Wind turbine setpoint reduction

Abstract

To provide methods for determining a maximum power setpoint for a wind turbine.SOLUTION: The present disclosure relates to methods for determining a maximum power setpoint for a wind turbine comprising: determining an ambient temperature; determining temperatures of one or more wind turbine components; and determining a current power output of the wind turbine. The methods further comprise determining the maximum power setpoint based at least partially on a thermodynamic model of the wind turbine components, the ambient temperature, the temperatures of the components of the wind turbine, and the present power output of the wind turbine. The present disclosure further relates to methods for determining a setpoint reduction, and to wind turbine control systems and wind turbines configured for such methods.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to wind turbines, and more particularly, to setpoint reduction and methods for determining a maximum output setpoint based on the temperature of wind turbine components.

Background Art

[0002] Generally, modern wind turbines are used to supply electricity to the power grid. This type of wind turbine generally includes a tower and a rotor disposed on the tower. The rotor, typically comprising a hub and a plurality of blades, is adapted to rotate under the influence of wind on the blades. Said rotation typically generates torque that is transmitted directly or via a gearbox via a rotor shaft to a generator. In this way, the generator produces electricity that can be supplied to the power grid.

[0003] The wind turbine hub may be rotatably coupled to the front of the nacelle. The wind turbine hub may be connected to a rotor shaft, which may then be rotatably mounted within the nacelle using one or more rotor shaft bearings disposed within a frame inside the nacelle. The nacelle is, for example, a housing disposed on top of a wind turbine tower that houses and protects additional components such as a gearbox (if present) and a generator, as well as a power converter and an auxiliary system, depending on the wind turbine.

[0004] In variable-speed wind turbines, the wind turbine controller can change the control settings of the wind turbine to adapt to various wind conditions. In particular, the blade pitch angle and generator torque can be changed to suit the wind conditions. Below the nominal or "rated" wind speed, the control objective is generally to maximize the power output of the wind turbine, i.e., to change the pitch and generator torque so that the maximum power output can be delivered to the power grid. Above the nominal wind speed (and depending on the surrounding conditions at the nominal wind speed), the control objective may be to keep the load under control, i.e., to change the pitch and generator torque to reduce the load on the wind turbine to an acceptable level, while maintaining the output at the highest possible level (taking load constraints into account).

[0005] Wind turbines can be used in a wide variety of environments, including onshore, offshore, and in both warm and cold climates. As ambient temperatures rise, the temperatures of wind turbine components can also rise. If ambient temperatures are very high or remain high for extended periods, the temperature of wind turbine components may become excessively high, and the operation of the wind turbine may need to be adapted to keep the temperature of the wind turbine components at an acceptable level.

[0006] Two different approaches are known to address this situation. In one known solution, different maximum power setpoints (i.e., power limits) are defined for different ambient temperatures. Such maximum power setpoints as a function of ambient temperature can be fixed by agreement between the wind turbine manufacturer and the operator.

[0007] During operation, ambient temperature can be monitored, and a predetermined maximum power setpoint is used depending on the ambient temperature. In particular, this method may result in the rated power not being delivered to the power grid when the nominal wind speed is exceeded, and instead a reduced amount of power being delivered. Wind turbine operation can be normal at lower wind speeds, and even if the maximum power setpoint is determined based on ambient temperature, the prevailing wind conditions may be such that this maximum power cannot be reached even under optimal operation. One drawback of this method is that the maximum power setpoint is generally set very conservatively, which affects the power output.

