A broadcast mechanism for real-time charging control of a fleet of plug-in electric vehicles

Since the adoption of plug-in electric vehicles (PEVs) is constantly increasing, in the coming years electrical distribution networks will face the problem of accommodating for massive and unpredictable extra loads with diverse operating patterns. In this paper, we propose a semi-decentralized architecture to control the charging process of a fleet of PEVs. To study the impact on a low voltage (LV) distribution grid, we first simulate an uncontrolled charging strategy, where PEVs start to charge at the rated power, as soon as they are plugged into the grid. This leads to practical issues, such as the transformer overloading, feeders overloading, voltage drops and high power losses. For alleviating the mentioned issues in scenarios with high penetration of PEVs, we propose a charging control strategy that allows to compute the charging power of each PEV using local controllers. The input for the local controllers is a coordination signal, computed in real-time by a central control unit, on the base of the grid state. Numerical simulations show the benefits of the proposed controlled charging strategy in terms of reduction of overloading, voltage drops and power losses. The proposed mechanism relies on broadcast information only, which is attractive for practical implementation.