind turbine can include an overspeed event, a pitch system failure, a blade deviation, or a combination thereof, or any other abnormal operation.

[0017] In another aspect, the disclosure relates to a system for controlling a wind turbine. The system can include a sensor system including at least one sensor operably coupled to a component of the wind turbine to detect an abnormal operating event of the wind turbine. The system can further include a controller communicatively coupled to the sensor system. The controller can include at least one processor configured to perform a plurality of operations. The plurality of operations can include any of the operations and / or features described herein.

[0018] TECHNICAL SOLUTION 1. A method for protecting a wind turbine from abnormal operation, the method comprising:

[0019] receiving, with a controller of the wind turbine, data indicative of an abnormal operation event of the wind turbine;

[0020] in response to receiving the data indicative of the abnormal operation event of the wind turbine, initiating, with the controller, an enhanced braking mode for the wind turbine, the enhanced braking mode characterized by operating a generator of the wind turbine at a torque setpoint that generates a maximum available torque for a given set of operating conditions and exceeds a nominal torque limit of the generator; and

[0021] operating, with the controller, the wind turbine in the enhanced braking mode.

[0022] TECHNICAL SOLUTION 2. The method of TECHNICAL SOLUTION 1, wherein the enhanced braking mode comprises a first enhanced braking mode, the method further comprising:

[0023] determining, with a converter controller of the wind turbine, an actual operating parameter for each of a plurality of electrical system components;

[0024] determining, with the converter controller, an actual operating limit for each of the electrical system components based on the determined actual operating parameter, the actual operating limit indicative of an operating parameter value below which the electrical system component maintains a nominal life expectancy value, wherein operating the electrical system component below the actual operating limit prevents a trip of the electrical system component;

[0025] determining, with the converter controller, an enhanced torque limit for the generator relative to the actual operating limit for each of the electrical system components and at least one mechanical limit of a drivetrain of the wind turbine; and

[0026] establishing, with the converter controller, the torque setpoint relative to the enhanced torque limit.

[0027] TECHNICAL SOLUTION 3. The method of TECHNICAL SOLUTION 2, wherein the actual operating parameter comprises at least one of a voltage, a current, and a temperature level of the electrical system components and a rotational speed of the generator.

[0028] TECHNICAL SOLUTION 4. The method of TECHNICAL SOLUTION 3, wherein the actual operating limit for each of the electrical system components is a value corresponding to at least one of a bridge switch device temperature, a coolant temperature, a generator temperature, and a modeled converter component temperature, the method further comprising:

[0029] detecting, with the converter controller, proximity of the actual operating parameters to corresponding actual operating limits; and

[0030] reducing, with the converter controller, the torque setpoint to prevent damage to or tripping of the electrical system components during application of the maximum available torque in the first enhanced braking mode.

[0031] Technical Solution 5. The method of Technical Solution 2, further comprising:

[0032] increasing, with the converter controller, the at least one actual operating limit for at least one electrical system component to extend a duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one actual operating limit decreases a life expectancy of the at least one electrical system component relative to a nominal life expectancy of the at least one electrical system component.

[0033] Technical Solution 6. The method of Technical Solution 1, wherein the enhanced braking mode comprises a second enhanced braking mode, and wherein the abnormal operating event indicates a failure of a blade or a tower of the wind turbine, the method further comprising:

[0034] overriding, with a converter controller of the wind turbine, a plurality of nominal operating thresholds corresponding to a plurality of electrical system components, wherein overriding the plurality of nominal operating thresholds increases a maximum value of the torque of the generator produced by the electrical system relative to a nominal torque limit; and

[0035] allowing an increased wear rate relative to a nominal wear rate of at least one of the plurality of electrical system components to facilitate generation of the maximum generator torque.

[0036] Technical Solution 7. The method of Technical Solution 6, wherein overriding the plurality of nominal operating thresholds comprises increasing at least one of a thermal protection limit, an overvoltage limit, an undervoltage limit, and a current limit of the electrical system.

[0037] Technical Solution 8. The method of Technical Solution 6, wherein allowing the increased wear rate of at least one of the plurality of electrical system components comprises allowing consumption of a remaining useful life of at least one of the plurality of electrical system components to generate the maximum available torque in the enhanced braking mode for a maximum duration.

[0038] TECHNICAL SOLUTION 9. The method of TECHNICAL SOLUTION 1, wherein the wind turbine further comprises a slip coupling that operably couples the generator to a gearbox of the wind turbine, the method further comprising:

[0039] monitoring, with the converter controller, a torque level of the slip coupling; and

[0040] reducing, with the converter controller, the torque of the generator when the torque level of the slip coupling approaches a release threshold of the slip coupling.

[0041] TECHNICAL SOLUTION 10. The method of TECHNICAL SOLUTION 1, wherein the abnormal operation of the wind turbine comprises an overspeed event.

[0042] TECHNICAL SOLUTION 11. The method of TECHNICAL SOLUTION 1, wherein the abnormal operation of the wind turbine comprises a pitch system failure.

[0043] TECHNICAL SOLUTION 12. The method of TECHNICAL SOLUTION 1, wherein the abnormal operation of the wind turbine comprises a blade deviation.

[0044] TECHNICAL SOLUTION 13. A system for controlling a wind turbine, the system comprising:

[0045] a sensor system comprising at least one sensor operably coupled to a component of the wind turbine so as to detect an abnormal operation event of the wind turbine;

[0046] a controller communicatively coupled to the sensor system, the controller comprising at least one processor configured to perform a plurality of operations, the plurality of operations comprising:

[0047] receiving data indicative of the abnormal operation event of the wind turbine,

[0048] responsive to receiving the data indicative of the abnormal operation of the wind turbine, initiating an enhanced braking mode for the wind turbine, the enhanced braking mode characterized by operating a generator of the wind turbine at a torque setpoint that generates a maximum available torque for a given set of operating conditions and exceeds a nominal torque limit of the generator; and

[0049] operating the wind turbine in the enhanced braking mode.

[0050] TECHNICAL SOLUTION 14. The system of TECHNICAL SOLUTION 13, wherein the enhanced braking mode is a first enhanced braking mode, and wherein the controller comprises a converter controller, the plurality of operations further comprising:

[0051] determining actual operating parameters for each of a plurality of electrical system components;

[0052] determining actual operating limits for each of the electrical system components based on the actual operating parameters, the actual operating limits indicating operating parameter values below which the electrical system components maintain a nominal life expectancy, wherein operating the electrical system components below the actual operating limits prevents tripping of the electrical system components;

[0053] determining an enhanced torque limit for the generator relative to the actual operating limits for each of the electrical system components and at least one mechanical limit of a drive train of the wind turbine; and

[0054] establishing the torque setpoint relative to the enhanced torque limit.

[0055] Technical Solution 15. The system of Technical Solution 14, wherein the actual operating parameters include at least one of voltage, current, and temperature levels of the electrical system components and a rotational speed of the generator.

