RF Power Source Servo Control for Distortion-Based Impedance Tuning
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Solution Overview
Problem
Current RF power systems face challenges in maximizing power transfer to matching networks due to systematic variations and non-zero reflected power, which are not effectively addressed by existing heuristic, feedback, and feedforward control methods.
Innovation Solution
The implementation of a radio frequency system that uses feedforward control to minimize distortion by determining a distortion value based on sinusoidal or cross-correlation functions, and providing impedance tuning values to adjust the matching network, complementing feedback control to correct power output errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If feedback control is used to minimize error between power setpoint and transferred power, then power transfer is maximized, but reflected power cannot be minimized to zero due to systematic variations
Solution Approach 1:
The patent introduces an intermediary calibration process that measures systematic errors in power sensing using known calibration loads. This calibration data serves as a mediator to correct the relationship between sensed power and actual power, eliminating the systematic variations that prevent reflected power minimization while maintaining accurate power measurement capability.
2Loss of energy
If phase difference based frequency adjustment is used to minimize phase difference and reverse power, then power transfer is improved, but quantitative errors occur due to systematic variations
Solution Approach 1:
The patent implements feedback control that uses calibration-derived correction factors to adjust frequency based on measured phase differences. The feedback loop continuously monitors power transfer and uses the calibration data to compensate for systematic phase measurement errors, enabling accurate frequency adjustment that minimizes reverse power without suffering from quantitative errors.
3Loss of energy
If heuristic search methods are used to tune frequency and minimize reverse power, then power transfer is maximized, but the approach cannot be represented by a transfer function
Solution Approach 1:
The patent transforms the heuristic search approach into a parameter-based control system by introducing calibration-derived parameters (correction factors, systematic error measurements) that convert the black-box heuristic method into a transfer-function-representable system. This allows frequency tuning to be controlled through measurable parameters while maintaining the ability to minimize reverse power effectively.
Data Source
AI summary
A radio frequency system includes a power amplifier that outputs a radio frequency signal to a matching network via a transmission line between the power amplifier and the matching network. A sensor monitors the radio frequency signal and generates first sensor signals based on the radio frequency signal. A distortion module determines a first distortion value according to at least one of (i) a sinusoidal function of the first sensor signals and (ii) a cross-correlation function of the first sensor signals. A first correction circuit (i) generates a first impedance tuning value based on the first distortion value and a first predetermined value, and (ii) provides feedforward control of impedance matching performed within the matching network including outputting the first impedance tuning value to one of the power amplifier and the matching network.