Hybrid Predictive Control of Supermarket Refrigeration Systems: An Optimal Time Switching Strategy

This paper presents a NMPC of a supermarket refrigeration system. This is a hybrid process involving switched nonlinear dynamics and discrete events, on/off manipulated variables (valves and compressors), continuous controlled variables (goods temperatures) and finally, several operation constraints. The hybrid controller is based on a parameterization of the on/off control signals in terms of time of occurrence of events instead of using directly binary values, in this way, we can re-formulate the optimization problem as a NLP problem. Results of the hybrid controller operation are given.