Parallel-connected bidirectional current-fed dual active bridge DC-DC converters with decentralized control

A decentralized control strategy with improved droop control is proposed for parallel-connected current-fed bidirectional DC-DC converters to achieve the flexible power architecture and modular design. The step-up or step-down function depends on the power flow direction. An improved droop control strategy is implemented by sensing the high-voltage side (HVS) voltage and low-voltage side (LVS) current. The operation principle and power sharing characteristics are analyzed. The system stability is demonstrated in detail based on small-signal model. Excellent power sharing can be achieved not only under steady state but also in dynamics. Besides, the system has the hot-swapping feature. A 2.5kW prototype composed of two modules is established to verify the effectiveness of the proposed control strategy.