Application of Quantized Discrete Event Simulation Methods to Naturally Coupled Systems

摘要

A method for applying quantized discrete event simulation (DEVS) methods to naturally coupled system models is defined. Pairing the DEVS formalism with the Modified Nodal Analysis technique allows for asynchronous discretization of events, instead of the typical uniform time discretization while automatically enforcing natural conservation laws, unlike signal flow methods that propagate the output of one model to the next without adding physical constraint equations. The mathematical equations for naturally coupled DEVS (NCDEVS) are presented along with example formulations for inductor and capacitor circuit elements. Results from application of the technique to an RLC circuit and to an LC filtered Half-Wave rectifier driving a Permanent Magnet DC Motor (PMDC) are presented and shown to be close to the well known analytical solutions. A significant benefit of the NCDEVS formulation is that it allows bi-directional power flow, as shown in the case of the PMDC motor, therefore the solver doesn't need to be aware if the PMDC motor acts as a motor or as a generator. Moreover using NCDEVS, the motor is modeled by one set of equations, regardless of the operating mode, in contrast to the signal flow method, where the solver needs to have two separate models, one for each case.