Method for controlling a wind turbine system in relation to braking of a yaw system

Abstract

The present invention relates to a method for controlling a wind turbine system, and more particularly to a controlled slip strategy for reducing the load on a yaw system by controlling a mechanical brake and a motor brake in a yaw drive actuator. When the yaw system (300) is in a non-yawing operating state, and the mechanical brake (400) is in an engaged state, and the yaw controller (308) determines or receives a signal indicative of a yawing moment, if the signal indicative of the yawing moment is above a signal threshold, the yaw controller (308) sends a brake signal to the yaw drive actuator to bring the motor into a braking state to apply a braking torque.

Description

Technical Field

[0001] The present invention relates to a method for controlling a wind turbine system, and more particularly to a method for controlling a yaw system by controlling a mechanical brake and a motor brake in a yaw drive actuator. Background Technology

[0002] The yaw system's task is to determine the cabin's orientation relative to the wind. Most of the time, the yaw system is inactive or stopped. It only activates to turn the cabin into the wind when the cabin's orientation needs to be changed, usually due to a change in wind direction.

[0003] In normal operating mode, the deviation of the nacelle from the wind direction (yaw angle) should be as small as possible to avoid power generation losses and reduce load. However, at the same time, the yaw system response should not be too sensitive to avoid continuous small yaw movements, which would reduce the lifespan of mechanical components.

[0004] In modern wind turbine systems, multiple yaw drive actuators are used in the yaw system to determine the orientation of the nacelle relative to the wind.

[0005] When the yaw system is inactive or stopped, the mechanical brakes are typically engaged. However, due to the size of modern wind turbine systems, the forces acting on the wind turbine (such as changes in wind direction) are considerable, and the loads on mechanical components can be very large, which may require a large and robust construction that includes gears and mechanical brakes.

[0006] Therefore, improved methods for controlling brakes in wind turbines would be advantageous, and more efficient and / or reliable methods for controlling mechanical brakes would be advantageous. Summary of the Invention

[0007] One object of the present invention is to provide a method for controlling a yaw system of a wind turbine such that the yaw system can handle loads on mechanical components in such a way that the size and cost of the mechanical components can be reduced compared to a system that handles the load solely through mechanical components.

[0008] Another objective of this invention is to improve the control method for wind turbines, particularly to improve the control method for increasing the service life of components in the yaw system.

[0009] Furthermore, another object of the present invention relates to the ability to operate a turbine with a partially faulty yaw actuator.

[0010] Therefore, in a first aspect of the invention, the above-mentioned object and several other objects are intended to be achieved by providing a method for controlling a wind turbine system, the wind turbine system including a nacelle, a tower and a yaw system, the yaw system including one or more yaw drive actuators and a yaw controller, the one or more yaw drive actuators including a motor and a mechanical brake;

[0011] The yaw system can operate in a yaw mode to rotate the nacelle relative to the tower, and the yaw system can also operate in a non-yaw mode.

[0012] The mechanical brake can operate in an engaged or disengaged state, and

[0013] - The motor can be operated in a braking state, wherein the motor applies braking torque to resist the movement of the cabin;

[0014] Among them, when

[0015] - The yaw system is in the non-yaw operating state, and

[0016] -The mechanical brake is engaged, and

[0017] When the yaw controller determines or receives a signal indicating the yaw torque, and

[0018] If the signal indicating yaw torque is higher than a signal threshold, the yaw controller sends a braking signal to the yaw drive actuator to cause the motor to enter the braking state to apply braking torque.

[0019] The yaw system includes multiple yaw drive actuators, each including a motor and a pinion gear connected to the yaw drive actuator. The yaw system also includes a yaw ring to which multiple actuators are connected. In one embodiment, the yaw drive actuator includes a variable frequency drive. The variable frequency drive is generally considered part of the yaw drive actuator, even if it can be placed separately from other parts of the yaw drive actuator. In other embodiments, the yaw drive actuator is not equipped with a variable frequency drive; instead, the yaw drive actuator receives on / off actuation signals directly from the yaw controller. In other embodiments, a soft starter may be applied to the yaw drive actuator. The braking signal is typically in the form of a command to yaw in the opposite direction of the yaw torque.

