Hybrid Si + SiC Neutral-Point-Clamped Dual-Active-Bridge Converter for High-Voltage Battery Energy Storage Systems

This paper presents a novel hybrid neutral-point-clamped (NPC) dual-active-bridge (DAB) converter for battery energy storage systems. The outer switches of the topology are SiC MOSFETs, while the inner switches are Si IGBTs. Compared with the traditional DAB converter, the NPC-based topology shows significant advantages including reduced voltage stress for each switch and lower electromagnetic interferences, making it suitable for high voltage applications. Combined with wide-bandgap semiconductors, the hybrid converter can achieve better efficiency under high frequency operation with a trivial increase in overall cost. A control method for the proposed hybrid NPC DAB converter is also introduced in this paper. Simulation results and analysis for a 1500-V, 150-kW battery energy storage system are presented.