Analysis, design and experimental results of a floating-output interleaved-input boost-derived DC-DC high-gain transformer-less converter

In transformer-less energy systems sourced from low and unregulated voltage generated by a fuel cell or photovoltaic source, the voltage gain of the power electronic conditioning stage is required to be as high as possible. Although component parasitic elements limit the practically realisable voltage gain of any converter topology, this becomes a critical issue in the case of the basic step-up converter. In this study, a high-gain interleaved boost-derived converter topology is discussed. The proposed converter topology offers modularity, lower ripple for both input current and output voltage, and lower voltage and current ratings of the various circuit elements when compared to the basic boost converter. Analysis, design and key converter waveforms operating in the continuous conduction mode are provided along with design guidelines. Experimental results taken from a 1 kW laboratory prototype operating at 60 kHz are presented to confirm the validity of the analysis and design considerations.