A plug-in hybrid electric vehicle (PHEV) uses an internal combustion engine to extend its cruising range, and to produce the electric power needed to be supplied to its electric motor when the charge level of the vehicle's battery becomes low and reaches a predetermined state of charge (SOC). Because of environmental issues, utilizing a gasoline-powered internal combustion engine in a PHEV is not an optimal solution. This paper provides a better solution by replacing the internal combustion engine with a small-size photovoltaic (PV) module mounted horizontally on the roof of the PHEV, and so this study proposes a novel battery/PV hybrid power source to be utilized in PHEVs. The proposed power source equipped with vehicle-to-grid (V2G) technology utilizes a 19.2 kWh Lithium (Li)-ion battery as the main energy storage device and a 200 W PV module as the clean and renewable energy based auxiliary power source. A prototype of the battery/PV hybrid power source has been constructed, and experimental verifications are presented that explicitly demonstrate utilizing the PV module adds 13.4 km to the cruising range of a PHEV with the weight of 1880 kg in a normal operation of the PHEV during two sunny days, and provides higher power efficiency (91.1%) and speed (121 km/h). Highly accurate DC-link voltage regulation and producing an appropriate three-phase stator current for the traction motor by using PWM technique are the other contributions of this work.