基于动态扩展算法的大型燃煤机组非线性协调控制系统设计

Design of Nonlinear Coordinated Control System Based on Dynamic Extended Linearization for Large-sized Coal-fired Power Units

为了从根本上解决单元机组在大范围变工况时的协调控制问题,克服非线性特征对系统控制品质的影响,论文应用反馈线性化原理,对大型燃煤机组的协调控制问题进行了直接非线性控制的研究。针对被控对象的特点,引入相对阶向量的动态扩展算法,得到了单元机组简化非线性模型的输出反馈控制律,该控制律可以实现全局意义下的精确反馈线性化,对线性化变换有定义的整个区域都是适用的;针对反馈线性化律作用下的伪线性系统,设计了二自由度I-PD控制结构,简单而有效地解决了伪线性系统对扰动敏感、鲁棒性差的问题,确保输出变量的精确跟踪。通过比较系统闭环传递函数与期望传递函数的对应项系数,可以方便整定出控制器参数。求得的控制器由比例或积分环节构成,形式简单,便于工程实现。在500MW燃煤机组非线性模型上的仿真试验证明了该协调控制系统的负荷跟踪能力、抗干扰性能及鲁棒性。

For overcoming the influence of process nonlinearities and improving the load-following capability, a nonlinear coordinated control system was developed for the large scaled coal-fired power units. Aiming at the characteristic of power generation units, feedback control law was deduced via the extension algorithm of vector relative degree. By the law, exactitude feedback linearization in universal can be realized. Then a two-degree-of-freedom I-PD structure was presented to improve the robustness and exact tracking of the pseudo-linear boiler-turbine system which was obtained by the feedback control law. Parameters of controller were tuned by comparing with corresponding coefficients of an anticipant close-loop transfer function matrix. Because of the simple form of controllers （composed with proportion or integral）, it can be realized in field easily. Several simulations based on a real 500MW boiler-turbine model were tested to prove the performance of the nonlinear coordinated control system.