Single‐phase hybrid discontinuous conduction mode SEPIC rectifiers integrated with ladder‐type switched‐capacitor cells

Abstract

In this study, a set of new single-phase pulse-width modulation (PWM) Single-ended primary-inductor converter (SEPIC) rectifiers are proposed, which integrates conventional SEPIC rectifier, three-state switch (TSS) and switched-capacitor (SC) concepts. A conventional ladder-type SC cell is modified so that it can be integrated with the SEPIC rectifier operating in discontinuous conduction mode. The set of new single-phase PWM SEPIC rectifiers are able to provide: (i) lower-voltage stress on the semiconductors; (ii) higher-output voltage; and (iii) a split-capacitor output voltage. The structure employs a TSS and three different implementations are proposed. Two of them are bridgeless versions, which can provide higher efficiencies. Hence, the proposed structures can support using the SEPIC rectifiers as step-up in many applications and thus it can broaden its field of use. The topologies and their topological states, a theoretical steady-state analysis, a theoretical analysis of the ladder-type SC cell integrated with the SEPIC rectifier, a dynamic model for the control and a design example are discussed herein. Furthermore, a 500 W prototype with a 220 V input voltage, two 200 V split-output voltages, 400 V total output voltage and 50 kHz switching frequency was designed to corroborate the theoretical study.