基于IMC和两级减温器相互配合控制的过热汽温控制方案

Superheated Steam Temperature Control Strategy Based on IMC and Two Desuperheaters Coordinate Control

针对大型火力发电厂的锅炉过热器出口蒸汽温度所具有的滞后特性、非线性和时变特性,设计了一种基于内模控制(IMC)和两级减温器相互配合控制的模糊PID串级控制方案,在国电龙山电厂2号机组2 070 t/h锅炉上测试该方案,调试结果表明,与已经得到广泛应用的串级PID控制方案相比较,该方案在稳态性能和动态性能上均有优良的调节品质,不仅能快速将扰动带来的影响转移到一级减温器,而且还能保证二级减温器的调节阀位始终处在比较理想的位置,对其他扰动仍有调节余地,明显提高了系统的抗变换性和控制效果。

The outlet temperature of boiler super heater in large scale thermal plant is with big-lagged,nonlinear and time-varying. A cascade control strategy of fuzzy PID based on internal model control principle and coordinate desuperheaters control was proposed. This control strategy was applied to 2 070 t / h boiler of No. 2 unit in Guodian Longshan power plant. The result of commissioning indicates that the new control strategy has better control quality than the traditional cascade PID control scheme that has been widely applied on either steady performance or dynamic performance. The effect of any disturbance can be quickly transferred to the first-stage desuperheater,and the second-stage desuperheater control valve can be always kept in appropriate position so as to respond to other disturbance with some leeway. The robustness of the system is obviously strengthened and better control effect is obtained.