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

This paper proposes a method for increasing the non-isolated 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 non-isolated 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 non-isolated rectifiers. The static and dynamic analyses are presented in the paper, 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.