Modeling of hybrid control systems using the DEVSLib Modelica library

DEVSLib is a free Modelica library, developed by the authors, that supports the Parallel DEVS formalism. The library is mainly designed to model discrete-event systems. It also includes interfaces to communicate the DEVSLib models with the rest of the Modelica libraries. Thus, the library can be used in the development of multi-domain and multi-formalism hybrid models using the object-oriented methodology supported by Modelica. This manuscript presents the hybrid system modeling capabilities included in DEVSLib. In particular, these functionalities are applied to the description of hybrid control systems. A case study of a supermarket refrigeration system, using the traditional control approach, is discussed. Three implementations of the plant and its controllers have been developed and are described. The system is simulated reproducing the day and night conditions, and the results from the three implementations are compared. DEVSLib is freely available for download at http://www.euclides.dia.uned.es.

Research highlights
► DEVSLib is a free Modelica library that supports the Parallel DEVS formalism.
► DEVSLib functionalities to describe hybrid control systems are discussed.
► The library can be used to describe discrete-time and event-based controllers.
► DEVSLib includes interfaces to combine its models with other Modelica libraries.
► A supermarket refrigeration system is included to ilustrate these functionalities.