IMPROVEMENT STUDY ON SOFT-SWITCHED QUASI-RESONANT DC/DC BOOST CONVERTER

This report describes a novel soft-switched quasi-resonant DC/DC boost converter.
Recently, remarkable efforts have been made in soft-switched quasi-resonant DC/DC
converters to reduce losses and improve power efficiency. This project presents a new
technique and it had improved the performance of the most recent study on soft-switched
quasi-resonant DC/DC boost converter, which is presented in Ba-Thunya and Prasad's
study [1]. The proposed converter employs an active snubber circuit with an auxiliary
switch in series with a clamp capacitor to reduce powerlosses in Ba-Thunya and Prasad's
original an active snubber circuit with an auxiliary switch and a clamp diode to reduce
power losses in Ba-Thunya and Prasad's original converter. The energy from the snubber
inductor after the auxiliary switch turn-off is returned to the input or delivered to the
output via the active snubber circuit, thus the voltage stress onthe main switch is reduced
and switching losses are minimized. Furthermore, the proposed converter reduces the
reverse-recovery-related losses of the boost rectifier by controlling the di/dt rate of the
rectifier current with the snubber inductor. This report describes the principle of
operation of the new soft-switched quasi-resonant DC/DC boost converter. The
feasibility study of the proposed converter is investigated using PSPICE program.