Active Load Control in Wind Turbine Operation

Protecting wind turbine generators from mechanical damage during heavy loads by preventing rotor-stator contact. The method involves adding a sliding pad connected to the stator. If the rotor tilts past a critical angle due to gravity forces, it contacts the sliding pad instead of the stator, preventing damage. The sliding pad provides a controlled contact point to avoid direct rotor-stator contact when the rotor tilts excessively under heavy loads.

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Self-regulating wind turbine generator that can adjust output voltage without mechanical components like blade pitch control or yaw systems. The generator has a rotor spinning with the wind turbine and a stator that can move inside the rotor's magnetic field. An actuator moves the stator closer to the rotor to increase voltage below a threshold and farther away to limit voltage above the threshold. This self-regulation allows maximum voltage extraction without overloading the system in high winds.

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Control method for wind turbines configured as virtual synchronous machines (VSMs) to improve grid stability and reduce mechanical loads after faults. The method involves controlling the wind turbine's power output based on the synchronous machine angle, using high-pass filtered rotational speed to determine damping power. It also uses comparisons of DC link voltage and grid power to determine chopper power. This allows the wind turbine to provide grid-forming properties similar to a synchronous generator while avoiding power oscillations and excessive mechanical loads after faults.

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System for measuring blade root loads in wind turbines without physical contact. It uses contactless sensors fixed to the hub to detect displacements of reference planes on the blades as they move. This allows estimating blade root loads without intrusive sensors. The hub-mounted sensors detect blade-relative displacements of the fixed reference planes. A controller processes the sensor data to determine blade root bending moments. This enables real-time load monitoring and control to optimize blade loads and pitch angles.

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Reducing sound emissions in wind turbine generators using active rectifiers with closed-loop control. The rectifiers are controlled based on the rotor position and number of pole pairs to reduce torque ripple and noise. The rectifier currents are predefined as equivalent variables. This involves modulating the partial currents of the two stators with the sixth harmonic instead of the twelfth harmonic to reduce magnetic forces and noise.

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Automatic identification of parameters for wind turbine generators to improve control performance, safety and reduce maintenance costs. The method involves controlling the generator to no-load start and shut down by adjusting blade pitch. During this transient, voltages and flux linkage can be measured to determine generator parameters like rotor angle, pole pairs, and flux linkage. Closing the circuit breaker at shutdown allows measuring stator resistance and inductance. This avoids manual parameter entry errors and reduces software versions compared to static tables.

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Neural network based control of wind turbines to optimize power extraction and robustness. The control uses a trained neural network to estimate the optimal rotor speed and maximum power for a wind turbine given the wind speed. This is done by feeding wind speed and tip speed ratio into the network and outputting the optimal rotor speed and maximum power. The wind turbine is then operated at the estimated optimal speed determined by the neural network for any wind condition. This allows the turbine to track maximum power and efficiently adjust rotor speed in response to wind changes.

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Optimizing the airgap between the stator and rotor of a large permanent magnet electric generator for wind turbines to improve performance while preventing collisions. A controller adjusts the current in the winding systems to generate radial magnetic forces that increase airgap when it's too small and decrease airgap when it's too large. Sensors measure the airgap at multiple locations around the generator. This allows more precise control than just a single airgap sensor.

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A system for accelerating the rotation of a vertical axis wind turbine rotor during startup to overcome the high inertia of the large blades. The system uses a combination of electric, pneumatic, and magnetic motors connected to the rotor shaft via a clutch and gearbox. The electric motor is connected to a compressed air tank. During startup, the electric motor spins the shaft up to a certain speed, then the pneumatic motor takes over and accelerates further using compressed air from the tank. The magnetic motor provides additional torque. The motors are controlled by a system that disconnects the generator and manages motor connections. This allows the turbine to reach operating speed without relying solely on the generator's torque during startup.

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Controlling wind turbine power output during frequency events on the grid to avoid the "wind-up" issue where the set point from the grid controller exceeds the turbine's output limits. During grid frequency deviations, the turbine's active power reference is set to the limit if the calculated reference is outside it. After the deviation, the reference ramps back to baseline instead of waiting for the set point to reach the limit. This ensures the turbine's output matches the reference during deviations and ramps immediately after, avoiding delays.

