Toward Ultrafast Charging of Electric Vehicles
The paper is devoted to the problems arising from the ultrafast (≤ 10 min) charging of an electric vehicle (EV). An ultrafast charging station (UFCS) must provide high power output with minimal influence on the electricity transmission system, which can only be achieved by the application of energy storage acting as an additional buffer between the vehicle and the grid. Besides storage, interfaces between a fast charging station and the outside environment (vehicle, utility grid) must be designed to fulfil a set of requirements. The main challenge is to be found within the specification of parameters for the design of future energy supply systems, providing for fast charging of the vehicle batteries while avoiding solicitations of the local distribution system which exceed its instantaneous power capabilities. The possible impact of an UFCS on the power distribution system is analysed with the stochastic approach, based on the utilisation of such a station. The general aspects of highly variable load profile clearly include the use of energy storage means that must be specified regarding both the energy storage and the instant power capabilities. Different technologies are analysed in terms of performances and costs. In conclusion, one of the important problems facing electric vehicles is the possibility of short-time charging, both as seen from the EV battery itself as well as from the local supply system. In this context, large load variations as seen from the local power system, at multiple levels, must be carefully assessed with special attention to feasible load changes at the coupling points. By addressing these technical issues as well as the financial constraints, the research aims at providing viable solution for broad ultrafast charging systems integration into the power distribution infrastructure.