A Double Uneven Power Converter-Based DC–DC Converter for High-Power DC Grid Systems

This paper presents a novel double uneven power converter-based dc–dc converter and its design and control methods. The main objectives are to reduce the power losses in the power semiconductor devices and to reduce the output filter inductance in a high-power (megawatt-level) dc–dc converter. The proposed converter utilizes two full-bridge converters in a special way to realize zero-current switching and to reduce the output filter inductance. The advantages of the proposed converter become more significant for high-power applications. A comparative simulation for a dc-grid wind farm application has been performed to verify the effectiveness of the proposed converter in high-power applications. It has been shown that the proposed converter not only requires less filter inductance but also has less power losses in the semiconductor devices. A small-scale prototype has been built to verify the operational principle of the proposed converter.