Buck-Boost-Type Unity Power Factor Rectifier With Extended Voltage Conversion Ratio

A buck–boost-type unity power factor rectifier is proposed in this paper. The main advantage of the proposed rectifier over the conventional buck–boost type is that it can perform input power factor correction (PFC) over a wider voltage conversion range. With a single switch, a fast well-regulated output voltage is achieved with a zero-current switch at turn-on. Moreover, the switch voltage stress is independent of converter load variation. The proposed converter is well suited for universal offline PFC applications for a low power range (< 150 W). The feasibility of the converter is confirmed with results obtained from a computer simulation and from an experimental prototype.