空调冷水二次泵压差模型不确定性的MFAC控制

Using MFAC to Control the Pressure Difference of Secondary Pump Aiming at Its Model Uncertainty

摘要:

中央空调冷水系统管路特性变化、设备老化等因素导致中央空调冷水系统二次泵压差模型具有不确定性,以致常规PID算法的调节性能变差,甚至在空调系统运行一段时间后出现不可控的现象;而无模型自适应控制(Model Free Adaptive Control,MFAC)是一种采用不依赖被控对象的具体数学模型的“泛模型”和一些“控制功能”的某种组合相结合的、具有参数自适应和结构自适应的控制方法;引入了无模型自适应控制算法,来改善中央空调冷水系统二次泵压差控制效果,确保系统的调节时间和超调量保持不变;仿真和实验结果表明:相对于PID控制,MFAC具有很强的鲁棒性和抗干扰能力及自适应能力,调节性能稳定,可以克服由于系统管路特性变化、设备老化等因素导致的中央空调冷水系统二次泵压差模型不确定性的情况,控制效果良好。

Abstract:

Some factors such as the changing pipeline characteristic make the pressure difference model of the second pump of chilled water system be uncertain in the central air condition, which maybe make the adjusting performance of PID algorithm get worse, even make the pressure difference of the second pump be out control. The MFAC (Model Free Adaptive Control) is a combined method with universal model and control function, which can runs without any model of control object and be parameter adaptive and structure adaptive. It is introduced in this paper to improve control result of the pressure difference of the second pump, which ensures that the settling time and the overshoot are good. The simulation and experiment show that the MFAC can overcome the uncertainty of model and control the pressure difference with good robust and anti-interference ability and adaptive ability comparing with the traditional PID control algorithm.