[0020] Yaw or rotation is understood, as commonly used in the art, as the rotation of the nacelle relative to the tower.

[0021] When the yaw system is in yaw operation, the nacelle rotates clockwise or counterclockwise relative to the tower. When the yaw system is in non-yaw operation, the nacelle does not rotate, and the mechanical or electric motor brakes typically keep the nacelle stationary. However, if the forces acting on the system are too great for the brakes to maintain their position, slippage may occur.

[0022] Regarding braking in this invention, mechanical braking and electric motor braking are distinguished. Mechanical braking is the braking torque from a friction brake installed at the motor, while electric motor braking is the counter-torque generated by the motor.

[0023] The mechanical brakes can be engaged or disengaged. The motor brakes can be engaged to apply braking torque against nacelle movement or rotation. The yaw system includes yaw rings, and braking torque is applied to the yaw rings to resist movement or rotation of the yaw system, thereby resisting nacelle movement or rotation. This includes applying counter-movement, i.e., applying counter-torque after the time of sliding stop, for example, to move the nacelle to its pre-slip position, or until the nacelle is back in the headwind.

[0024] When the yaw controller receives or detects a signal indicating yaw torque, if the yaw torque is higher than the signal threshold, the yaw controller sends a signal to the yaw drive actuator to activate the motor brake and apply braking torque to the yaw ring by entering a braking state. Yaw torque is the torque applied to the yaw system by an external force, usually caused by changes in wind direction.

[0025] In addition, there is bearing friction, which creates frictional torque. When used to apply active torque, the motor must overcome this frictional torque. On the other hand, bearing frictional torque helps reduce the load on the drive when the engine compartment should be stopped.

[0026] Typically, the motor is active during active yaw and under high external loads requiring motor actuation; otherwise, the mechanical brakes are engaged. In one embodiment, the motor operates as a generator brake under high external loads and allows the nacelle to slip at a controlled load level. When slippage above a signal threshold is detected in the mechanical brakes, all mechanical brakes are released and the motor is activated in a braking state, causing the motor to create an anti-slip torque. The maximum capacity of the brakes is less than the capacity of the gearbox and pinion, so slippage will occur in the brakes before exceeding the design load of the gearbox and pinion.

[0027] Currently, in existing technological solutions, yaw drive actuators are designed to handle the highest possible loads. A significant benefit of using the method of this invention is avoiding designing the yaw drive to the highest load, thus allowing for a reduction in the size of critical components within the yaw system. Furthermore, the slippage capability can reduce the load on other components and may also reduce the risk of oscillations. Additionally, the slippage function can reduce the amount of wear experienced by existing mechanical yaw motor brakes, thereby increasing the service life of components in the yaw system.

[0028] The motor is preferably an electric drive motor, typically an asynchronous induction motor, but it can also be a permanent magnet motor. Each motor is powered by a separate frequency converter or controllable power supply, thereby achieving motor control. According to this embodiment, the motors can be controlled individually or centrally. Alternatively, the motor can be a hydraulic drive motor.

[0029] In embodiments using variable frequency drives, the drive is connected to the motor controller in the yaw system and receives output signals from the motor controller.

[0030] The tower can be any support structure or configuration on which one or more nacelles can be mounted and rotated relative to the tower. The tower may include support arms on which the nacelles are mounted; therefore, the phrase "rotate the nacelles relative to the tower" also covers the case where the nacelles placed on the support arms are rotated. Furthermore, it is possible in embodiments where the support arms are rotatable relative to the tower, so that when the support arms rotate relative to the tower, the nacelles simultaneously rotate relative to the tower; therefore, the phrase "rotate the nacelles relative to the tower" also covers this case.

[0031] According to one embodiment, the method includes: the yaw controller determining a signal indicating yaw torque by detecting slippage of a mechanical brake.

[0032] Slippage can be detected, for example, by detecting changes in the motor position.

[0033] In one embodiment, the signal indicating the yaw torque is detected by the motor controller, for example, by detecting the voltage level or receiving an encoder signal.

