Abstract
This paper presents a new technique for a controlled charging/discharging of the PHEV's battery considering the network status on a real-time basis. A control strategy is developed to secure the operation of power system irrespective of the number of vehicles and their connection place. The proposed control strategy utilizes an improved normalized steady-state voltage stability index that is easy to compute in the distribution management systems. A fuzzy logic controller (FLC) is used for evaluating the battery level of charging/discharging of individual PHEV connected to the distribution network. The controller is a part of the smart charger which uses the battery state of charge and the stability index as input variables. Based on the FLC output, the interface converter of a PHEV decides the desired charging/discharging levels of the battery. The developed controller ensures the secure operation of the distribution system during charging since only empty batteries will have a high priority to charge. A time domain, as well as 24-hour time-series simulations, are used to test the proposed control method. The results show that the developed control method guarantees secure operation, whatever the number and location of PHEVs connected to the studied system.