Ion Engine Frequency Generator Resonance Tracking Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Ion engines face challenges in maintaining resonant frequency stability due to plasma ignition, leading to potential plasma extinction or failure to ignite, caused by changes in the resonant frequency of the resonant circuit.

Innovation Solution

A control device for a frequency generator that acquires and processes voltage and current waveforms to determine temporal offsets between rising edges, generating switching signals to adjust the switch-on time based on the imbalance between positive and negative offsets, ensuring operation at resonant frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the resonant circuit is operated at its resonant frequency, then power losses are minimized and plasma ignition is maintained, but the resonant frequency changes when plasma is ignited, causing the circuit to deviate from resonance

Engineering Contradiction:
Improvepower lossesVSAvoidresonant frequency stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The control device continuously monitors the voltage and current waveforms of the resonant circuit, determines the temporal offset between them, and adjusts the switching signal based on this feedback to maintain resonance despite plasma ignition changes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system automatically detects and corrects its own frequency deviations by analyzing the temporal offset between voltage and current waveforms and self-adjusting the switching signal without external intervention

Inventive Principle:
Principle #25Self-service

2Reliability

If the resonant frequency is not tracked accurately, then the frequency generator cannot adapt to plasma ignition changes, but complex frequency tracking mechanisms increase device complexity

Engineering Contradiction:
Improveplasma ignition reliabilityVSAvoidfrequency control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or electronic frequency tuning mechanisms with a digital processing approach that uses simple waveform sampling and temporal offset calculation to achieve accurate frequency tracking

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control device changes the switching signal parameters (timing and duration) based on the detected temporal offset, allowing the system to adapt to frequency changes without adding complex hardware

Inventive Principle:
Principle #35Parameter changes

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 precise adjustment of the resonant frequency, minimizing power losses and maintaining plasma ignition, thereby enhancing the efficiency and reliability of ion engines.

Implementation Method 1

In the so-called radio-frequency ion engine, the ions are generated by means of inductive coupling of a high-frequency signal

Methodology Applied
Scientific EffectInductive coupling: Electromagnetic Induction

Implementation Method 2

In order to generate this high-frequency signal, usually a resonant circuit or frequency generator is used

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3386275B1Frequency control for a frequency generator of an ion engine
Publication Date: 2021.12.15 TESAT SPACECOM GMBH & CO KG
  • EP3386275B1 patent drawingFigure 1~2
  • EP3386275B1 patent drawingFigure 3~4

AI summary

A control device (100) for a frequency generator (50) is provided. The control device (100) comprises an acquiring unit (110) and a processing unit (120). The acquiring unit (110) is configured to acquire a voltage course and a current course of a determinable number of periods of the frequency generator (50) and to transmit these to the processing unit (120). The processing unit (120) is configured to determine a temporal offset (Δt1) between a rising edge of the current course and a rising edge of the voltage course for each period of the determinable number of periods, and further to determine if this temporal offset (Δt1) is positive or negative. The processing unit is furthermore configured to determine a difference between the number of periods with positive temporal offset and the number of periods with negative temporal offset within the determinable number of periods, and to generate and adapt a switching signal for a switch-on time of the voltage course if the number of periods with positive temporal offset differs from the number of periods with negative temporal offset.