A Three-Port DC-DC Power Converter Based on GaN Devices

The cascaded interleaved bidirectional Buck/Boost LLC Three-port DC-DC converter has the advantages of wide voltage input range, Zero-Voltage-Switching (ZVS) on the primary side and low input current ripple. The three-port converter can be categorized into five distinct operational modes and three power transmission modes. This paper takes a operational mode as a representative example to analyze its operational characteristics and employs the time-domain analysis technique to derive the voltage gain curves. The application of Gallium Nitride (GaN) power devices to the converter is expected to further reduce the volume and improve the efficiency. In this paper, an RC+regulated diode driver circuit is used to drive GaN power semiconductors with advantages of high-speed safety switch and negative level turn-off. Finally, a 15W cascaded interleaved bidirectional Buck/Boost LLC three-port DC-DC converter experimental platform based on GaN is built.