Analysis and design of a high power factor AC/DC converter with an active ripple filter

This paper presents analysis and design of a high power factor AC/DC converter with an active ripple filter by using supercapacitors as energy storage. In the normal operating mode, the AC/DC converter feeds power to load and charges supercapacitors. The supercapacitors are charged from the output of the AC/DC converter through a bidirectional DC/DC converter. If supercapacitors voltage is between 70 to 90 percent of its rated value, the bidirectional DC/DC converter is controlled as an active ripple filter for reducing ripple voltage at the output end of the AC/DC converter. In case of an ac line is interrupted, the stored energy in the supercapacitors is fed to load. The later operating mode is called the backup operating mode. In this paper the proposed system is investigated by software simulation. The results from MATLAB/Simulink show the proposed system offer a fast transient response in output voltage control and a lower ripple voltage at the output end of the AC/DC converter.