Wind Turbine Yaw Control with Dynamic Threshold
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Solution Overview
Problem
Conventional yaw control logic for wind turbine generator systems fails to effectively reduce wind direction deviation when wind direction changes gradually over a long time, often resulting in increased mechanical wear due to excessive yaw rotations and inefficient system performance.
Innovation Solution
A yaw control technique that performs yaw rotations based on two conditions: one for high randomness in wind direction changes and another for gradual changes over time, using threshold values and duration settings to minimize rotations while maintaining efficiency, and includes a control logic that reverses wind direction deviation signs and adjusts threshold values dynamically to catch transitional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional yaw control logic with fixed threshold is used, then the number of yaw rotations is reduced, but the average wind direction deviation is not reduced when wind direction changes gradually over time
Solution Approach 1:
The patent applies dynamics by making the threshold value time-dependent rather than fixed. The threshold θ(t) increases over time according to a monotonic non-decreasing function, allowing the control system to adapt to gradually changing wind directions. This dynamic threshold enables the system to tolerate larger deviations during transitional periods while maintaining strict control during stable periods, thereby improving both reliability and productivity.
Solution Approach 2:
The patent changes the parameter of the threshold value from a constant to a time-varying parameter. By making the threshold θ(t) a function of time that monotonically increases, the system can accommodate gradual wind direction changes without triggering unnecessary yaw rotations, thus maintaining system efficiency while ensuring proper wind alignment when needed.
2Reliability
If frequent yaw rotations are performed to maintain zero wind direction deviation, then wind direction alignment is improved, but mechanical wear of rotation and braking mechanisms increases
Solution Approach 1:
The dynamic threshold θ(t) allows the system to differentiate between temporary deviations and persistent misalignments. By increasing the threshold over time, the system avoids reacting to transient wind direction changes, thereby reducing unnecessary yaw rotations and mechanical wear while still correcting sustained deviations that affect performance.
Solution Approach 2:
The control apparatus continuously monitors wind direction deviation and compares it against the time-varying threshold θ(t). This feedback mechanism ensures that yaw rotations are only performed when the deviation persists beyond the dynamic threshold, optimizing the balance between maintaining alignment and reducing mechanical wear.
3Device complexity
If a fixed threshold value is used for yaw control, then control logic is simple, but the system cannot catch transitional changes in wind direction at appropriate timing
Solution Approach 1:
The time-dependent threshold θ(t) enables the system to be more responsive during early transitional periods when the threshold is lower, while becoming more tolerant during later stages when the threshold has increased. This dynamic behavior allows the system to catch transitional changes at appropriate timings without requiring complex predictive algorithms.
Solution Approach 2:
By pre-defining the threshold function θ(t) to increase over time, the system prepares in advance for gradual wind direction changes. This preliminary configuration allows the control logic to automatically adapt to changing conditions without requiring real-time complex calculations, thus reducing response time while maintaining simplicity.
Data Source
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AI summary
A wind turbine generator system is provided with a nacelle supporting a wind turbine rotor, a nacelle rotation mechanism, an anemometer, and a control apparatus controlling the nacelle rotation mechanism. Said control apparatus calculates the wind direction deviation from the wind direction measured by the anemometer and the direction of the wind turbine rotor. Said control apparatus performs a yaw rotation of the nacelle by the nacelle rotation mechanism when any of conditions (1) and (2) is satisfied; the condition (1) is a condition under which a state where the absolute value of said wind direction deviation is equal to or more than a first threshold value continues for a first duration predetermined, and the condition (2) is a condition under which a state where the absolute value of said wind direction deviation is equal to or more than a second threshold value larger than said first threshold value continues for a second duration shorter than said first duration.