多模型预测函数控制及其在槽式光热发电中的应用

Research on the multi-model predictive function control and its application in the solar parabolic trough power system

太阳能集热系统是槽式光热发电系统中的核心部分,但该集热系统具有扰动多、大滞后和大惯性等控制难点。针对这些控制难点,建立了适合控制器设计的简化分段非线性模型,并设计了基于预测函数控制策略的集热系统出口导热油温度控制系统,上述控制策略具有以下3方面特点:(1)可以解决被控对象的大滞后、大惯性问题;(2)对预测函数控制策略中的约束条件进行简化,无需进行二次规划计算,使得计算量大大减小,并易于实现工程应用;(3)结合多模型策略解决控制对象的非线性问题。研究结果表明:预测函数控制策略在调节速度、超调量以及稳定性方面的控制效果均明显优于传统PID控制策略;与未简化的多模型预测控制相比,简化后的多模型预测函数控制的最大动态偏差增大了13%,但计算量大大降低,控制器的实时性也得到增强。

The solar parabolic trough system is the core part of solar-thermal power system. But due to the shortcomings like frequent disturbance, large lags and inertia, this system is not easy robe controlled. For this, a simplified piecewise nonlinear model suitable for controller design is built in this paper. Also, an output thermal oil temperature control system is designed based on the predictive functional control strategy, which has the following three characteristics： First, problems like large lag and inertia of the controlled plant could be solved by predictive function control; Besides, constraints of predictive functional control algorithm is simplified, making it easy to perform the calculation andto be used for practice without quadratic programming; Finally, multi-model strategy was used to solve the nonlinear problems of the controlled plant. The result shows that, regardless of response time, the maximum overshoot or stability, the proposed algorithm overwhelms the traditional PID strategy, in addition, compared to the non-simplified multi-model predictive control, the maximum dynamic deviation of the simplified one is increased by 13%. However, the computational load is greatly reduced and the real-time performance of the controller is also enhanced.