Application Of Internal Model Controller Base On Support Vector Machine In The Gas Collector Pressure Control

The stability of gas collector pressure is an important guarantee for the normal production of coke oven, which directly affects the product quality, production efficiency, equipment life and environmental pollution. But gas collector pressure system of multiple coke oven is a highly nonlinear, degeneration, asymmetrical and complex control system, with multivariable coupling and strong disturbance characteristics, that is difficult to establish accurate mathematical model, so the conventional control method is difficult to achieve the ideal control effect.In this paper, the research background is from the control system of coke oven gas collector pressure in a coking plant in Hebei. According to the coking production process and the characteristics of gas collector pressure system research and analysis, the system of gas collector pressure in coke oven divided into two parts, one is the variable frequency adjustable speed subsystem of blower and the other is the gas collector pressure subsystem. The former is used to stabilize the suction before primary cooler, and the latter is used to eliminate the coupling effect between the multiple gas collector pressure. Respectively, this paper designed different controllers to regulate and control, to guarantee the gas collector pressure on the stability of the control.According to different working conditions in the production of coke oven, the internal model control based on least squares support vector machine(LSSVM_IMC) and nonlinear PID composite switching control strategy is adopted in the variable frequency adjustable speed subsystem of blower, for keeping the stability of suction before primary cooler. Under normal production conditions, the suction fluctuates with the change of total gas, and the system uses the LSSVM IMC controller, online tracking blower speed control system model of the controlled object, with real-time adjustment of the controller parameters. It can effectively inhibit the effect caused by unknown disturbances. Under the abnormal condition which is mainly due to the pushing coke, coal and reversing switch ammonia and other manual operation, using nonlinear PID control to eliminate system interference and keep the suction stable. The two control strategies are coordinated, which can keep the suction before the primary cooler in the normal range according in the different working conditions. In addition, this paper uses the variable gain PI and decoupling control method to eliminate the coupling effect between the gas collectors' pressure.The MATLAB simulation and production site operating curve results show that the composite control and decoupling method meet the requirements of the production process. It not only can restrain unpredictable disturbance effectively, but also eliminate coupling effect of gas collectors' pressure, that wel realize tracking the setting value of system fast with good robustnes. The gas collector pressure control system has certain feasibility and popularization value.