Zero‐voltage‐switching buck converter with low‐voltage stress using coupled inductor

Abstract

This study presents a new zero-voltage-switching (ZVS) buck converter. The proposed converter utilises a coupled inductor to implement the output filter inductor as well as the auxiliary inductor which is commonly employed to realise ZVS for switches. Additional magnetic core for the auxiliary inductor in traditional ZVS converters is eliminated and hence reduced cost is achieved. Moreover, thanks to the series connection between the input and output, the switch voltage stress in the steady state is reduced and thus the ZVS operation can be easier achieved. Then the leakage inductor current circulating in the auxiliary switch is decreased, contributing to reduced conduction losses. In particular, low-voltage rating devices with low on-state resistance can be adopted to further improve efficiency in applications with non-zero output voltage all the time, such as the battery charger. Furthermore, the reverse-recovery problem of the diode is significantly alleviated by the leakage inductor of coupled inductor. In the study, operation principle and steady-state analysis of the proposed converter are presented in detail. Meanwhile, design considerations are given to obtain circuit parameters. Finally, simulations and experiments on a 200 W prototype circuit validate the advantages and effectiveness of the proposed converter

A new family of non‐isolated PWM DC–DC converter with soft switching

“…To solve these problems, soft-switching techniques are introduced. In DC-DC converters, various soft-switching techniques are presented such as resonant [1][2][3], active clamp [4][5][6], zero-current transition (ZCT) [7][8][9][10], zero-voltage transition (ZVT) [11][12][13], zero voltage zero current transition (ZVZCT) [14] converters and so on.…”

“…But they have high circulating current and a duty cycle loss which cause increased conduction losses and decreased voltage gain, respectively. In ZCT, ZVT and ZVZCT converters [7][8][9][10][11][12][13][14], the auxiliary circuit acts during switching intervals to provide zero voltage or current before switching instants. These converters use pulse-width modulation (PWM) to control the output voltage but they have at least two switches in their structure.…”

Isolated bidirectional converter with minimum active switches for high‐voltage ratio achievement and micro‐grid applications

“…Isolated bidirectional DC/DC converter (IBDC) is generally based on single-phase and H-bridge topology with an isolation transformer [7][8][9][10][11]. A converter incorporates coupled inductor [12][13][14][15][16], voltage multiplier cell [17][18][19][20], and/or Z-source technique [21,22] that are common approaches and can be able to provide high-ratio voltage conversion under reasonable duty cycle. However, there is serious voltage spike across active switch, which is caused from the energy releasing of the leakage inductance of transformer during switching transition.…”

A Family of Magnetic Coupling DC-DC Converters With Zero-Voltage-Switching Over Wide Input Voltage Range and Load Variation

“…To attain high density and efficiency, soft-switching techniques are utilized in high-frequency DC-DC converters. Among these techniques, zero-voltage-switching (ZVS) [3]- [26] including quasi-resonant ZVS, active-clamping ZVS, zero-voltage-transition (ZVT), and magnetic coupling ZVS converters have been intensively studied to eliminate turn-on losses, which is the dominant switching losses in the majority carrier devices, such as MOSFET.…”

“…In references [23]- [26], coupled inductors were employed to achieve ZVS for synchronous DC-DC converters over a wide range of input voltage and load variation. The auxiliary circuit is relatively simple because it is composed of an auxiliary diode and a coupled winding.…”