Traveling Wave Tube Cathode Current Control for Satellite Power Efficiency

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Solution Overview

Problem

Traveling wave tube modules in communications satellites face inefficiencies in power management, particularly when operating in idle mode, leading to excessive power loss and thermal issues in the last collector stage, which complicates design and increases cost.

Innovation Solution

A method that dynamically adjusts the cathode current of the traveling wave tube between amplifier and idle modes by monitoring and evaluating measured variables, allowing for optimal efficiency in both modes without the need for additional collector stages, thereby reducing power loss and thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If an additional collector stage is introduced to reduce power dissipation in the last stage during idle mode, then power loss is reduced, but device complexity and weight increase

Engineering Contradiction:
Improvepower loss in collector stageVSAvoidcomplexity of power supply and traveling-wave tube
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent changes the operating parameters of the existing collector stages by dynamically adjusting the cathode current between idle mode and amplifier mode. This allows the single-stage collector to operate efficiently in both modes without adding hardware complexity, resolving the contradiction between reducing power loss and maintaining device simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic control of the cathode current based on operational mode detection. By switching between idle current and operating current values, the system adapts the power dissipation characteristics of the collector stage to match the current operational requirements, eliminating the need for additional collector stages while maintaining thermal safety

Inventive Principle:
Principle #15Dynamics

2Temperature

If the voltage at the last collector stage is set to a lower value to limit power loss during idle mode, then thermal safety is improved, but efficiency during saturation operation decreases

Engineering Contradiction:
Improvethermal safety of collector stageVSAvoidefficiency of traveling wave tube
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the cathode current based on operational mode rather than using fixed voltage settings. During idle mode, reduced current limits power dissipation and protects the collector thermally. During amplifier mode, full current restores efficiency. This dynamic adaptation resolves the contradiction between thermal safety and operational efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the cathode current parameter dynamically based on detected operational conditions. By monitoring whether the traveling wave tube is saturated or not, the system adjusts the cathode current to optimize both thermal performance and efficiency at different operating points

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the cathode current is reduced in idle mode to reduce power loss, then power loss is reduced, but the traveling wave tube cannot achieve optimal efficiency when activated

Engineering Contradiction:
Improvepower loss in idle modeVSAvoidefficiency of signal amplification
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system implements dynamic cathode current control that switches between idle current and operating current based on detected signal conditions. This ensures minimal power consumption during idle mode while restoring full efficiency when amplification is required, resolving the contradiction between idle power loss and amplification productivity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs periodic monitoring of operational parameters (such as input signal presence or power consumption levels) to determine when to switch between idle and amplifier modes. This periodic detection and response mechanism ensures the cathode current is optimized for the current operational state, balancing power loss reduction with maintained productivity

Inventive Principle:
Principle #19Periodic action

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

This approach allows for efficient operation in both amplifier and idle modes, reducing power loss by up to 50% in the last collector element, maintaining thermal safety without the need for additional collector stages, thus creating a lightweight and cost-effective traveling wave tube module.

Implementation Method 1

In a traveling wave tube, a high frequency signal is amplified by directing an electron beam past a generally helical conductor through which the high frequency signal flows. With a suitable design of the conductor and the electron beam, energy can be transferred from the electron beam to the high-frequency signal.

Methodology Applied
Scientific EffectElectron beam energy transfer: Electron Beam

Data Source

PatentEP2775612B1Method for operating a travelling-wave tube module
Publication Date: 2018.07.18 TESAT SPACECOM GMBH & CO KG
  • EP2775612B1 patent drawingFigure 1~2
  • EP2775612B1 patent drawingFigure 3~4

AI summary

The method involves receiving a radio frequency signal (22) from an antenna (12) of a satellite (10). A determination is made whether the radio frequency signal is amplified. The cathode current of a traveling wave tube (30) is increased to a predetermined value, if the radio frequency signal is amplified. The radio frequency signal is amplified with the traveling wave tube. The cathode current is reduced to a predetermined rest value, if the radio frequency signal is not amplified. An independent claim is included for a traveling wave tube module.