Open-circuit fault diagnosis of dual active bridge DC-DC converter with extended-phase-shift control

This paper proposes a simple and fast fault diagnosis strategy for bidirectional isolated dual-active-bridge DC-DC converter with the extended-phase-shift control to improve reliability. The fault diagnosis strategy utilizes the average values of the voltage to quickly identify failures position and devices in either transistors or diodes without adding any hardware cost. First, two conditions are classified according to the direction of the inductor current on the primary side. Then, a comprehensive operation analysis during normal and faulty conditions is presented. Based on the characterization of open-circuit faults in diodes and transistors, open circuit faults diagnose strategy is derived and validated through both simulation and experimental test for different fault conditions.