Bi-directional active-filter-integrated AC/DC converter without electrolytic capacitor and extra power switches

In this paper, a cost-effective single-phase bidirectional active-filter-integrated AC/DC converter is proposed. It provides simultaneous functions of power factor correction (PFC), DC voltage regulation and active power decoupling for mitigating the low-frequency DC voltage ripple, without an electrolytic capacitor and extra power switches. Such a converter is readily available from a conventional H-bridge converter with minor hardware modification. Detailed principles of operation, controller design of the converter are provided in the paper. The feasibility of the converter is then confirmed experimentally through a 210 W rectification system. A stable DC output with merely 1.9% ripple is realized with two 50 μF film capacitors. In contrast, for the same ripple performance, a 514 μF capacitor is required in conventional converters without an active filter. Additionally, the uncompromised or even improved efficiency performance is another unique feature of the proposed converter.