[0008] In another known solution, the temperature of the wind turbine components is measured during operation, and corresponding thresholds for the wind turbine components are predefined. If the temperature of the wind turbine components remains below the corresponding threshold, the maximum power setpoint is unaffected; i.e., the nominal rated power can be delivered to the grid under favorable wind conditions. When the temperature of one of the wind turbine components reaches the corresponding threshold, the power is (generally) significantly reduced to cool the wind turbine component. One drawback of this approach is that, when the power is reduced, it generally needs to be reduced quickly to ensure the safe operation of the components. Thus, power fluctuations can be large. Another drawback is that, if the operation is based on component temperature (rather than ambient temperature), the wind turbine operator cannot know in advance, or reasonably estimate, how often the power setpoint reduction will be necessary over the entire lifespan of the wind turbine or over an entire year. [Overview of the project]

[0009] One aspect of the present disclosure provides a method for determining a maximum power setpoint for a wind turbine. The method includes the steps of determining the ambient temperature, determining the temperature of one or more wind turbine components, and determining the current power output of the wind turbine. The method further includes the step of determining the maximum power setpoint based at least in part on a thermodynamic model of the wind turbine components, the ambient temperature, the temperatures of the wind turbine components, and the current power output of the wind turbine.

[0010] This embodiment provides a method for determining the maximum power setpoint, taking into account not only ambient temperature but also other factors. Because the actual temperature of the components is also taken into account, overly cautious approaches are avoided, and operation is not excessively restricted, even when the ambient temperature is (temporarily) high, as long as the wind turbine components can actually continue normal operation without compromising the safety or performance of the components. A balanced approach is provided that considers not only the actual current temperature but also predictions. Therefore, this method is based not only on current measurements and responses thereto, but also on the modeled behavior of the wind turbine components.

[0011] In a further embodiment, a wind turbine control system is provided for controlling a wind turbine. The control system is configured to determine the ambient temperature, the temperature of one or more wind turbine components, and the current output of the wind turbine. The control system is further configured to determine a maximum output setpoint, at least in part, based on a thermal model of the wind turbine components, the ambient temperature, the temperatures of the wind turbine components, and the current output of the wind turbine.

[0012] In a further embodiment, a method is provided for determining a setpoint reduction of a wind turbine. The method includes the steps of measuring a first temperature of a first electrical component of the wind turbine and measuring a second temperature of a second electrical component of the wind turbine. The method further includes the steps of determining an ambient temperature and determining the current output of the wind turbine. The method also includes the steps of determining a future first temperature profile in a first prediction window based on the measured first temperature, the determined ambient temperature, and the current output of the wind turbine, and determining a future second temperature profile in a second prediction window based on the measured second temperature, the determined ambient temperature, and the current output of the wind turbine. A setpoint reduction of the wind turbine is determined if the future first temperature profile reaches a first temperature threshold established for the first electrical component, or if the future second temperature profile reaches a second temperature threshold established for the second electrical component.

[0013] Throughout this disclosure, nominal power or “rated power” should be understood as the maximum power output under standard operation of the wind turbine, that is, this nominal power or rated power may be delivered to the power grid at wind speeds exceeding the nominal wind speed.

[0014] Throughout this disclosure, the maximum power setpoint should be understood as the maximum power output of a wind turbine independent of prevailing wind conditions, i.e., even when the wind speed is high enough to deliver more power to the grid, and in particular the nominal rated power to the grid, the operation of the wind turbine is limited to produce less power than possible.

[0015] "Setpoint reduction" should be understood as wind turbine operation limited to power generation and transmission to the grid below nominal or rated output. This operational limitation is due to circumstances other than prevailing wind conditions. Furthermore, within this disclosure, this operational limitation is due to temperature or thermal limitations, including predetermined ambient and component temperatures, as well as thermal limitations relating to either ambient or component temperatures. [Brief explanation of the drawing]

[0016] [Figure 1] This diagram schematically shows a perspective view of an example of a wind turbine. [Figure 2] Figure 1 is a simplified internal view of an example of a wind turbine nacelle. [Figure 3] This figure schematically shows an example of a maximum output setpoint curve based on ambient temperature. [Figure 4] This diagram schematically illustrates an example of how the maximum output setpoint, based on ambient temperature, can excessively reduce the output. [Figure 5] This figure shows an example of a method for determining the maximum output setpoint. [Figure 6] This figure shows an example of a method for determining the maximum output setpoint. [Modes for carrying out the invention]

[0017] The embodiments of the present invention are described below in detail, with one or more examples shown in the drawings. Each example is presented to illustrate the invention and is not intended to limit it. Indeed, it will be apparent to those skilled in the art that various modifications and changes can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can also be used in conjunction with another embodiment to bring about further embodiments. Thus, the present invention is intended to encompass such modifications and changes that fall within the scope of the appended claims and their equivalents.

