The Research Of Fuzzy-DMC For Main Steam Temperature System Of 600MW Supercritical Unit

In the case of resource and fuel increasingly grim shortages, generator sets are moving towards high-parameter, high capacity direction. At present, because supercritical unit has a strong advantage in the lower coal consumption, saving energy and emissions, the supercritical units increasingly become the main unit in thermal power generating units. Also, with the increased capacity of the units, unit control parameters of the system are increasingly demanding quality requirements.The main stream temperature is an monitored important parameter during the operation of the unit, which is too high or too low will affect the safe operation of the unit. The main stream temperature of supercritical units is an complex objects with large inertia, large delay, nonlinear and time-varying characteristics. Conventional PID control strategy is difficult to obtain satisfactory control quality. In order to make the main stream temperature to achieve satisfactory results, this article introduce dynamic matrix and fuzzy control to main stream temperature control system. The secondary loop still uses PI controller and the main circuit uses dynamic Matrix Controller(DMC) and fuzzy control combined control methods. On the one hand, through the dynamic matrix controller according to the given value and the actual output, the controller output of the next few moments can be predicted. Thus it can guarantee the controller act in advance. On the other hand, through the fuzzy controller, according to the predicted output and the actual output of the deviation, it fixed dynamic matrix controller output. Thus it can enhance anti-jamming performance and control system robustness properties. The method is applied to a 600 MW supercritical unit and the simulation results show that the main stream temperature can quickly stabilize the tracking set point change, and the system is able to achieve satisfactory control effect when the main stream temperature object changed greatly and outside interference. It shows a superior robustness properties and robustness.