Intelligent charging strategy for PHEVs in a parking station based on Multi-objective optimization in smart grid

With the increasing popularity of Plug-in Hybrid Electric Vehicles (PHEVs), the public charging infrastructure construction such as charging station and PHEV charging enabled parking station has also appeared. The problem of scheduling large-scale of PHEVs in such centralized charging infrastructure should be considered to avoid adverse effects on the power system because of their uncontrolled charging. For example, lots of PHEVs´ charging simultaneously at period of peak-load may pose a wide pressure on the grid´s peak regulation. In this paper, an intelligent charging strategy which can decide each PHEV´s charging power at each time step is proposed for a cluster of PHEVs in a parking station based on time of use (TOU) price. A mathematic optimal model with the muti-objective function (i.e. minimizing the charging cost and minimizing load variance) is also given considering several constraints such as the chargers´ power limit and charging efficiency. The proposed strategy only considers PHEVs as controllable load, but it´s also applicable to situations where other controllable load are added in the future. In this paper, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used to solve the optimization problem and the matlab calculation results validate the effectiveness of the proposed strategy.