[0034] According to one embodiment, the method includes: a yaw controller determining a signal indicating yaw torque based on determining the slip probability of a mechanical brake.

[0035] When slippage or the possibility of slippage is detected, the yaw controller sends a signal to the yaw drive actuator, which then activates the motor braking torque to counteract the slippage. The motor braking torque is the counter-torque generated by the motor.

[0036] The likelihood of slippage can be determined by analyzing the external forces acting on the wind turbine system. External forces detected by multiple sensors generate a yawing moment. If this yawing moment becomes so large that slippage or a risk of slippage exists, the yawing controller can signal the yawing drive actuator to apply counter-torque to counteract the yawing moment.

[0037] According to one embodiment, the method includes: one or more yaw drive actuators including an encoder for detecting slip or slip probability, and wherein a signal indicating yaw torque is based on a signal from the encoder.

[0038] An encoder is a device in a yaw drive actuator that detects motor speed and motor position (the motor angle relative to the initial position) if a change in position angle is detected; this can be used as an indication of slippage.

[0039] Encoders can be used to detect slippage, but encoders may not be present in all motors. For example, encoders may be present only on selected motors, such as only on two motors. Furthermore, embodiments without any encoders are also possible.

[0040] According to one embodiment, the method includes: a yaw controller determining a signal indicating a yaw moment by detecting movement of the cabin. That is, the signal indicating the yaw moment is based on a yaw position signal obtained from a yaw position detector.

[0041] The signal indicating yaw moment can be based, for example, on a measurement of absolute yaw slip exceeding a certain limit, i.e., how much the cabin has rotated since the last yaw motor stopped and the brakes were activated, which can be obtained by subtracting the current yaw position from the last stopping position. The signal indicating yaw moment can also be based on the yaw speed, for example, obtained by differentiating the cabin position signal, and on a measurement when the yaw speed exceeds a specified limit.

[0042] In one embodiment, when the cabin position has moved 2 degrees during non-yaw operation, a braking signal can be applied to the yaw drive actuator.

[0043] In embodiments, the signal or threshold indicating the yaw moment may also depend on wind speed, power generation, rotor / generator speed, and other parameters describing the severity of slip. Furthermore, sensor signals from various sensors used to detect these values, such as thrust, blade load, wind direction, gyroscope signals, and accelerometer signals, can be used to estimate the yaw moment and, together with the yaw moment, to estimate the likelihood of slip.

[0044] In an embodiment, the threshold can be set lower for higher wind speeds, higher power production, higher rotor / generator speeds, and higher slip speeds in order to react earlier in these conditions.

[0045] In one embodiment, if the turbine is not producing electricity or is producing low amounts of electricity, the threshold can be set higher to reduce the number of times the motor is activated.

[0046] According to one embodiment, the method includes: releasing a mechanical brake when a signal indicating yaw torque is higher than a signal threshold. This release can be immediate.

[0047] If slippage is detected, and if the slippage exceeds a threshold, the slippage may continue, causing significant wear to the mechanical brake. In this embodiment, the mechanical brake is released when the yaw torque exceeds a signal threshold to avoid damage and wear to the mechanical brake.

[0048] According to one embodiment, the method includes releasing a mechanical brake when a signal indicating yaw torque is above a signal threshold and the braking torque applied by the motor is greater than a minimum torque. To change the applied torque, a variable frequency drive may be required. In embodiments without a variable frequency drive, the mechanical brake may be released based on an alternative input or simply be released immediately.

[0049] Before releasing the mechanical brake, it is advantageous that the motor has already begun braking by applying a braking torque that counteracts the yaw moment, so that the motor brake gradually takes over the braking of the yaw system from the mechanical brake, thus avoiding the sudden release of the mechanical brake.

[0050] According to one embodiment, the method includes: when a signal indicating yaw torque is higher than a signal threshold, the braking torque applied by the motor ramps up until a selected braking torque is applied.

[0051] By ramping up the braking torque applied by the motor, the torque affecting the mechanical brake will gradually decrease, thus avoiding sudden changes in the mechanical brake that could potentially damage other components in the yaw system.

