A stacked-bridge-based dual-active-bridge (DAB) converter is proposed to achieve bidirectional power transfer between the storage battery and 800V dc micro-grid. MOSFETs with lower voltage ratings can be applied to high-voltage applications. Moreover, an asymmetric pulse-width modulation (APWM) plus phase shift modulation (PSM) hybrid modulation scheme is proposed to realize voltage match over a wide voltage range. A wider zero-voltage-switching (ZVS) range can be achieved over a wide battery voltage range. To verify the concept, a 1-kW rated prototype is designed to link an 800V dc bus and a 100V-200V energy storage unit.
