Flexible and Modular Model for Smart Trolleybus Grids

The reduction of climate-changing emissions is vital, especially in urban areas. To reach this goal, the decarbonization of the public transport sector is crucial. Dynamic conductive power transfer through catenary systems is potentially a carbon-neutral solution. This paper focuses on trolleybus grids, already established in several metropolises, which are re-emerging as a smart city-oriented electrified transport system. A better integration of trolleybus grids with renewable sources, energy storage, and the existing electric network of the urban area is necessary to increase the efficiency of the system and optimize energy flows, favouring the transition towards smarter and greener cities. Moreover, trolleybus systems may act as a DC backbone for charging stations powering private electric vehicles, thus contributing to a closer interconnection between public and private mobility. A modular model of the electric traction grid in Matlab-Simulink is explored to simulate the actual complexity of novel trolleybus network topologies. By means of graphical and numerical results illustrating the behaviour of the main electrical line parameters, the model flexibility towards the inclusion of smart city-oriented technologies, such as stationary battery energy storage systems and electric vehicle chargers, is verified in this work. The trolleybus electrical infrastructure of the city of Bologna was chosen as a case study.