Hybrid modeling in Modelica based on the synchronous data flow principle

Abstract

The unique features of the object-oriented modeling language Modelica to model combined continuous time and discrete event systems are discussed. A hybrid Modelica model is described by a set of synchronous differential, algebraic and discrete equations leading to deterministic behaviour and automatic synchronization of the continuous and discrete parts of a model. The consequences of this view are discussed and demonstrated at hand of a new method to model ideal switching elements such as ideal diodes, ideal thyristors or friction. At event instants this leads to mixed continuous/discrete systems of equations that have to be solved by appropriate algorithms.