Transformer Isolated Buck-Boost Converters

Abstract

-Of the single-switch dc-to-dc converters, those with the buck-boost voltage transfer function offer the best potential for transformer coupling, hence isolation, at the kilowatt level. This paper highlights the limitations of the traditional magnetic coupled, buck-boost topology. Then four split-capacitor transformer-coupled topologies (specifically the Cuk, sepic, zeta, and new converters) with a common ac equivalent circuit, that do not temporarily store core magnetic energy as does the traditional isolated buckboost converter nor have a core dc magnetizing current bias as with the sepic and zeta transformer coupled topologies, are explored. Core dc bias capacitive voltage compensation is a practical design constraint in three of the four topologies, while all four must cater for stray and leakage inductance effects. Simulations and experimental results for the new converter at 408W that support the transformercoupled, single-switch dc-to-dc converter concepts are investigated.

Modular Multilevel Converters for Large-Scale Grid-Connected Photovoltaic Systems: A Review

“…Accordingly, several SM circuit topologies have emerged from such constraints. Employing HFTs in these SMs, while operating at high switching frequency (<20 kHz), will reduce their total size considerably and, hence, higher power density is obtained [87]. There is always a trade-off between these requirements and the SM cost, losses, and complexity.…”

“…Several papers have evaluated the progress of the SM designs of isolated converter topologies for PV systems [27,85,[87][88][89][90][91]. Reference [27] presented a general structure for modular energy conversion system suitable for the large-scale PV systems, which is shown in Figure 15.…”

DC-to-DC Converter Topologies for Wireless Power Transfer in Electric Vehicles

“…Non-isolated and isolated versions of Ćuk and SEPIC converter have been used in the literature [25][26][27][28][29][30]. Magnetically coupled single-switch buck-boost converters (namely isolated Ćuk, Zeta, SEPIC, and P5) have been presented in [1]. Four DC-to-DC converters shown in Fig.…”

“…The conventional coupled SEPIC and Zeta converters involve turning a shunt inductor into a coupled transformer which always has a core dc bias current. Alternatively, a transformer-coupled with a splitcapacitor that are utilized in the Ćuk converter family employs the transformer without a dc flux bias [1,2]. This paper proposes converter topologies with buck-boost transfer functions that can be utilized for wireless power transfer without a dc flux bias.…”

Analysis and Design of Isolated SEPIC Converter with Greinacher Voltage Multiplier Cell

“…Basic single-switch isolated topologies are: flyback, ZETA, SEPIC and Ćuk. Among these options, isolated SEPIC converter is a very good choice, since it provides continuous input current and can significantly reduce the dc magnetizing current with the appropriate choice of voltage multiplier cells (VMCs), allowing to use a transformer instead of coupled inductor (Williams. 2016).…”