Study On Steam Temperature Control Of Supercritical Once-through Boiler

Since its introduction into China in the 1980 s,supercritical units have made important contributions in saving energy and relieving environmental pressure.They are one of the units that have been vigorously developed in recent years.However,compared with the traditional unit,the supercritical unit system has a complicated structure,which brings many new challenges to the field operators.The stable control of the main steam temperature has always been a difficult point in supercritical boiler control.The water spray desuperheating system using PID controller is one of the most effective ways to control the main steam temperature.However,the main steam temperature object has large inertia and large delay.The conventional PID controller has the disadvantages of untimely control and poor anti-disturbance capability.In order to improve the performance of the PID controller,based on the establishment of the controlled object mechanism model and the identification object transfer function,the fuzzy control concept is introduced and the fuzzy PID controller is designed.The new controller can be based on the deviation and deviation variation in real time.The parameters of the PID control are modified to improve the dynamic performance and anti-interference ability of the system.The control effect of the large inertia large delay object is significantly improved compared with the conventional PID controller.The intermediate point temperature has a great influence on the stability of the main steam temperature.In this paper,while studying the fuzzy PID controller,the disturbance channel model of the intermediate point temperature to the outlet steam temperature is identified,and the feedforward controller is designed.The simulation results show that the fuzzy PID control system with intermediate point temperature feedforward has good dynamic characteristics and strong anti-interference ability.