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Summary: In this paper, a new stacked bidirectional non‐isolated DC‐DC converter for uninterruptible power supply applications is presented. It is a stacked adaptation of the classical bidirectional boost/buck converter and presents improvements such as low number of components; low voltage and current stress on components; high efficiency; and simplicity of operation. In addition, in this paper, the modeling and control of the proposed converter are done, and a comparative evaluation among proposed converter with similar topologies is evaluated. A prototype of 1 kW, 144 to 400 V, is developed in laboratory to validate the theoretical evaluations of proposed converter. Besides that, the proposed converter is also evaluated under different dynamic condition, which illustrates the effectiveness of the converter. Finally, the maximum efficiency obtained is 96.38% in step‐up mode and 95.7% in step‐down mode. [ABSTRACT FROM AUTHOR]

Summary: This article presents three topologies of high‐voltage gain DC–DC converter based on boost converter with three‐winding coupled inductor. Before proposing these converters, a cascade cell connection synthesizing approach was initially evaluated. This approach allowed the generation of a set of six high‐voltage gain converters. However, only three converters present good performance. Thus, to demonstrate the advantages, disadvantages, and limitations of each converter, the following characteristics are evaluated: the operating principle of the proposed converter, gain of voltage, voltage, and current stress, in addition to the factors of total voltage stress and total current stress, factors that indicate the choice of components with lower intrinsic resistances. To validate these analyses, a 250 W, 30 V/400 V prototype was implemented experimentally, reaching a maximum efficiency of 96%. [ABSTRACT FROM AUTHOR]

Summary: In this article, different autotransformer structures are discussed, demonstrating their connection and voltage gain characteristics. In this sense, an autotransformer structure was chosen that presents a high voltage gain with a low transformation ratio (N), thus seeking to reduce the leakage inductance and volume. From there, this structure is integrated into the isolated boost converter, thus generating a new high step‐up DC‐DC topology. The proposed converter presents as main characteristics: high voltage gain, low voltage stress on the components, continuous input current, low number of components, simplicity of operation and control, and high efficiency. To validate the theoretical evaluations, a 200 W, 30 V/400 V prototype was built in the laboratory, achieving a maximum efficiency of 96.25%. [ABSTRACT FROM AUTHOR]

High step‐up converters are often used in photovoltaic applications due to low voltage of photovoltaic modules. In this paper, two new topologies, obtained with the insertion of voltage multiplier cells on secondary side of isolated SEPIC, are proposed. They have the advantages of continuous input current, isolation, high efficiency, and high voltage gain, being suitable for low power applications. To perform this study, theoretical and comparative analyses are accomplished. They include a description of each converter, tables, and curves with relevant information, such as voltage gain, total voltage stress, and total current stress. Moreover, the identification of the use of coupled inductor or transformer based on the analysis of DC magnetizing current is presented. Theoretical analysis and experimental results on 37.4/400 V, 50 kHz, and 200 W prototypes of selected isolated SEPIC with voltage doubler cell and voltage quadrupler cell are presented to validate the proposed topology and concept, where the maximum efficiency obtained for the converter with doubler cell is 96.85%, while for the converter with quadrupler cell is 97.75%. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a new bidirectional nonisolated DC‐DC (direct current–direct current) converter to interface microgrid energy storage systems is proposed. This converter is based on the classical bidirectional boost/buck converter, the most used converter in microgrids and can operate both in step‐down and step‐up modes. Besides that, this converter presents low number of components, low voltage and current stress on components, simplicity of operation, low current ripple from low‐side power supply, and two different modes of operation: synchronous and asynchronous. In addition, in this paper, the modeling, control, and power losses estimate of the proposed converter are carried out and the performance of the converter in different aspects of the microgrid application is evaluated, such as step load, abrupt power flux change, and transient analysis. A prototype of 1 kW, 144 to 400 V, is developed in the laboratory to validate the theoretical evaluations of the proposed converter. Besides that, the proposed converter is also evaluated under different dynamic condition which illustrates the effectiveness of the converter. Finally, the maximum efficiency obtained is 97.1% for 500 W working in step‐down operation. [ABSTRACT FROM AUTHOR]

High step‐up DC‐DC converters are commonly used in new energy applications such as DC microgrid, photovoltaic cell, and fuel cell. Thus, this article introduces a new nonisolated high step‐up DC‐DC converter based on active switched coupled inductor with a voltage multiplier cell. The proposed converter presents low current and voltage stress across the switches owing of the dual active switches structure. Besides that, by the voltage multiplier cell (one diode and one capacitor), the voltage gain of proposed converter is increased. In addition, it can be highlighted that the proposed converter has low component count, simplicity of operation in continuous and discontinuous conduction mode, and energy stored in the leakage inductor that is recycled in the capacitor of voltage multiplier cell. This article discussed the principle of operation, the ideal and nonideal voltage gain, external characteristic, voltage and current stress, design guidelines, and performance comparison with previous high step‐up converters. Finally, a prototype circuit with input power 300 W, input voltage 30 V, and output voltage 400 V was built in the laboratory to verify the theoretical evaluation, and the maximum achieved efficiency was 95.35% at nominal power 300 W. [ABSTRACT FROM AUTHOR]

This paper presents a non‐isolated high step‐up buck–boost with a coupled inductor DC–DC converter relevant for distributed photovoltaic (PV) generation systems. The proposed topology can reach high voltage gain through the combination of a buck–boost converter with a coupled inductor. The configuration of the proposed converter allows to achieve a natural voltage clamp circuit for the switch, recovering the energy stored in the leakage inductance of the coupled inductor. Moreover, the converter allows soft‐switching conditions, that is, Zero Current Switching (ZCS) for the diodes and nearly ZCS for the active switch. Also, the proposed converter presents a low component count and common ground connection of the input and output. The proposed converter is evaluated theoretically by the principle of operation in continuous‐conduction mode (CCM) and discontinuous‐conduction mode (DCM), voltage gain derivation, external characteristics, semiconductor voltage stress, current stress, and design guidelines. Finally, a 650‐W, 36/380‐V, 50‐kHz prototype was built in the laboratory to experimentally evaluate the proposed converter, which reached a maximum efficiency rate of 96.58%. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new voltage multiplier with a small number of components, composed of a coupled inductor and a switched capacitor cell, which allow four different configurations. To evaluate these configurations, these cells were integrated into the boost converter, thus generating four new high voltage gain topologies. These topologies have different characteristics: thus, the principle of operation, voltage gain, voltage and current stress, and design guidelines of each converter were evaluated. Finally, four prototypes of 30 V/400 V and 200 W were built and evaluated experimentally. [ABSTRACT FROM AUTHOR]