[0052] According to one embodiment, the method includes: releasing a mechanical brake when slippage is detected and the slippage speed is higher than a threshold speed.

[0053] If the sliding speed exceeds the threshold speed, there is a risk that the sliding will continue, and since the mechanical brake cannot hold the system, releasing the mechanical brake prevents damage and ensures a controlled stop of the system. The release of the mechanical brake can be immediate or can wait for the motor brake to engage.

[0054] According to one embodiment, the method includes: when slippage is detected, determining a slippage speed, and wherein an applied braking torque is set according to the slippage speed.

[0055] The braking torque applied by the motor can be set to be proportional to the slip speed or proportional to the detected yaw torque.

[0056] According to one embodiment, the method includes: a yaw controller receiving measurements from multiple sensors, and the yaw controller using the measurements to determine the likelihood of a slip.

[0057] At numerous locations on a wind turbine system, sensors are present to detect a variety of measurements, such as thrust, blade load, wind direction, gyroscope signals, and accelerometer signals. The method of this invention can utilize these sensors to estimate yaw moment using measurements from them, and together with the yaw moment, estimate slip probability.

[0058] According to one embodiment, the method includes: measurements received by the yaw system from multiple sensors, including measured thrust, estimated thrust and / or blade load and / or wind direction and / or gyroscope signals in the nacelle and / or accelerometer signals in the nacelle and / or signals from torque sensors or torque transducers.

[0059] According to one embodiment, the method includes: the signal indicating the yaw moment is based on signals from a plurality of yaw drive actuators, and signals from a subgroup of the yaw drive actuators are ignored.

[0060] Signals from multiple yaw drive actuators are typically the speed of the motor, but can also be changes in the angular position of the motor.

[0061] Using only signals from a selected subgroup of yaw actuators may be advantageous. Some yaw actuators may exhibit atypical behavior, often measured by the encoder, such as a motor speed that differs significantly from the average motor speed; therefore, ignoring these atypical measurements may be beneficial. The behavior of a yaw actuator can become atypical due to, for example, gear failure. Furthermore, some yaw actuators that can be ignored through selection (e.g., selections made by the operator to set ignore parameters in the system settings) (e.g., yaw actuators without encoders) can be disregarded.

[0062] In a typical embodiment, braking torque is applied when the signal indicating yaw torque is above a signal threshold. However, in another embodiment, braking torque may be applied only after the yaw torque has decreased below the signal threshold and until a specific stopping criterion is met.

[0063] In one embodiment, braking torque is applied until the initial stopping position is reached; that is, braking torque is first applied to stop the slide, and then the nacelle is moved back to the pre-sliding position. In another embodiment, braking torque is applied until the nacelle is upwind, i.e., the relative wind direction is close to zero. It is advantageous to apply braking torque with respect to the yaw error relative to the wind direction, because the wind direction may change as the yaw system slides.

[0064] In another embodiment, the stopping criterion may also involve the cabin's movement speed, such that braking torque is applied until the cabin's movement speed is below a predetermined speed.

[0065] According to one embodiment, the method operates on a wind turbine system comprising multiple nacelles, and the yaw system is arranged to rotate one or more of the multiple nacelles, i.e., a so-called multi-rotor turbine.

[0066] In multi-rotor turbines, nacelles can be mounted on support arms or on other support structures that allow for the installation of more nacelles on the same wind turbine system. The method of this invention can be used individually for multiple nacelles, so that a single nacelle placed on a support arm can rotate while other nacelles do not. The method can also be used to rotate all nacelles by rotating the entire structure on which multiple nacelles are mounted, thereby causing multiple nacelles to rotate simultaneously. The multiple nacelles then rotate relative to the tower, thus each individual nacelle also rotates relative to the tower.

[0067] According to one embodiment, the method includes: the yaw system receiving a measurement or estimated trust for each of a plurality of rotors, and using the trust difference among the plurality of rotors to determine a signal indicating yaw torque to detect slip probability.

[0068] In a multi-rotor turbine, the yaw moment acting on the yaw system can be estimated by analyzing the confidence differences measured or estimated for multiple rotors.

