Single Stage High Power Factor Converter for Charging Applications

The proposed PFC converter features sinusoidal input current, three level output characteristic, and a wide range of output dc voltages, and it will be very suitable for high-power applications where the output voltage can be either lower or higher than the peak ac input voltage, e.g., plug-in hybrid electric vehicle charging systems. Moreover, the involved dc/dc buck conversion stage may only need to process partial input power rather than full scale of the input power, and therefore the system overall efficiency can be much improved. Through proper control of the buck converter, it is also possible to mitigate the double-line frequency ripple power that is inherent in a single-phase ac/dc system, and the resulting load end voltage will be fairly constant. The dynamic response of this regulation loop is also very fast and the system is therefore insensitive to external disturbances. The simulation results are presented to show the effectiveness of this converter as well as its efficiency improvement against a conventional two-stage solution.