Adaptive PID Control Of Electrode System Of Electric Arc Furnace Based On Neural Network

Based on the reform of a 70-ton electric arc furnace(EAF)control system in a steel plant,this thesis designs a computer network control system for the 70-ton EAF based on WinAC RTX.In the system,Siemens WinAC RTX and ET200 are selected as the controller and remote control station respectively.Then,the construction of the system network,the selection of software and hardware and the configuration of the monitoring system are carried out.The electrode control system for EAF is a multivariable,nonlinear,strong coupling,time-varying,harsh working environment and strong random interference system.Taking the electrode control system of EAF as the core,the design and simulation of three-phase electrode regulating system model algorithm based on BP neural network self-tuning PID parameters and RBF neural network on-line identification system are carried out.A simulation platform is built in the laboratory to simulate the three-phase electrode control effect.Firstly,for the characteristics of the model of the electrode adjustment system,such as unstable,strong coupling and large interference,the Jacobian information,decoupling and anti-interference ability of the neural network identification model are studied respectively in the control algorithm.In order to speed up the identification of the model and make the selection of clustering radius reasonable,the nearest neighbor clustering RBF neural network with variable clustering radius and online learning function is selected.The Jacobian information identified contains the information of object coupling,which is applied to BP network to tune the parameters of PID controller to achieve decoupling effect.The simulation results of MATLAB show that this method has certain decoupling ability and anti-interference ability,simultaneously indicate the feasibility and stability of the decoupling control scheme based on model identification and BP network tuning PID parameters.Then according to the technological requirements of the EAF and the characteristics of the control system,the application design scheme based on WinAC in the EAF control system is proposed.In the design scheme,the advanced computer network control technologies such as Profibus-DP bus and Ethernet are adopted,and the WINAC controller,STEP7 configuration software and WINCC monitoring software of Siemens are applied.The dynamic link library program for data acquisition,storage and control output of the system is developed by using Visual C++ and WinAC ODK development toolkit.The new EAF control system under the field bus environment is established,which realizes the functions of process control,monitoring and alarm,remote monitoring and data acquisition of the EAF control system.