Interactive charging strategy of electric vehicles connected in Smart Grids

Electric vehicles (EV´s) represent an important future load on the electric utility system which, if implemented in a large scale without control, may lead to grid problems such as power losses and voltage deviations. However, if properly managed, it could increase power plant utilization and reduce the average cost of generating electricity. This paper proposes and analyzes two novel interactive charging strategies for scales of electric vehicles connected in Smart Grid. The first decentralized approach is controlled directly by the electric vehicle charging controller. Six charging modes included in this strategy adjust schedule of electric vehicles charging operation automatically and ensure the charging orderly. The other is centralized charging strategy. With the aim of minimizing power losses and voltage deviations, the optimal algorithm in charging management system also takes into consideration not only the information like current SOC, the battery capacity and connecting time but also the electricity grid constraints. Both of them optimize EV´s charging schedules and charging rates. In addition, a two-way communication network based on Zigbee and other communication technology is established to ensure the implement of the interactive charging control. The success of this charging strategy can be an important theoretical meaning and promotional value for EV.