Variable-Frequency Plasma Ignition for Impedance Transition Control

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Solution Overview

Problem

The ignition and maintenance of atmospheric pressure plasmas are challenging due to high impedance transitions during power coupling, leading to equipment failure from current surges and impedance changes.

Innovation Solution

A system utilizing a variable frequency AC power source, transformer, and a programmed microprocessor to control power frequency for plasma ignition and maintenance, employing an asymmetric ballast transformer with a secondary primary winding to manage impedance transitions and prevent equipment damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power is coupled into atmospheric pressure plasma during ignition, then plasma is ignited and maintained, but current surges and impedance transitions cause equipment failure

Engineering Contradiction:
Improveequipment reliabilityVSAvoidcurrent surges and impedance transitions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the operating frequency of the AC power source during plasma ignition and maintenance. The microprocessor monitors plasma conditions and varies the frequency to track the resonant frequency of the plasma load, ensuring optimal power coupling while avoiding current surges and impedance transitions that would damage equipment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback control where the microprocessor continuously monitors plasma ignition status and impedance characteristics, then adjusts the power source frequency accordingly. This closed-loop control prevents harmful current surges by detecting plasma formation and adapting the driving frequency to maintain stable operation.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If variable frequency control is implemented, then plasma ignition and maintenance is achieved, but system complexity increases

Engineering Contradiction:
Improveplasma ignition and maintenance capabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The microprocessor serves multiple functions: it controls the variable frequency power source, monitors plasma ignition status, detects impedance changes, and adjusts operating parameters. This multi-functional approach consolidates control logic into a single component, reducing overall system complexity despite the added capability for adaptive frequency control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system effectively ignites and maintains atmospheric pressure plasmas without damaging power supplies by minimizing current spikes and impedance fluctuations, ensuring stable plasma operation.

Implementation Method 1

a transformer, a cable connected to a secondary winding of the transformer

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The gas presents a high impedance to the power source, while the resultant plasma appears as a low impedance load to the power source

Methodology Applied
Scientific EffectPlasma: Plasma

Data Source

PatentEP3956921B1System for plasma ignition and maintenance of an atmospheric pressure plasma
Publication Date: 2025.10.01 ATMOSPHERIC PLASMA SOLUTIONS INC
  • EP3956921B1 patent drawingFigure 1A
  • EP3956921B1 patent drawingFigure 1B
  • EP3956921B1 patent drawingFigure 2

AI summary

A system for plasma ignition and maintenance of an atmospheric pressure plasma. The system has a variable frequency alternating current (AC) power source, a transformer, a cable connected to a secondary winding of the transformer, a programmed microprocessor for control of power to the atmospheric pressure plasma. The microprocessor is configured to a) at pre-ignition, power the AC power source at an operational frequency fop higher than the resonant frequency fr, b) decrease the operational frequency fop of the AC power source until there is plasma ignition, and c) after the plasma ignition, further decrease the operational frequency fop of the AC power source to a frequency lower than the resonant frequency fr.