基于模型预测的定风量系统串级控制研究

Model Predictive-Based Cascade Control of Constant Air Volume Air-conditioning System

针对定风量系统室内温度的控制,提出了一种基于模型预测的串级控制方法,用以提高室内温度控制的鲁棒性和精确度。该方法根据实时的负荷情况,利用送风温度预测模型预测系统需要的送风温度,并以此作为设定值,通过冷水阀门开度调节进行控制,使得送入空调区域的冷量始终满足负荷需求,进而实现室内温度的鲁棒控制。采用TRNSYS软件建立定风量空调系统模拟平台,对该控制方法的控制特性进行测试。测试结果表明,相比传统的比例积分(PI)算法直接追踪室内温度的方法,提出的串级控制方法能够明显的提高室内温度控制的鲁棒性和精确度。

This paper proposes a model predictive-based cascade control method for the space air temperature control of constant air volume(CAV)system aiming at improving the robustness and accuracy of the space air temperature control.This method uses the supply air temperature prediction model to predict the system demand supply air temperature based on the real-time load condition.The predictive value is used as the set-point and controlled by adjusting the cold water valve opening.It can guarantee the cooling capacity supplied to the air-conditioning area always to satisfy the load demand for realizing the robust control of the space air temperature.TRNSYS software was used to build a simulation platform of the CAV air-conditioning system to test the control performance of the control method.The results show that the cascade control method proposed in this paper can improve the robustness and accuracy of the space air temperature control significantly when compared with the method using conventional PI algorithm to track the space air temperature directly.