This paper presents an active topology for power decoupling in single-phase ac-dc converters, featuring the effective suppression of low-frequency power ripple which is an inherent problem in single-phase energy conversion systems. This topology is composed of an H-bridge circuit and a ripple power-decoupling circuit. The ripple power-decoupling circuit shares one bridge arm with the H-bridge circuit so it has less additional components: just one IGBT, one diode, and an energy-storage inductor. Its modulation strategy is properly devised to coordinate the operation of decoupling circuit and H-bridge circuit. To enhance the power-decoupling performance, a direct ripple power-cancellation method based on energy-storage inductor is proposed. A multiresonant controller with feed-forward control is introduced for fast and precise current tracking. The effectiveness of this topology has been verified by detailed simulation studies as well as the laboratory prototype experiment results.