基于扰动观测器的压缩式制冷系统改进Smith预估解耦控制

Improved Smith Predictive Decoupling Control Based on Disturbance Observer for Compression Refrigeration System

为解决压缩式制冷系统运行时存在的时滞、耦合及外部干扰等问题,提出一种基于扰动观测器(DOB)的改进Smith预估解耦控制方案.首先,在常规Smith预估控制结构中引入DOB对系统总体扰动进行观测;然后,利用一阶Pade近似将系统模型中的时滞环节做线性化处理,进而通过串联对角矩阵的方式实现系统解耦;最后,根据ITAE(Integral of Time-weighted Absolute Error)最小评价准则完成控制器参数整定,并分析了系统鲁棒稳定性.仿真结果表明:该方法较好地实现压缩式制冷系统解耦的同时,使系统获得了更强的鲁棒性及抗扰性,并且约有0.6%的节能效果.

Since compression refrigeration system has problems of delay, coupling and external disturbance, an improved Smith predictive decoupling control based on disturbance observer has been proposed. First, the disturbance observer is used to observe overall disturbances of the system in the conventional Smith predictive control structure. The time-delay element is linearized by first-order Pade model. Then a diagonal matrix is applied to decouple the compression refrigeration system. Finally, the tuning of the controller parameter is realized based on the minimization of ITAE criterion, and the robust stability of the whole control system is discussed. Through the simulation, the proposed method can provide a better decoupling, better robustness and immunity for the compression refrigeration system. Moreover, it saves about 0.6% energy.