[0018] Figure 1 shows a perspective view of an example of a wind turbine 160. As shown, the wind turbine 160 includes a tower 170 extending from a support surface 150, a nacelle 161 mounted on the tower 170, and a rotor 115 coupled to the nacelle 161. The rotor 115 includes a rotatable hub 110 and at least one rotor blade 120 coupled to the hub 110 and extending outward from the hub 110. For example, in the illustrated embodiment, the rotor 115 includes three rotor blades 120. However, in alternative embodiments, the rotor 115 may include more or fewer rotor blades 120 than three. Each rotor blade 120 may be spaced around the hub 110 to facilitate the rotation of the rotor 115 and to allow kinetic energy from the wind to be converted into usable mechanical energy, and subsequently electrical energy. For example, the hub 110 may be rotatably coupled to a generator 162 (Figure 2) positioned within the nacelle 161 to enable the production of electrical energy.

[0019] Figure 2 shows a simplified internal view of an example of the nacelle 161 of the wind turbine 160 of Figure 1. As shown, the generator 162 may be located within the nacelle 161. Generally, the generator 162 may be coupled to the rotor 115 of the wind turbine 160 to generate electricity from the rotational energy generated by the rotor 115. For example, the rotor 115 may include a main rotor shaft 163 coupled to the hub 110 for rotation together with the hub 110. The generator 162 may then be coupled to the rotor shaft 163 so that the rotation of the rotor shaft 163 drives the generator 162. For example, in the illustrated embodiment, the generator 162 includes a generator shaft 166 rotatably coupled to the rotor shaft 163 through a gearbox 164.

[0020] It should be understood that the rotor shaft 163, gearbox 164, and generator 162 can generally be supported within the nacelle 161 by a support frame or bed plate 165 located at the top of the wind turbine tower 170.

[0021] The nacelle 161 may be rotatably coupled to the tower 170 through a yaw system 20 such that the nacelle 161 can rotate about the yaw axis YA or there may be other ways to position the rotor at a desired angle with respect to the wind. If a yaw system 20 is present, such a system typically comprises a yaw bearing having two bearing components configured to rotate relative to each other. The tower 170 is coupled to one of the bearing components and the bedplate or support frame 165 of the nacelle 161 is coupled to the other bearing component. The yaw system 20 comprises an annular gear 21, a plurality of yaw drive units 22 having motors 23, a gearbox 24, and a pinion 25 for meshing with the annular gear 21 to rotate one of the bearing components relative to the other.

[0022] As described above, the blade 120 is coupled to the hub 110 by a pitch bearing 100 between the blade 120 and the hub 110. The pitch bearing 100 comprises an inner ring 103 and an outer ring 104. The wind turbine blade can be attached to either the bearing inner ring or the bearing outer ring, while the hub is connected to the other. The blade 120 can perform a relative rotational movement with respect to the hub 110 when the pitch system 107 is actuated. Thus, in FIG. 2, the inner bearing ring can perform a rotational movement with respect to the outer bearing ring. The pitch system 107 in FIG. 2 comprises a pinion 108 that meshes with an annular gear 109 provided on the inner bearing ring to rotate the wind turbine blade around the pitch axis PA.

[0023] FIG. 3 schematically shows an example of a maximum output set point curve based on ambient temperature. For various ambient temperatures, a maximum output is defined. Such a contract can be included in a contract between a wind turbine manufacturer and a wind turbine operator or client.

[0024] At relatively low ambient temperatures, the maximum output may be the nominal output of the wind turbine. At lower ambient temperatures, there is no risk that the temperature of the components reaches the operating limit and thus no reduction in output is necessary.

