新型电力系统中，火电机组的深度、频繁调峰给SCR烟气脱硝系统带来剧烈的干扰，抗扰动成了SCR控制系统的核心任务，传统的串级PID控制难以满足机组深度调峰的需求。自抗扰控制(ADRC)在扰动抑制方面优势显著，但是先进控制理论存在突出的理论严谨性与工业实用性之间的矛盾，难以在工程应用中推广。为此，本文提出了一种两步重构的SCR烟气脱硝系统抗扰PID控制方法。第一步，对控制对象进行分解，将普通串级PID控制重构成串级自抗扰控制(CADRC)；第二步，基于扰动估计和补偿原理，将串级自抗扰控制(CADRC)重构成抗扰PID控制；然后基于H∞控制整定控制系统参数。仿真实验证明，抗扰PID控制继承了自抗扰控制(ADRC)突出的扰动抑制能力，而且鲁棒性好、结构简单，其控制品质优于普通串级PID控制，具有良好的工程应用前景。两步重构抗扰PID控制是借力PID的工程基础实现自抗扰控制(ADRC)平滑应用的又一典型案例。

In the new power system, the deep and frequent peak regulation of thermal power units brings severe disturbances to the SCR flue gas denitrification system, disturbance rejection has become the primary task of SCR control system，and traditional cascade PID control is difficult to meet the needs of deep peak regulation of units.Active Disturbance Rejection Control (ADRC) has significant advantages in disturbance rejection,but advanced control theory has a prominent contradiction between theoretical rigor and industrial practicality, making it difficult to apply in engineering.Therefore, in this paper,a? disturbance rejection PID control method based on two-step reconstruction for SCR flue gas denitrification system is proposed.The first step is to decompose the control plant and reconstruct the ordinary cascade PID control into cascade active disturbance rejection control (CADRC);The second step is to reconstruct the cascaded active disturbance rejection control (CADRC) into disturbance rejection PID control based on disturbance estimation and compensation principles;Then adjust the control system parameters based on H∞ control.The simulation experiments have shown that disturbance rejection PID control inherits the outstanding disturbance rejection ability of active disturbance rejection control (ADRC), and has good robustness and simple structure. Its control quality is superior to ordinary cascade PID control, and it has good engineering application prospects.The disturbance rejection PID control based on two-step reconstruction is another typical case of utilizing the engineering foundation of PID to achieve smooth application of Active Disturbance Rejection Control (ADRC).