Optimal Control of Stationary Lithium-Ion Capacitor-Based Storage Device for Light Electrical Transportation Network

Storage systems are recognized as a viable mean for improving the performances of electrified transportation systems. The recent literature highlighted some significant solutions to design problems thanks to procedures-based upon optimization theory. More specifically, an analytical solution can be deduced based on the formulation of an isoperimetric problem. This formulation exhibits the intrinsic ability to determine the optimal storage size, once the train power absorption has been fixed. Unfortunately, the analytical expression is not very advantageous to the control because it includes terms that require both real-time traction load estimation and its prediction over the whole traction cycle. The originality of this paper lies in the suitable simplification of the control structure, avoiding both traction load estimation and the heavy computations linked to predictive analysis. The storage device control law is reduced to an appropriate constant voltage over the whole traction cycle. The traction load prediction is performed offline, and the robustness of the consequent control law is tested against random variations in significant traction parameters. Some comparisons are made using other control strategies proposed in the technical literature. Finally, numerical and experimental results confirm the validity of the affected assumptions.