基于智能积分的电站锅炉主汽温PID控制

Main Steam Temperature PID Control of an Utility Boiler Based on the Intelligent Integration

分析了PID控制算法与热工被控对象数学模型的关系,指出误差及导数结果中包含关于热工对象的丰富信息,加强对这些信息的分析可以提高PID控制器的性能。闭环系统在阶跃扰动下的动态过程可分为两个阶段:第一个阶段是处于远离热力学平衡态的非平衡定态。在较长的时间内围绕其某个固有频率维持高阶振荡。第二个阶段是闭环系统进入了线性非平衡热力学范围,PID调节器退化为积分调节器。以系统自由能耗散率为参数,提出了基于智能积分的PID控制算法,能动态改变比例增益和积分作用,有效地提高系统快速性和稳定性。通过某锅炉主汽温对象的仿真实验表明,其性能优于常规PID控制器。

Analyzed was the relationship between the PID control algorithm and the mathematical model for thermotechnical controlled objects and pointed out were that aboundant information about the thermotechnical objects is contained in the errors and derivative results.To strengthen the analysis of the foregoing information can enhance the performance of the PID controllers.The transient process of a closed loop system under a stepped disturbation can be divided into two stages: the first stage is a non-balanced stationary state away from the balance state in thermodynamics.In a relatively long time period,the CFB boiler,flying ash,nitrogen isothermal adsorption,pore structure intrinsic frequency will maintain its high order oscillation.The second stage is that the closed loop system enters into its linear non-balanced thermodynamic range.In such a case,the PID controllers will be degraded to integral ones.With the free energy dissipation rate of the system serving as a parameter,a PID control algorithm was proposed based on an intelligent integration.The algorithm can transiently change the proportional gain and integration action,and effectively enhance the speediness and stability of the system.A simulation test of the main steam object of a boiler indicates that the performance of the control algorithm is superior to that of conventional PID controllers.