Generator DC Link Damping for Drive Shaft Torsional Oscillation
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Solution Overview
Problem
Existing damping systems for electrical generators, particularly in aircraft applications, face challenges such as space and weight constraints, inability to dynamically adjust to varying torque conditions, and power loss due to mechanical and electrical dampers.
Innovation Solution
A damping system that integrates a feedforward circuit with a ripple sensor to adjust the DC link voltage of an electrical generator, thereby damping torsional oscillations in the drive shaft. This system uses a combination of load resistance and capacitance to absorb or reflect unwanted ripple power, optimizing damping power in phase with the ripple power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a mechanical damper is used to reduce torsional oscillation, then the drive shaft oscillation is reduced, but weight and volume increase
Solution Approach 1:
The patent replaces the mechanical damper with an electrical damping system that uses the generator's electrical load to absorb torsional oscillations. The electrical damper converts mechanical oscillation energy into electrical energy, which is then dissipated through resistive loading, eliminating the need for heavy mechanical damping components.
Solution Approach 2:
The patent extracts the damping function from a separate mechanical component and integrates it into the electrical system. By taking out the mechanical damper and replacing it with electrical loading, the system achieves damping without the associated weight and volume penalties.
2Stability of the object's composition
If a mechanical damper is used to reduce torsional oscillation, then the drive shaft oscillation is reduced, but device volume increases
Solution Approach 1:
The patent replaces the mechanical damper with an electrical damping system that uses the generator's electrical load to absorb torsional oscillations. The electrical damper converts mechanical oscillation energy into electrical energy, which is then dissipated through resistive loading, eliminating the need for bulky mechanical damping components.
Solution Approach 2:
The electrical loading system serves dual purposes: it provides the necessary electrical load for power generation and simultaneously functions as a damper for torsional oscillations. This multi-functionality eliminates the need for separate damping components, reducing overall system volume.
3Stability of the object's composition
If a capacitor is used to filter rectified output, then voltage fluctuations are reduced, but power loss increases
Solution Approach 1:
The patent employs dynamic electrical loading that actively adjusts to varying torque conditions and oscillation amplitudes. Unlike static capacitive filtering, the electrical damper dynamically modulates the load to optimize damping effectiveness while minimizing power loss, adapting to real-time operating conditions.
Solution Approach 2:
The system uses feedback control to monitor torque oscillations and adjust the electrical load accordingly. This feedback mechanism ensures that damping power is applied only when needed, reducing unnecessary power loss while maintaining voltage stability and oscillation control.
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 proposed damping system effectively reduces or eliminates torsional oscillations in the drive shaft by dynamically adjusting the DC link voltage, thereby minimizing power loss and accommodating varying torque conditions without the need for additional space or weight.
Implementation Method 1
an electrical damper that absorbs ripple in the mechanical torque
Implementation Method 2
use a capacitor to filter a rectified output of the generator that may reactively absorb fluctuations in the electrical load
Implementation Method 3
a damper including a damping converter and resistor coupled to a DC output of the damping converter
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
A damping system can include a sensor disposed to measure an amplitude of a speed ripple of a drive shaft of a generator, and can include a feedforward circuit connected to the sensor and to the generator. The feedforward circuit can determine a phase angle formed by a load resistance and a load capacitance driven by the generator, calculate a voltage signal value based on the amplitude and the phase angle, and can adjust a DC link voltage provided by the generator and across the load resistance according to the voltage signal value.