燃气发电锅炉主汽压滑模预测优化控制策略

Sliding Mode Predictive Optimization Control Strategy of Main Steam Pressure in Gas-Fired Power Boiler

针对燃气发电锅炉主汽压控制的非线性、纯滞后和强干扰特点,提出了一阶时延模型的主汽压滑模预测优化控制策略。利用广义预测控制对滑模控制器的增益及主汽压作出实时预测,根据主汽压预测偏差对滑模增益进行反馈校正和滚动优化,以降低滑模控制系统的抖振。对煤气调节阀的流量特性进行非线性补偿,通过优化目标函数求出离散形式的最佳控制律。仿真结果表明:与常规PID、滑模控制和动态矩阵控制相比,模型适配时所提出的控制策略使调节时间最多减少19.1 s,超调量最多降低16.4%;滑模函数抖振小,系统抗干扰及鲁棒性良好。工程应用表明:使用所提策略后,系统抖振比单一滑模控制的降低60%,主汽压控制偏差小于±0.05 MPa,系统稳定性和抗干扰能力明显提高。

Aiming at the characteristics of non-linearity,pure lag and strong interference in the main steam pressure control of gas-fired power boilers,a first-order time-delay model of the main steam pressure sliding mode predictive optimization control strategy is proposed.The generalized predictive control is used to make real-time predictions of the gain and main steam pressure of the sliding mode controller.According to the prediction deviation of the main steam pressure,feedback correction and rolling optimization are exerted on the sliding mode gain to reduce the chattering of the sliding mode control system.By providing a nonlinear compensation to the flow characteristics of the gas control valve,the best control law in discrete form is obtained via optimizing the objective function.Compared with conventional PID control,sliding mode control and dynamic matrix control,the simulations show that the proposed control strategy during model adaptation reduces the adjustment time by up to 19.1 s and the overshoot by up to 16.4%;the sliding mode function chattering is small,and the system has good anti-interference,following and robust performances.The engineering application indicates that once adopting the proposed strategy,the system chattering is reduced by 60%compared with single sliding mode control,the main steam pressure control deviation is less than±0.05 MPa,and the system stability and anti-interference ability are significantly improved.