[0069] This invention can be implemented in a control system for controlling the yaw of a wind turbine.

[0070] A second aspect of the invention relates to a wind turbine, wherein the wind turbine further includes a control system for controlling the yaw of the wind turbine system according to the first aspect.

[0071] A third aspect of the invention relates to a computer program product comprising software code adapted to control a wind turbine when executed on a data processing system, the computer program product being adapted to perform the method of the first aspect.

[0072] Different parts of a motor controller can be implemented in separate computer programs, or as different functions within the same computer program running on the same or different microprocessors. Similarly, the motor controller and yaw controller can be implemented in different software programs running on different computers or microprocessors, or in the same software program running on the same computer or microprocessor, or in any combination thereof.

[0073] In general, various aspects and embodiments of the present invention can be combined and coupled in any possible manner within the scope of the present invention. These and other aspects, features, and / or advantages of the present invention will become apparent from the embodiments described below and will be elucidated with reference to the embodiments described below. Attached Figure Description

[0074] Embodiments of the invention will be described by way of example only with reference to the accompanying drawings, wherein:

[0075] Figure 1 The illustration shows a wind turbine.

[0076] Figure 2 The illustration shows a wind turbine configured as a multi-rotor wind turbine.

[0077] Figure 3 The diagram illustrates the yaw system.

[0078] Figure 4 This is a schematic diagram of a yaw motor.

[0079] Figure 5 An embodiment of the procedure for determining when to disengage the mechanical brake and engage the motor brake is illustrated.

[0080] Figure 6 An embodiment of the procedure for determining when to engage the mechanical brake and disengage the motor brake is illustrated.

[0081] Figure 7 The illustration shows an embodiment where the signal indicating the yaw moment is based on the yaw position signal obtained from the yaw position detector.

[0082] The accompanying drawings illustrate one way of implementing the invention and should not be construed as limiting other possible embodiments to fall within the scope of the appended claims. Detailed Implementation

[0083] Figure 1A wind turbine 100 (also commonly referred to as a wind turbine generator, WTG) is shown, comprising a tower 101 and a rotor 102 with at least one rotor blade 103. Three blades are typically used, but a different number can also be used. The blades 103 are connected to a hub 105, which is arranged to rotate together with the blades. The rotor is connected to a nacelle 104, which is mounted on top of the tower 101 and adapted to drive a generator located within the nacelle 104 via a drivetrain. The rotor 102 can rotate in the presence of wind. The rotational energy of the rotor blades 103 caused by the wind is transferred to the generator via a shaft. Thus, the wind turbine 100 is able to convert the kinetic energy of the wind into mechanical energy by means of the rotor blades, and subsequently into electrical energy by means of the generator. The generator is connected to a power converter for injecting the generated electricity into the mains power grid.

[0084] Figure 2 An alternative wind turbine 100 configured as a multi-rotor wind turbine is shown. The multi-rotor wind turbine includes multiple nacelles 104. As shown above, the nacelles 104 can be supported via a tower 101 and support arms 106 extending outward from the tower 101, such that the nacelles are positioned away from the tower and on opposite sides of the tower. Two arm heights are shown here, but embodiments with a single arm height and three or more heights are also possible. Alternatively, as shown below, the nacelles 104 can be supported by an inclined tower 101 extending from a base 130 (e.g., the ground or a floating base), such that two or more nacelles 104 are sufficiently spaced apart from each other at a given height. Embodiments of the invention can be used with both multi-rotor and single-rotor wind turbines.

[0085] Figure 3 An embodiment of a yaw system 300 according to the present invention is shown. In the illustrated example, the yaw system 300 includes a plurality of yaw drive actuators 301, ten of which are in Figure 3 As shown in the diagram. In other configurations, more or fewer yaw drive actuators 301 may be used. Each yaw drive actuator 301 includes a motor 302 and a pinion 304; in this embodiment, the motor 302 is an electrically driven motor. The pinion 304 connects the yaw drive actuator 301 and the yaw ring 305. In the illustrated embodiment, the yaw drive actuator 301 includes a variable frequency drive (VFD) 306. However, the VFD is not required and can be replaced by a power supply, or possibly a soft starter.

