Non-Isolated PFC SEPIC Rectifier in IPOP Connection With Current Self-Sharing Capability

This article proposes a method for increasing the nonisolated rectifiers’ power capability by adding more modules in parallel without the drawback of increasing current control complexity. The article applies the method to conceive a SEPIC rectifier from input- and output-parallel connection (IPOP) of modular nonisolated conventional SEPIC rectifiers in discontinuous conduction mode (DCM) operating. The main attribute of the proposed structure is to provide a current self-sharing capability in IPOP connection, with no extra current control. The current-balancing mechanism approaches herein for the SEPIC topology are applicable to all nonisolated rectifiers. The static and dynamic analyses are presented in the article, as well as the output characteristic analysis to show the self-sharing capability when the rectifier operates in DCM. A single voltage-control system is proposed for the modular connection, and there is no need for output-current control per module to guarantee a balanced power and input-current control to guarantee a high-power factor. A 1500 W prototype with three modules is designed, built, and tested in the laboratory to verify the theoretical analysis. The peak of efficiency was 93%, and the input current harmonic distortion was 2.85%, leading to a power factor of 0.999.