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Neural network based control of wind turbines that efficiently tracks and adjusts maximum power as wind speed changes. A neural network model is trained using wind speed and tip speed ratio samples to output maximum power and optimum rotor speed. This model is used to control the wind turbine's reference angular speed instead of directly tracking maximum power. This allows the turbine to rapidly adapt to changing wind speeds and extract maximum power. The neural network is trained using a dataset of averaged wind speeds, which is then used to test the model's accuracy. The neural network output is used to control the wind turbine's rotor speed for optimal power extraction.

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Accurately determining the angular position of a wind turbine generator shaft using an encoder sensor to improve wind turbine control and component lifespan. The method compensates for imperfections in the encoder sensor signal that can lead to inaccurate position and speed determination. It involves receiving the encoder position signal, determining a compensation signal to counteract the encoder distortions, and modifying the position signal by applying the compensation signal. This improves the accuracy of the angular position determination, which can then be used in wind turbine control functions like speed and torque control.

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Vertical wind turbine with a blade pitch motor that allows optimal blade angle adjustment for maximum efficiency and longevity. The blade pitch motor is mounted between the upper and lower blade sections, allowing symmetric torque distribution along the blade span. The pitch motor also supports the blade weight. This avoids external actuators and guys for blade angle control. The pitch motor can have absolute and relative position sensors. The turbine also has a compact transmission with planetary stages. The control calculates optimal blade angles based on wind speed and direction. This enables continuous, smoothest blade pitch control compared to discrete steps.

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Optimizing power generation in a wind farm by dynamically adjusting the operating parameters of individual wind turbines based on local wind shear conditions. The method involves measuring or predicting the vertical wind shear profile above the wind farm. This profile is then used to determine optimal adjustments to turbine settings like blade pitch, rotor speed, and yaw angle. These adjustments are made in real-time to optimize overall farm power production considering the non-standard wind shear profile and turbine interactions.

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Modular tower damper system for wind turbines that can easily adjust mass and natural frequency to effectively dampen oscillations. The system uses detachable liquid dampers attached to the tower sections. Each damper has a container filled with a specific amount of liquid that sets the damper's natural frequency. Multiple dampers can be installed on a tower section. The mass and frequency of each damper can be customized by choosing the liquid volume. This allows tailoring damping for different tower sizes and wind conditions.

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A wind turbine blade design with self-aligning pitch control that maximizes performance by automatically adjusting blade angle of attack in response to changing wind speeds. The blade has a spar stub that allows the airfoil section to rotate freely around its longitudinal axis. The axis is located forward of the airfoil's aerodynamic center. The blade is mass balanced around this axis. This configuration causes the blade to trim itself to the optimal angle of attack for lift vs. drag based on wind and rotational velocity. Any perturbations cause the blade to rotate back to trim.

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Optimizing the operation of wind turbines to maximize lifetime or energy production by automatically determining the best combination of control features based on user-selected targets. The optimization involves estimating the optimization parameter (lifetime, energy, power demand satisfaction) for different combinations of activated control features, and selecting the combination that best meets the target while considering boundary conditions. The method considers the impact of all possible feature combinations to find the optimal strategy.

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Operating wind turbines in high winds to reduce loads on the rotor and components like the tower and nacelle. When winds exceed the cut-out speed, the turbine idles with the blades feathered. Instead of just holding the blades fixed, the method involves moving them around a predetermined orientation. This alternating motion reduces loads compared to fixed feathering. By determining the optimal orientation for low loads, the turbine can operate safely in extreme winds while avoiding excessive loading.

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Controlling a wind turbine's yaw system to actively dampen rotor blade vibrations without restricting power output. The yaw system rotates the nacelle to align with the wind. By adding feedback control that depends on vibration mode data, the nacelle position is adjusted to suppress blade vibrations at specific frequencies. This active damping reduces vibrations without significant power loss, unlike passive measures like adding weight or stiffness. The feedback loop uses filters and amplification to dampen blade vibrations at frequencies corresponding to rotor speeds.

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A stability evaluation method and system for direct-drive wind turbine generators that allows online assessment and parameter adjustment to improve stability of the system. The method involves calculating the energy gradient at the wind turbine terminal using voltage, current, and angle measurements. A negative energy gradient indicates instability. The gradient is influenced by factors like PLL parameters, wind turbine current levels, and transmission line resistance. By understanding these relationships, the method proposes adjustments to critical parameters like PLL gains and wind turbine current limits to improve stability.

