A fast analog controller for a unity-power factor AC/DC converter

This paper presents an analog implementation of a fast controller for a unity-power-factor (UPF) AC/DC converter. Unlike low bandwidth controllers associated with many state-of-the-art UPF converters this fast controller can exercise control action at a rate comparable to the switching frequency rather than the line frequency. In order to accomplish this while maintaining unity power factor, the fast controller employs a ripple-feedback cancellation scheme. In addition to responding faster to disturbances, the controller facilitates the replacement of bulky bus capacitors with smaller, less expensive alternatives