A Library for Synchronous Control Systems in Modelica

Abstract

Based on the synchronous language elements introduced in Modelica 3.3, a library is described to utilize the new features in a convenient way for graphical model definition of sampled data systems. The library has elements to define periodic clocks and event clocks that trigger elements to sample, subsample or super-sample partitions synchronously. Optionally, quantization effects, computational delay or noise can be simulated. Continuous-time equations can be automatically discretized and utilized in a sampled data system. This is demonstrated by using the inverse of a nonlinear plant model in the feed forward path of a discrete controller of a mixing unit.