ICP Power Supply Timing Control Without High-Frequency Switching Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems for inductively coupled plasma (ICP) devices face challenges in controlling power efficiently without increasing complexity, leading to high-frequency switching noise and reduced reliability.
Innovation Solution
A power supply system that includes an inverter to convert DC power to AC, an impedance matching circuit, and a controller to adjust the powering and freewheeling periods to precisely control the power supplied to the load, using PID gain factors and limiting the freewheeling period to maintain stability and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional power supply control methods are used to control power to ICP devices, then power control is achieved, but device complexity increases and high-frequency switching noise is generated
Solution Approach 1:
The patent applies periodic action by dividing the power supply cycle into distinct powering periods and freewheeling periods. The controller selectively activates switching elements during powering periods to deliver power to the ICP device, then enters freewheeling periods where switching elements are turned off but current continues to flow through freewheeling diodes. This periodic on-off cycling enables precise power control while avoiding continuous high-frequency switching that generates noise.
Solution Approach 2:
The patent extracts the high-frequency switching operation from the power control mechanism. Instead of using high-frequency PWM switching to control power, the invention separates the power delivery function (during powering periods with switching elements on) from the power control function (by adjusting the duration and frequency of powering periods). This extraction eliminates the need for high-frequency switching while maintaining precise power control capability.
2Power
If high-frequency switching is used to control power supply, then power control precision is improved, but high-frequency switching noise is generated
Solution Approach 1:
The patent replaces high-frequency continuous switching with low-frequency periodic switching. Powering periods are followed by freewheeling periods where no switching occurs. By extending the cycle period and reducing switching frequency, the patent maintains power control precision through timing adjustments while significantly reducing high-frequency switching noise generation.
Solution Approach 2:
The patent converts the potential harm of abrupt current interruption during switching into a beneficial freewheeling mode. During freewheeling periods, current continues to flow through diodes rather than being abruptly stopped, which eliminates switching spikes and noise. The freewheeling path transforms what would be harmful switching transients into smooth current decay, benefiting both noise reduction and component protection.
3Power
If conventional power supply methods are used, then power delivery is achieved, but stress is applied to the power supply causing malfunction
Solution Approach 1:
The patent implements beforehand cushioning by providing freewheeling diodes that are ready to conduct current before any potential switching stress occurs. When switching elements turn off, the freewheeling diodes immediately provide a safe current path, cushioning the switching elements from voltage spikes and reverse current stress. This protective mechanism is prepared in advance and automatically activates, preventing malfunctions and extending power supply reliability.
Solution Approach 2:
The patent reduces stress on power supply components by implementing periodic rest periods through freewheeling modes. During freewheeling periods, main switching elements are turned off and experience no electrical stress, while current continues to flow safely through diodes. This periodic interruption of stress exposure allows components to recover and operate within safe limits, preventing cumulative damage and malfunction.
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 system improves reliability by precisely controlling power supply to ICP devices without generating high-frequency switching noise, enhancing the stability and performance of the power supply.
Implementation Method 1
an inverter configured to direct current (DC) power into alternating current (AC) power
Data Source
AI summary
A power supply includes an inverter configured to direct current (DC) power into alternating current (AC) power, an impedance matching circuit configured to supply the AC power to a load; and a controller configured to adjust disposition of a powering period, in which the AC power is output, and a freewheeling period, in which the AC power is not output, to adjust a power amount of the power supplied to the load through the impedance matching circuit by the inverter.