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This paper introduces a novel topology called the dual-path step-down converter with auxiliary switches to minimize voltage stress and enable wide voltage conversion ranges. The proposed dual-path step-down converter with auxiliary switches, which uses an inductor and flying capacitor as power conversion components, helps to reduce the voltage stress on the power switches. By adding auxiliary switches, the proposed topology achieves the same voltage conversion ratio range as that of a conventional buck converter. Additionally, soft-start technology is incorporated to reduce the initial inrush current. Furthermore, this paper introduces a system-level design procedure for DC-DC converters. Designed for low-power applications with lithium-ion (Li-ion) batteries, the proposed converter steps down the battery voltage to 1.2 V. With a 380 nH inductor and a 5 µF output capacitor, the converter attains a peak efficiency of 90% under the conditions of 2.7 V to 1.2 V conversion.

A new bidirectional flyback converter is introduced in this study. To provide soft-switching condition, two identical auxiliary circuits are applied to both sides of the converter, without using any extra switches. These circuits do not impose high voltage or current stresses on the converter. To transfer the power in each direction, only one switch is gated through pulse-width modulation technique. So, the control circuit of this converter is very simple. Regardless of the power flow direction, the switch of the converter is turned on under zero-current condition and is almost turned off under zero-voltage condition. The experimental results of the proposed bidirectional converter are presented to verify the theoretical analysis.

In this study, a new configuration for cascaded voltage source multilevel inverter based on series connection of improved sub multilevel inverter module is presented. An algorithm is proposed to determine the magnitude of dc voltage source to generate a large number of output voltage levels with reduced device count. It is especially suitable for of renewable energy applications. To demonstrate the advantages of proposed configuration, the comparative analysis provided with other multilevel configurations in term of a number of switches, gate driver circuits and blocking voltage on switches. The comparison results confirm that the proposed configuration offers less number of components. Moreover, the magnitude of blocking voltage on switches and losses are lower in the proposed configuration. Multicarrier based sinusoidal pulse width modulation scheme is adopted for generating switching signals using dSPACE real-time controller. To validate the performance of proposed topology under steady state and dynamic condition are carried out using simulation on MATLAB/Simulink and experimental implementation.

This paper proposes a single-phase, soft-switching, high step-up ac–dc converter based on a diode-capacitor voltage multiplier (DCVM) with a power factor correction (PFC). By applying the PFC technology, the proposed converter promises a near-unity power factor and a low distortion line current, while providing an adjustable, high step-up dc voltage that the conventional DCVM circuits cannot achieve. To reduce the switching losses, an auxiliary circuit for implementing a soft commutation is added to the power stage of the proposed converter. For operating at a fixed switching frequency, both the main and the auxiliary switches in the power stage are turned off with the zero-current transmission (ZCT). The operating principle, the design considerations and the control strategy of the proposed converter all are detailed and investigated in this paper. A 1.2 kV/500 W laboratory prototype, which employs a commercial PFC IC UC3854 as a controller, is built for test, measurement and evaluation. Under the full-load conditions, the measured power factor, the total harmonic distortion of the line current and the system efficiency are 99.6, 4.86 and 94%, respectively. The experimental results demonstrate the validity of the proposed converter.

In this paper, the zero voltage switching (ZVS) in active clamp forward converter is investigated. The investigation starts with discussing the basic operating principle of active clamp forward converter (ACFC). The current mode control ZVS ACFC design procedure is also presented in detail. A prototype forward converter with dc input of 16V, output voltage 5V operating at rated output load of 4A and a switching frequency 400 khz is provided to analyse the main mosfet switching waveform under zero voltage condition.

This paper presents a novel soft-switching boost DC-DC converter, which uses an edge-resonant switch capacitor based on the pulse width modulation PWM technique. These converters have high gain voltage due to coupled inductors, which work as a transformer, while the boost converter works as a resonant inductor. Upon turning on, the studied soft switching circuit works at zero-current soft switching (ZCS), and upon turning off, it works at zero-voltage soft switching (ZVS) while using active semiconductor switches. High efficiency and low losses are obtained while using soft switching and auxiliary edge resonance to get a high step-up voltage ratio. A prototype model is implemented in the Power Electronics Laboratory, Assiut University, Egypt. Seventy-two-panel PV modules of 250 W each were used to simulate and execute the setup to examine the proposed boost converter.

Giant viruses are a group of eukaryotic double-stranded DNA viruses with large virion and genome size that challenged the traditional view of virus. Newly isolated strains and sequenced genomes in the last two decades have substantially advanced our knowledge of their host diversity, gene functions, and evolutionary history. Giant viruses are now known to infect hosts from all major supergroups in the eukaryotic tree of life, which predominantly comprises microbial organisms. The seven well-recognized viral clades (taxonomic families) have drastically different host range. Mimiviridae and Phycodnaviridae, both with notable intrafamilial genome variation and high abundance in environmental samples, have members that infect the most diverse eukaryotic lineages. Laboratory experiments and comparative genomics have shed light on the unprecedented functional potential of giant viruses, encoding proteins for genetic information flow, energy metabolism, synthesis of biomolecules, membrane transport, and sensing that allow for sophisticated control of intracellular conditions and cell-environment interactions. Evolutionary genomics can illuminate how current and past hosts shape viral gene repertoires, although it becomes more obscure with divergent sequences and deep phylogenies. Continued works to characterize giant viruses from marine and other environments will further contribute to our understanding of their host range, coding potential, and virus-host coevolution.

Phase-shifted full-bridge topologies are widely used in medium- and high-power DC/DC converters due to their small size and high switching frequency. However, there are few studies on the application of broadband inverters. In the traditional phase-shift full-bridge inverter with a fully resonant load, the problem of current commutation which leads to hard switching is often encountered, to overcome such an issue, an auxiliary current source network is introduced to realize the zero-voltage turn-on of the lagging bridge arm. The working modes of the converter are analyzed in detail, and the parameters of the auxiliary current source network are designed. The simulation verification is carried out by MATLAB/Simulink in a wide frequency range from 10 kHz to 500 kHz. Finally, an experimental circuit board is designed, and the experimental results show that the topology can achieve soft switching in a frequency range from 10 kHz to 200 kHz and has a certain applicability.

This study presents a new design and implementation of a three-phase hybrid multilevel inverter (MLI) using space vector modulation. The proposed MLI consists of a reduced number of dc sources and switches to minimise the control complexity. The developed topology consists of two stages: main stage and auxiliary stage. The main stage is a conventional three-phase inverter with one high-voltage input dc source and six switches. The auxiliary stages contain three individual cells. Each cell consists of two switches and one low-voltage input dc source. This topology is a modular type and without changing the previous connection it can be extended for more number of output voltage levels by adding certain number of auxiliary stages. A space vector modulation control technique has been utilised in order to generate different switching sequences. The special feature of the proposed system is its capability to maximise the number of voltage levels using a reduced number of isolated dc voltage sources and electronic switches. A prototype has been developed and tested for various modulation indexes to verify the control technique and performance of the topology. Experimental results validate the simulation results and the experimental results show a good similarity with the simulation results.

In this study, a new family of pulse width modulation DC–DC converters is introduced. The proposed converters have one switch that turns on at zero current switching condition and turns off at zero voltage switching condition. The proposed auxiliary circuit can be used instead of converter switch in any non-isolated and isolated DC–DC converter. The buck converter from this converter family is analysed and its operating modes are discussed. The design considerations are presented and a prototype is realised. The experimental results confirm the validity of theoretical analysis.