[0025] At higher ambient temperatures, especially when the wind turbine continues to operate at its maximum capacity for some time, the temperature of the components may reach the operating limit. To protect the wind turbine components and ensure safe operation, the output of the wind turbine may be limited and the maximum output setpoint may be reduced.

[0026] However, there is no direct or linear relationship between the ambient temperature and the component temperature. In particular, the component temperature may lag behind the ambient temperature. Furthermore, the component temperature depends not only on the ambient temperature but also on the thermal history and inertia of the components, and the thermal history and inertia also depend on the power production in the recent operation of the wind turbine.

[0027] Figure 4 schematically shows an example of how the maximum output setpoint based on the ambient temperature can overly reduce the output. The upper part of Figure 4 schematically shows how the ambient temperature can vary throughout the day. Based on a curve such as the output reduction curve shown in Figure 3, the output setpoint may be reduced as soon as the ambient temperature reaches a predetermined (contractual) limit. The setpoint reduction may remain effective until the ambient temperature sufficiently decreases.

[0028] The middle part of Figure 4 shows how the component temperature progresses. It can be seen that even when the ambient temperature is high, the component (safety or operating) temperature limit may not actually be reached. As described above, the ambient temperature is an important factor indicating the component temperature, but other factors, such as the recent output, also have an impact. For example, if the wind turbine has been stopped for a period for maintenance, the temperature of the components may actually be much lower than expected.

[0029] The central portion of Figure 4 also schematically illustrates how excessive limitation of the power setpoint can be avoided in an example of the present disclosure. In one aspect of the present disclosure, a method is provided for determining the maximum power setpoint of a wind turbine, the method comprising the steps of determining the ambient temperature, determining the (current) temperature of one or more wind turbine components, and determining the current power of the wind turbine. Based on the ambient temperature, the temperatures of the wind turbine components, and the current power of the wind turbine, as well as a thermodynamic model of the wind turbine components, the maximum power setpoint can be determined.

[0030] In particular, as shown in Figure 4, temperature predictions of wind turbine components may be performed. The temperature prediction may be a temperature profile within a prediction window and / or may include predicting one or more future maximum temperatures of wind turbine components within a time window. In the example in Figure 4, it can be seen that the predictions show that the wind turbine components have not reached their limits, and therefore, even if the ambient temperature reaches a high level, a reduction in the power setpoint was not necessary.

[0031] Such a method may be performed substantially continuously, for example, every minute or every 5 to 30 minutes, during which the temperature may be determined and the maximum output setpoint may be recalculated. This method may be performed at a constant frequency or at a variable frequency. For example, the frequency of determination, measurement, and / or calculation may increase as the temperature approaches the critical temperature.

[0032] In some examples, wind turbine components include one or more of the following: power converters, generators, and transformers, or components of these components. The components that can define the operating limits of a wind turbine are generally the electrical components. In a generator, the generator stator and generator rotor may be monitored separately and have individual threshold temperatures.

[0033] In some examples, the method may include the steps of determining the temperature of a first wind turbine component, determining the temperature of a second wind turbine component, and determining a first maximum power setpoint based at least partially on the temperature of the first wind turbine component, the ambient temperature, and the current power output of the wind turbine. The method may further include the steps of determining a second maximum power setpoint based at least partially on the temperature of the second wind turbine component, the ambient temperature, and the current power output of the wind turbine, and selecting the lower of the first and second maximum power setpoints as the maximum power setpoint of the wind turbine. Different components may have different thermal and operating limits. Depending on the situation, one component (e.g., a transformer) may be approaching its thermal limit, while another component (e.g., a power converter) is not. Thus, each electrical component may define different maximum power setpoints. The operation of the wind turbine can be limited by selecting the lowest of the maximum power setpoints.

[0034] In this example, determining the maximum power setpoint may include predicting the future maximum temperature of one or more wind turbine components within a time window. The time window may be 5 minutes to 4 hours, specifically 10 minutes to 1 hour.

