High-voltage battery charging system for use in electric vehicle

A high-voltage battery charging system is installed in a vehicle body of the electric vehicle for charging a high-voltage battery unit within the vehicle body. The high-voltage battery charging system includes a rectifier circuit, a power factor correction circuit and a non-isolated DC-DC converting circuit. The rectifier circuit is connected to a common terminal for rectifying an AC input voltage into a rectified voltage. The power factor correction circuit is connected to the rectifier circuit and a bus for increasing a power factor and generating a bus voltage. The non-isolated DC-DC converting circuit is connected to the power factor correction circuit and the high-voltage battery unit for charging the high-voltage battery unit, wherein no transformer is included in the non-isolated DC-DC converting circuit.