Zero-voltage DC/DC converter with asymmetric pulse-width modulation for DC micro-grid system

摘要

This paper presents a zero-voltage switching DC/DC converter for DC micro-grid system applications. The proposed circuit includes three halfbridge circuit cells connected in primary-series and secondary-parallel in order to lessen the voltage rating of power switches and current rating of rectifier diodes. Thus, low voltage stress of power MOSFETs can be adopted for high-voltage input applications with high switching frequency operation. In order to achieve low switching losses and high circuit efficiency, asymmetric pulse-width modulation is used to turn on power switches at zero voltage. Flying capacitors are used between each circuit cell to automatically balance input split voltages. Therefore, the voltage stress of each power switch is limited at V-in/3. Finally, a prototype is constructed and experiments are provided to demonstrate the circuit performance.