Application Of Variable-parameter PID Control In High-power Air Heating System

According to the actual needs of the project,based on the analysis of the original hot gas supply control system of an icing wind tunnel,this paper focuses on the research of hot gas temperature control algorithm according to the characteristics and requirements of large supply flow range,wide pressure range,large heating power,wide hot gas temperature control range,high temperature control accuracy and short adjustment time,The main research and design work are as follows.Firstly,the original hot gas supply control system is analyzed and studied comprehensively,including the characteristics of the controlled object,the hardware structure of the control system,the operation process,and the interference factors affecting the temperature control accuracy.Then,in order to meet the requirements of new system function and technical index,the hot gas supply control system is reformed and designed,especially the optimization design of hot gas temperature control unit.Through the open-loop experiment of the temperature control system,the preliminary mathematical model of the controlled object of the heater is established,and then several control algorithms for the hot gas temperature control are mainly studied,including the conventional PID algorithm,fuzzy PID algorithm,neural network PID algorithm and variable parameter PID algorithm,and the simulation analysis and comparison are carried out.The results show that the variable parameter PID control algorithm has better control effect,It is suitable for the control of hot gas temperature in this system.On the basis of the above research and design,this paper designs the electrical heating module,temperature detection module,PLC control module and other hardware modules of the hot gas temperature control unit,and builds the hot gas supply system.At the same time,it designs the upper computer monitoring program of the system based on LabVIEW software tools.Finally,the experimental verification is completed in the optimized design of the actual hot gas supply system,that is,several temperature control experiments are carried out in the hot gas supply flow range,pressure range and temperature range required by the project,It can improve the control precision of hot gas temperature and speed up the adjustment time.