A Capacitor Fault-Tolerant Scheme for Dual-Active-Bridge DC/DC Converter

Recently, the dual-active-bridge (DAB) DC/DC converters are widely utilized in renewable energy systems. Lots of research on the optimization of DAB converters has been conducted, including novel topologies, modulation schemes, control schemes, and fault-tolerant schemes for active switches or riding-through, etc. However, there is a limited fault-tolerant scheme developed for capacitor failure in DAB converters so far, due to the low-device redundancy. To address this important issue, a capacitor fault-tolerant scheme is proposed in this paper. With the proposed scheme, the DAB converter can maintain power transfer sustainability even if the port capacitors break down. Besides, potential voltage spikes can also be suppressed by the proposed scheme when the snubber function of port capacitors is lost. Subsequently, the modulation scheme, topology characters, and control scheme are elaborated in this paper. Finally, the experimental results based on a scale-down laboratory prototype are presented to verify the feasibility of the proposed fault-tolerant scheme.