Single stage single switch AC/DC converters with high input power factor and tight output voltage regulation

A single stage single switch AC/DC converter topology based on the concept of Direct Power Transfer (DPT) is proposed. The topology is derived from the integration of a flyback converter and a center tapped flyback-forward converter which are separated by a bulk capacitor to store the difference of the instantaneous input and output power. The flyback converter gives inherent power factor correction (PFC) and the center tapped flyback-forward converter gives tight output voltage regulation. The intermediate DC link voltage is clamped at a preset value. Simulation studies have been carried out to understand the behavior of the circuit. A 100 W (20 V, 5 A) experimental prototype is designed, developed and the performance is evaluated. From the experimental results, it can be inferred that the proposed topology limits the intermediate DC link voltage and gives better efficiency than the conventional single stage converter topologies.