Multi-rotor turbine in-plane vibration damping
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Solution Overview
Problem
Multi-rotor wind turbines face increased fatigue and reduced lifespan due to side-to-side motion, which existing dampening techniques do not adequately address, especially considering the unique angled trajectories of rotors mounted laterally on arms extending from a common tower.
Innovation Solution
A system comprising a controller that uses sensors to generate signals for in-plane motion, determining pitch offsets to produce rotating or oscillating forces in the rotor plane, accounting for both lateral and vertical displacements, thereby counteracting side-to-side motion by adjusting blade pitch angles to optimize dampening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple rotors are mounted laterally on arms extending from a common tower, then reduced component, installation, and transportation costs are achieved, but side-to-side motion increases fatigue and reduces lifespan
Solution Approach 1:
The system uses active vibration control by generating counter-vibrations through blade pitch adjustments. The controller produces an in-plane force with a phase dependent on the rotor assembly trajectory to counteract the side-to-side motion, effectively using mechanical vibration principles to reduce fatigue on the tower structure while maintaining the multi-rotor configuration
Solution Approach 2:
The system dynamically changes the pitch angle parameter of the blades based on detected in-plane motion. By adjusting the pitch offsets in real-time according to the rotor assembly's trajectory, the system modifies aerodynamic forces to counteract side-to-side motion, thereby reducing fatigue without changing the physical structure
2Reliability
If existing side-to-side tower dampening techniques are applied to multi-rotor turbines, then some dampening effect is achieved, but the unique angled trajectories of laterally mounted rotors are not adequately addressed
Solution Approach 1:
The system applies different pitch offsets to individual blades based on their specific position and the rotor assembly's angled trajectory. Rather than uniform dampening, the control strategy tailors the in-plane force generation to the local conditions of each rotor assembly's motion, making the dampening effective for the unique geometry of laterally mounted rotors
Solution Approach 2:
The system uses dynamic pitch adjustment rather than static dampening. The pitch offsets are continuously modified based on real-time detection of in-plane motion and the rotor assembly's trajectory, allowing the system to adapt to the dynamic angled paths that laterally mounted rotors follow during side-to-side motion
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces moment fatigue in multi-rotor wind turbines by generating forces that counteract side-to-side motion, extending the lifespan and operational efficiency of the turbines.
Implementation Method 1
determine pitch offsets for controlling pitch angles of the plurality of blades of the first rotor assembly to produce an in-plane force in the form of a rotating or an oscillating force in the rotor plane
Data Source
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AI summary
Embodiments herein describe in-plane vibration damping techniques for MR turbines. The MR turbines can include arms that extend from a common tower and support multiple rotors. Because the rotors are disposed laterally away from the tower, side-to-side motion of the tower causes the rotors to have an angled trajectory that includes both lateral and vertical displacement. In addition, a rotor disposed on one side of the tower in MR turbine can have a very different trajectory than a rotor disposed on the opposite side of the tower. To account for the vertical displacement and the different trajectories, in one embodiment, a controller can use different phase offsets for each rotor when calculating pitch offsets for performing in-plane vibration damping. In another embodiment, the controller can use both the lateral and vertical accelerations of the rotors to identify the pitch offsets for the rotors to perform in-plane vibration damping.