[0035] In some examples, the future maximum temperature of a wind turbine component may be compared to one or more corresponding predetermined temperature thresholds of the wind turbine component. In examples, the method may further include the steps of defining the maximum power setpoint of the wind turbine as the rated nominal power if the future maximum temperature of the wind turbine component is below the corresponding predetermined temperature threshold, and defining a reduced power setpoint of the wind turbine if the future maximum temperature of one or more wind turbine components is above the corresponding predetermined temperature threshold. Thus, if the predicted future maximum temperature is below the predetermined threshold (and therefore within the acceptable operating limits), the maximum power setpoint remains unaffected and adheres to the rated (design) power. The maximum power setpoint is affected only if necessary according to the prediction. Depending on the wind conditions, the operation of the wind turbine is adapted to deliver power according to the established maximum power setpoint.

[0036] Figures 5 and 6 illustrate an example of a method for determining the maximum power setpoint. Figures 5 and 6 schematically illustrate a method for determining the setpoint reduction of a wind turbine, which includes the steps of measuring a first temperature of a first electrical component of the wind turbine and measuring a second temperature of a second electrical component of the wind turbine. The method further includes the steps of determining the ambient temperature and determining the current power output of the wind turbine. Finally, the method further includes the steps of determining a future first temperature profile in a first prediction window based on the measured first temperature, the determined ambient temperature, and the current power output of the wind turbine, and determining a future second temperature profile in a second prediction window based on the measured second temperature, the determined ambient temperature, and the current power output of the wind turbine. Finally, the method also includes the step of determining the setpoint reduction of the wind turbine if the future first temperature profile reaches a first temperature threshold established for the first electrical component, or if the future second temperature profile reaches a second temperature threshold established for the second electrical component.

[0037] As shown in Figure 6, determining the future first and second temperature profiles may involve calculating the first and second temperature profiles based on thermodynamic models of the first and second electrical components. The thermodynamic model of the wind turbine components may include one or more mathematical equations, including empirical factors or constants, that attempt to describe the thermal behavior of the electrical components. Specific characteristics of the electrical components may be included in the corresponding models. The models may also include constants, factors, or parameters that reflect how the operation of the wind turbine affects the operation of individual wind turbine components.

[0038] The inputs to the thermodynamic model may include ambient temperature, the temperature of the components themselves, and the output of the wind turbine. Further inputs may include a forecast time window. In the example, further inputs may include weather forecasts, e.g., forecasts of future ambient temperature profiles, and / or forecasts of future wind profiles, including one or more of the following: wind direction, wind shear, wind veer, wind direction, turbulence, etc. In addition to or instead of this, future wind turbine power output may be used. Such future wind turbine power output may be based on estimated or forecasted future wind speeds.

[0039] A thermodynamic model can estimate, calculate, or otherwise determine the prediction of temperature progression over time. The output of the thermodynamic model may include the maximum temperature of a component within the predicted time window, i.e., the highest temperature the component will reach within the predicted time window based on the module's input. The output of the thermodynamic module may include, for example, a temperature profile of the component within the predicted window, including the variation in component temperature over time.

[0040] Different components may dictate different setpoint reductions.

[0041] As shown in Figure 5, taking into account the different setpoint reductions of different components such as the main wind turbine transformer, wind turbine generator, and power converter, the setpoint reduction of the wind turbine may be determined as the most restrictive setpoint. In the example in Figure 5, an actual setpoint reduction occurs only if one or more of the setpoint reductions of the individual components are determined to be lower than the nominal output of the wind turbine.

[0042] As shown in Figure 5, the resulting setpoint reduction can be supplied to a wind turbine controller that controls, for example, the operating settings of the pitch system and generator torque. Other operating settings include, for example, the yaw angle. Actual operating settings depend not only on the setpoint reduction but also on the prevailing wind conditions. In the example, the method may further include the steps of pitching the blades and / or reducing the rotor speed in order to operate according to the setpoint reduction. By pitching the blades and reducing the rotor speed, the output can be reduced.

[0043] In some examples, the first and second prediction windows may be the same. In other examples, different components may have different prediction windows.

