Research And Design For RF Generator In ICP Source

ICP source(Inductive Coupled Plasma Source)is a key component of high-end analytical instruments such as mass spectrometers and spectrometers,and usually,a complete Inductively Coupled Plasma Source(ICP Source)is composed of RF generators,matching boxes and other parts.As an important part,RF generators have always been a hot spot in research at home and abroad.With the advancement of science,the performance of RF power devices is getting stronger and stronger,which directly promotes the development of the RF field.However,due to the distortion of RF signals in transmission,power loss and interference,RF generators are difficult in design and application.This paper conducts in-depth research from the aspects of RF circuit design theory,RF power amplification circuit design,supporting peripheral circuit design and prototype test and detection,and the main work is as follows:(1)On the basis of in-depth study of theory,through the analysis and comparison of the principles and applications of various types of amplifiers,this paper determines that the RF power amplifier structure combining class E and class AB is the most suitable amplifier structure according to the requirements of ICP sources for RF generators.(2)According to the theoretical calculation,the design parameters of the class E amplification circuit are obtained.The simulation design of the class AB amplifier single tube was realized by the Advanced Design System(ADS)simulation software,and the correctness of the circuit design was verified by the harmonic balance method simulation.According to the power requirements,the topology of the final AB class AB amplifier circuit is designed.(3)Design the peripheral circuits supporting the RF power amplification circuit,mainly including interface circuits,current monitoring circuits,constant temperature control circuits,RF power detection circuits,RF power control circuits and protection circuits.The protection circuit includes temperature protection circuit,current protection circuit,power protection circuit and reflective power protection circuit.(4)Assemble the prototype and test platform,and conduct functional tests on the designed RF power amplification circuit and peripheral circuits.The test results show that the output waveform and frequency of the RF power amplifier are stable,and the output RF power can reach up to 2000 W;At 1800 W,the efficiency can reach 60%,and the output power fluctuation is less than 0.1%,which can meet the requirements of ICP sources for RF generators.