Single stage bridgeless buck-boost PFC converter for low output voltage application

An additional DC-DC converter is needed for traditional boost power factor correction (PFC) converter to obtain low output voltage. When using buck type topology, the distortion of input current is large because no power is transferred to output when gird voltage is lower than output voltage. Thus, the buck-boost type topology becomes priority in the low output voltage application. Compared with the classic cascaded buck-boost PFC converter, the proposed single stage bridgeless buck-boost topology has lower semiconductors counts, and lower devices counts in the conduction loop which means less conduction losses. The tapped inductor is employed to achieve more attenuation. Thus, the proposed topology suits the low output voltage application very well. The One Cycle Control (OCC) is adopted to achieve good dynamic performance and the elimination of multiplier can simplify the control circuit and reduce the cost. The simulated results and their analysis show preliminarily that: (1) the proposed topology is feasible and has the merits of simple structure and less conduction losses; (2) the power factor correction using OCC is reliable and has the advantages of low current distortion and high power factor. © 2015, Northwestern Polytechnical University. All right reserved.