Design and Improvement of Soft-Switched Quasi-Resonant Boost Converter

In this paper, a new soft-switched quasi-resonant DC/DC boost converter was proposed. 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 to greatly improve the performance of the most recent study on soft-switched quasi-resonant DC/DC converters by using active snubber circuit with an auxiliary switch and a clamp diode to reduce the reverse-recovery–related losses of the boost rectifier by controlling the di/dt rate of the rectifier current with a snubber inductor connected in series with the main switch. The energy from the inductor in series with the main switch after the switch turn-off is returned to the input to deliver to the output via the active snubber. By connecting a clamp diode between the anode of the snubber diode and ground to eliminate the parasitic ringing between the junction capacitance of the boost rectifier and the snubber inductor, the stress of the rectifier is therefore minimized. This paper explains the principle of operation of the new soft-switched quasi-resonant DC/DC converters. The feasibility of the proposed circuit is made by PSPICE simulation.