模糊自整定PID在脱硝控制系统中的应用

Application of the Fuzzy Self-Turning PID in the Denitration Control System

针对火电厂脱硝控制系统的大迟延、非线性、时变等特点,提出了一种模糊自整定PID控制策略。对脱硝控制系统中选择性催化还原(SCR)烟气脱硝原理和传统的出口NOx控制策略进行了研究。根据系统的性能指标,确定了PID参数的模糊规则整定表。分析了初始论域对系统控制性能的影响,根据遗传算法得到初始的PID参数,利用模糊推理原则修改PID参数,以满足被控对象变化时的需求。通过Matlab对不同负荷下的被控对象进行了仿真。其结果表明:与传统PID控制策略相比,模糊自整定PID控制策略在快速性、准确性、鲁棒性方面有了明显的提升。该控制策略可有效应用于脱硝控制系统。

In accordance with the characteristics of NOX reduction control system in coal - fired power plant, e. g. , large time delay,non - linearity and time - varying, etc. ,a control strategy based on fuzzy self - tuning PID is proposed. The principle of selected catalytic reduction（ SCR） flue gas denitration and traditional outlet NOX control strategy in NOX reduction control system are studied. Then, according to the performance indexes of system,the fuzzy rule tuning table of PID parameters is determined. The influence of the initial domain on control performance of system is analyzed, the initial PID parameters is obtained according to genetic algorithm, and the PID parameter are modified by the fuzzy inference principle, to meet the demand for varying controlled object. Simulation of controlled objects under various loads is conducted by using Matlab. The results show that comparing with the traditional strategy, the rapidity, accuracy and robustness have greatly improved by the fuzzy self - tuning PID control strategy. This control strategy can be effectively applied in the NOX reduction control system.