Unified Systems for Traction and Battery Charging of Electric Vehicles: A Sustainability Perspective

Abstract

This paper presents an analysis of unified systems for traction and battery charging of electric vehicles (EVs), regarding operation modes and implementation cost, when compared to dedicated systems that perform the same functionalities. Concerning the interface of the EV battery charging system with the power grid, four operation modes are analyzed: (1) grid-to-vehicle (G2V); (2) vehicle-to-grid (V2G); (3) vehicle-to-home (V2H); and (4) vehicle-for-grid (V4G), which, by using a unified system for traction and battery charging, can be linked both to single-phase and three-phase power grids. Moreover, a cost estimation is performed for EV unified systems and for dedicated systems that can perform the same functionalities when connected to the power grid, in order to prove the advantages of the system unification. The cost estimation is based on two power levels, namely 6 kW (single-phase), related to domestic installations and slow battery charging, and 50 kW (three-phase), related to industrial installations and fast battery charging. The relevance of unified systems for traction and battery charging of EVs is proven for single-phase and three-phase power grids both in terms of operationality and implementation cost.