Optimal Control Framework and Scheme for Integrating Plug-in Hybrid Electric Vehicles into Grid

With the growing plug-in hybrid electric vehicles (PHEVs) integrated into the power grid, a large number of onboard batteries need to be charged via the infrastructure such as dedicated charging station and the parking lots. In this paper, a control framework is proposed to manage the charging and discharging by using vehicle-to-grid technology. In order to analyze the effect of the PHEV charging to the grid and the corresponding coordinated strategies, this paper describes a simulation model. Initially, the uncontrolled PHEV charging scenarios are performed. The load flow algorithm is applied to calculate the power distribution and power losses on a 33-bus test system. The results indicate the inadequacy of the current power system capacity for the growing electricity demand from PHEVs. Therefore, an optimal control algorithm is derived for PHEV charging and discharging to minimize the total real power loss. Compared to the uncontrolled PHEV charging results, the optimal control algorithm can achieve the maximum loss reduction. Moreover, the voltage drop at each node is limited within a tolerable range while the tightened branch current restrictions are satisfied.