Reseach On Coordinated Control Based On The Dissipative Theory For Supercritical Unit

Coordinated control system is a very important part of the supercritical unit. At present, most of the coordinated control systems are designed on the basis of indirect energy balance, but the disadvantage of the method is that the main steam pressure of the unit is prone to fluctuate when the variable load operation or calorific value of coal changes greatly. So how to reduce the fluctuations of the main steam pressure is the emphasis and difficulty on the premise of the load tracking its set point fast.Dissipative theory is a theory to analyze the system stability in the perspective of energy balance. It provides a new way for the design of a control system. The article used the dissipative theory to analyze a class of two-input and two-output nonlinear system, and constructed the stabilizing feedback control law. Through the mechanism and the simplify analysis of the supercritical unit operation, the article established the simple mathematical model of the supercritical unit. Then the model is pretreated, and the control law is introduced into the model, after that the L2 gain controller is constructed. The simulation results showed that the L2 gain controller has good control effects on dynamic performance, disturbance rejection and load adaptability. In order to make dissipative theory into practice, the article made a research on nonlinear PID coordination controller design based on the dissipative theory. First of all, the article analyzed a class of linear system and a kind of two input single output nonlinear system by using the dissipative theory, and constructed the corresponding stabilizing feedback control law. Then the model is pretreated. After pretreatment, the system is divided into two subsystems. According to the actual circumstances of the various subsystems respectively to design of the controllers, the PID controller is finally constructed. From simulation results, we can see that the PID controller can satisfy the demand of coordination control of the supercritical unit.