Oscillator Generator Harmonic Control for Inductively Coupled Plasma

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Solution Overview

Problem

Existing generators face challenges in efficiently sustaining inductively coupled plasmas due to instability during ignition and impedance matching issues, leading to potential transistor damage and reduced sensitivity in mass spectrometry applications.

Innovation Solution

A generator system that operates in both driven and oscillation modes, using a processor-controlled oscillation circuit with high-order ceramic low-pass filters and impedance matching, enabling independent control of voltage and current to sustain plasmas and adapt to changing impedance during sample introduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a generator operates in oscillation mode to sustain inductively coupled plasma, then plasma stability is improved, but harmonic emissions increase causing interference

Engineering Contradiction:

Improveplasma stabilityVSAvoidharmonic emissions

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

A low-pass filter is introduced as an intermediary component between the oscillation circuit and the induction device. This filter mediates the electrical connection by allowing the fundamental oscillation frequency to pass through while blocking harmonic frequencies, thus maintaining plasma stability through the oscillation mode while reducing harmful harmonic emissions that would otherwise interfere with detection systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If impedance matching is performed quickly to adapt to changing plasma conditions, then plasma sustainment efficiency is improved, but control circuit complexity increases

Engineering Contradiction:

Improveimpedance matching speedVSAvoidcontrol circuit complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The control circuit incorporates feedback mechanisms that continuously monitor plasma impedance conditions and automatically adjust matching network parameters in real-time. This feedback loop enables rapid adaptation to changing plasma conditions without requiring complex manual intervention or overly sophisticated control algorithms, achieving fast impedance matching through intelligent automated control.

Inventive Principle:

Principle #23Feedback

3Reliability

If high power is delivered to the induction device for efficient plasma ignition, then ignition reliability is improved, but transistor breakdown risk increases

Engineering Contradiction:

Improveignition reliabilityVSAvoidtransistor breakdown

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Protective circuitry and impedance matching networks are configured in advance to cushion and limit the maximum power delivered to the induction device. These pre-configured protection mechanisms ensure that during high-power ignition operations, the power transistors are protected from exceeding their breakdown voltage or current ratings, thus maintaining ignition reliability while preventing transistor damage through beforehand protective measures.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 minimizes transistor breakdown, enhances impedance matching speed, and improves plasma stability and sensitivity in mass spectrometry, allowing for efficient plasma ignition and sustainment across varying conditions.

Implementation Method 1

a generator configured to sustain an inductively coupled plasma in a torch body... the oscillation circuit configured to electrically couple to an induction device and provide power to the induction device in an oscillation mode to sustain the inductively coupled plasma

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

the circuit comprises a low pass filter configured to filter a feedback signal provided to the power transistor

Methodology Applied

Scientific EffectFilter (electronic): Filter (electronic)

Data Source

PatentUS10104754B2Oscillator generators and methods of using them

Publication Date: 2018.10.16 PERKINELMER U S LLC

AI summary

Certain embodiments described herein are directed to generators that can be used to sustain a plasma. In some embodiments, the generator comprises an oscillation circuit configured to electrically couple to an induction device and provide power to the induction device in an oscillation mode to sustain the inductively coupled plasma in a torch body, the circuit configured to provide harmonic emission control during sustaining of the inductively coupled plasma in the torch body in the oscillation mode of the generator.