二次再热机组汽温系统的串级自抗扰预测控制

Cascade Active Disturbance Rejection Predictive Control for Superheated Steam Temperature of Ultra-supercritical Double-reheat Unit

为适应当前和未来新能源电力规模化接入电网,火电机组的深度调峰对过热汽温控制提出了更高要求,而常规的串级PID控制方案很难取得满意的控制品质。因此,提出一种动态矩阵控制与自抗扰控制相结合的串级自抗扰预测控制策略,为了克服控制量等不确定性扰动因素以及补偿时滞环节,副回路采用适应于快过程且能对扰动实时估计与补偿的离散型预估自抗扰控制器控制;为了增强系统的设定值跟踪能力和鲁棒性,主回路采用适应于慢过程的动态矩阵控制。以超超临界二次再热机组的汽温模型为仿真对象,各项性能指标计算结果表明,相比于其他串级控制,所提出的控制方法具有更加优良的设定值跟踪、抗扰动和鲁棒性等性能。

In order to adapt to the current and future large-scale renewable energy integration in grid,the conventional superheated steam temperature(SST)cascade PID control scheme of thermal power unit is difficult to achieve higher control quality under the requirement of depth peak load cycling.To this end,this paper introduced cascade active disturbance rejection predictive control strategy combining dynamic matrix control(DMC)and active disturbance rejection control(ADRC),to improve the SST control performance.Specifically,in order to overcome uncertain disturbance factors such as control variables and compensate time delay,discrete predictive ADRC control was adopted in the inner-loop,which is more suitable for fast process and can estimate and compensate disturbance in real time.And the predictor part of the aforementioned control was to predict the inner-loop output to compensate the influence of time delay.Besides,DMC adapted to slow process was also employed in the outer-loop for enhancing the set-point tracking ability and robustness.Taking the ultra-supercritical superheated temperature system as an example,simulation results show that the proposed control strategy has better performance of set-point tracking,disturbance rejection and robustness than other cascade control methods.