[0056] Technical Solution 16. The system of Technical Solution 15, wherein the actual operating limits for each of the electrical system components are values corresponding to at least one of a bridge switch device temperature, a coolant temperature, a generator temperature, and a modeled converter component temperature, the plurality of operations further comprising:

[0057] detecting proximity of actual operating parameters to corresponding actual operating limits; and

[0058] reducing the torque setpoint in order to prevent damage to or tripping of the electrical system components during application of the maximum available torque in the first enhanced braking mode.

[0059] Technical Solution 17. The system of Technical Solution 14, wherein the plurality of operations further comprise:

[0060] increasing the at least one actual operating limit for at least one electrical system component in order to extend a duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one actual operating limit decreases a life expectancy of the at least one electrical system component relative to the nominal life expectancy of the at least one electrical system component.

[0061] TECHNICAL SOLUTION 18. The system of TECHNICAL SOLUTION 13, wherein the enhanced braking mode is a second enhanced braking mode, wherein the controller comprises a converter controller of the wind turbine, and wherein the abnormal operating event indicates a failure of a blade or tower of the wind turbine, the plurality of operations further comprising:

[0062] overriding a plurality of nominal operating thresholds corresponding to a plurality of electrical system components, wherein overriding the plurality of nominal operating thresholds increases a maximum value of the torque of the generator produced by the electrical system relative to a nominal torque limit; and

[0063] allowing an increased wear rate relative to a nominal wear rate of at least one of the plurality of electrical system components to facilitate generation of the maximum generator torque.

[0064] TECHNICAL SOLUTION 19. The system of TECHNICAL SOLUTION 18, wherein overriding the plurality of nominal operating thresholds comprises increasing at least one of a thermal protection limit, an overvoltage limit, an undervoltage limit, and a current limit of the electrical system.

[0065] TECHNICAL SOLUTION 20. The system of TECHNICAL SOLUTION 13, wherein the wind turbine further comprises a slip coupling operably coupling the generator to a gearbox of the wind turbine, and wherein the controller comprises a converter controller, the plurality of operations further comprising:

[0066] monitoring a torque level of the slip coupling; and

[0067] reducing the torque of the generator when the torque level of the slip coupling approaches a release threshold of the slip coupling.

[0068] These and other features, aspects, and advantages of the present application 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 application and serve to explain the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0069] A complete and enabling disclosure of the present application, including its best mode, directed to one of ordinary skill in the art, is set forth in the specification which follows, and is illustrated in the accompanying drawings which are:

[0070] Figure 1 FIG. 1 illustrates a perspective view of one embodiment of a wind turbine according to the present disclosure;

[0071] Figure 2 FIG. 2 illustrates a perspective cutaway view of one embodiment of a nacelle of a wind turbine according to the present disclosure;

[0072] Figure 3 FIG. 2 illustrates a schematic diagram of one embodiment of a drive train of a wind turbine according to the present disclosure;

[0073] Figure 4 FIG. 3 illustrates a schematic diagram of one embodiment of an electrical system for use with a wind turbine according to the present disclosure;

[0074] Figure 5 FIG. 4 illustrates a schematic diagram of one embodiment of a controller for use with a wind turbine according to the present disclosure;

[0075] Figure 6 FIG. 5 illustrates a schematic diagram of one embodiment of control logic of a system for controlling a wind turbine according to the present disclosure;

[0076] Figure 7 FIG. 6 illustrates a schematic diagram of one embodiment of a portion of the control logic of FIG. 5 corresponding to a first braking mode; Figure 6

[0077] Figure 8 FIG. 7 illustrates a schematic diagram of one embodiment of a portion of the control logic of FIG. 5 corresponding to a second braking mode; and Figure 6

[0078] Figures 9A-9C FIG. 8 illustrates a graphical representation of one embodiment of operating limits and torque limits of an electrical system of a wind turbine according to the present disclosure.

[0079] The repeated use of reference characters in the present specification and drawings is intended to represent the same or similar features or elements of the application. DETAILED DESCRIPTION

[0080] Reference will now be made in detail to embodiments of the application, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the application and is not meant as a limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present application encompass such modifications and variations as come within the scope of the appended claims and their equivalents.

[0081] As used herein, the terms "first", "second", and "third" can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0082] ​​Unless otherwise defined, the terms "coupled," "fixed," "attached to" and the like, mean both directly and indirectly coupled, fixed, or attached, and the like.

[0083] Approximating language as used herein with respect to a quantity is adequate for use in this application in which such quantity is approximated and / or measured, as opposed to precision quantities. Quantities in physical measurements or dimensions are understood to be approximations and / or are rounded off, absent an opposite indication, to one significant digit retained, additional digits being discarded by ordinary rounding-off techniques. In this context a quantity can be a positive or negative quantity. "Approximating language" used herein for the purpose of utilizing the natural idioms of the English language includes quantities, parameter values, and / or numerical values that are purposefully rounded off - e.g., "about 5.00" rather than "5.00"; and "approximately twenty" rather than the trite "twenty". It will be further understood that the use of relationships "such as" and "for example" to describe a quantity by using a comparison is not intended to limit the quantity to the extreme values described in such relationships - rather those extreme values are provided so as to more particularly describe various quantitatively dependent relationships. It is to be further understood that the use of relational terms, if any, are intended to convey a certain mean- ing to the reader, and under no circumstances is the description to be understood to mean that the claimed subject matter encompasses or is in any way limited by the described relationship.

[0084] Herein and throughout the specification, ranges are used as endpoints, and include all sub-ranges contained therein unless otherwise noted. For example, all ranges disclosed herein are open-ended ranges, unless otherwise specified. As an example, a range of "1.0- 10.0" is a disclosure of each and every number and range of numbers between and including 1.0 and 10.0, unless otherwise indicated.

[0085] Generally, the present disclosure relates to systems and methods for controlling a wind turbine to protect the wind turbine from abnormal operation. In particular, the present disclosure includes systems and methods that facilitate operating a generator at a generator set point that enables generating the maximum available torque for a given set of operating conditions. The set point can exceed the nominal torque limit for the generator.

[0086] According to the present disclosure, the systems and methods can include a first enhanced braking mode that can be employed when an abnormal operating event does not indicate a failure of the rotor and / or the tower of the wind turbine. Since the nominal torque limit is typically set to ensure safe operation of the wind turbine under substantially all operating conditions, the nominal torque limit can be rather conservative. This conservatism can be reflected in the nominal operating limits for various components of the electrical system. As a result, under actual conditions that affect the wind turbine at the time of an abnormal operating event, the components of the electrical system can actually be safely operated at a level above the corresponding nominal operating limit. By determining actual operating limits for the various components based on the actual operating conditions, the controller can determine an enhanced torque limit for the generator that exceeds the nominal torque limit. This in turn can facilitate generating and applying the maximum available torque to decelerate the rotor of the wind turbine. In other words, the first braking mode can exploit the difference between the nominal design limit and the actual operating limit of the various components to generate the maximum torque that can be generated under the given conditions.

