In the practical requirement for high-efficiency, high power density and high-performance in the 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 the fields of 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 scheme as well as reduced EMI noise.
However, most of soft-switched quasi-resonant PWM converters developed so far include some inherent items which have to be solved such as reduced power conversion efficiency due to significant circulating current generation. In recent years, the newly modified prototype of 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 rectifier circuit. Its operating principle and unique features are described as compared with the previously developed DC-DC converter. Operating performance of this converter in steady-state are illutrated and disccused including the simulated analytical and experimental results.