Enhancing phase balance in electric vehicle clusters: a smart charging approach using phase mode switching

European low voltage distribution systems are primarily three-phase four-wire networks, where the three phases have uneven load connections. With the rising number of electric vehicles (EVs) in the market, the charging behaviors of the single-phase EVs are inevitably leading to a more severe phase unbalance issue in the grid. To address such concerns, this paper proposes a smart charging control scheme that utilizes phase mode switching functions of electric vehicle supply equipment (EVSE). The connected three-phase EVs can be switched to single-phase charging mode by charging only at the first phase, hence alleviating the congestion on the other phases of the cluster. A case study using charging data from a real-world situation in a public working place in Athens is conducted, to demonstrate the functionality of the proposed phase mode switching method. The simulation outcomes reveal that the phase mode switching scenario reduces the collective charging time by 8.4% and improves maximum phase power unbalance by 31% compared to the benchmark scenario. The results indicate that the smart charging control manages to effectively mitigate the phase power unbalance issues among three phases and allows the cluster to charge with more flexibility.