Microwave power source, microwave plasma system, ignition method and self-tuning method

Abstract

The invention discloses a microwave power source, a microwave plasma system, an ignition method and a self-tuning method. The microwave power source comprises: a microwave signal generator used for generating a microwave signal; a signal adjusting unit used for adjusting the amplitude and phase of the microwave signal and loading pulse signals with different frequencies and duty ratios; a semiconductor amplification unit; a signal transmission and load detection unit used for sending the microwave signal amplified by the semiconductor amplification unit to a load and detecting the sent microwave signal and a microwave reflection signal generated by the load to obtain a detection sampling signal; and a control unit used for receiving and analyzing the detection sampling signal so as to control the signal emission frequency of the microwave signal generator and / or control the adjusting mode of the signal adjusting unit according to the analysis result. According to the invention, automatic ignition frequency searching, an automatic ignition process and a self-tuning process are achieved, and the problems that existing traditional microwave plasma equipment is difficult to ignite automatically and work stably are solved.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to the Chinese Patent Application No. 2020101914439 filed with the China Patent Office on March 18, 2020, the entire contents of which are incorporated herein by reference. technical field [0003] The invention relates to the technical field of plasma physics, in particular to a microwave power source, a microwave plasma system, an ignition method and a self-tuning method. Background technique [0004] Microwave plasma refers to the use of electromagnetic wave transmission energy to excite gas to generate ionization to form plasma. Compared with other methods to stimulate plasma, microwave plasma has the following advantages: 1. Higher degree of ionization and decomposition, 2. Higher electron temperature, thus Reach a lower plasma temperature, 3. There is no electrode, and there will be no pollution caused by electrode loss. 4. The working pressure range is wide and can be applied to...

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Problems solved by technology

[0006] 1) It is difficult to realize automatic ignition: According to the principle of microwave plasma torch, the output frequency of microwave power source must be in the optimal excitation response frequency band of torch tube. Traditional microwave plasma torch uses magnetron as microwave power source. The frequency is unstable and uncontrollable, making it difficult to motivate the torch to automatically ignite;

[0007] 2) It is impossible to achieve the unity of automatic ignition and automatic maintenance: the load matching state of the plasma torch tube is quite different before generating plasma and after successfully exciting the plasma. Once the automatic ignition is successful, the microwave power source needs to be able to quickly To track and adapt to load changes, the microwave power source of the traditional plasma torch cannot be automatically optimized and matched, resulting in low microwave energy coupling efficiency after ignition, requiring manual adjustment of transmission matching;

[0008] 3) Poor time-varying adjustability: During the entire working process of the microwave plasma torch, with the change of temperature, air flow and gas, it is necessary to adjust the transmission matching between the microwave power source and the torch tube in real time to achieve a better energy coupling effect. The microwave plasma torch is difficult to achieve this, and when the working state changes, there will be interruptions

[0009] The above defects are also the root cause of the difficulty in achieving large-scale industrialization of traditional microwave plasma torches in practical applications.

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