Phase-Controlled Resonant Oscillator for Fast RF Load Tracking
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Solution Overview
Problem
Conventional AC power delivery systems, particularly those using radio frequency (RF) power sources, struggle to efficiently deliver power to loads with rapidly changing resonant frequencies, such as in pulsed plasma systems, due to the inability of existing impedance matching circuits to adjust frequency and impedance quickly enough.
Innovation Solution
A resonant phase-controlled oscillator circuit with a feedback loop that includes a sensor and a phase shifter, allowing for rapid adjustment of the phase of the feedback signal to match the changing resonant frequency of the load, thereby optimizing power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional impedance matching circuits are used, then power delivery is efficient at a fixed resonant frequency, but the system cannot adapt when the resonant frequency changes rapidly
Solution Approach 1:
The patent implements a phase-locked loop (PLL) that dynamically adjusts the resonant frequency of the AC power source to match the changing resonant frequency of the load. The PLL continuously locks onto the load's resonant frequency by comparing phase signals and adjusting the frequency accordingly, enabling real-time adaptation without manual intervention or slow mechanical adjustments.
Solution Approach 2:
The system employs a feedback mechanism where a sensor detects the load's resonant frequency, generates a phase signal, and feeds it back to the PLL. The PLL uses this feedback to continuously adjust and maintain synchronization with the load's resonant frequency, ensuring efficient power transfer even as conditions change.
2Adaptability or versatility
If adjustable impedance matching circuits are used, then the system can adapt to changing load impedance, but the adjustment speed is too slow for rapidly changing resonant frequencies
Solution Approach 1:
The patent replaces conventional mechanical or electronic impedance matching circuits with a PLL-based frequency synthesis system. Instead of mechanically adjusting matching components, the system electronically generates and adjusts the operating frequency to match the load's resonant frequency, achieving much faster response times and eliminating mechanical adjustment delays.
3Loss of energy
If the resonant frequency is changed to match the load, then power delivery efficiency is improved, but conventional frequency adjustment methods are too slow
Solution Approach 1:
The PLL dynamically and continuously adjusts the frequency of the AC power source to track the load's resonant frequency in real-time. This dynamic frequency adjustment ensures that the system operates at peak efficiency throughout the entire pulsing cycle, minimizing power loss even as the load conditions change rapidly.
Solution Approach 2:
The system performs preliminary frequency adjustment by pre-synchronizing the power source frequency with the load's resonant frequency before power delivery begins. The PLL locks onto the target frequency in advance, ensuring that when power delivery starts, the system is already optimized for efficient energy transfer.
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 resonant phase-controlled oscillator circuit enables efficient power delivery to rapidly changing loads by adjusting frequency and impedance on a microsecond timescale, preventing power loss and instability in systems like pulsed plasma systems.
Implementation Method 1
a phase shifter coupled between the control input and the sensor. The phase shifter is configured to adjust a phase of the feedback signal to provide a conditioned feedback signal at the control input
Implementation Method 2
a feedback circuit including a sensor coupled to the RF power and configured to generate a feedback signal using the RF power
Implementation Method 3
AC power sources may also produce AC power at much higher frequencies. For example, one particular category of AC power source is a radio frequency (RF) power source, which produces AC power at a frequency in the RF portion of the electromagnetic spectrum
Data Source
AI summary
A resonant oscillator circuit includes an amplifier that includes a control input and a power output configured to deliver radio frequency (RF) power to a resonant load, and a feedback circuit. The feedback circuit includes a sensor coupled to the RF power, and a phase shifter coupled between the control input and the sensor. The sensor is configured to generate a feedback signal using the RF power. The phase shifter is configured to adjust a phase of the feedback signal to provide a conditioned feedback signal at the control input. The resonant oscillator circuit may be included as part of an RF system that includes a controller operatively coupled to the sensor and the phase shifter. The controller may be configured to control the phase shifter to adjust the phase of the feedback signal according to a sensor signal received from the sensor.