The control quality of the intermediate point enthalpy of supercritical units directly affects the control quality of water-fuel ratio and main-steam temperature of the once-through boilers, it also relates to economic and stable operation of the supercritical units. In order to realize high quality control for the intermediate point enthalpy, this paper proposed a fuzzy control scheme for intermediate point enthalpy of the feed-water temperature, which overcomes the contradiction between the quick response of the intermediate point enthalpy control and the stability of separation interface of the separator. In this method, a mechanism model of the once-through boiler in a 600 MW supercritical unit is adopted as the control object, the feed-water temperature is introduced into the intermediate point enthalpy control system model, and two widely used control schemes (modifying feed-water quantity and modifying feed-coal quantity) for water-coal ratio are combined via fuzzy control. The simulation results show that, the improved intermediate point enthalpy control system for feed-water temperature has advantages of both rapid response in feed-water quantity control and stability in feed-coal quantity control, which effectively considers both the economy and safety during the regulation and gains satisfied control effect.%超临界机组中间点焓值的控制品质直接影响直流锅炉的水煤比和主蒸汽温度的控制质量,关系到超临界机组的经济安全运行.为了达到对中间点焓值高品质控制的目的,本文利用某超临界600 MW机组直流锅炉的Simulink机理模型作为控制对象,将给水温度作为前馈引入到中间点焓值控制系统模型中,将目前广泛应用的修正给水量控制方案和修正给煤量控制方案通过模糊控制相结合,提出基于给水温度的中间点焓值模糊控制方案,解决了中间点焓值控制响应快速性与汽水分离器分离界面稳定性的矛盾.仿真结果表明,改进的中间点焓值控制系统具有修正给水量控制方案的快速性和修正给煤量控制方案的稳定性,有效兼顾中间点焓值控制系统调节过程的经济性与安全性,在中间点焓值控制中得到了满意的控制效果.
展开▼