[0086] Motor 302 may be an asynchronous induction motor type, and may be controlled individually via on / off control or via VFD control. In embodiments with VFD control, motor 302 can operate according to a four-quadrant control scheme. Variable frequency drive 306 in Figure 3The variable frequency drive 306 is observed to be located in a central cabinet and connected to the motor controller 307; however, the variable frequency drive 306 can also be placed in other locations.

[0087] Motor 302 includes an encoder for detecting the motor's position. This encoder is a position gauge, and the motor speed can be derived from the angular change in position. The encoder is used to detect the speed of motor 302 and return the speed to the frequency converter drive 306.

[0088] An encoder can be used for each motor 302 to detect the position and speed of the motor 302 and ensure large load sharing while avoiding overloading any of the motors 302.

[0089] The motor controller 307 can be arranged to output a torque reference to the variable frequency drive 306. The motor controller 307 receives information about the motor speed through communication with the encoder, the respective variable frequency drive 306, or with the yaw controller 308. Furthermore, based on input from the wind direction device 309, the motor controller 307 receives signals from the yaw controller 308 regarding when to yaw and in which direction. However, the yaw controller 308, the wind direction device 309, and the cables used for power input and communication are not part of the yaw system 300.

[0090] The yaw controller 308 can control the yaw system 300, and the yaw controller 308 activates the motor controller 307 when yaw is required.

[0091] The yaw controller 308 may be part of the turbine controller, such as part of the control module of the turbine controller, or it may be a dedicated controller connected to the turbine controller.

[0092] As a complement to or alternative to applying an encoder at the motor, a yaw position sensor 310 may be present. The yaw position sensor may be, for example, an optical sensor that detects the cabin position from the position of the detected yaw ring. Another example includes a GPS mounted at the rear of the cabin, which can detect the absolute cabin position.

[0093] Figure 4 This is a schematic diagram of an electric yaw drive actuator 301 including a mechanical brake 400. The mechanical brake 400 is connected to the motor 302 and the pinion 304 via a motor shaft 416. The mechanical brake 400 can be designed in different ways, but... Figure 4The arrangement includes a friction surface 414 that forms the interface between the stationary portion 410 of the motor and the rotating portion (specifically, the brake disc 412). Furthermore, the mechanical brake 400 includes a spring and a coil (not shown). The mechanical brake 400 is normally closed, meaning that if the coil is not energized, the spring creates a force on the friction surface 414 that prevents rotation of the motor 302 by engaging the friction surface 414 of the brake disc 412. When the coil is energized, it creates a force that counteracts the spring pressure, releasing the mechanical brake 400 and thus impeding rotation of the motor 302 and the pinion 304. The pinion 304 engages with a yaw ring 305, and when the mechanical brake 400 brakes the pinion 303, the pinion 304 impedes rotation of the nacelle 104.

[0094] In one embodiment, the yaw system can be implemented to include three operating states:

[0095] a) "Stopped by brakes", where the mechanical brake 400 is engaged. In this state, the detection of slippage in the mechanical brake 400 can be set to active. In one embodiment, if slippage in the mechanical brake 400 is detected to be above a signal threshold, the state changes to "Stopped by motors".

[0096] b) "Motor-driven stop", where motor 302 is actively controlled to apply braking torque to resist movement of the cabin 104, meaning the electric motor brake is activated. In this embodiment, the mechanical brake 400 disengages in this state; however, in some cases, the "motor-driven stop" state can also be selected before disengaging the mechanical brake 400.

[0097] c) Clockwise or counterclockwise "yawing", including active yawing. The rotation direction, speed, and torque of the nacelle 104 can be set via input signals. The "yawing" state is controlled by commands from the yawing controller 308.

[0098] The yaw system 300 can be configured to change the state from "stopped by brake" to "stopped by motor" when the slip angle is higher than a threshold.

