Zero‐voltage switching full‐bridge DC/DC converter with parallel‐connected output and without output inductor

Abstract

This study presents a soft-switching converter without output inductor. The features of the proposed converter are zero-voltage switching (ZVS) for all power switches, load current sharing and high circuit efficiency. Full-bridge converter with phase-shift pulse-width modulation (PWM) is adopted to regulate the output voltage. Based on the resonant behaviour by the output capacitance of MOSFETs and the resonant inductance, active switches can be turned on at ZVS during the transition interval. Thus, the switching losses of power MOSFETs are reduced. The voltage stress of power switches is clamped to DC bus voltage. Four transformers are connected in series in the primary side. Each transformer can be operated as an inductor to smooth the output current or a transformer to achieve electric isolation and power transfer from input side to output side. Therefore no output inductor is needed in the secondary side. Two centre-tapped rectifiers connected in parallel are used in the secondary side to achieve load current sharing. Finally, experiments based on a 960 W (48 V/20 A) laboratory prototype are provided to demonstrate the performance of proposed converter.

Series-Connected High Frequency Converters in a DC Microgrid System for DC Light Rail Transit

“…Zero-voltage switching converters [12][13][14][15] have been proposed to achieve a low switching loss. Asymmetric pulse-width modulation [16][17][18], frequency modulation [19][20][21] and a phase-shift pulse-width modulation (PWM) scheme [22][23][24] are general PWM control schemes used in DC/DC converters to regulate load voltage and also realize the mechanism of the zero-voltage turn-on switching. Therefore, the high efficiency converters can be obtained.…”

Frequency-Controlled Current-Fed Resonant Converter with No Input Ripple Current

“…Power converters with soft-switching turn-on or turn-off characteristics have been proposed and studied to overcome these problems. Duty cycle control [8][9][10][11][12][13] and frequency control schemes [14][15][16] are normally used to regulate load voltage and also reduce switching losses under zero-voltage or zero-current. The advantages of duty cycle control with fixed switching frequency are easy implementation with commercial integrated circuits and many available circuit topologies.…”

High‐efficiency duty‐cycle controlled full‐bridge converter for ultracapacitor chargers

“…Full-bridge dc-dc converters have been widely used for high-frequency high-power applications [1][2][3]. Especially, for high output current applications such as ultracapacitor chargers, a current-doubler rectifier is used to reduce the output current ripple [4].…”