基于多模型切换的锅炉主蒸汽温度预测控制

Multi-model switching based predictive control for main steam temperature in boiler

火电厂锅炉主蒸汽温度具有大迟延、大惯性、参数时变等特点,当工况发生大的变化时,采用基于单一模型的传统PID控制难以维持满意的控制效果。为此,提出一种基于多模型切换的预测控制方法。首先建立多个典型工况的对象模型;再设计不同模型下的最佳动态矩阵控制器;然后设计切换策略选出最合适的控制器来削弱变工况(特别是负荷变化)对主蒸汽温度系统的影响;最后通过Matlab仿真验证所提方法的有效性。仿真结果比较分析表明,多模型动态矩阵控制方法优于传统PID控制,多模型切换提高了固定参数模型预测控制的鲁棒性。

The main steam temperature in the thermal power plant boiler has the characteristics such as large delay,strong inertial,time varying parameters and so on.When the condition changes greatly,it is difficult to maintain satisfactory control results using traditional PID control based on a single model.To solve this problem,this paper presents a predictive control method based on multi-model switching.Firstly,the object models are established under a number of typical conditions.Secondly,the best dynamic matrix controller under different models are designed.Thirdly,the switching strategy is designed to select the most appropriate controller to mitigate the effects of varied operating conditions(especially load changes)on the main steam temperature system.Finally,the validity of the proposed method is verified through Matlab simulation.The simulation results show that the proposed method is superior to the traditional PID control,and the multi-model switching improves the robustness of the fixed parameter model predictive control.