High-Frequency Power Supply Control for IMD Reflected Wave Reduction
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Solution Overview
Problem
Existing high-frequency power supply systems experience intermodulation distortion (IMD) leading to fluctuating reflected wave power on the first power supply side due to the second power supply's ON and OFF periods, making it difficult to reduce reflected wave power effectively using conventional frequency modulation control.
Innovation Solution
Implementing frequency modulation control in the second power supply ON period and frequency offset control in the OFF period, combined with impedance matching, to stabilize the first power supply's output frequency and reduce reflected wave power across both periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If frequency modulation control is performed continuously to reduce reflected wave power caused by IMD, then reflected wave power is reduced during the second power supply ON period, but reflected wave power increases during the second power supply OFF period
Solution Approach 1:
The patent applies periodic action by switching between frequency modulation control and frequency offset control based on the pulse modulation cycle of the second power supply. Frequency modulation control is applied during the ON period when IMD occurs, and frequency offset control is applied during the OFF period when IMD does not occur, optimizing reflected wave power reduction for each phase.
Solution Approach 2:
The patent implements dynamics by making the control method adaptive to the operational state of the second power supply. The control system dynamically switches between frequency modulation and frequency offset control strategies based on whether the second power supply is in ON or OFF state, allowing optimal performance across varying conditions.
2Loss of energy
If impedance matching operation is performed to reduce reflected wave power, then matching efficiency improves, but the operation time exceeds the pulse modulation cycle time
Solution Approach 1:
The patent replaces the mechanical impedance matching operation with electronic frequency control. Instead of physically adjusting matching components which takes time, the system uses frequency modulation and frequency offset control to achieve reflected wave power reduction, eliminating the time-consuming mechanical adjustment process.
3Ease of operation
If the first power supply operates at a fixed fundamental frequency, then the system is simple to operate, but intermodulation distortion causes reflected wave power fluctuations
Solution Approach 1:
The patent changes the frequency parameter of the first power supply dynamically. By applying frequency modulation during the ON period and frequency offset control during the OFF period, the system adjusts the operating frequency to minimize IMD-related reflected wave power while maintaining operational simplicity through automated control.
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 are repeated. The first power supply performs frequency modulation control in a second power supply ON period, and outputs a first forward wave voltage having a first fundamental frequency in a second power supply OFF period.