Wind Turbine Yaw Control with Dual-Loop Filtering
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Solution Overview
Problem
Modern wind turbine yaw control systems face challenges in accurately tracking wind direction due to filtering methods that reduce wear but compromise tracking accuracy, leading to increased wear on components and errors during steady-state conditions.
Innovation Solution
A yaw control system that incorporates a controller using a low-pass filtered signal for relative wind direction and a second feedback signal indicative of the yaw actuator's real-time activity, with filters having equal or differing time constants to compensate for filtering delays, allowing for improved accuracy and reduced wear by optimizing control algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a low pass filter is applied to the wind direction signal to reduce yaw actuator activation and minimize wear, then the wear on yaw components is reduced, but the tracking accuracy of wind direction deteriorates
Solution Approach 1:
The control system is divided into two independent control loops: an outer loop that uses a low-pass filtered wind direction signal to determine when yaw activation is needed (reducing wear), and an inner loop that uses an unfiltered or less-filtered signal to maintain accurate tracking. This segmentation allows each loop to optimize for its specific function without compromising the other.
Solution Approach 2:
A secondary control loop acts as an intermediary between the filtered wind direction signal and the yaw actuator. This inner loop compensates for the delays introduced by filtering by responding to more immediate signal changes, thereby maintaining tracking accuracy while the outer loop manages actuator activation frequency to minimize wear.
2Object-generated harmful factors
If filtering is applied to reduce yaw actuator wear, then wear is minimized, but yaw error increases during steady-state conditions
Solution Approach 1:
The system implements feedback control in both loops. The outer loop feedback uses the filtered signal to determine when yaw activation should occur, while the inner loop feedback uses a less-filtered signal to correct tracking errors in real-time. This dual-feedback mechanism ensures that wear is reduced while maintaining high yaw heading accuracy during steady-state operation.
Solution Approach 2:
The system changes the filtering parameters (time constants) differently for the two control loops. The outer loop uses a longer time constant to reduce activation frequency and wear, while the inner loop uses a shorter time constant to maintain responsiveness and accuracy. This parameter differentiation allows simultaneous optimization of both wear reduction and tracking precision.
3Productivity
If filtering time constant is increased to reduce wear, then actuator activation frequency decreases, but response time to wind direction changes increases
Solution Approach 1:
The response time requirement is segmented between two loops: the outer loop uses a long time constant to determine activation timing (optimizing efficiency), while the inner loop uses a short time constant to execute rapid corrections (optimizing response speed). This segmentation allows the system to be both efficient and responsive.
Solution Approach 2:
The outer loop performs preliminary action by using the long-time-constant filtered signal to determine when yaw activation should occur, reducing unnecessary activations and improving efficiency. The inner loop then performs the actual rapid response to track wind direction changes accurately, ensuring fast response without compromising overall system efficiency.
Data Source
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AI summary
A wind turbine including yaw control comprising a controller receiving an input signal, and providing an output control signal to a yaw actuator. The input signal to the controller is based on: a first feedback signal that is indicative of the relative wind direction determined with respect to the wind turbine, wherein the first feedback signal is filtered with a first low pass filter; and a second feedback signal that is indicative of the activity of the yaw actuator. The control technique of the invention significantly improves the ability of a yaw system to maintain a zero degree yaw error during steady state wind conditions, or in other words to maintain an accurate heading of the nacelle pointing into the wind, as well as reducing the maximum yaw error experienced during yaw system activation.