Soft-Switched Ultra-High Step-Up DC-DC Converter with Cost Efficiency and High Power Density for DC Microgrid Applications

This paper introduces an innovative ultra-high step-up (UHSU) DC-DC topology, specifically designed for DC microgrid applications. The proposed design integrates two coupled inductors (CIs) with a quadratic boost circuit to achieve an exceptionally high voltage gain. Key advantages of this topology include its ability to deliver an ultra-high voltage boost, reduced reverse recovery issues in diodes, minimized voltage stress on switching devices, continuous input current, and a shared ground connection linking the input and output. Furthermore, the converter incorporates soft-switching capabilities for most semiconductor components, enhancing efficiency and reducing energy losses. By maintaining low voltage stress across the switches, the design ensures superior performance and reliability. A thorough examination of its operational modes is presented, accompanied by a comparative analysis with alternative topologies to highlight the advantages of the proposed UHSU converter. Ultimately, the effectiveness of the design is proven through experimental testing of a $600-\mathrm{W}$ prototype operating at a switching frequency of 50 kHz, with an input voltage of 30 V and an output voltage of 600 V.