[0087] The system and method can also include a second enhanced braking mode in combination with the first enhanced braking mode. The second enhanced braking mode can be employed when the abnormal operating event indicates a failure of the rotor and / or the tower of the wind turbine. In the second enhanced braking mode, the controller can override the nominal operating thresholds of various electrical system components to facilitate increasing the maximum amount of torque on the generator. Thus, overriding the nominal operating thresholds can result in an increased wear rate on the components relative to the nominal wear rate. In other words, in the second enhanced braking mode, the consequences for the wind turbine of continuing operation under the abnormal operating event can justify accepting damage to various components of the electrical system to facilitate slowing the rotor as quickly as possible. For example, in operation of the component(s) above the nominal operating limits, excessive loading or damage to the component(s) can be tolerated to facilitate generating forces to slow the rotor. For example, the generator of the turbine can be operated at a generator set point that tolerates the generator producing generator torque in excess of the nominal generator torque limit. It should be appreciated that generating torque in excess of the torque limit can, for example, result in an increase in operating temperatures of various components of the electrical system that can degrade the components of the electrical system.

[0088] Reference will now be made to the 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 mounted on the tower 102, and a rotor 108 coupled to the nacelle 106. The rotor 108 includes a rotatable hub 110 and at least one rotor blade 112 coupled to and extending outward from the hub 110. For example, in the illustrated embodiment, the rotor 108 includes three rotor blades 112. However, in alternative embodiments, the rotor 108 can include more or less than three rotor blades 112. Each rotor blade 112 can be spaced about the hub 110 to facilitate rotating the rotor 108 to enable kinetic energy from the wind to be converted into usable mechanical energy and subsequently into electrical energy. For example, the hub 110 can be rotatably coupled to an electric generator 118 Figure 2 of the electrical system 150 positioned within the nacelle 106 to permit electrical energy to be generated.

[0089] The wind turbine 100 can also include a controller 200 centralized within the nacelle 106. However, in other embodiments, the controller 200 can be located within any other component of the wind turbine 100 or at a location external to the wind turbine. Moreover, the controller 200 can be communicatively coupled to any number of components of the wind turbine 100 in order to control the components. As such, the controller 200 can include a computer or other suitable processing unit. Thus, in several embodiments, the controller 200 can include suitable computer-readable instructions that, when implemented, cause the controller 200 to be configured to perform various different functions, such as receiving, transmitting, and / or executing wind turbine control signals.

[0090] Referring now to Figures 2-4 , a simplified interior view of one embodiment of the nacelle 106, a schematic diagram of one embodiment of the drive train 146, and an exemplary electrical system 150 of the wind turbine 100 shown in Figure 1 As shown, the generator 118 can be coupled to the rotor 108 in order to generate electrical power from the rotational energy generated by the rotor 108. For example, as shown in the illustrated embodiment, the rotor 108 can include a rotor shaft 122 coupled to the hub 110 for rotation therewith. The rotor shaft 122 can be rotatably supported by the main bearing 144. The rotor shaft 122 can in turn be rotatably coupled to a high speed shaft 124 of the generator 118 through an optional gearbox 126 connected to the bedplate support frame 136 by one or more torque arms 142. As generally understood, the rotor shaft 122 can provide a low speed, high torque input to the gearbox 126 in response to rotation of the rotor blades 112 and the hub 110. The gearbox 126 can then be configured with a plurality of gears 148 to convert the low speed, high torque input into a high speed, low torque output to drive the high speed shaft 124 and thus the generator 118. In embodiments, the gearbox 126 can be configured with a plurality of gear ratios in order to produce varying rotational speeds of the high speed shaft for a given low speed input or vice versa.

[0091] In embodiments, the wind turbine 100 can include a brake 152 positioned to arrest rotation of the rotor 108. In at least one embodiment, the brake 152 can be oriented to engage the high speed shaft 124. The brake 152 can be configured to further slow the rotor 108 that has already been slowed and / or to temporarily hold the rotor 108 stationary.

[0092] In additional embodiments, the brake 152 can be employed in conjunction with or as an adjunct to other components that slow the rotor 108. For example, in embodiments, the rotor 108 can be slowed via torque generated by the generator 118. As the generator 118 can generate torque opposite the rotation of the rotor 108, the high speed shaft 124 can be equipped with a slip coupling 154. The slip coupling 154 can prevent damage to components of the drivetrain 146 due to overloading of the drivetrain 146. As such, the slip coupling 154 can have a release threshold above which the slip coupling 154 can permit the first portion 162 and the second portion 164 of the high speed shaft 124 to have different rotational speeds. It should be appreciated that if the torsional moment at the slip coupling 154 exceeds the release threshold, the generator 118 can be communicatively decoupled from the rotor 108. In such an event, the torque generated by the generator 118 can not be available to slow the rotor 108.

[0093] Each rotor blade 112 can also include a pitch control mechanism 120 configured to rotate the rotor blade 112 about its pitch axis 116. Each pitch control mechanism 120 can 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 embodiments, the pitch drive motor 128 can be coupled to the pitch drive gearbox 130 such that the pitch drive motor 128 imparts a mechanical force to the pitch drive gearbox 130. Similarly, the pitch drive gearbox 130 can be coupled to the pitch drive pinion 132 so as to rotate therewith. The pitch drive pinion 132, in turn, can be in rotational engagement with a pitch bearing 134 coupled between the hub 110 and the corresponding rotor blade 112, such that rotation of the pitch drive pinion 132 causes rotation of the pitch bearing 134. Thus, in such embodiments, rotation of the pitch drive motor 128 drives the pitch drive gearbox 130 and the pitch drive pinion 132, thereby rotating the pitch bearing 134 and the rotor blade(s) 112 about the pitch axis 116. Similarly, the wind turbine 100 can include one or more yaw drive mechanisms 138 communicatively coupled to the controller 200, where each yaw drive mechanism(s) 138 is configured to change the angle of the nacelle 106 relative to the wind (e.g., by engaging a yaw bearing 140 of the wind turbine 100).

[0094] Still referring to Figure 2In embodiments, the wind turbine 100 can include an environmental sensor 156 configured to collect data indicative of one or more environmental conditions. The environmental sensor 156 can be operably coupled to the controller 200. Thus, in embodiments, the environmental sensor(s) 156 can be, for example, a wind vane, an anemometer, a lidar sensor, a thermometer, a barometer, or other suitable sensor. The data collected by the environmental sensor(s) 156 can include measurements of wind speed, wind direction, wind shear, gusts, wind veer, atmospheric pressure, and / or temperature. In at least one embodiment, the environmental sensor(s) 156 can be mounted to the nacelle 106 at a downwind location of the rotor 108. In alternative embodiments, the environmental sensor(s) 156 can be coupled to or integrated with the rotor 108. It should be appreciated that the environmental sensor(s) 156 can include a network of sensors and can be positioned remote from the turbine 100.