[0044] In some examples, the method may further include the steps of predicting the ambient temperature profile within a prediction window and calculating first and second temperature profiles taking the predicted ambient temperature profile into account. The predicted ambient temperature profile within the prediction window can be used as input to a thermodynamic model. Similarly, the predicted wind speed or the corresponding predicted future output (under normal unrestricted operation) can also be used as input.

[0045] In some examples, the method may further include the steps of measuring the third temperature of a third electrical component of a wind turbine, determining a future third temperature profile in a third prediction window based on the measured third temperature, the determined ambient temperature, and the current output of the wind turbine, and determining a setpoint reduction of the wind turbine when the future first temperature profile reaches a first temperature threshold established for the first electrical component, or when the future second temperature profile reaches a second temperature threshold established for the second electrical component, or when the future third temperature profile reaches a third temperature threshold established for the third electrical component. The first, second, and third electrical components include a power converter, a generator, and a main transformer.

[0046] In the example, if the future first, second, and third temperature profiles do not reach the first, second, and third temperature thresholds, respectively, the original output rating can be maintained.

[0047] In further embodiments, a wind turbine control system is provided for controlling a wind turbine, configured to perform any of the examples of the methods described herein. In particular, the wind turbine control system may be configured to determine the ambient temperature, the temperature of one or more wind turbine components, and the current output of the wind turbine, and may be further configured to determine a maximum output setpoint based at least in part on a thermal model of the wind turbine components, the ambient temperature, the temperatures of the wind turbine components, and the current output of the wind turbine.

[0048] In some examples, the wind turbine control system may be further configured to compare a determined maximum power setpoint with a theoretical output based on current wind conditions, and to operate the wind turbine according to the determined maximum power setpoint if the determined maximum power setpoint is lower than the theoretical output based on current wind conditions.

[0049] In a further embodiment, a wind turbine is provided that includes such a control system. Such a wind turbine may include one or more sensors for determining the temperature of the wind turbine components. Such a wind turbine may further include sensors or a system for determining the ambient temperature. The ambient temperature may also be provided by the metmast or an adjacent wind turbine.

[0050] Those skilled in the art will further understand that the various exemplary logic blocks, modules, circuits, and algorithmic steps described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly demonstrate this hardware- and software compatibility, various exemplary components, blocks, modules, circuits, and steps are generally described above in relation to their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in various ways for each specific application.

[0051] The various exemplary logic blocks, modules, and circuits described in connection with the disclosure herein may be implemented or realized using one or more general-purpose processors, digital signal processors (DSPs), cloud computing architectures, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic controllers (PLCs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to realize the functions described herein. The general-purpose processor may be a microprocessor, but instead, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors working with a DSP core, or any other combination of computing devices that are such configurations.

[0052] This disclosure also relates to a computing system adapted to perform any of the methods disclosed herein.

[0053] This disclosure also relates to a computer program or computer program product which includes instructions (code) that, when executed, perform any of the methods disclosed herein.

[0054] A computer program may be in the form of object code, such as source code, object code, code intermediate source, and partially compiled forms, or any other form suitable for use in process implementation. A carrier may be any entity or device capable of carrying a computer program.

[0055] When implemented in software / firmware, the functionality may be stored as one or more instructions or codes on or transmitted through a computer-readable medium. Computer-readable medium includes both computer storage media and communication media, including any media that facilitate the transfer of computer programs from one location to another. Storage media can be any available media accessible by a general-purpose or dedicated computer. Such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD / DVD or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other media that can be used to carry or store desired program code means in the form of instructions or data structures, and can be accessed by a general-purpose or dedicated computer or general-purpose or dedicated processor. Any connection is also appropriately referred to as computer-readable medium. For example, if software / firmware is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. As used herein, disk and disc include compact disc (CD), laser disc (disc), optical disc (disc), digital versatile disc (disc) (DVD), floppy disk (disk), and Blu-ray disc (disc), where a disk typically reproduces data magnetically and a disc (disc) reproduces data optically using a laser. Combinations of the above should also be included within the scope of computer-readable media.

