The electrification of transport is one of the key parts of the present aim to reduce undesirable vehicular emissions in the atmosphere. While the full electrification of personal vehicles is mostly associated with employing a big battery pack on the board and charging on (static) charging stations, another interesting possibility appears in the case of public transport -dynamic drawing of the power from overhead wires. Regarding vehicles moving on the road, this concept is used by trolleybuses or hybrid trolleybuses, i.e. vehicles combining power from the overhead wires and batteries.A replacement of classic buses (with a combustion engine) with (hybrid) trolleybuses is hardly possible without an appropriate adjustment of public transport lines and the necessary infrastructure. For this purpose, a simulation of the adjusted public transport service may be used to identify weaknesses of the proposed solution.This paper presents a new vehicle device and a new additional part of road infrastructure in SUMO. It introduces device.elecHybrid based on existing device.battery, extending its functionality and tailoring it for the needs of hybrid trolleybuses. In addition, overhead wires and traction substations are implemented. As the voltage and electric currents in the overhead wires depend on traffic, the overhead wire parameters are optionally evaluated by a built-in electric circuit solver using Kirchhoff's laws.The proposed changes allow us to simulate hybrid trolleybus in-motion charging under the overhead wire. The extensions can be immediately used in micro-simulations or even (in a simplified version) in the meso-simulation mode.
Proper traffic simulation of electric vehicles, which draw energy from overhead wires, requires adequate modeling of traction infrastructure. Such vehicles include trains, trams or trolleybuses. Since the requested power demands depend on a traffic situation, the overhead wire DC electrical circuit is associated with a non-linear power flow problem. Although the Newton-Raphson method is well-known and widely accepted for seeking its solution, the existence of such a solution is not guaranteed. Particularly in situations where the vehicle power demands are too high (during acceleration), the solution of the studied problem may not exist. To deal with such cases, we introduce a numerical method which seeks maximal suppliable power demands for which the solution exists. This corresponds to introducing a scaling parameter to reduce the demanded power. The interpretation of the scaling parameter is the amount of energy which is absent in the system, and which needs to be provided by external sources such as on-board batteries. We propose an efficient two-stage algorithm to find the optimal scaling parameter and the resulting potentials in the overhead wire network. We perform a comparison with a naive approach and present a real-world simulation in the part of the Pilsen city in the Czech Republic. These simulations are performed in the traffic micro-simulator SUMO, a popular open-source traffic simulation platform.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.