[0095] Additionally, the wind turbine 100 can include a sensor system 160 having a plurality of operational sensors 158. The sensor system 160 can be configured to detect performance of the wind turbine 100 in response to environmental conditions. For example, the operational sensor(s) 158 can be a rotational speed sensor operably coupled to the controller 200. The operational sensor(s) 158 can be directed to the rotor shaft 122 and / or the generator 118 of the wind turbine 100. The operational sensor(s) 158 can collect data indicative of rotational speed and / or rotational position of the rotor shaft 122, and thus the rotor 108, in the form of rotor speed and / or rotor azimuth angle. In embodiments, the operational sensor(s) 158 can be an analog tachometer, a direct current tachometer, an alternating current tachometer, a digital tachometer, a contact tachometer, a non-contact tachometer, or a time and frequency tachometer.

[0096] In embodiments, the sensor system 160 can be configured to monitor operational parameters of the electrical system 150. For example, the sensor system 160 can monitor voltage, current, and / or temperature levels of various components of the electrical system 150. Thus, in embodiments, the operational sensor(s) 158 can be a current meter, a voltage meter, an ohmmeter, a thermometer, and / or any other suitable sensor for monitoring operational parameters of the electrical system 150.

[0097] It should also be appreciated that, as used herein, the term "monitoring" and variations thereof indicates that the various sensors of the wind turbine 100 can be configured to provide a direct measurement of the parameter being monitored or an indirect measurement of such parameter. Thus, the sensors described herein can be used, for example, to generate a signal related to the parameter being monitored, which can then be utilized by the controller 200 to determine a condition or response of the wind turbine 100.

[0098] With particular reference to Figure 4 In embodiments, the electrical system 150 can include various components for converting kinetic energy of the rotor 108 into electrical output in an acceptable form to a connected power grid. For example, in embodiments, the generator 118 can be a doubly-fed induction generator (DFIG). The generator 118 can be coupled to the stator bus 166 and the power converter 168 via a rotor bus 170. In such a configuration, the stator bus 166 can provide output multiphase power (e.g., three-phase power) from the stator of the generator 118, and the rotor bus 170 can provide output multiphase power (e.g., three-phase power) from the rotor of the generator 118. Additionally, the generator 118 can be coupled to a rotor-side converter 172 via the rotor bus 170. The rotor-side converter 172 can be coupled to a line-side converter 174, which in turn can be coupled to a line-side bus 176.

[0099] In embodiments, the rotor-side converter 172 and the line-side converter 174 can be configured for normal operating mode in a three-phase pulse width modulation (PWM) arrangement using insulated gate bipolar transistors (IGBTs) as switching devices. Other suitable switching devices can be used, such as insulated gate commutated thyristors, MOSFETs, bipolar transistors, silicon controlled rectifiers, and / or other suitable switching devices. The rotor-side converter 172 and the line-side converter 174 can be coupled via a DC link 173, with a DC link capacitor 175 across the DC link 173.

[0100] In embodiments, the power converter 168 can be coupled to a controller 200, which is configured as a converter controller 202 that controls operation of the power converter 168. For example, the converter controller 202 can send control commands to the rotor-side converter 172 and the line-side converter 174 to control modulation of switching elements used in the power converter 168 to establish a desired generator torque setpoint and / or power output.

[0101] As in Figure 4Further depicted, in embodiments, the electrical system 150 can include a transformer 178 that couples the wind turbine 100 to an electrical grid 179. In embodiments, the transformer 178 can be a three-winding transformer that includes a high voltage (e.g., greater than 12 KV AC) primary winding 180. The high voltage primary winding 180 can be coupled to the electrical grid 179. The transformer 178 can also include a medium voltage (e.g., 6 KV AC) secondary winding 182 coupled to the stator bus 166 and a low voltage (e.g., 575 V AC, 690 V AC, etc.) auxiliary winding 184 coupled to the line bus 176. It should be appreciated that the transformer 178 can be a three-winding transformer as depicted, or alternatively can be a two-winding transformer having only the primary winding 180 and the secondary winding 182; can be a four-winding transformer having the primary winding 180, the secondary winding 182, and the auxiliary winding 184, as well as additional auxiliary windings; or can have any other suitable number of windings.

[0102] In additional embodiments, the electrical system 150 can include an auxiliary feeder 186 coupled to the output of the power converter 168. The auxiliary feeder 186 can act as a power source for various components of the wind turbine system 100. For example, the auxiliary feeder 186 can power fans, pumps, motors, and other suitable components of the wind turbine system 100.

[0103] In embodiments, the electrical system 150 can also include various circuit breakers, fuses, contactors, and other devices to control and / or protect various components of the electrical system 150. For example, in embodiments, the electrical system 150 can include a grid circuit breaker 188, a stator bus circuit breaker 190, and / or a line bus circuit breaker 192. The circuit breaker(s) 188, 190, 192 of the electrical system 150 can connect or disconnect corresponding components of the electrical system 150 when conditions of the electrical system 150 approach operational thresholds of the electrical system 150.

[0104] Reference is now made to Figures 5-8 presented are schematic diagrams of various embodiments of a system 300 for controlling a wind turbine 100 according to the present disclosure. As in the previous figures, the system 300 includes a wind turbine 100, a power converter 168, a stator bus 166, a line bus 176, and a transformer 178. The system 300 also includes a controller 302 that is coupled to the wind turbine 100, the power converter 168, the stator bus 166, the line bus 176, and the transformer 178. The controller 302 can be configured to control and / or protect the wind turbine 100, the power converter 168, the stator bus 166, the line bus 176, and the transformer 178. Figure 5In particular, the diagram can be included in a schematic illustration of one embodiment of suitable components that can be included within the system 300. For example, as shown, the system 300 can include a controller 200 communicatively coupled to the operational sensors 158 and the environmental sensor(s) 156 of the sensor system 160. Also, as shown, the controller 200 includes one or more processors 206 and associated memory device(s) 208 configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations and the like as disclosed herein and storing relevant data). Additionally, the controller 200 can also include a communication module 210 to facilitate communication between the controller 200 and various components of the wind turbine 100. Moreover, the communication module 210 can include a sensor interface 212 (e.g., one or more analog-to-digital converters) to allow conversion of signals transmitted from the sensor(s) 156, 158 into signals that can be understood and processed by the processor(s) 206. It should be appreciated that the sensor(s) 156, 158, 160 can be communicatively coupled to the communication module 210 using any suitable means. For example, as shown in the Figure 4 In particular, the diagram can be included in a schematic illustration of one embodiment of suitable components that can be included within the system 300. For example, as shown, the system 300 can include a controller 200 communicatively coupled to the operational sensors 158 and the environmental sensor(s) 156 of the sensor system 160. Also, as shown, the controller 200 includes one or more processors 206 and associated memory device(s) 208 configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations and the like as disclosed herein and storing relevant data). Additionally, the controller 200 can also include a communication module 210 to facilitate communication between the controller 200 and various components of the wind turbine 100. Moreover, the communication module 210 can include a sensor interface 212 (e.g., one or more analog-to-digital converters) to allow conversion of signals transmitted from the sensor(s) 156, 158 into signals that can be understood and processed by the processor(s) 206. It should be appreciated that the sensor(s) 156, 158, 160 can be communicatively coupled to the communication module 210 using any suitable means. For example, as shown in the

[0105] 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 controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits, and other programmable circuits. Additionally, the memory device(s) 208 can generally include memory elements including, but not limited to, computer readable medium, such as random access memory (RAM), computer readable nonvolatile memory, such as flash memory, floppy drives, digital versatile discs (DVDs), compact discs - read only memories (CD-ROMs), and / or other suitable memory elements. Such memory device(s) 208 can generally be configured to store suitable computer readable instructions that, when implemented by the processor(s) 206, cause the controller 200 to be configured to perform various functions, including but not limited to detecting abnormal operating events and initiating an enhanced braking mode for the wind turbine 100 as described herein, as well as various other suitable computer-implemented functions.

