Eddy Current Torsional Damper for Generator Rotor
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Solution Overview
Problem
Generators experience torsional instability due to oscillations in rotational speed, leading to fatigue failure of mechanical components, and existing damping systems either compromise transient performance or require complex and costly control hardware, with mechanical spring-mass damper systems being ineffective across wide frequency bands.
Innovation Solution
A torsional damper system using an eddy current coupling with a flywheel and permanent magnets to provide passive mechanical damping, where the flywheel is rotated synchronously with the generator rotor, utilizing an eddy current conducting ring to absorb and release inertia and damp rotational oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If active damping systems are used to damp torsional oscillations, then torsional stability is improved, but generator transient performance deteriorates and control complexity increases
Solution Approach 1:
The patent replaces active electronic control systems with a passive mechanical eddy current damping system. The eddy current damper uses electromagnetic induction to generate damping forces without requiring external power or control electronics, thereby eliminating control hardware complexity while maintaining torsional stability.
Solution Approach 2:
The eddy current damper is self-regulating and requires no external control input. The damping force automatically adjusts based on the relative speed between the rotor and flywheel, providing adaptive torsional damping without control logic or sensors.
2Stability of the object's composition
If mechanical spring-mass damper systems are used, then torsional damping is provided, but effectiveness across wide frequency bands is reduced
Solution Approach 1:
The eddy current damper provides continuously variable damping characteristics through the eddy current conducting ring's interaction with the magnetic field. The damping force naturally adapts to different oscillation frequencies and amplitudes, providing broad frequency band effectiveness unlike fixed-tuning spring-mass systems.
3Device complexity
If generators are directly coupled to gas turbine engines, then mechanical simplicity is improved, but torsional loads increase and mechanical damping is reduced
Solution Approach 1:
The eddy current damper acts as an intermediary element between the rotor and flywheel, providing mechanical damping through electromagnetic forces. This intermediary damping mechanism reduces torsional loads while maintaining the direct coupling configuration, avoiding the need for complex gear systems.
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
Effectively reduces torsional oscillations across a broad frequency band, minimizing stress and fatigue in generator components without the need for active control systems, thus prolonging component life and reducing maintenance needs.
Implementation Method 1
The eddy current coupling can use permanent magnets and an eddy current conducting ring of material positioned in the magnetic fields of the permanent magnets to provide engagement
Implementation Method 2
an array of permanent magnets mounted to the flywheel and a ring of eddy current conducting material positioned in magnetic fields of the permanent magnets
Implementation Method 3
the flywheel is rotated synchronously with the generator rotor, utilizing an eddy current conducting ring to absorb and release inertia and damp rotational oscillations
Data Source
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AI summary
A generator rotor torsional damper system includes a prime mover for generating rotational force, a generator stator, a generator rotor (30) rotatably supported relative to the generator stator and configured to receive a rotational force input from the prime mover, a flywheel (56) rotationally supported relative to the generator rotor by bearings (58), and an eddy current coupling operably connected between the flywheel and the generator rotor such that rotation of the generator rotor induces rotation of the flywheel in a common rotational direction through engagement by the eddy current coupling.