为有效提高大范围变工况时单元机组的负荷适应能力,克服非线性特征对系统运行性能的影响,该文基于反推法,针对一个典型的锅炉—汽轮机单元非线性模型,经过工作点的坐标平移、模型的适当简化,将其分解为2个具有一个相同控制输入的子系统,对于各个子系统,通过合理选择虚拟控制变量,逐步构造出偏差信号的李亚普诺夫函数,进而设计出非线性机炉协调控制器,并将其转换为PID控制器形式。针对某500MW锅炉-汽轮机单元进行的仿真试验表明,基于反推PID方法的协调控制器具有良好的给定值跟随性、抗干扰性、负荷适应性和鲁棒性。
To improve the load adaptability of power generation unit and reduce the influence of process nonlinearities in wide range working conditions, a nonlinear coordinated controller of boiler-turbine unit was presented. Backstepping method and a typical nonlinear boiler-turbine unit model were adopted to deduce this controller. After coordinates transposing and model simplifying, the typical model was separated into two subsystems, which have one same input from controller. Some dummy variables were introduced to construct the Lyapunov function of output error signals for each subsystem. After deducing, the nonlinear control law was transferred to PID form that could be realized in practice easily. The dynamic performance, disturbance rejection, load adaptability and robustness of this nonlinear coordinated controller are proved by simulation tests on a 500 MW boiler- turbine units.