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Method to improve reactive power capability of wind turbines with doubly-fed induction generators (DFIGs) by intelligently managing generator speed in low wind conditions. The method involves transitioning to a secondary operational mode when certain parameters like rotor speed drop below thresholds. In this mode, the turbine increases generator speed at the expense of active power production. This allows maintaining reactive power capability in low wind conditions where DFIGs have limited reactive power capacity. The mode is selectable by command. The method balances maximizing active power versus reactive power capability.

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Vertical axis wind turbine rotor design to prevent blade stall and improve power generation by actively changing blade pitch as they enter stall regions. Sensors determine when blades are approaching stall angles based on fluid flow direction. Controllers provide blade pitch adjustments to prevent stall. Actuators alter blade pitch about their rotation axis using linked plates and rods. This local pitch change mitigates stall by adjusting blade angle as fluid conditions change.

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Operating wind turbines more efficiently by using real-time loading and travel data to estimate component damage accumulation and make adjustments to preventive maintenance and turbine operation. Instead of relying on simulated loading histories, the method involves generating actual cumulative loading histograms based on the measured or estimated loading and travel metrics during turbine operation. This allows accurate damage tracking and decision making based on the true fatigue experience of the components. The histograms are applied to life models to determine current damage levels and actions like shutdown, power reduction, or maintenance scheduling are implemented based on that.

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Vertical axis wind turbine rotor design to prevent blade stall and improve power generation. The rotor blades have active pitch control to avoid stall in unfavorable wind conditions. Sensors detect when blades are approaching stall regions based on wind direction. Controllers provide pitch adjustments for those blades to mitigate stall. Actuators physically alter the blade pitch angles as commanded. This active pitch control allows the blades to operate more efficiently across a wider range of wind speeds.

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Controlling wind turbines to rapidly shut down the rotor in response to blade liberation events. The method involves using estimated response signatures for different blade loss scenarios compared to actual sensor data during normal operation. If actual responses exceed the estimated values, it indicates blade loss. The turbine then initiates a rapid shutdown sequence that overrides normal limits, allows component damage, and accelerates rotor deceleration to protect the turbine.

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Wind turbine system with adjustable blades that optimize lift and drag forces at all wind speeds. The turbine has multiple rotating blade assemblies with pivoting sub-panels. The main rotor and blades rotate tangentially to the wind. The sub-panels can rotate independently during each rotation to continuously optimize the blade attack angle. This allows forward drag to be maximized and reverse drag minimized. The sub-panels also open/close to further reduce reverse drag. Sensors monitor wind, rotor speed, etc. to dynamically adjust the blade angles. This improves efficiency across wind speeds and prevents damage at high speeds.

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Neural network based control of wind turbines using permanent magnet synchronous generators (PMSG) that can efficiently and robustly track maximum power at varying wind speeds. The control involves training a neural network with wind speed and other parameters to output optimum rotor speed and maximum power. This network is then used to control the PMSG turbine based on real-time wind speed measurements, allowing the turbine to operate at maximum power in varying winds.

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Preventing stall in vertical axis wind turbines by actively controlling blade pitch to avoid stall regions. A sensor determines when blades are entering stall regions based on fluid flow direction. An actuator alters blade pitch to prevent stall. The sensor could be a vane indicating fluid flow direction with contact wires. The actuator could be a swashplate with input rods connecting to blades and blade pitch link rods. This allows modifying blade pitch as the turbine rotates to prevent stall in specific regions.

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Optimizing power production and load reduction in floating wind turbines by inclining the platform into the wind instead of keeping the tower vertical. This brings the rotor plane perpendicular to the wind direction, reducing energy loss and loads compared to a horizontal rotor. The platform inclination is determined based on wind speed and direction to find the optimal angle for that condition. This involves sensors, controllers, and ballast systems to incline the platform dynamically. It allows floating wind farms to operate at higher efficiencies and lower loads compared to fixed-foundation turbines.

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Controlling a wind turbine during grid faults to allow ride-through capability while preventing excessive mechanical loads. The technique involves dynamically adjusting the drivetrain damping settings based on the number of grid faults. For the first fault, the damping is tuned for power performance. For subsequent faults, the damping is adjusted to prioritize reducing mechanical loads. This allows the turbine to ride through multiple faults without tripping, while preventing excessive loads during prolonged fault sequences.