[0099] The yaw system 300 can be configured to change the state from "stopped by motor" to "stopped by brake" when it receives a signal from the turbine controller that the yaw torque has been below a given threshold for a period of time, or when the torque applied by the motor 302 has been below the threshold for a period of time.

[0100] Figure 5 The diagram illustrates an example of the procedure for determining when to disengage the mechanical brake 400 and utilize motor braking, transitioning from "stopped by brake" to "stopped by motor." Initially, the yaw system 300 is in the "stopped by brake" state. θtrig The triggering state depends on the motor shaft angle; its triggering mode switches to "motor-driven stop". If θ trig Above the signal threshold θ unlock The status changes to "Stopped by motor". θ trig θ is the angle by which the motor shaft 416 moves from its initial position. unlock This is the signal threshold that triggers mode switching. If |θ trig |>θ unlock Then the status changes to "stopped by motor".

[0101] If the change since the last check is below the minimum threshold θ reset :|θ trig (T c (k)-θ trig (T c (k-1)|<θ reset Then each T c Check angle θ once per second trig And reset θ trig This ensures that slight swipes over extended periods will not trigger the change to "motor stopped".

[0102] During the "stopped by brake" period, the angular movement of motor shaft 416 is continuously monitored. Trigger state θ trig Based on the measured change in motor shaft angle. Each T c Time period, state θ trig With lower threshold level θ reset Compare, if θ trig <θ reset If so, reset. The angle movement should be higher than the low angle threshold θ. reset So that in a short period of time T c No reset afterwards.

[0103] If there is negligible slippage in the mechanical brake 400, or if the actual movement is integral noise on the speed signal over a longer period of time, this ensures that motor control is not activated. If θ trig >θ reset The trigger state will change continuously according to the motor shaft angle. If θ trig >θ unlock The mechanical brake 400 is released, and the "motor stop" control is activated.

[0104] Figure 6 The illustration shows an example of a procedure for determining when to engage the mechanical brake 400 and disengage the motor brake, from "stopped by the motor" to "stopped by the brake".

[0105] τ motorThis is the motor braking torque; when "stopped by motor", motor 302 must apply this motor braking torque to counteract the yaw torque. τ brake When the vehicle is stopped by the brakes, the mechanical brake 400 must apply a braking torque to counteract the yaw moment.

[0106] In T unlock At this point, the mode changes to "stopped by motor", the mechanical brake 400 is released and τ brake The value becomes zero, and instead, motor 302 enters the braking state and applies motor braking torque τ. motor , τ motor It becomes τ capacity .

[0107] When τ motor Become lower than τ lock , τ lock It is below the nominal sliding level τ capacity At a certain level, timer T trig Start. When timer T trig Runtime T lock At that time, the motor torque required to maintain the yaw system at 300 degrees without slipping was already below τ. lock Time T lock The mode changes to "stopped by brake". Now, the mechanical brake 400 at time T B They engage and take over braking from motor 402. Motor torque τ motor By τ motor The slope decreases to zero, and τ... brake Increase.

[0108] Figure 7 The illustration depicts an embodiment where the signal indicating yaw moment is based on a yaw position signal obtained from a yaw position detector. The yaw position signal can be represented in various ways. For example, the yaw position can be an angle, i.e., the cabin angle. This angle can be represented, for example, relative to absolute zero or relative to the previous stopping position. The yaw position detector can be used, for example, when the yaw motor is not equipped with a VFD.

[0109] exist Figure 7 In A, the cabin position in angular form is displayed as a function of time, while Figure 7 B shows the reaction motor torque as a function of time. In the illustrated embodiment, the motor torque is applied in an on / off manner. During the first time period P1, the nacelle is positioned at angle γ0, and the motor is in a braking state due to the constant angle. At time t1, the nacelle begins to slide (time period P...). 12 Once it is detected that the cabin position has moved by the predetermined amount to γ. sA braking signal is then provided to the yaw drive actuator, causing the motor to apply braking torque. The nacelle continues to slide until the applied motor braking torque is sufficient to overcome the load causing the nacelle to slide, thus stopping the slide. This occurs during time period P2 and at a yaw angle of γ. m Stop at t3.

