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This paper presents a new methodology for synthesis of high-gain step-up DC-DC converters. This methodology is based on the differential connection of two basic non-isolated DC-DC converters, in which the output voltages are respectively positive and negative with reference to a common terminal. Any load connected between these positive and negative terminals is subjected to a differential voltage equivalent to the sum of the voltages individually synthetized by each basic converter. When only non-isolated basic DC-DC converters (boost, buck-boost, Cuk, single-ended primary-inductor converter, and Zeta) are considered, six differential converters may be derived by the proposed methodology; nevertheless, voltage lifting techniques based on gain cells can also be applied to further extend the gain, resulting in others high-gain topologies. Besides the proposition of the methodology, the paper investigates the operating principle of the derived converters under different modulation strategies, evaluates the possibility of eliminating redundant components after integration, and correlates the obtained converters with already existing topologies. In fact, it is demonstrated that several high-gain step-up DC-DC converters previously published could be addressed as particular cases of differential connections of basic converters. Experimental results are presented to validate the methodology herein proposed.

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This paper proposes a differential connection between the conventional boost and the mirrored SEPIC converters and the combination of them using switched-capacitor cells. The integration results in a single stage power structure that provides high-voltage gain and high efficiency. The article approaches a detailed static-dynamic analysis and a comparison in relation to other structures presented in the literature. In addition, to corroborate the theoretical analysis and the operation stages of the proposed converter, a 200 W prototype, with a switching frequency at 50 kHz, an output voltage from 300 to 400 V and an input voltage of 20 V, is evaluated. An efficiency peak of 96.78% was reached at 100 W.

Summary The switched capacitor differential boost inverter (SCDBI) is a single‐stage single‐phase step‐up bidirectional inverter, in which the voltage gain lifts as the number of switched‐capacitor cells increases. When this inverter is applied to grid‐connection as herein proposed, its capacitive output‐voltage feature enables a grid current with low ripple, even when a simple L filter is employed. In addition, the SCDBI is free of high frequency common mode voltage, which mitigate the common mode current circulation between the input and output sources. These attributes favor the employment of this inverter in grid‐connected systems. Although these are positive aspects, the SCBDI also presents some challenges related to its nonlinear voltage gain and high‐order dynamic models. In this paper, a reduced order dynamic model is derived to simplify the SCDBI modeling and a static gain linearization technique is proposed in order to simplify the control strategy, therefore enabling the use of classical control methods. Experimental results achieved from a 250 W prototype, dc input voltage of 60 V, and electrical grid of 220 V rms, corroborated the inverter operation, in which a peak efficiency of 90% and a grid‐current total harmonic distortion less than 5% were reached.