High Reliability,High Frequency Power Source Design For ICP

The method of generating plasma is divided into different methods such as low pressure,electric arc and high frequency induction in the industrial field according to its realization principle.Among them,the high-frequency induction plasma generator has the characteristics of no electrode loss and large arc column diameter,so it is widely used in production and experiments.And according to the different coupling modes of power supply and plasma,it can be divided into inductively coupled plasma(ICP)generator and capacitively coupled plasma(CCP)generator,of which ICP source is the most widely used.The energy of the ICP source is provided by a high-frequency power source,and most of the traditional power sources are based on vacuum tubes.The output network does not have the function of automatic impedance matching,and manual adjustment is required.This leads to the possibility of excessive power reflection and serious heating of the plasma generator during use,which may cause the circuit to burn out.Therefore,it is necessary to study and design a high-frequency power source with automatic impedance matching and high reliability.The research content of this topic is divided into two parts.The first part is the hardware circuit part,which mainly includes drive circuit,power amplifier circuit,matching circuit,protection circuit,coupling circuit and detection circuit.Regarding the power amplifier circuit,after analyzing and researching the power amplifier circuit,it is decided to adopt the class E power amplifier circuit,and its theoretical efficiency can reach 100%.The coupling circuit uses a lumped-parameter dual directional coupler,and uses the coupling characteristics of transformers in series and parallel to design a coupling circuit with a coupling degree of 30 d B.The detection circuit uses a diode peak detection circuit,which has a simple structure and stable performance to meet the design requirements.Regarding the simulation of the hardware circuit,ADS and Multisim software are mainly used,and the printed circuit board is drawn using Altium Designer.The second part is the software part.It is well known that efficient matching algorithms can quickly,accurately and stably realize impedance matching of circuits.The matching algorithms are divided into classic gradient descent algorithms,particle swarm algorithms based on intelligent theory,and simulated annealing algorithms.In order to improve the efficiency and speed of matching,this design researched and modeled the simulated annealing algorithm,and simulated the actual search iteration process in Matlab.In addition,because the power supply is required to be able to output a 13.56 Mhz continuous sine wave and 1k W power,the power stability is 5%.Therefore,in order to increase the reliability of the design,this design creatively carried out a joint simulation of the hardware circuit and the matching algorithm in Simulink.The analysis of the results shows that after applying the impedance matching algorithm,the output efficiency of the high-frequency power source is 90.6%,which lays a theoretical foundation for the construction of real hardware circuits.Finally,a low-level programmable system-on-a-programmable-chip(SOPC)with incident reflected voltage acquisition,matching and protection control was built on the FPGA,and the u COS II operating system was used for multi-task management.This dissertation focuses on the power source for ICP and designs a high-frequency power source system with automatic impedance matching and protection mechanism.