[0106] With particular reference to Figure 6 As shown at 302, the system 300 can be configured to receive data 304 indicative of an abnormal operating event of the wind turbine 100. For example, in embodiments, the controller 200 can receive data 304 from the sensor system 160 indicative of an overspeed event, a pitch system failure, a false pitch command, a power / battery backup failure, and / or a blade departure event that can indicate a likelihood of an increased level of damage to the wind turbine 100 if the wind turbine 100 continues to operate.

[0107] For example, in embodiments, the data 304 can reflect a response of a wind turbine 100 component to an unbalanced load caused by a loss of a portion of the rotor blades 112. In embodiments, the data 304 can reflect the response of the component to the rotor load in the form of a load magnitude and / or a load direction. For example, in embodiments, the load direction can be along or corresponding to the pitch axis 116. In such embodiments, a load corresponding to the pitch axis 116 can be indicative of a loss of some or all of the rotor blades 112. In additional embodiments, the data 304 can indicate an acceleration vector of the component, such as the nacelle 106, the tower 102, or the rotor 108. The data 304 can also include a vibration characteristic corresponding to a blade loss event. In various embodiments, the vibration characteristic can be indicative of a vibration level / characteristic in the rotor blades 112, the hub 110, the nacelle 106, the tower 102 base and / or top, and / or any other component of the wind turbine 100.

[0108] In additional embodiments, the data 304 can indicate a loss of communication with at least one of the sensors of the operating sensor(s) 158. For example, a shedding event can also sever a communication coupling of one element of the sensor system 160 coupled to the rotor blade 112. In further embodiments, the data 304 can include an acoustic characteristic of the wind turbine. In such embodiments, a change in the acoustic characteristic of the wind turbine 100 can indicate a shedding event. In yet further embodiments, the data 304 can indicate a bending moment imparted to the rotor shaft 122 and / or the tower 102. It should be appreciated that an increase in the bending moment can indicate an unbalanced load generated by the rotor 108 in response to a blade shedding event. It should be further appreciated that the data 304 can include additional characteristics and / or combinations of characteristics indicative of abnormal operation of the wind turbine 100.

[0109] In embodiments, as shown at 306, the controller 200 of the system 300 can be configured to initiate an enhanced braking mode for the wind turbine 100 in response to receiving the data 304 indicative of an abnormal operating event. The enhanced braking mode can be characterized by operating the generator 118 at a torque setpoint that generates a maximum available torque for a given set of operating conditions. The torque setpoint can exceed a nominal torque limit 308 (FIG. 9) for the generator 118. It should be appreciated that the nominal torque limit 308 can indicate a torque level that can be produced by the generator 118 without damaging and / or tripping components of the electrical system 150 under all operating conditions of the wind turbine 100. Thus, in embodiments, establishing the torque setpoint above the nominal torque limit can permit overloading or damage to components of the electrical system 150. It should be further appreciated that overloading or damage to the component(s) of the electrical system 150 can be accepted in favor of rapidly slowing the rotor 108 following an abnormal operating event.

[0110] As shown at 310, the converter controller 202 of the system 300 can operate the wind turbine 100 in the enhanced braking mode. By operating the wind turbine 100 in the enhanced braking mode, the converter controller 202 can facilitate generation of a generator torque having a magnitude greater than would be generated under the nominal torque limit 308 in other circumstances. This, in turn, can be used to slow the rotor 108 at a rate greater than would be achieved while adhering to the nominal torque limit 308. It should be appreciated that utilizing the electrical system 150 to generate an increased rate of deceleration can be used to prevent / mitigate damage to the wind turbine 100 in response to an abnormal operating event.

[0111] As depicted at 312, in embodiments, the converter controller 202 of the system 300 can be configured to monitor a torque level of the slip coupling 154. It should be appreciated that in embodiments in which the torque level of the slip coupling 154 exceeds a release threshold of the nominal slip coupling 154, the slip coupling 154 can operatively disengage the generator 118 from the rotor shaft 122. In such embodiments, the torque generated by the generator 118 can then not be available to assist in the slowing of the rotor 108. Accordingly, the system 300 can detect, at 314, the proximity of the torque level to the release threshold. In instances in which the torque level is not proximate to the release threshold, the converter controller 202 can maintain, at 316, the torque setpoint in order to continue to decelerate the rotor over the shortened time interval. However, in embodiments in which the torque level of the slip coupling 154 is proximate to the release threshold, the converter controller 202 can decrease, at 318, the torque setpoint in order to maintain the operative coupling between the generator 118 and the rotor 108.

[0112] Still referring specifically to Figure 6 In embodiments, the system 300 can determine, at 320, whether the abnormal operating event indicated by the data 304 indicates a failure of the blade 112 or the tower 102 of the wind turbine 100. In embodiments in which a failure of the blade 112 or the tower 102 is not indicated, the system 300 can initiate a first enhanced braking mode 322. In contrast, in embodiments in which a failure of the blade 112 or the tower 102 is indicated, the system 300 can initiate a second enhanced braking mode 324.

[0113] Referring now to Figure 7 , a schematic diagram of one embodiment of control logic of portions of the system 300 corresponding to the first braking mode 322 is depicted. In embodiments in which the first braking mode 322 is initiated, the converter controller 202 can determine, at 326, actual operating parameters for each of a plurality of components of the electrical system 150 using sensor data 328 from the sensor system 160. The actual operating parameters can include voltage, current, and / or temperature levels of various components of the electrical system 150 and a rotational speed of the generator 118 for a given operating condition of the wind turbine 100. It should be appreciated that the actual operating parameters can vary during operation of the wind turbine 100.

[0114] Referring to Figure 7 and also to FIG. 9, as shown at 330, the converter controller 202 can determine, based on the determined actual operating parameters, actual operating limits 332 for each of the electrical system components. The operating limits 332 for the plurality of components of the electrical system 150 are graphically combined in Figures 9A-9C to present a continuous plot line in each graph. Additionally, Figures 9A-9CEach of the actual operating limits 332 represents the same component's operating limit 332 under different operating conditions of the wind turbine 100.

[0115] In embodiments, the actual operating limits 332 can indicate operating parameter values for various components of the electrical system 150 below which a nominal life expectancy value is maintained. In other words, in embodiments in which the component(s) are operated below the actual operating limits 332, the wear rate of the component can not be affected, but when operated above the actual operating limits 332, the wear rate can be accelerated. As such, operating the components of the electrical system 150 below the actual operating limits 332 can prevent tripping of the electrical system components.

