High Gain Switched-Inductor-Double-Leg Converter With Wide Duty Range for DC Microgrid

In a dc microgrid, efficient high gain converters are needed to raise the voltage level of low voltage power sources such as photovoltaic, fuel cells, etc. In this article, a high-gain switched-inductor-double-leg converter for dc microgrid is proposed. The proposed converter is capable of providing higher gain devoid of using any transformer, coupled inductor, and multiple voltage lifting techniques, e.g., triple lift, quadruple lift, super lift, etc. The operating modes of the converter are controlled using three switches in double duty mode. Compared to single duty converter, the double duty converter provides a flexibility in selection of duty cycle for switch to achieve desired output voltage and controlling inductor current ripple magnitude by selecting appropriate duty cycles. Moreover, two duty cycles make the converter capable of achieving high gain with wide duty range and an individual switch does not need to operate at very large duty cycle to achieve high voltage gain. The topological description, operating principles, steady-state voltage gain analysis during continuous conduction mode and discontinuous continuous mode, boundary condition, and voltage and current analysis, efficiency analysis, comparison and design of the proposed are presented. The proposed converter is tested in laboratory to validate its feasibility and performance.