Analysis and Fault-Tolerant Operation of IGBT Multi Transistor Open Circuit Faults in DBSRC Converters

With the continuous development of power electronic devices and technology, dual bridge series resonant DC-DC converter (DBSRC) has become the main converter topology used in the new generation of high-frequency on-board auxiliary converters. In order to improve the stability and reliability of auxiliary converters with DBSRC as the core, a study was conducted on the IGBT multi-transistors open circuit fault of DBSRC under phase-shifting closed-loop control. The operating mechanism and characteristics of DBSRC after input and output side faults were analyzed and elucidated. Secondly, a fault-tolerant operation strategy for high-frequency vehicle mounted auxiliary converters based on output power adjustment is proposed. Without changing the DBSRC topology and phase-shifting control method, the input voltage of the auxiliary converter is monitored in real-time and the output power of the auxiliary converter is dynamically adjusted to limit the resonant current stress and resonant capacitor voltage stress within a safe threshold, achieving fault-tolerant operation. Verify its effectiveness through simulation and provide ideas for fault detection of cascaded DBSRC.