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Automatically tuned mass damper for wind turbine towers that can adapt its natural frequency to match the tower's oscillation frequency. This reduces tower movements and vibrations at critical wind speeds. The damper has a suspended pendulum structure with adjustable length, a sensor to measure tower movements, and a processor to optimize damper frequency in real time. It aims to prevent excessive tower oscillations by dynamically tuning the damper to match tower natural frequency.

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Method and apparatus for controlling renewable energy generation to provide constant frequency power at variable loads. It uses a voltage regulator with feedback from the load and feedforward from the renewable source to maintain output frequency. This allows maximizing baseload power from fluctuating renewables like wind and water. The regulator replaces mechanical speed converters in motor equivalent generators. It replaces variable voltage transformers in MG sets. The regulator connects between the renewable source and load, using a servo motor to adjust voltage for constant frequency.

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Device for damping vibrations in structures like wind turbine towers using two rotatably mounted elements with unequal radii to reduce vibrations. The inner element has a smaller radius than the outer element. This configuration allows the device to dampen vibrations without generating undesirable moments and parasitic vibrations that can occur with split elements. The device uses a controller to synchronize the rotations of the inner and outer elements based on real-time measurements of structure vibrations.

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A method to avoid tripping of wind turbines caused by excessive currents in the power electronic converter. The method involves temporarily increasing the generator speed above nominal if certain operational parameters indicate potential converter tripping. This reduces converter currents and avoids tripping. The generator speed is then lowered back to nominal once the parameters indicate converter operation is safe again.

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Control method for wind turbines in off-grid conditions that improves stability, power production, and wear in idling or self-sustaining modes. The method involves setting a fixed blade pitch angle in idle/self-sustaining modes and controlling the trim actuator to set a target rotor speed. This allows stable rotor speed and power production without continuously pitching the blades. The fixed pitch prevents blade pitch fluctuations that can destabilize the rotor, while the trim actuator adjusts the blade shape to match the desired speed.

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Modifying the natural frequency of a wind turbine tower to prevent resonance with blade passing and rotor frequencies. The modification involves suspending weights from the upper flange of the tower using rigid supports. By adding weights to the tower top, it increases the natural frequency. This provides a way to customize the tower frequency to separate it from the blade passing and rotor frequencies if they become too close due to variation in tower mass or foundation stiffness. It avoids the need for large design tolerances or safety margins for eigenfrequency separation.

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Dynamic wind turbine rotational speed control to prevent destructive forces on the turbine. It uses a speed control assembly with a rotating stop that limits blade rotation when wind speed is high. The stop attaches to the blade and rotates against it due to centrifugal forces. At a certain speed, the stop forces the blade to change pitch and reduce power, lowering the speed. This prevents excessive forces on the turbine when wind speeds increase. The stop's rotation is controlled by a torsion spring that engages when speed exceeds a threshold.

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Tunable mass damping device for wind turbines to reduce tower oscillations. The device has a connecting rod with a weighted assembly at the lower end and a top connecting assembly at the upper end. The top connecting assembly has an anti-rotation mechanism with a fixing plate attached to the tower and a movable plate connected to the rod. The plates are joined by connecting shafts with elastic layers between them. This allows the rod to rotate but compresses the elastic layers to dampen vibrations. The weighted assembly can be adjusted to change the center of gravity and tuned for optimal damping.

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Fast frequency response method for wind turbines to improve grid stability by utilizing inertial energy stored in the turbine rotor to quickly arrest frequency drops after grid disturbances. The method involves overproducing power from the turbine in response to grid frequency changes, which slows the rotor. A dynamic adaptive gain adjusts the overproduction level based on wind speed and penetration to optimize grid support. This prevents large frequency overshoots and dips compared to fixed gains.

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Operating a wind turbine's power converter to smoothly reduce power output during grid abnormalities without damaging the generator. The method involves separately controlling the line-side converter connected to the grid and the machine-side converter connected to the generator. When grid abnormalities require power reduction, the line-side converter reduces grid output. The machine-side converter reduces generator torque to match the lower grid power. If the generator power falls below grid power, excess power is dissipated in resistors. This allows separate, coordinated power setpoints for the grid and generator converters during grid abnormalities to prevent generator damage.

