Interleaved Bidirectional Buck Converter for Mild Hybrid Applications adopting Monolithic GaN technology

The mild-hybrid vehicle's market requires more and more compact and efficient 48/12V conversion systems that control the bidirectional power flow and safeguard the battery life. This paper presents an interleaved three-phase converter based on the emerging GaN technology. The main feature of the proposed solution is a substantial improvement of the whole system efficiency with respect to the converters already available on the market based on silicon. The good features of the GaN devices allow improving the converter performance even at high switching frequencies, up to 500kHz. The GaN-based synchronous buck exploits the monolithic integration of half-bridge power devices helping to achieve efficiency peaks around 95%. The figure of merit shows a quite constant value in a wide operating range thanks to the reduction of the used channels at low loads, moreover, the interleaving modulation also ensure the reduction of the output current ripple.