Plasma Source Switch Timing Using Load Resonant Frequency

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Solution Overview

Problem

Existing plasma source systems face instability and efficiency issues due to the need for frequent retuning of synthetic frequencies to match varying resonant frequencies of the plasma load, leading to potential damage and reduced performance.

Innovation Solution

A plasma source system using zero volt switching resonant topology, where the switching power frequency is directly aligned with the resonant frequency of the load, eliminating the need for synthetic frequency generation and allowing for faster response to frequency changes, thereby stabilizing zero volt switching across wide frequency variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a synthetic frequency generation circuit with phase lock loop is used to match resonant frequency, then frequency matching capability is improved, but system stability deteriorates when resonant frequency varies

Engineering Contradiction:

Improvefrequency matching capabilityVSAvoidsystem stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes the synthetic frequency generation circuit (VCO and phase lock loop) entirely from the system. Instead of generating a synthetic frequency and comparing it with the resonant frequency, the system directly uses the resonant frequency of the plasma load itself to control the switching power source. This extraction of the problematic circuit eliminates the instability issue while maintaining frequency matching capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses the resonant frequency signal from the plasma load itself to control the switching timing, rather than relying on an external synthetic frequency generation circuit. The load's own resonant frequency becomes the control reference, making the system self-regulating and inherently stable against frequency variations.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If frequent retuning of synthetic frequency is performed to match varying resonant frequency, then frequency tracking is improved, but system efficiency and reliability deteriorate

Engineering Contradiction:

Improvefrequency trackingVSAvoidsystem efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

By removing the synthetic frequency generation and retuning mechanism, the system eliminates the inefficiencies associated with frequent retuning operations. The direct use of resonant frequency eliminates the need for retuning cycles, maintaining continuous efficient operation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system maintains continuous efficient power transfer by directly coupling the switching frequency to the resonant frequency without interruption for retuning. The useful action of power transfer continues uninterrupted, avoiding the efficiency losses that occur during retuning transitions.

Inventive Principle:

Principle #20Continuity of useful action

3Loss of energy

If switching devices are switched just before resonant current reaches zero to achieve zero voltage switching, then power loss is reduced, but switching timing precision requirement increases

Engineering Contradiction:

Improvepower lossVSAvoidswitching timing precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The system uses feedback from the resonant current zero-crossing detection to precisely control the switching timing. The switching devices are triggered based on the actual current waveform, ensuring they switch at the optimal moment to achieve zero voltage switching and minimize power loss.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The resonant frequency signal from the load itself provides the timing reference for switching, eliminating the need for external timing circuits. This self-generated timing signal ensures precise switching timing aligned with the current waveform, achieving zero voltage switching naturally.

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 approach enhances stability and efficiency by directly utilizing the resonant frequency of the plasma load, reducing the need for expensive oscillators and minimizing power loss, ensuring consistent plasma control and operation even with significant frequency variations.

Implementation Method 1

The resonant frequency of the resonant load defines the frequency of the switching power eliminating e need for a synthesized frequency generation circuit

Methodology Applied

Scientific EffectResonance: Resonance