A novel soft-switching PWM dc-dc converter with high-frequency transformer link and its open-loop regulation characteristics

Abstract

In the practical requirement for high efficiency, high power density, and high performance in switched‐mode power supplies and their related application systems, a variety of circuit topologies of dc‐dc converters incorporating soft‐switching PDM, PFM, and PWM control schemes have attracted special interest in low‐power and high‐power applications. Some types of quasi‐resonant soft‐switching PWM converters have remarkable advantages, such as lowered switching losses of power semiconductor devices, reduced dynamic electrical stresses, constant‐frequency operation, simple control schemes, and reduced EMI noise. However, most soft‐switched quasi‐resonant PWM converters developed so far include some inherent problems which must be solved, such as reduced power conversion efficiency due to significant circulating current generation. In recent years, a newly modified prototype soft‐switched PWM dc‐dc converter with a high‐frequency transformer link has been proposed, which is capable of excluding circulating current operation mode. This paper presents a novel high‐frequency transformer link soft‐switching PWM dc‐dc converter using active switches in the rectifier circuit. Its operating principles and unique features are described and compared with previously developed dc‐dc converters. The operating performance of this converter in the steady state is illustrated and discussed, including simulated analytical and experimental results. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(3): 81–93, 1997

A High‐Frequency‐Link Secondary‐Side Phase‐Shifted ZVS‐PWM DC–DC Converter with ZCS Active Rectifier

“…However, problems still remain in practice; thus additional circuitry is required, and the parameters of these circuits must be designed accurately in order to expand the S-SW range of the controlled phase switches. In contrast to PPS-PWM, the authors proposed a secondary-side phase-shift PWM (SPS-PWM) with phaseshift control on the secondary side (rectifier side) of the HF transformer, and reported its distinctive circuit operation, excellent circulating current reduction, and wide range of S-SW [11][12][13][14][15][16]. Fig.…”