[0116] In embodiments, the component of the electrical system 150 having the lowest actual operating limit 332 can establish a trip threshold 333 for the electrical system 150. Thus, operating the electrical system 150 below the trip threshold 333 can prevent tripping of the electrical system 150. It should be appreciated that tripping the electrical system 150 can impede the ability of the system 300 to slow the rotor 108 in response to an abnormal operating event of the wind turbine 100.

[0117] In embodiments, determining the actual operating limits 332 can include receiving environmental and operating sensor data 334 from the sensor system 160 and corresponding environmental sensor(s) 156. The converter controller 202 can utilize the environmental and operating sensor data 334 to determine individualized actual operating limits 332 for each of the components of the electrical system 150 based on the nominal design data for each of the components based on detected environmental and operating conditions. For example, in embodiments, the actual operating limits 332 can be measured values or values modeled on measured values corresponding to bridge switch device temperature, coolant temperature, converter component temperature, and / or generator temperature. In such embodiments, the actual operating limits 332 can represent a temperature threshold (nominal operating threshold) for the component(s) based on the nominal design of the component and the environmental temperature and / or operating conditions of the wind turbine 100. It should be appreciated that in embodiments in which the component(s) can be operated in high temperature environments, the maximum acceptable temperature of the component can be lower than the maximum acceptable temperature of the component for embodiments in which the environmental temperature is relatively low. It should be further appreciated that the association of the actual operating limits 332 with the environmental and operating sensor data 334 can result in a floating limit that varies in response to changes in the environmental and / or operating state of the wind turbine 100.

[0118] As depicted at 336, the converter controller 202 can be configured to determine an enhanced torque limit 338 that can be supported by the electrical system 150 without tripping various components of the electrical system 150 or reducing the nominal life expectancy of various components of the electrical system 150. The enhanced torque limit 338 can be established based on the actual operating limit 332 for each component of the electrical system 150 and based on various mechanical limits 340 of the driveline 146. For example, the enhanced torque limit 338 can be established with a value that is at least 95% of the lowest actual operating limit 332 of a component of the electrical system 150 so long as the value of the enhanced torque limit 338 does not exceed a mechanical limit 340 of the driveline 146, such as a release threshold of the slip coupling 154. It should be appreciated that the enhanced torque limit 338 can allow the converter controller 202 to apply a maximum torque available that takes into account ambient temperature, cable temperature, component temperature, and / or generator capability.

[0119] It should be appreciated that establishing the enhanced torque limit 338 based on the actual operating limit 332 of the electrical system 150 for a given environmental and operating condition can facilitate utilizing the torque producing capability of the generator 118 that can not have been available while adhering to the nominal torque limit 308. Thus, establishing a torque setpoint for the generator 118 relative to the enhanced torque limit 338 at 340 can facilitate applying a maximum available torque to slow the rotor 108 at 342.

[0120] In embodiments, the converter controller 202 can detect, at 344, the proximity of the actual operating parameter to the corresponding actual operating limit 332. For example, in embodiments, the converter controller 202 can receive sensor data 328 from the sensor system 160 indicating that a coolant temperature of a component of the electrical system 150 has risen and is approaching the actual operating limit 332 for the component. In response to detecting the proximity of the actual operating parameter to the corresponding actual operating limit 332, the converter controller 202 can reduce, at 346, the torque setpoint of the generator 118 to prevent damage to or tripping of the electrical system component during application of the maximum available torque in the first enhanced braking mode 322.

[0121] In response to detecting the proximity of the actual operating parameter to the corresponding actual operating limit 332, the converter controller 202 can increase at least one of the actual operating limits 332 as represented by line 350 at 348 in further embodiments. Increasing the actual operating limit(s) 332 to line 350 can allow for an extension of the duration of maximum available torque applied in the first enhanced braking mode 322. However, increasing the actual operating limit(s) 332 can decrease the life expectancy of the corresponding electrical system component(s) relative to the nominal life expectancy of the component(s). For example, increasing the actual operating limit(s) 332 for the component(s) can result in the consumption of the fatigue margin of the component(s).

[0122] Referring now to Figure 8 , a schematic diagram depicting one embodiment of a portion of the control logic of the system 300 corresponding to the second braking mode 324. In embodiments in which the second braking mode 324 is initiated, the converter controller 202 can override the plurality of nominal operating thresholds corresponding to the plurality of electrical system components at 352. In embodiments, overriding the plurality of nominal operating thresholds can increase the maximum value of the generator torque 356 generated by the electrical system 150 relative to the nominal torque limit 308 at 354.

[0123] In embodiments, the system 300 can be configured to override the plurality of nominal operating thresholds at 352 by raising the thermal protection limits, overvoltage limits, under-voltage limits, and / or current limits of the electrical system 150 or components of the electrical system 150.

[0124] In embodiments, the second braking mode 324 can include allowing an increased wear rate of the component(s) relative to the nominal wear rate of the component(s) of the electrical system 150 at 358. In such embodiments, the increased wear rate can be allowed to facilitate the application of the maximum generator torque 356 at 360. For example, generating the maximum available torque 356 by the generator 118 can result in thermal damage to the component(s) of the electrical system 150 of the wind turbine 100. In such embodiments, the electrical system 150 can act as a circuit breaker for the wind turbine 100, where the wear or damage to the electrical system 150 is accepted in order to prevent / mitigate more significant damage to the rotor 108 or the wind turbine 100 caused by the abnormal operating event.

[0125] In embodiments, increasing the wear rate of the component(s) of the electrical system 150 can include allowing the full remaining useful life of the component(s) to be consumed. It should be appreciated that allowing the remaining useful life of the component(s) to be consumed can facilitate generating the maximum available torque 356 for the longest duration in the second enhanced braking mode 324.

[0126] Moreover, a skilled artisan will recognize the interchangeability of various features from different embodiments. Similarly, the various methods described herein and the other known equivalents for such methods can be performed by special purpose software implemented by one or more processors. The order of any method steps can be different from those described herein, unless specifically stated otherwise, and indeed all methods steps can be performed in an instrument other than the one(s) described. In addition, any of the various features or aspects of the systems and methods described herein can be implemented in hardware, software, or firmware, or any combination thereof, and can be implemented alone or in combination with any of the other features or aspects described herein. Of course, the various features and aspects of the systems and methods described herein can be implemented in any desired order.

[0127] This written description uses examples to disclose the application, including the best mode, and also to enable any person skilled in the art to practice the application, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the application is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent

[0128] Further aspects of the application are provided by the subject matter of the following clauses:

[0129] Clause 1. A method for protecting a wind turbine from abnormal operation, the method comprising: receiving, with a controller of the wind turbine, data indicative of an abnormal operation event of the wind turbine; in response to receiving the data indicative of the abnormal operation event of the wind turbine, initiating, with the controller, an enhanced braking mode for the wind turbine, the enhanced braking mode characterized by operating a generator at a torque setpoint that generates a maximum available torque for a given set of operating conditions and exceeds a nominal torque limit of the generator; and operating, with the controller, the wind turbine in the enhanced braking mode.

