A hierarchical charging strategy for electric vehicles considering the users´ habits and intentions

With the rapid growth of electric vehicles (EVs), charging large-scale EVs will affect the security and economy of power system operation. When developing the charging strategy, not only technical and economic issues but also the patterns of EVs´ utilization should be considered. This paper presents a hierarchical charging strategy for EVs considering both system level and user level benefits, together with the travel habits and intentions of users. Firstly, a system level charging strategy is proposed as a multi-objective optimization problem, which can minimize the customers´ charging fees, reduce the peak-valley difference and smooth the load fluctuation. Then a distribution charging strategy of EVs at user level based on the users´ habits and intentions is presented, which aims for the minimization of each EV battery´s charging times based on historical travel miles and real-time State of Charge (SOC). Finally, a case study indicates the effectiveness of proposed methodology to meet the requirements of power system and users.