[0110] In the illustrated embodiment, the wind direction has changed during the slide, and in order to position the nacelle against the wind, a motor braking torque is applied until the stopping criterion (i.e., including P3) is met. At time t4, the nacelle position matches the wind direction, and the motor stops.

[0111] Although the invention has been described in conjunction with specific embodiments, it should not be construed as limiting it in any way to the examples presented. The scope of the invention is defined by the appended claims. In the context of the claims, the terms "comprising" or "including" do not exclude other possible elements or steps. Furthermore, references such as "a" or "an" should not be construed as excluding a plurality. The use of reference numerals in the claims relating to elements indicated in the drawings should also not be construed as limiting the scope of the invention. Moreover, the various features mentioned in different claims may be advantageously combined, and the mention of these features in different claims does not preclude the possibility and advantage of combining features.

Claims

1. A method for controlling a wind turbine system, the wind turbine system including a nacelle (104), a tower (101), and a yaw system (300), the yaw system (300) including one or more yaw drive actuators (301) and a yaw controller (308), the one or more yaw drive actuators (301) including a motor (302) and a mechanical brake (400); - The yaw system (300) can operate in a yaw mode to rotate the nacelle (104) relative to the tower (101), and the yaw system (300) can operate in a non-yaw mode, and - The mechanical brake (400) can operate in an engaged or disengaged state, and - The motor (302) can be operated in a braking state, wherein the motor (302) applies braking torque to resist the movement of the cabin (104); in, when - The yaw system (300) is in the non-yaw operating state, and - The mechanical brake (400) is in the engaged state, and - The yaw controller (308) determines or receives a signal indicating the yaw moment by detecting the movement of the cabin (104), and If the signal indicating yaw torque is higher than the signal threshold, the yaw controller (308) sends a braking signal to the yaw drive actuator to cause the motor (302) to enter the braking state to apply braking torque.

2. The method for controlling a wind turbine system according to claim 1, wherein, The yaw controller (308) determines the signal indicating the yaw torque by detecting the slippage of the mechanical brake (400).

3. The method for controlling a wind turbine system according to claim 1, wherein, The yaw controller (308) determines the signal indicating the yaw torque based on the determination of the slip probability of the mechanical brake (400).

4. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, The one or more yaw drive actuators (301) include an encoder for detecting slip or slip probability, and wherein the signal indicating yaw torque is based on a signal from the encoder.

5. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, The signal indicating the yaw moment is based on the yaw position signal obtained from the yaw position detector.

6. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, When the signal indicating yaw torque is higher than the signal threshold, the mechanical brake (400) is released.

7. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, When the signal indicating yaw torque is higher than the signal threshold and the braking torque applied by the motor (302) is greater than the minimum torque, the mechanical brake (400) is released.

8. The method for controlling a wind turbine system according to any one of claims 2-3, wherein, When slippage is detected and the slippage speed is higher than the threshold speed, the mechanical brake (400) is released.

9. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, When slippage is detected, the slippage speed is determined, and the applied braking torque is set according to the slippage speed.

10. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, The yaw controller (308) receives measurements from multiple sensors and uses these measurements to determine the likelihood of slippage.

11. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, The signal indicating the yaw torque is based on signals from a plurality of yaw drive actuators (301), wherein signals from a subgroup of yaw drive actuators (301) are ignored.

12. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, Apply the braking torque until the stopping criteria are met.

13. The method for controlling a wind turbine system according to any one of claims 1-3, wherein, The wind turbine system includes multiple nacelles (104), and the yaw system (300) is arranged to rotate one or more of the multiple nacelles (104), wherein the yaw system (300) receives a measurement or estimated confidence for each of the multiple rotors (102), and the confidence difference of the multiple rotors (102) is used to determine the signal indicating the yaw moment to detect the possibility of slippage.

14. A wind turbine system, the wind turbine system comprising a control system for controlling a brake of the wind turbine system, wherein, The control system is configured to perform the steps of the method according to any one of claims 1-13.

15. A computer program product comprising software code adapted to control a wind turbine system when executed on a data processing system, said computer program product being adapted to perform the method of any one of claims 1-13.

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