In order to provide a cost-effective solution for accommodating the increasing electric vehicles (EVs) and maximizing their benefits to the grid, a novel EV intelligent integrated station (IIS) making full use of ex-service batteries, is proposed in this paper. It first presents the framework and characteristics of IISs by describing its components, including a dispatching center, multipurpose converter devices, a charge exchange system, and an echelon battery system. The grid status, batteries exchanging requests, and energy capacity of IISs are monitored timely to offer inputs for its optimal operation. The concept of generalized energy is thereby introduced to systematically understand the energy/power flow between IISs and EVs, as well as between IISs and power grids. Then, a novel charging and discharging control strategy for managing EVs is presented. Compared with existing approaches, the proposed control strategy can offer peak load shifting when meeting EV battery charging/exchanging requests. The experimental results demonstrate the effectiveness and benefits of the control strategy in terms of providing peak load shifting for the power grid. This integrated station concept can maximize the benefits of EVs, and the retired batteries more flexibly and effectively.Index Terms-Electric vehicle (EV), generalized energy, intelligent integrated station (IIS), optimal charging, smart grid.

Abstract:The increasing number of electric vehicles (EVs) connected to existing distribution networks as time-variant loads cause significant distortions in line current and voltage. A novel EV's intelligent integrated station (IIS) making full use of retired batteries is introduced in this paper to offer a potential solution for accommodating the charging demand of EVs. It proposes the concept of generalized energy in IIS, based on the energy/power flow between IIS and EVs, and between IIS and the power grid, to systematically evaluate the energy capacity of IIS. In order to derive a unique and satisfactory operation mode, information from both the grid (in terms of load level) and IIS (in terms of its energy capacity and EVs battery charging/exchanging requests) is merged. Then, based on the generalized energy of different systems, a novel charging/discharging control strategy is presented and whereby the operating status of the grid and energy capacity of IIS are monitored to make reasonable operation plans for IIS. Simulation results suggest that the proposed IIS offers peak load shifting when EV battery charging/exchanging requests are satisfied compared to existing charging stations. OPEN ACCESSEnergies 2015, 8 4189

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