基于多变量内模解耦的CFB锅炉燃烧控制研究

Study on CFB Boiler Combustion Control Based on Multivariable IMC Decoupling Strategy

为提高CFB锅炉燃烧系统的自动控制品质,分析了系统主蒸汽压力和床温对象在调节过程中的相互作用,提出解耦的系统控制结构.通过选取上述强耦合对象,以一次风量和给煤量作为调节量,采用补偿的多变量内模解耦控制策略实现了该两输入两输出(TITO)系统的解耦.给出了解耦控制器的详细设计过程,通过设计能够有效抵消缓慢极点或主导极点的滤波器以加快响应速度.在综合ISE指标的基础上发展了基于超调量和调节时间的参数整定指标.对所设计控制器进行次最优降阶,并验证输入、输出扰动性能和模型失配鲁棒性,仿真结果表明:所采用的解耦控制策略是有效的.

To improve the automatic control quality of CFB boiler combustion system,ageneral decoupling control structure was proposed for the system based on analysis of the interaction between main steam pressure and bed temperature in the adjustment process.Taking the primary air flow and the coal feed rate as adjustment variables,the decoupling of this strongly coupled two-input two-output(TITO)system was achieved through the use of compensated multivariable decoupling internal model control(IMC)strategy. Design process of the decoupling controller was described in detail,while an improved filter designed to effectively offset the slow or dominant pole during the process to speed up response.Parameter tuning index based on overshoot and settling time of response was developed on the basis of comprehensive ISE index. By applying the suboptimal model reduction to the controller and verifying its robustness in the case of input/output disturbance and model mismatch,the decoupling strategy is proved to be effective.