Design And Implementation Of Combined Pressure Control System For Inductively Coupled Plasma Generator

When hypersonic vehicle flies near the space layer,plasma sheath will be produced,and the communication "black barrier" phenomenon will appear.The two platforms of plasma generation and control and wave propagation experiment can constitute a scientific inductively coupled plasma generation device,which can support the research of electromagnetic science problems of plasma in near space.Air pressure combined control system is composed of air supply system and vacuum system,which is the key subsystem of inductively coupled plasma generation device.Through the joint control of electric regulating valve and vacuum pump,the stable control of flow and pressure can be realized.The topic of this paper has great scientific application value.In view of the special experimental flow and purpose of inductively coupled plasma generation device,this paper designs a set of practical and feasible control system,which realizes the function of stable air intake and balanced air pressure.After understanding the research status and development of air intake and pressure control at home and abroad,the following aspects of work are carried out:Firstly,this paper analyzes the relationship between the controlled quantity and the input quantity based on the inductively coupled plasma generation device’s air intake and exhaust process and the theory of vacuum technology.Based on the data obtained from the step response experiment on the experimental platform,the mathematical model of the air pressure combined control system is established,and the dynamic response expression,system delay and other parameters are determined.The coupling between each control loop is analyzed,and the coupling effect is found.Based on the compensatory principle,the feedforward compensator was designed,and the decoupling control model of the double control loop was built to realize decoupling control.The simulation results verified the stability and anti-interference ability of the decoupled system.Then,according to the dynamic characteristics of the air pressure joint control system,the single neuron PID control algorithm is applied to the actual control process.At the same time,the basic single neural algorithm is analyzed,combined with the expert control knowledge,the parameter tuning aspect is proposed to optimize,the actual system is simulated,the simulation results show that the algorithm has more advantages,better control effect and dynamic characteristics both in the aspects of suppressing overrun and speeding up the adjustment time.According to the air traffic control process,the use of Siemens 300 series PLC for control system hardware and software design and implementation,combined with Win CC developed the human-computer interaction interface,including the parameter setting,data tracking,condition monitoring and alarm log,and realize the inductively coupled plasma generating device of intuitive and convenient operation,finally got through the experiment system steady-state error is within 5%,verify the accuracy and the feasibility of the control algorithm of the model.In this paper,from theoretical analysis to experimental modeling,from algorithm simulation to algorithm implementation,the overall design and implementation of the air pressure joint control system is completed.Through experiments,it is verified that each performance of the system can meet the requirements of the project.The system has strong reliability and high control precision,which provides a good and stable flow field environment for inductively coupled plasma electromagnetic experiments.