Auto-Tuned Pendulum Damper for Tower Oscillation Control
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Solution Overview
Problem
Wind turbine towers experience severe oscillations due to vortex shedding, especially during construction, which can lead to significant deflections without adequate damping measures.
Innovation Solution
An automatically tuned mass damper system with a suspended pendulum structure, adjustable via sensors and tuning means to match the natural frequency of the tower, is secured to the tower structure to dampen oscillations effectively. The system can be attached before or during tower assembly and features a robust suspension in multiple wires, with real-time frequency adjustment to optimize damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rigid pendulum arrangement with adjustable length is used to damp tower motion, then the natural frequency of the pendulum can be changed to match tower frequency, but the device complexity increases due to adjustment mechanisms
Solution Approach 1:
The patent applies the dynamics principle by making the pendulum length adjustable through a winch mechanism that can be operated remotely or automatically. This allows the natural frequency of the pendulum to be dynamically changed to match the tower's natural frequency at different construction stages, resolving the contradiction between adaptability and complexity by providing adjustment capability through a relatively simple winch-based system rather than complex mechanical linkages
Solution Approach 2:
The patent applies parameter changes by modifying the physical parameter of pendulum length to change its natural frequency. By adjusting the length parameter through the winch mechanism, the system can adapt to different tower frequencies during construction without changing the fundamental structure of the damper, thus achieving adaptability with minimal complexity increase
2Reliability
If a pendulum arrangement suspending inside the tower interacts with friction members to dissipate energy, then damping effect is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent applies the taking out principle by removing the complex internal friction members and multi-component suspension system from within the tower structure. Instead, it uses a simpler pendulum damper that hangs freely and dissipates energy through air resistance and structural damping, achieving reliable damping effect without the complexity of internal friction mechanisms
Solution Approach 2:
The patent converts the previously harmful or unnecessary complexity of friction members into a benefit by relying on natural damping mechanisms. The pendulum utilizes air resistance and the inherent damping of the tower structure itself, turning what could be seen as insufficient damping into an advantage by eliminating the need for complex additional damping components
3Reliability
If multiple damper units are installed on the tower structure, then damping effectiveness is improved, but the weight and cost of the tower structure increase
Solution Approach 1:
The patent applies partial action by installing a single optimized damper unit rather than multiple units. The damper is designed with sufficient mass and appropriate natural frequency to provide effective damping on its own, avoiding the need for multiple lighter units. This resolves the contradiction by achieving adequate damping effectiveness with minimal weight addition through careful single-unit design rather than multiplying components
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 automatically tuned mass damper effectively reduces tower oscillations by optimizing the natural frequency of the pendulum structure to match the tower's frequency, providing robust damping and preventing severe deflections, even at critical wind speeds.
Implementation Method 1
a suspended pendulum structure (501)
Implementation Method 2
a suspended pendulum structure (501)
Implementation Method 3
a sensor (521) adapted for measuring movements of the tower structure
Implementation Method 4
tuning means (505) configured for adjusting a natural frequency of the suspended pendulum structure (501) in response to measured movements of the tower structure
Implementation Method 5
adjusting the length of the free wire sections (503)
Data Source
Figure 1
Figure 2~2b
Figure 3
AI summary
The present invention relates to a damper unit for damping oscillations of a tower structure when secured thereto, the damper unit comprising a damper unit structure adapted for attachment to the tower structure, a pendulum structure, a suspension arrangement for suspending the pendulum structure from the damper unit structure such that the pendulum structure is allowed to displace from a neutral position for the pendulum structure, the suspension arrangement comprising one or more wires for suspending the pendulum structure, a sensor adapted for measuring oscillations of the tower structure, and tuning means configured for adjusting the natural frequency of the suspended pendulum structure in response to measured oscillations of the tower structure. The present invention further relates to an associated method.