Supervisory Control of a Solar Air Conditioning Plant with Hybrid Dynamics

The control of solar plants is challenging for several reasons, one of which is that the solar irradiation that represents the main energy source cannot be manipulated and is subject to large fluctuations due to changes of the weather conditions. For the solar air conditioning plant considered in this work, which is located at the University of Seville, Spain, additional difficulties arise from the presence of discretely switched valves and pumps and autonomous switches of the continuous dynamics which make it a hybrid system. The main control goal for this process is to minimize the consumption of auxiliary energy while ensuring a safe and robust operation even in the face of large disturbances. The available hybrid models of the plant that are suitable for algorithmic controller synthesis or model-predictive control do not represent the process dynamics accurately enough to ensure a robust plant operation under all conditions. In this paper, a supervisory control scheme is presented that was designed based on a thorough investigation of the energetic aspects of the solar plant and on several identification experiments at the real plant. The application of the control scheme to the real solar plant and to the simulation model illustrates the robustness and the efficiency of the approach.