A Soft-Switched SEPIC-Based High Voltage Gain DC-DC Converter for Renewable Energy Applications

Recently, many nonisolated high-gain dc-dc converters have been proposed. However, most of these converters operate in a hard switching environment and have high diode reverse recovery currents. Besides, the boost capability of these converters still needs to be further improved. To address the above shortcomings, a novel single-switch soft-switched high voltage gain dc-dc converter based on a single-ended primary inductor converter (SEPIC) topology is presented in this article. The proposed converter utilizes quasi-resonant (QR) operation to achieve soft-switching conditions and alleviate the diode reverse recovery problem. In addition, the proposed converter integrates a Y-source network, which makes the voltage gain regulation more flexible. The steady-state analysis and design consideration have been presented. The loss analysis has been conducted. A small signal analysis has been carried out. Comparisons between various converters have been performed. Finally, a 200 W prototype validates the effectiveness of the proposed converter. When the output power reaches 200 W, the efficiency of the proposed converter is 95.238%.