Ion Thruster Grid Clear Circuits for Short Circuit Removal

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Solution Overview

Problem

Existing ion thruster grid clear circuits are limited in effectively addressing short circuits caused by material deposits, which can lead to reduced thruster effectiveness and operational downtime, as they often require high energy and have limited capability in clearing short circuits at high voltages.

Innovation Solution

The implementation of a dual-grid clear circuit system, comprising a low-voltage grid clear circuit and a high-voltage grid clear circuit, where the high-voltage circuit applies a high voltage to initiate an arc, enabling the low-voltage circuit to direct higher currents and clear deposits effectively, even at high-voltage short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single high-voltage grid clear circuit is used to clear short circuits, then the ability to clear high-voltage shorts is improved, but the energy consumption increases and the circuit complexity increases

Engineering Contradiction:

Improveability to clear high-voltage shortsVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The grid clear circuit is divided into two separate circuits: a low-voltage grid clear circuit (first circuit) and a high-voltage grid clear circuit (second circuit). The controller selectively activates the appropriate circuit based on the detected short circuit voltage level, avoiding the energy waste of always operating a high-voltage circuit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the voltage parameter dynamically by selecting different clear circuits based on the detected short circuit conditions. The controller detects whether the short circuit occurs at high voltage or low voltage and activates the corresponding circuit, optimizing energy usage while maintaining clearing effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a single high-voltage grid clear circuit is used to clear short circuits, then the ability to clear high-voltage shorts is improved, but the device complexity increases

Engineering Contradiction:

Improveability to clear high-voltage shortsVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Device complexity

If prior art grid clear circuits are used, then the structure is simple, but the capability to clear short circuits at high voltages is limited

Engineering Contradiction:

Improvecircuit structure simplicityVSAvoidcapability to clear short circuits

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The system achieves multi-functionality by incorporating both low-voltage and high-voltage grid clear circuits, allowing it to handle both low-voltage and high-voltage short circuit conditions. The controller selectively activates the appropriate circuit based on the detected voltage level, providing universal clearing capability across different operating conditions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If grid clear circuits are not used, then the energy consumption is low, but the thruster service life is reduced due to short circuits

Engineering Contradiction:

Improveenergy consumptionVSAvoidthruster service life

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The grid clear circuits enable the thruster to self-diagnose and self-repair short circuit conditions. The controller detects shorts and automatically activates the appropriate clear circuit, allowing the thruster to clear its own faults without external intervention, thereby extending service life while minimizing unnecessary energy consumption.

Inventive Principle:

Principle #25Self-service

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 dual-circuit approach enhances the ability to clear a wider variety of short circuit conditions, reducing energy requirements, extending thruster service life, and minimizing maintenance costs by effectively removing deposits and preventing short circuits.

Implementation Method 1

the high-voltage circuit applies a high voltage to initiate an arc

Methodology Applied

Scientific EffectArc discharge: Electric Arc

Implementation Method 2

the low-voltage circuit to direct higher currents and clear deposits effectively

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2722278B1Ion propulsion systems comprising thruster grid clear circuits and methods to clear thruster grids

Publication Date: 2019.09.18 THE BOEING CO

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AI summary

Thruster grid clear circuits and methods to clear thruster grids (206, 208) are disclosed. An example apparatus includes a low voltage grid clear circuit (212) to apply first energy to a grid at a first voltage, and a high voltage grid clear (214) circuit to detect a failure of the applied energy to clear a short circuit condition of the grid and to apply second energy to the grid at a second voltage higher than the first voltage.