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Active wake control for floating wind farms to improve power generation and reduce loads on the turbines. It involves measuring wind fields at the turbines, determining wake properties, predicting wake propagation through the farm, and actively repositioning the turbines to minimize wake influence. This allows precise wake steering and reduction compared to fixed turbines. The system uses sensors, drones, LIDAR, and repositioning devices like boats, AUVs, and actuators to move and rotate turbines out of each other's wakes.

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Computer-implemented method for determining control parameters of a wind turbine or gas turbine when a component malfunctions. The method involves simulating turbine operation with the faulty component functioning at reduced capacity. By identifying the maximum power level possible given the component failure, improved control parameters can be derived to operate the turbine without further damage. The simulation uses a turbine model with input parameters like wind speed and component failures. This allows estimating the revised operating point that maximizes power without overloading the turbine.

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Vertical wind turbine design with optimized blade control and reduced energy losses for higher efficiency. The turbine operates in a partial load range of 3-12 m/s winds. Cam disks determine blade pitch angles continuously for smoother control. Blade-mounted sensors measure wind conditions close to the blades. The pitch motors have torsionally rigid rotors clamped to the blades. The motors have sealed bearings and housings for lubrication. The blade sections connect between hub bearings and the motor shaft. This allows optimal blade-motor transitions. The motors are enclosed in aerodynamic cases. A control device calculates setpoints based on wind sensors and adjusts the blades precisely.

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Ducted counter-rotating wind turbine with active actuators in the duct to efficiently harvest wind energy. The turbine has a duct with fixed stators and a central shaft. The rotary components like generators and blades have independent degrees of freedom. The blades can rotate and move axially. This allows blade position adjustment based on wind speed. The duct has a non-rotating nose cone to prevent vibrations. The turbine also has an active actuator in the duct that can move the blades relative to each other. This allows blades to cross without interference. The duct has a chassis to support the turbine and maintain coaxial alignment. The counter-rotating generators have separate inducer and induced sections.

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Method for controlling wind turbine power output to prevent excessive mechanical loading. It involves limiting power changes to avoid rapid torque fluctuations that can overload the wind turbine. The method uses setpoints, filters, and recovery times to gradually ramp power instead of abrupt steps. This reduces oscillations in the generator and rotor torque. The wind turbine also monitors oscillations and grid frequencies to guide power changes and prevent excitation.

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Operating a wind turbine in partial load conditions while minimizing rotor thrust and maximizing power production. The method involves limiting rotor thrust by increasing pitch angle and optimizing power production for the new angle. This balances reducing thrust versus power loss. The optimization is based on a ratio of power coefficient to thrust coefficient. The throttled pitch angles and corresponding power curves are predefined for various wind speeds. In full load, operate normally but with reduced speed and increased torque. This allows throttling at any wind speed below rated. The throttled curves are predefined for different pitch angles.

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Operating wind turbines based on actual load histories rather than simulations to optimize maintenance and lifespan. The method involves tracking component loading and travel metrics during turbine operation. Cumulative load histograms are generated from the actual data. A life model is applied to these histograms to determine actual component damage accumulation. Corrective actions are implemented based on the damage levels.

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Controlling a multirotor wind turbine to balance thrust and reduce loads when differences occur between the thrust acting on multiple rotors. The method involves monitoring thrust imbalance, identifying factors like wind shear or blade faults causing differences, and adjusting rotor speeds, blade pitch, yaw angle, etc. to counteract the imbalance and optimize power production. This reduces loads on the tower and other structures compared to just letting the imbalance persist.

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A wind turbine drive train with a modular, easily replaceable torque limiter to protect the generator from excessive loads. The torque limiter assembly has a torque limiter that disconnects the generator rotor from the torque shaft under high overload conditions to prevent damage. The assembly also includes separate torque and hub shafts connecting the rotor and generator rotor, allowing the torque limiter to isolate and service them separately.

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Pitch varying system for wind turbine blades that replaces the conventional gear-driven pitch variation mechanism to improve reliability, reduce maintenance costs, and enhance pitch control performance. The system uses segmented linear actuators instead of a central gear. This eliminates tooth wear and abrasion issues between the gear and bearing during pitch variation, particularly in small angle ranges. The segmented actuators clamp tracks on the blade pitch bearing to drive pitch change. A control method sequences the actuators based on the pitch angle range to optimize pitch variation.

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