High-Frequency Power Supply Matching for IMD Reflected Power
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Solution Overview
Problem
The existing high-frequency power supply systems experience intermodulation distortion (IMD) leading to fluctuations in reflected wave power, particularly on the first power supply side, due to the difference in impedance between the second power supply ON and OFF periods.
Innovation Solution
The system incorporates a first power supply and a second power supply, along with matching circuits, where the first power supply performs frequency modulation control during the second power supply ON period and frequency offset control during the OFF period, while the matching circuits adjust impedance to minimize reflected wave power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first matcher performs matching operation using intermediate impedance for both ON and OFF periods, then the matching is simplified, but the difference in load-side impedance between ON and OFF periods becomes large
Solution Approach 1:
The first matcher dynamically adjusts its matching parameters based on the operational state of the second power supply. During ON period, it performs matching optimized for the impedance conditions with IMD present. During OFF period, it adjusts to match the different impedance conditions without IMD. This dynamic adjustment reduces the impedance difference between states while maintaining manageable complexity through state-dependent control.
2Measurement precision
If the second power supply performs pulse modulation with long cycle time to allow matching operation, then the matching accuracy improves, but the productivity of the system decreases
Solution Approach 1:
The system uses feedback control where the first power supply and first matcher continuously monitor and adjust to the impedance conditions created by the second power supply's pulse modulation. This feedback mechanism allows accurate matching to be maintained even with shorter cycle times, as the system adapts in real-time rather than requiring long settling periods between modulation cycles.
Data Source
AI summary
A high-frequency power supply system according to the present disclosure includes a first power supply, a second power supply, a first matcher, and a second matcher. The second power supply performs pulse modulation of repeating an ON operation of outputting a second forward wave voltage and an OFF operation of not outputting the second forward wave voltage. The first power supply performs frequency modulation control in a second power supply ON period, and performs frequency offset control of outputting a forward wave voltage having a fundamental frequency obtained by adding an offset frequency to a fundamental frequency in a second power supply OFF period.