Eddy Current Damper for Wind Turbine Pendulum Vibration
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Solution Overview
Problem
Existing vibration absorber systems for tall, slender structures like wind turbines face challenges in achieving low-wear, temperature-independent, and linear damping while minimizing material costs and maintaining effectiveness over time.
Innovation Solution
An eddy current damper system is employed, comprising a magnetic field generating device and a conductor arrangement with a sliding interface, where the magnetic field is moved relative to the conductor to induce eddy currents, converting kinetic energy into heat and providing damping that is proportional to the pendulum's speed, with a focus on minimizing friction and maintaining a constant air gap for efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction damping or elastomer damping is used in the vibration absorber, then damping effect is achieved, but wear and aging occur reducing reliability over time
Solution Approach 1:
The patent replaces mechanical friction damping and elastomer damping with electromagnetic eddy current damping. The damper comprises a magnetic field generating device (permanent magnets or electromagnets) and a conductor arrangement that generates eddy currents when the pendulum oscillates, creating a magnetic drag force for damping without mechanical contact, thereby eliminating wear and aging issues
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the moving pendulum and the stationary damper structure. The magnetic field couples the motion of the pendulum to the conductor, transferring energy through electromagnetic induction rather than direct mechanical contact, which prevents wear while maintaining effective damping
2Stability of the object's composition
If conventional dampers are used, then damping is provided, but temperature dependence and non-linearity affect damping consistency
Solution Approach 1:
The patent changes the damping mechanism from material-based (friction, elastomer properties) to field-based (electromagnetic). The eddy current damping force depends on the square of the velocity and the magnetic field strength, providing a predictable, linear relationship that is independent of temperature variations and aging, ensuring consistent damping performance
Solution Approach 2:
By replacing mechanical damping materials with electromagnetic fields, the system eliminates temperature-dependent material properties. The magnetic field strength and conductor characteristics remain stable across temperature ranges, providing consistent damping behavior in varying environmental conditions
3Reliability
If the pendulum mass is increased to improve damping, then vibration reduction improves, but the weight and material costs increase
Solution Approach 1:
The electromagnetic damping mechanism provides high damping forces without requiring large pendulum masses. The eddy current braking effect generates significant resistive forces that can effectively damp vibrations even with moderate mass, reducing the trade-off between damping effectiveness and weight
Solution Approach 2:
The damping force from eddy currents is velocity-dependent, providing maximum damping when the pendulum moves fastest (at the extremes of its oscillation). This periodic damping action is highly efficient at controlling vibrations without requiring excessive mass, as the damping force naturally peaks when most needed
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 eddy current damper system effectively reduces vibrations by converting kinetic energy into heat, offering a low-wear, temperature-independent, and linear damping solution that maintains performance over the entire oscillation range with minimal maintenance, suitable for both passive and active vibration control systems.
Implementation Method 1
the relative movement of the conductive plate and magnet arrangement can also generate eddy currents here to dampen vibrations
Implementation Method 2
an eddy current damper uses electrical currents that are induced by a magnetic field that is moved relative to another element when the pendulum moves
Implementation Method 3
These eddy currents then generate heat. The energy thus withdrawn from the oscillating movement leads to the damping of the oscillation
Data Source
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AI summary
The oscillation damper arrangement has a pendulum (6) which is hung at the high slender building. A damper mass (7) and a damper unit (8) are suspended in the pendulum. The damper unit is designed as an eddy current damper. The eddy current damper is provided with the magnetic field generating units (12,22) and a conductor arrangement (18). The conductor plate of conductor arrangement is arranged in parallel direction of movement of the pendulum, and is made of aluminum, copper and alloy.