부산대학교 도서관

The four-switch buck–boost converter possesses features that enable both voltage step-up and step-down, and positive output voltage. This converter has gained widespread popularity in applications that require a wide input voltage range. By utilizing pulsewidth modulation (PWM) plus phase-shift control, all power switches can achieve zero-voltage-switching across the entire input voltage and load range. Additionally, this control scheme minimizes ripple and rms value of the inductor current, thereby achieving high efficiency. This article aims to simplify the implementation of PWM plus phase-shift control and enhance the dynamic performance by approximating the phase-shift duty cycle. A 420-W prototype is fabricated and tested in the laboratory for verification.