[0130] Clause 2. The method of any preceding clause, wherein the enhanced braking mode comprises a first enhanced braking mode, the method further comprising: determining, with the converter controller of the wind turbine, actual operating parameters for each of the plurality of electrical system components; determining, with the converter controller, actual operating limits for each of the electrical system components based on the determined actual operating parameters, the actual operating limits indicating operating parameter values below which the electrical system components maintain a nominal life expectancy, wherein operating the electrical system components below the actual operating limits prevents tripping of the electrical system components; determining, with the converter controller, an enhanced torque limit for the generator relative to the actual operating limits for each of the electrical system components and at least one mechanical limit of a drivetrain of the wind turbine; and establishing, with the converter controller, a torque setpoint relative to the enhanced torque limit.

[0131] Clause 3. The method of any preceding clause, wherein the actual operating parameters comprise at least one of a voltage, a current, and a temperature level of the electrical system components and a rotational speed of the generator.

[0132] Clause 4. The method of any preceding clause, wherein the actual operating limits for each of the electrical system components are values corresponding to at least one of a bridge switch device temperature, a coolant temperature, a generator temperature, and a modeled converter component temperature, the method further comprising: detecting, with the converter controller, a proximity of the actual operating parameters to the corresponding actual operating limits; and reducing, with the converter controller, the torque setpoint in order to prevent damage to or tripping of the electrical system components during application of the maximum available torque in the first enhanced braking mode.

[0133] Clause 5. The method of any preceding clause, further comprising: increasing, with the converter controller, at least one actual operating limit for at least one electrical system component in order to extend a duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one actual operating limit decreases a life expectancy of the at least one electrical system component relative to a nominal life expectancy of the at least one electrical system component.

[0134] Clause 6. The method of any preceding clause, wherein the enhanced braking mode comprises a second enhanced braking mode, and wherein the abnormal operating event indicates a failure of a blade or a tower of the wind turbine, the method further comprising: overriding, with the converter controller of the wind turbine, a plurality of nominal operating thresholds corresponding to the plurality of electrical system components, wherein overriding the plurality of nominal operating thresholds increases a maximum value of torque generated by the electrical system at the generator relative to the nominal torque limit; and permitting an elevated wear rate relative to a nominal wear rate of at least one of the plurality of electrical system components in favor of generating the maximum generator torque.

[0135] Clause 7. The method of any preceding clause, wherein overriding the plurality of nominal operating thresholds comprises increasing at least one thermal protection limit, overvoltage limit, undervoltage limit, and current limit of the electrical system.

[0136] Clause 8. The method of any preceding clause, wherein accommodating the increased rate of wear of at least one of the plurality of electrical system components comprises allowing consumption of a remaining useful life of at least one of the plurality of electrical system components in order to generate a maximum available torque for a longest duration in the enhanced braking mode.

[0137] Clause 9. The method of any preceding clause, wherein the wind turbine further comprises a slip coupling operably coupling the generator to a gearbox of the wind turbine, the method further comprising: monitoring, with the converter controller, a torque level of the slip coupling; and reducing, with the converter controller, a torque of the generator when the torque level of the slip coupling approaches a release threshold of the slip coupling.

[0138] Clause 10. The method of any preceding clause, wherein the abnormal operation of the wind turbine comprises an overspeed event.

[0139] Clause 11. The method of any preceding clause, wherein the abnormal operation of the wind turbine comprises a pitch system failure.

[0140] Clause 12. The method of any preceding clause, wherein the abnormal operation of the wind turbine comprises a blade deviation.

[0141] Clause 13. A system for controlling a wind turbine, the system comprising: a sensor system comprising at least one sensor operably coupled to a component of the wind turbine so as to detect an abnormal operation event of the wind turbine; a controller communicatively coupled to the sensor system, the controller comprising at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving data indicative of an abnormal operation event of the wind turbine, responsive to receiving the data indicative of the abnormal operation of the wind turbine, initiating an enhanced braking mode for the wind turbine, the enhanced braking mode characterized by operating a generator at a torque setpoint that generates a maximum available torque for a given set of operating conditions and exceeds a nominal torque limit of the generator; and operating the wind turbine in the enhanced braking mode.

[0142] Clause 14. The system of any preceding clause, wherein the enhanced braking mode is a first enhanced braking mode, and wherein the controller comprises a converter controller, the plurality of operations further comprising: determining an actual operating parameter for each of the plurality of electrical system components; determining an actual operating limit for each of the electrical system components based on the actual operating parameter, the actual operating limit indicating an operating parameter value below which the electrical system component maintains a nominal life expectancy value, wherein operating the electrical system component below the actual operating limit prevents a trip of the electrical system component; determining an enhanced torque limit for the generator relative to the actual operating limit for each of the electrical system components and at least one mechanical limit of a drivetrain of the wind turbine; and establishing a torque setpoint relative to the enhanced torque limit.

[0143] Clause 15. The system of any preceding clause, wherein the actual operating parameter comprises at least one of a voltage, a current, and a temperature level of the electrical system component and a rotational speed of the generator.

[0144] Clause 16. The system of any preceding clause, wherein the actual operating limit for each of the electrical system components is a value corresponding to at least one of a bridge switch device temperature, a coolant temperature, a generator temperature, and a modeled converter component temperature, the plurality of operations further comprising: detecting a proximity of the actual operating parameter to the corresponding actual operating limit; and reducing the torque setpoint in order to prevent damage to or tripping of the electrical system component during application of the maximum available torque in the first enhanced braking mode.

[0145] Clause 17. The system of any preceding clause, wherein the plurality of operations further comprise: increasing at least one actual operating limit for at least one electrical system component in order to extend a duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one actual operating limit decreases a life expectancy value of the at least one electrical system component relative to a nominal life expectancy value of the at least one electrical system component.

[0146] Clause 18. The system of any preceding clause, wherein the enhanced braking mode is a second enhanced braking mode, wherein the controller comprises a converter controller of the wind turbine, and wherein the abnormal operating event indicates a failure of a blade or a tower of the wind turbine, the plurality of operations further comprising: overriding a plurality of nominal operating thresholds corresponding to the plurality of electrical system components, wherein overriding the plurality of nominal operating thresholds increases a maximum value of torque generated by the electrical system at the generator relative to the nominal torque limit; and permitting an increased wear rate relative to a nominal wear rate of at least one of the plurality of electrical system components in favor of generating the maximum generator torque.

[0147] Clause 19. The system of any preceding clause, wherein the overriding the plurality of nominal operating thresholds comprises increasing at least one of a thermal protection limit, an overvoltage limit, an undervoltage limit, and a current limit of the electrical system.

[0148] Clause 20. The system of any preceding clause, wherein the wind turbine further comprises a slip coupling operably coupling the generator to a gearbox of the wind turbine, and wherein the controller comprises a converter controller, the plurality of operations further comprising: monitoring a torque level of the slip coupling; and reducing a torque of the generator when the torque level of the slip coupling approaches a release threshold of the slip coupling.

