| In this paper,the control system of the fused magnesia furnace based on Siemens1200 series PLC is designed on the background of the actual fused magnesia furnace project.According to the production and control requirements,the selection of hardware configuration of the lower computer,the design of the upper computer monitoring system and the field electrical design were carried out.For three-phase fused magnesia furnace system is nonlinear,time-varying,and frequent disturbance,the characteristics of strong coupling,in fused magnesium furnace electrode control system as the core,the main circuit on the electrode coupling model is established on the basis of the three-phase electrode regulating system based on BP neural network self-tuning PI L-M parameters algorithm design and simulation research,has obtained the ideal effect.fused magnesia has the characteristics of high melting point,strong oxidation resistance,dense structure,stable chemical performance,high compressive strength and strong corrosion resistance,etc.It has been widely used in metallurgy,chemical industry,aerospace and nuclear industry.At present,our country mainly uses three-phase alternating current fused magnesia furnace to produce fused magnesia,but the melting process of fused magnesia furnace in industrial production is far from automatization.At the same time,due to the influence of unreasonable electrical design and current coupling,there are some unreasonable energy consumption and resource waste in the production process.Therefore,the establishment of a stable,reliable,easy to maintain and automatic production capacity of the furnace control system is of great significance to the development prospects of the whole industry.The main work of this paper can be divided into the following aspects:First of all,on the basis of consulting a large number of relevant data and studying the existing electric melting process of some electric melting magnesium furnace,I got familiar with the equipment composition,working principle and technological process of the electric melting magnesium furnace,and carried out the overall design of the software and hardware of the three-phase electric melting magnesium furnace control system.TIA PORTAL V14 was used to complete the hardware configuration and PLC programming design of the lower computer,and the wiring diagram of IO port on site was drawn according to the selection of PLC and related modules.WinCC V7.4 configuration software is used to complete the upper computer monitoring screen design.On the basis of a large amount of literature review and the design of field electrical system,the electrode circuit of fused magnesium furnace is simplified appropriately,and then the mathematical model of electrode current and voltage coupling is established by using the correlation law between current,voltage and impedance.Finally,according to the actual control requirements and melting characteristics of fused magnesia furnace,a PI self-tuning electrode regulation algorithm based on L-M BP neural network was designed to improve the shortcomings of traditional PI control methods in control speed and stability,and the decoupling performance was verified by simulation.PI controller parameters are learned and trained online by L-M BP neural network,which ensures the stability of the system and improves the speed of the control system. |
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