Bridgeless power factor correction (PFC) converter has obtained abundant popularity due to its praiseworthy merits of optimized conduction losses in semiconductors. In this paper, a novel bridgeless SEPIC PFC converter with improved conduction losses and simple circuit structure are proposed by using bidirectional power switch. Compared to conventional full-bridge SEPIC PFC converter, the proposed bridgeless SEPIC PFC converter features an improved efficiency by reducing the number of semiconductors in currentflowing path. Compared to the-state-of-art bridgeless SEPIC PFC converters, the proposed bridgeless SEPIC PFC converter possesses simple circuit structure and less component. The operation principle in discontinuous conduction mode (DCM) with inherently PFC and zero-current switching are analyzed. Finally, a 100W simulated model are built aiming to certify the superiority of the proposed bridgeless SEPIC PFC converter.

PFC，Bridgeless SEPIC converter，Higher efficiency, GaN MOSFETs