부산대학교 도서관

A new fully soft-switched nonisolated high-step-down converter is presented in this article. The proposed converter utilizes only one switch and a self-driven synchronous rectifier to implement a fully soft-switched pulsewidth modulation high-step-down converter. In addition, the single switch does not require an isolated gate drive, which further simplifies the converter control. The main switch is turned on and off under zero-current-switching and zero-voltage-switching (ZVS) conditions, respectively. The extended duty cycle enables the converter to have a wide input voltage range and reduce the switch current stress. Also, the self-driven synchronous rectifier turns on and off under ZVS condition. These merits have contributed to the improved efficiency of the proposed converter with respect to other counterparts. To verify the converter characteristics, a 150 V to 12 V converter prototype operating at 100 W and 100 kHz is implemented and the results indicate 97% efficiency at full load.