Wind Turbine Rotor Oscillation for Load Reduction
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Solution Overview
Problem
Wind turbines experience high mechanical loads during idling in high winds, which can lead to increased stress on components and reduced lifespan.
Innovation Solution
The method involves operating the rotor to move around a predefined desired angular orientation with respect to the axis of rotation in an alternating fashion when the generator is not in a power generating mode, thereby reducing mechanical loads on wind turbine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor is allowed to rotate freely during idling in high winds, then the wind turbine can avoid flutter and reduce some loads, but the mechanical loads on components become comparatively high during prolonged storms
Solution Approach 1:
The rotor orientation is changed from a static fixed position to a dynamic alternating motion around a desired angular orientation. The rotor moves back and forth in a controlled manner rather than rotating freely or staying fixed, adapting its position dynamically to reduce mechanical loads on components during idling in high winds
Solution Approach 2:
The rotor is operated to move around a predefined desired angular orientation in an alternating fashion, creating a periodic motion pattern. This oscillating movement replaces the conventional free rotation or fixed position, systematically varying the rotor orientation to minimize stress on structural components during prolonged storm conditions
2Reliability
If the rotor blades are positioned at fixed angular positions (feather position) to limit wind loads, then the wind turbine can operate safely in high winds, but the mechanical loads on components remain high during prolonged storms
Solution Approach 1:
The rotor transitions from a static fixed angular position to a dynamic alternating motion around a desired angular orientation. This dynamic positioning allows the system to maintain safety margins while reducing sustained mechanical loads on components during prolonged storm conditions
Solution Approach 2:
Instead of maintaining a fixed feather position, the rotor is operated to move periodically around the desired angular orientation. This periodic motion distributes the mechanical stress over time and across different angular positions, reducing the cumulative load on components during extended high-wind events
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A method (1000-1004) for operating a wind turbine (10, 11) including a drive train (64) including a generator (42) and a rotor shaft (44) mechanically connected with the generator (42) and having an axis (30) of rotation, and a rotor (18) having rotor blades (22-22c). The rotor (18) is mechanically connected with the rotor shaft (44) and rotatable about the axis (30) of rotation. The method (1000-1004) includes determining (1100) that the generator (42) is not operating in a power generating mode, and operating (1200) the rotor (18) to move around a predefined desired angular orientation (αdes) with respect to the axis (30) of rotation in an alternating fashion.