A Single-Switch ZVS High Step-Up DC–DC Converter With Stacked Voltage Multiplier Cell

This article proposes a new single-switch high step-up dc–dc converter with soft-switching characteristics in renewable energy systems. The converter consists of a Sepic-based network integrating a build-in transformer and a voltage multiplier cell (VMC) stacked on the output. It achieves ZVS turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> for the switch in a certain load range by designing proper components’ parameters without adding any additional devices. In addition, the converter has a simple structure with a small number of components, which contributes to the power density and efficiency. Because of the three-winding build-in transformer and stacked VMC, the voltage gain is increased, the voltage stress on the output capacitors is reduced, and the converter is more flexible. Furthermore, all diodes achieve ZCS turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small>, which improves the efficiency. A resonant operation reduces the turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current, which in turn reduces the turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> loss of the switch. The steady-state operation principle, soft-switching conditions, and comparisons have been analyzed in detail. Then, the properties of the converter are verified by designing a 500 W prototype in the laboratory. The peak efficiency reaches 95.44% at 300 W and the efficiency at a rated power is 94.16%. The typical experimental waveforms of the proposed converter agree well with the theoretical analysis.