Claims

1. A method for protecting a wind turbine from abnormal operation, the method comprising: The controller of the wind turbine is used to receive data indicating abnormal operating events of the wind turbine; In response to receiving data indicating the abnormal operation event of the wind turbine, the controller is used to activate an enhanced braking mode for the wind turbine, the enhanced braking mode being characterized by operating the wind turbine's generator at a torque setpoint that generates the maximum available torque for a given set of operating conditions and that the torque setpoint exceeds the generator's nominal torque limit. as well as The controller is used to operate the wind turbine in the enhanced braking mode. The enhanced braking mode includes a first enhanced braking mode, and the method further includes: The converter controller of the wind turbine is used to determine the actual operating parameters for each of the multiple electrical system components; The converter controller is used to determine the actual operating limits for each of the electrical system components based on determined actual operating parameters, the actual operating limits indicating the following operating parameter values: below which the electrical system component maintains its nominal life expectation, wherein operating the electrical system component below the actual operating limits prevents the electrical system component from tripping; The converter controller is used to determine the enhanced torque limit for the generator relative to the actual operating limits for each of the electrical system components and at least one mechanical limit of the wind turbine's drivetrain; and The converter controller is used to establish the torque setpoint relative to the enhanced torque limit.

2. The method according to claim 1, wherein, The actual operating parameters include the generator speed and at least one of the voltage, current and temperature levels of the electrical system components.

3. The method according to claim 2, wherein, The actual operating limit for each of the electrical system components is a value corresponding to at least one of the bridge switch temperature, coolant temperature, modeled converter component temperature, and generator temperature, and the method further includes: The converter controller is used to detect the approximation of actual operating parameters to corresponding actual operating limits; and The converter controller is used to reduce the torque setpoint in order to prevent damage to or tripping of the electrical system components during the application of the maximum available torque in the first enhanced braking mode.

4. The method according to claim 1, further comprising: The converter controller is used to increase the at least one practical operating limit for at least one electrical system component in order to increase the duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one practical operating limit reduces the expected life of the at least one electrical system component relative to its nominal life.

5. The method according to claim 1, wherein, The enhanced braking mode includes a second enhanced braking mode, and wherein the abnormal operating event indicates a failure of the wind turbine blades or tower, the method further includes: The converter controller of the wind turbine is used to perform override control on multiple nominal operating thresholds corresponding to multiple electrical system components, wherein the override control on the multiple nominal operating thresholds increases the maximum value of the torque of the generator generated by the electrical system relative to the nominal torque limit; and An increased wear rate relative to the nominal wear rate of at least one of the plurality of electrical system components is permitted to facilitate the generation of the maximum generator torque.

6. The method according to claim 5, wherein, Override control of the plurality of nominal operating thresholds includes increasing at least one thermal protection limit, overvoltage limit, undervoltage limit, and current limit of the electrical system.

7. The method according to claim 5, wherein, Allowing for the increased wear rate of at least one of the plurality of electrical system components includes allowing the consumption of the remaining service life of at least one of the plurality of electrical system components in order to generate the maximum available torque for the longest duration in the enhanced braking mode.

8. The method according to claim 1, wherein, The wind turbine further includes a sliding coupling that operatively connects the generator to the gearbox of the wind turbine, and the method further includes: The converter controller is used to monitor the torque level of the sliding coupling; and When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the converter controller is used to reduce the torque of the generator.

9. The method according to claim 1, wherein, The abnormal operation of the wind turbine includes overspeed events.

10. The method according to claim 1, wherein, The abnormal operation of the wind turbine includes pitch system failure.

11. The method according to claim 1, wherein, The abnormal operation of the wind turbine includes blade deflection.

12. A system for controlling a wind turbine, the system comprising: A sensor system comprising at least one sensor operatively coupled to a component of the wind turbine to detect abnormal operating events of the wind turbine. A controller communicatively coupled to the sensor system, the controller including at least one processor configured to perform a plurality of operations, the plurality of operations including: Receive data indicating the abnormal operation event of the wind turbine. In response to receiving data indicating the abnormal operation of the wind turbine, an enhanced braking mode for the wind turbine is initiated, characterized by operating the wind turbine's generator at a torque setpoint that generates maximum available torque for a given set of operating conditions and that the torque setpoint exceeds the generator's nominal torque limit; and The wind turbine is operated in the enhanced braking mode. Wherein, the enhanced braking mode is a first enhanced braking mode, and wherein the controller includes a converter controller, and the plurality of operations further include: Determine the actual operating parameters for each of the multiple electrical system components; Based on the actual operating parameters, an actual operating limit is determined for each of the electrical system components, the actual operating limit indicating the following operating parameter value: below which the electrical system component maintains its nominal life expectation, wherein operating the electrical system component below the actual operating limit prevents the electrical system component from tripping; The enhanced torque limit for the generator is determined relative to the actual operating limits for each of the electrical system components and at least one mechanical limit of the wind turbine's drivetrain; and The torque setpoint is established relative to the enhanced torque limit.

13. The system according to claim 12, wherein, The actual operating parameters include the generator speed and at least one of the voltage, current and temperature levels of the electrical system components.

14. The system according to claim 13, wherein, The actual operating limit for each of the electrical system components is a value corresponding to at least one of the bridge switch temperature, coolant temperature, modeled converter component temperature, and generator temperature, the plurality of operations further comprising: To test the approximation of actual operating parameters to their corresponding actual operating limits; and The torque setpoint is reduced to prevent damage to or tripping of the electrical system components during the application of the maximum available torque in the first enhanced braking mode.

15. The system according to claim 12, wherein, The plurality of operations further include: Increase the at least one actual operating limit for at least one electrical system component to increase the duration of the maximum available torque in the first enhanced braking mode, wherein increasing the at least one actual operating limit reduces the expected life of the at least one electrical system component relative to its nominal life.

16. The system according to claim 12, wherein, The enhanced braking mode is a second enhanced braking mode, wherein the controller includes a converter controller for the wind turbine, and wherein the abnormal operation event indicates a failure of the wind turbine blades or tower, the plurality of operations further including: Override control is applied to multiple nominal operating thresholds corresponding to multiple electrical system components, wherein the override control of the multiple nominal operating thresholds increases the maximum value of the torque of the generator generated by the electrical system relative to the nominal torque limit; and An increased wear rate relative to the nominal wear rate of at least one of the plurality of electrical system components is permitted to facilitate the generation of the maximum generator torque.

17. The system according to claim 16, wherein, Override control of the plurality of nominal operating thresholds includes increasing at least one thermal protection limit, overvoltage limit, undervoltage limit, and current limit of the electrical system.

18. The system according to claim 12, wherein, The wind turbine further includes a sliding coupling that operatively connects the generator to the gearbox of the wind turbine, and wherein the controller includes a converter controller, and the plurality of operations further include: Monitor the torque level of the sliding coupling; and When the torque level of the sliding coupling approaches the release threshold of the sliding coupling, the torque of the generator is reduced.

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