A More Efficient Single-Phase AC/DC Converter With Automatic PFC and Power Decoupling Capability

Reducing power transmission path is a new trend to increase the whole efficiency. Moreover, the electrolytic capacitors (E-caps) are another essential criterion for judging the performance of converters. Based on this, a novel single-stage ac/dc converter is proposed in this article, which demands fewer power semiconductors compared to previous works due to the time-sharing power devices; thus lower cost and higher power density are achieved. The power flow of the decoupling circuit is further optimized, where most of the energy is designed to transfer directly to the load, reducing the intermediate link and only absorbing pulsating power with the film capacitor, thus higher efficiency is guaranteed. Additionally, a simple control scheme is presented, where near perfect power factor (PF) is obtained. Finally, all the superior performances of the proposed light-emitting diode (LED) driver are verified by an experimental prototype with a rated output power of 100 W.