System approach to the pre-design of electric propulsion systems for road vehicles

The current critical environmental context has increased the interest in electric vehicles. However, the evaluation of which one is the best choice, for the electric vehicle components, generally requires a series of experimental tests to be carried out, which can be quite costly and not as adequate as an engineering project must be. Therefore, this paper presents an approach, based on the RFLP method, which can help the designer, during the pre-design of an electric propulsion system, to choose the best configuration for the components of an electric vehicle power-train, reducing the costs related to physical experimentation on a laboratory test benches or on a real electric vehicle. The aim of this paper is to provide a computational tool that could virtually simulate the behavior of a designed electric propulsion system facilitating the solution of the most common problems encountered on the domain of battery-powered vehicles. The case study considered in this work is power-train for an electric scooter. The first step of this work consists in defining simulation models to simulate the power-train in terms of vehicle performance and energetic consumption. In the second step, those models are parameterized and validated through experimentations on a physical electric power-train installed in a laboratory of Istituto Motori (National Research Council of Italy). The validation of the evaluated models allows to carry out simulation tests on different alternative configurations of the electric power-train in the most varied drive conditions. At the end, the proposed model of the whole power-train system is used to carry out a study for the right design of the battery pack.