Piezoelectric Plasma Generator Ion Ratio Control

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Solution Overview

Problem

Existing plasma generators using piezoelectric transformers have a fixed ratio of positive to negative ions due to the inherent properties of these transformers, limiting the ability to adjust the ion ratio for specific applications like water purification, where a customizable ion ratio is advantageous.

Innovation Solution

Incorporating an ion separation electrode and a drive circuit that allows for adjustable potential application to the ion separation electrode, enabling control over the ratio of positive to negative ions in the plasma generated, even when using a piezoelectric transformer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a piezoelectric transformer is used to generate plasma, then the efficiency of plasma generation is improved, but the ratio of positive to negative ions becomes fixed and cannot be adjusted

Engineering Contradiction:
Improveplasma generation efficiencyVSAvoidadjustability of ion ratio
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The plasma generation system is segmented into two independent functional parts: the piezoelectric transformer for plasma generation and the ion separation electrode for ion ratio control. This segmentation allows each component to perform its specialized function optimally while maintaining overall system efficiency and adjustability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An ion separation electrode is introduced as an intermediary component between the plasma source and the output. This mediator selectively separates positive and negative ions through applied electric fields, enabling independent control of the ion ratio without affecting the plasma generation efficiency of the piezoelectric transformer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the steepness of voltage slopes in a piezoelectric transformer is increased to generate more ions, then the quantity of ions is improved, but the ratio of positive to negative ions remains fixed

Engineering Contradiction:
Improvequantity of ionsVSAvoidcontrol over ion ratio
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The ion separation electrode performs preliminary separation of ions immediately after plasma generation. By applying electric fields in advance of the final output, the system establishes the desired ion ratio before the plasma is delivered to the application point, ensuring both sufficient ion quantity and precise ratio control.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the electric field parameters (voltage, polarity, strength) at the ion separation electrode to selectively attract or repel specific ion types. This parameter control allows independent adjustment of the positive-to-negative ion ratio while maintaining the total ion quantity generated by the piezoelectric transformer.

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 configuration allows for the generation of plasma with a desired ratio of positive to negative ions, leveraging the efficiency of piezoelectric transformers while accommodating applications requiring specific ion ratios, such as water purification.

Implementation Method 1

a piezoelectric transformer (2) that is suitable for ionizing a process gas

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

If a potential is applied to the ion separation electrode, these ions with an opposite charge are attracted and repelled ions with the same charge

Methodology Applied
Scientific EffectIon separation by electric field: Ion Repulsion/Attraction

Data Source

PatentEP3338518B1Plasma generator and method for setting an ionic ratio
Publication Date: 2021.11.03 TDK ELECTRONICS AG
  • EP3338518B1 patent drawingFigure 1~2

AI summary

The present invention relates to a plasma generator (1) which has a piezoelectric transformer (2) which is suitable for ionizing a process gas, an ion separation electrode (7) and a drive circuit (8) which is suitable for applying a potential to the ion separation electrode (7). The invention further relates to a method for setting the ratio of positive to negative ions in a plasma which is generated by a plasma generator (1).