[0056] While only a few examples are disclosed herein, other substitutions, modifications, uses, and / or equivalents are possible. Furthermore, all possible combinations of the examples described are also covered. Therefore, the scope of this disclosure should not be limited by any particular example, but should be determined solely by a fair reading of the appended claims. [Explanation of Symbols]

[0057] 20 Yaw System 21 Ring gear 22 Yaw drive device 23 Motor 24 Gearbox 25 pinion 100 pitch bearing 103 Inner ring 104 Outer ring 107 Pitch System 108 pinion 109 Ring gear 110 Hub 115 Rotor 120 rotor blades 150 Support surface 160 Wind Turbine 161 Nacer 162 Generators 163 Main rotor shaft 164 Gearbox 165 Support frame, bed plate 166 Generator shaft 170 Wind Turbine Towers PA pitch axis YA yaw axis

Claims

1. 1. A method for determining a maximum power set point of a wind turbine (160), comprising: determining an ambient temperature; Determining a temperature of one or more wind turbine components; determining a current power output of the wind turbine (160); determining the maximum power set point based at least in part on a thermodynamic model of the wind turbine components, the ambient temperature, temperatures of the components of the wind turbine (160), and the current power output of the wind turbine (160); A method comprising:

2. The method of claim 1 , wherein the wind turbine components include one or more of a power converter, a generator (162), and a transformer.

3. determining a temperature of a first one of the wind turbine components and determining a temperature of a second one of the wind turbine components; determining a first maximum power set point based at least in part on the temperature of the first wind turbine component, the ambient temperature, and the current power output of the wind turbine; determining a second maximum power set point based at least in part on the temperature of the second wind turbine (160), the ambient temperature, and the current power output of the wind turbine (160); selecting the lower of the first maximum power set point and the second maximum power set point as a maximum power set point for the wind turbine (160); The method of claim 1 , comprising:

4. The method of claim 1 , wherein determining the maximum power set point comprises predicting a future maximum temperature of one or more of the wind turbine components within a time window based on the thermodynamic model.

5. The method according to claim 4, wherein the time window is between 5 minutes and 4 hours, in particular between 10 minutes and 1 hour.

6. The method of claim 4 , comprising comparing the future maximum temperature of the wind turbine component to one or more corresponding predetermined temperature thresholds of the wind turbine component.

7. 7. The method of claim 6, further comprising: defining a maximum power set point of the wind turbine (160) as a rated nominal power output if the future maximum temperatures of the wind turbine components are below the corresponding predetermined temperature thresholds; and defining a reduced power set point of the wind turbine (160) if one or more future maximum temperatures of the wind turbine components are above the corresponding predetermined temperature thresholds.

8. The method of claim 1 , wherein the maximum power set point is also based on a predicted future wind speed and / or a predicted future ambient temperature.

9. 9. The method of claim 1, further comprising pitching blades and / or reducing rotor speed to operate in accordance with the reduced power setpoint.

10. A wind turbine control system for controlling a wind turbine (160), comprising: Determine the ambient temperature, Determining a temperature of one or more wind turbine components; determining a current power output of the wind turbine (160); determining the maximum power set point based at least in part on a thermodynamic model of the wind turbine components, the ambient temperature, temperatures of the components of the wind turbine (160), and the current power output of the wind turbine (160); A wind turbine control system configured as follows:

11. 11. The wind turbine control system of claim 10, further configured to compare the determined maximum power set point to a theoretical power output based on current wind conditions, and operate the wind turbine (160) according to the determined maximum power set point if the determined maximum power set point is below the theoretical power output based on the current wind conditions.

12. The wind turbine control system of claim 10 , further configured to predict one or more future maximum temperatures of the wind turbine component within a time window based on the thermodynamic model.

13. The wind turbine control system of claim 10 , wherein the wind turbine components include one or more of a generator (162), a power converter, and a transformer.

14. A wind turbine (160) comprising a wind turbine control system according to any one of claims 10 to 13.

15. The wind turbine (160) of claim 14 comprising one or more sensors for determining the temperature of the wind turbine components.

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