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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