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In this article, a new soft-switching auxiliary circuit structure for the synchronous rectification noninverting buck–boost converter (NIBBC) is proposed. This new auxiliary circuit, which contains a fully coupled inductor (or a transformer), a snubber inductor, a capacitor, and a power diode, will provide zero voltage switching (ZVS) turn-ON conditions for all power transistors of the proposed NIBBC. In addition, waveform ripples in the auxiliary circuit of the output side are reduced, and then the output current ripple is also reduced. Meanwhile, the current across the main inductor is not affected by the auxiliary circuit. In order to analyze the proposed NIBBC, operating principles, soft-switching implementation conditions, and main characteristics of the proposed NIBBC are presented in this article. Finally through building a 400-W experimental prototype, key waveforms and measuring efficiency curves are obtained. Experiment result shows that all transistors of the new NIBBC operate under ZVS conditions. The efficiency of the proposed NIBBC is improved by comparing to the triangular current mode soft-switching NIBBC. [ABSTRACT FROM AUTHOR]

This letter proposed a new soft-switching non-inverting buck–boost converter (NIBBC) by introducing the magnetic coupling effect to an existing soft-switching dc/dc converter. The new NIBBC obtains two superiorities: one magnetic core is removed to improve the efficiency; the magnetic coupling effect can give an adjustable soft-switching range. Operating principles and converter characteristics of the new NIBBC are presented. An experimental prototype of the new NIBBC is built, and switching waveforms and the efficiency are measured. Experimental results show that the new NIBBC can obtain soft-switching conditions and has efficiency improvement comparing to hard-switching converter and another soft-switching dc/dc converter. [ABSTRACT FROM AUTHOR]

This brief summarizes soft-switching methods for the non-inverting buck-boost converter (NIBBC). Then a new zero voltage switching (ZVS) NIBBC is proposed. This new NIBBC employs a triple coupled inductor, two resonant inductors, and two auxiliary diodes. All transistors of this new NIBBC will work under ZVS conditions. Furthermore the current across the main inductor will be continuous during all the period, and therefore its ripples will be small. Benefit from low current ripples of the main inductor, ripples and harmonics of the output current are also reduced. To verify this new NIBBC, an experimental platform was built, and waveforms (voltage and current) and efficiency are measured. Measuring results show that ZVS conditions of all transistors are obtained. And the efficiency of the new NIBBC is higher than traditional continuous conduction mode and triangular current mode NIBBCs. [ABSTRACT FROM AUTHOR]

In this paper, several new coupled-inductor-based soft-switching dc–dc converters are proposed. These converters are obtained by changing the coupled branch of several existing dc–dc converters. Meanwhile they have similar characteristics to these existing converters, and provide more choices for the practical application. Then by applying an existing efficiency improvement method, which is used in the buck-type soft-switching converter, to all abovementioned converters, several new converters with efficiency improvement characteristics are obtained. This efficiency improvement method utilizes the low conduction performance of the transistor to reduce the loss. In addition, this method has the same control complexity to original topologies, because the auxiliary transistor has the same control timing to one of main transistors. The characteristic of new converters and efficiency improvement method are presented by analyzing two new topologies (boost-type converters). Finally simulation and experimental results are given and analyzed by designing a prototype. Based on these results, soft-switching conditions and efficiency improvement capability are verified. [ABSTRACT FROM AUTHOR]

In this paper, a soft-switching topology is proposed for the bidirectional dc–dc converter. In order to achieve soft-switching conditions, the auxiliary circuits including a small inductor and two capacitors are introduced to the bidirectional dc–dc converter. By generating and keeping a recycle current in the auxiliary circuits, the proposed topology can provide soft-switching conditions for both switches of the bidirectional dc–dc converter in fixed frequency control application. Meanwhile, no auxiliary switches are introduced. Due to the existence of the auxiliary circuits, the proposed topology can also reduce the current ripple in the main inductor. Based on this soft-switching method, a family of bidirectional soft-switching dc–dc topologies is derived. These topologies have the similar structures and the same characteristics. The topology deduction, operating principles, and design guidelines are presented in detail. Finally, an experimental prototype is built to verify the analysis and characteristics of the proposed topologies. [ABSTRACT FROM PUBLISHER]

This letter presents a novel topology for a buck dc–dc converter with soft-switching capability, which operates under a zero-current-switching condition at turn on and a zero-voltage-switching condition at turn off. In order to realize soft switching, based on a basic buck converter, the proposed converter added a small inductor, a diode, and an inductor coupled with the main inductor. Because of soft switching, the proposed converter can obtain a high efficiency under heavy load conditions. Moreover, a high efficiency is also achieved under light load conditions, which is significantly different from other soft-switching buck converters. The detailed theoretical analyses of steady-state operation modes are presented, and the detailed design methods and some simulation results are also given. Finally, a 600 W prototype is built to validate the theoretical principles. The switching waveforms and the efficiencies are also measured to validate the proposed topology. [ABSTRACT FROM AUTHOR]

This paper presents a novel topology for a nonisolated bidirectional dc–dc converter with soft-switching capabilities, which usually operates at a zero-voltage-switching (ZVS) condition. A nonisolated dc–dc converter combines a buck converter and a backward boost converter into one circuit, which consists of a half-bridge power switch, an inductor, and capacitors. In order to realize ZVS conditions, the proposed converter utilizes a coupled inductor, a small independent inductor, and auxiliary switches and diodes. Due to ZVS, switching stress on switch components is reduced, and the reverse recovery problem of MOSFET antiparallel body diodes is also eliminated. Moreover, the operating modes of the proposed converter can be switched between a ZVS mode and a conventional hard-switching mode on the basis of load conditions. The soft-switching mode is for heavy loads, and the hard-switching mode is for light-load conditions. Therefore, the highest efficiency can be obtained at almost all load ranges. The detailed theoretical analyses in each mode are presented, and a 1-kW prototype is also built to verify the principle of the circuit and the theoretical analysis. [ABSTRACT FROM PUBLISHER]