Nonisolated DC-DC Converters With Wide Conversion Range for High-Power Applications

This paper presents the conception of a family of dc-dc converters with wide conversion range (WCR) based on the multistate switching cell (MSSC) for high-power, high-current applications. The resulting topologies allow achieving high-voltage step-up/step-down in a modular approach, as the WCR-MSSC cell is obtained by using isolated secondary windings coupled to the autotransformer of the MSSC with series-connected controlled rectifiers. Depending on the transformer turns ratio, it is possible to adjust the static gain and reduce the voltage stresses across the main switches, thus allowing the use of metal-oxide-semiconductor field-effect transistors (MOSFETs) with low on-resistance $R_{\mathrm {DS}(\mathrm{\scriptscriptstyle ON})}$ , as efficiency is improved as a consequence of minimized conduction losses. A dc-dc boost-type converter based on the four-state switching cell is also implemented, thoroughly analyzed, and evaluated experimentally to demonstrate the advantages associated with the proposed approach in the conception of novel dc-dc converter topologies for this purpose.