A Multi-functional Fast Electric Vehicle Charging Technique

Abstract

For many distribution network operators (DNOs), the phases to which single-phase loads are connected is unknown. This can present a problem in terms of unbalanced loading across phases, which will be significantly exacerbated by the future impact of large-scale electric vehicle (EV) charging loads. In addition, the implementation of EV charging systems can give rise to the presence of significant harmonics on power systems, as a result of converter operation. Therefore, this paper proposes a fast EV charging technique that incorporates phase balancing and harmonic suppression features. This allows multiple and important functions that are necessary for the improved operation of a local distribution network to be achieved through the installation of a single unit. Consequently, units based on the proposed technique suit the large-scale and strategic deployment in distribution networks. The paper describes the technique in detail, presenting relevant theory and the control strategy. To demonstrate the applicability of the proposed technique, simulated results of a 50 kW fast EV charger are presented under various unbalanced load conditions.