A New High Voltage Gain Transformerless Dual- Duty-Triple-Mode DC–DC Converter With Reduced Voltage Stress Across Components

This article proposes a new high step-up nonisolated transformerless dc–dc converter topology for dc microgrid applications. By effectively incorporating a modified active switched-inductor network with a new configured switched capacitor network, the proposed design achieves an exceptionally high voltage gain while significantly reducing the voltage stress across the components. A notable feature of the proposed dual-duty-triple-mode (DDTM) converter is its flexibility in achieving a high voltage gain through various combinations of duty cycles. Furthermore, the converter's triple-mode operation reduces turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> switching losses in the input switches and activates the output switch under zero-voltage switching conditions, thereby increasing overall efficiency. Moreover, the second duty cycle introduces an additional degree of freedom to the design process. The operation principles, steady-state analysis, design considerations, efficiency calculations, and small-signal modeling with controller design are provided. To demonstrate the superiority of the proposed converter, a comparative analysis is conducted with other recently published relevant and DDTM converters, illustrating that the proposed converter offers significantly higher voltage gain, considerably lower voltage stress across components, higher efficiency, and lower cost. Ultimately, to validate the proposed design, a 500 W lab-based prototype (20 to 400 V) is constructed and subjected to thorough evaluation.