Fault-Tolerant Topology of Dual Active Bridge Converter for On-Board Charger in Electric Vehicles

The on-board chargers (OBCs) are commonly utilized in electric vehicles (EVs) due to their cost-effectiveness and ease of installation. The performance of EVs to supply power back to the grid has sparked interest in bidirectional power flow solutions. Dual-active-bridge (DAB) dc-dc converters have gained prominence as a promising power interface between energy storage components and the power bus. However, failures in the active devices of DAB converters can result in converter disconnection. In this article, a fault-tolerant DAB (FT-DAB) converter is proposed to improve the reliability of the OBC. In order to ensure uninterrupted operation in short-circuit and open-circuit faults of the semiconductors, the topology of the single-phase DAB is modified in such a way that the single transformer is replaced with dual-transformers in addition to employing an H5 structure for each bridge. The proposed FT-DAB converter is investigated in various faulty conditions, in which, the post-fault performance and the maximum level of the output power are discussed in detail. Finally, the FT-DAB is prototyped and tested under various post-fault scenarios. Experimental test results validate the reliable and uninterrupted operation of the FT-DAB.