二自由度模型驱动PID控制系统参数整定方法及应用

Parameter tuning method for two degree of freedom model driven PID control and its application

针对工业生产过程中存在的大迟延及大惯性特性,或者存在的开环系统不稳定特性的一类难控对象,为了提高其控制性能,使用一种二自由度模型驱动PID控制系统。该系统可以通过比例微分补偿器将此类实际被控生产过程转变成带有时滞的一阶等效被控对象,并使得等效对象的时间常数比实际被控过程小的多。分析了该系统的结构设计原理及参数整定方法,并将其应用到具有大时延及大惯性特点的循环流化床锅炉主蒸汽压力自动控制系统中。实验结果表明,该系统比经典PID控制和模糊自校正PID控制具有更好的设定值跟踪能力和更强的抗干扰性能。同时该系统结构简单,实时性好,控制参数易于整定,方便采用生产现场使用的DCS系统组态实现,易于推广应用。

In order to improve the control performances of the large inertia with large time delay process and the unstable process,the two degree of freedom model driven PID control system are in-troduced. The actual controlled process can be changed into a first-order model with dead time by PD feedback compensator of the system. The time constant of the first-order model is much smaller than that in actual controlled process. Its structure design principle and the parameter tuning method are analyzed. It is applied to the main steam pressure controlled process with large inertia and large time delay of the circulating fluidized bed boiler. The research results show that the two degree of freedom model driven PID control system has better control performance than the conventional PID control system and the fuzzy auto tuning PID control system. It has the advantages of simple structure,good real-time performance,and its design and implementation are very convenient in the DCS system. So it is easy to be popularized and applied.