Bidirectional series-resonant DC-DC converter with fault-tolerance capability for smart transformer

The Series-Resonant dc-dc converter (SRC) is widely used in several application and it became very popular in Smart Transformer application. In this application, fault tolerance is a highly desired feature and it is obtained through redundancy. This paper proposes a reconfiguration scheme for the SRC for the case of failure in one semiconductor, which could drastically reduce the need of redundancy. Using the proposed scheme, the full-bridge based SRC can be reconfigured in a half-bridge topology, in order to keep the converter operational even with the failure (open circuit or short circuit) of one switch. The theoretical analysis is carried out for the unidirectional SRC and then extended to the bidirectional topology, since bidirectionality is required in smart transformer application. To verify the feasibility of the proposed scheme, the converter is tested experimentally in a 700 V to 600 V prototype with 10 kW of output power. A IGBT short-circuit fault is tested and the results confirms the effectiveness of the proposed approach.