Plug-in electric vehicles (PEVs) will rapidly receive much more attention as a global transportation facility. Although PEVs have an environmental advantage, the charging/discharging process may cause many challenges for the electric power utilities. Therefore, it is crucial to study and analyze the influence of connecting PEVs on power distribution systems. For instance, microgrids can effectively integrate PEVs alongside distributed generators (DGs), control systems, protection devices, energy storage systems, and various load types. Consequently, microgrids can benefit from the charging/discharging process of PEVs. This paper presents a complete model of grid-connected microgrid combining micro wind turbine generator (MWTG), photovoltaic arrays (PV), and PEVs. The aim is to study the impact of PEVs charging/discharging process on the voltage stability of the microgrid. For this purpose, electric transient analyzer program (ETAP) is employed as the computer simulation platform. Various simulation results show the influence of PEVs penetration on the microgrid and its obvious effect over the voltage levels of the power system.