Switched flyback PFC converter for wide AC input voltage range

This paper proposes a switched flyback PFC converter for a universal input range applications. Conventional controllers have large number of components to realize the wide range voltage input, which reduces the efficiency. The proposed converter supports worldwide power supplies by two flyback converter and two additional switches. The proposed converter is based on two flyback converters and switches the connections of them in series or parallel according to the input voltage. Moreover, the proposed circuit is driven by the Triangular Current Mode (TCM) with variable frequency (VF) to achieve zero-voltage switching (ZVS). However, the VF causes the input current distortion because the input current is not proportional to the input voltage by changing the duty ratio. Therefore, this paper proposes the compensation method of the input current distortion using the TCM. The fundamental operation is demonstrated by the simulation and experiment. As the simulation result, it was confirmed that the input current distortion was improved by 99.2%. In the experimental result, the proposed circuit drives the power factor of 99.9 % by 1.0 p.u. in DCM operation.