Battery charger plays an important role in the battery and electric vehicle technology. Due to on-board type of charger it should be light in weight and should occupy less space as it should be on the vehicle all the time, so the smaller the better and of course, it is very important to minimize the cost of the charger. For a plug-in hybrid electric vehicle (PHEV), when the battery is charging from the grid, the vehicle should be parked. The traction system components are normally not engaged during the charging time, thus it is possible to reconfigure these components for the battery charger system. In this paper, an innovative integrated battery charger is presented. The operation mode of charger can be divided into three modes: boosting drive motor mode, directly drive motor mode and charging mode. The analysis of these three modes has been explained in detail and the control scheme is also introduced in this paper. The simulation model is built using Matlab/Simulink software, and simulation results have been presented to verify the operation for battery charger, showing the system has good operation performance.