Storage Device Sizing for a Hybrid Railway Traction System by Means of Bicausal Bond Graphs

In this paper, the application of bicausal bond graphs for system design in electrical engineering is emphasized. In particular, it is shown how this approach is very useful for model inversion and parameter dimensioning. To illustrate these issues, a hybrid railway traction device is considered as a case study. The synthesis of a storage device (a supercapacitor) included in this system is then discussed

Bond-graph-based model simplification for system analysis: application to a railway traction device

Heterogeneous and multifield systems can be homogeneously modelled using bond graphs. Even if this formalism contributes to making the system analysis easier, simplifying the device modelling as much as possible is also required in order to obtain the ‘just accurate enough model’ with respect to the design objectives. Two simplification methods are investigated in this paper: the model order reduction algorithm (MORA), depending on the energetic transfers in the systems, and the singular perturbation method (SPM), based on element dynamics. Each method is directly applied on bond graphs. To illustrate their application, a railway traction device is considered as an example. The results obtained by both methods are compared and the conditions of use are analysed. Finally, these two processes have proved their efficiency to reduce the computation time and to simplify the system analysis