Open-Circuit Fault Diagnosis Method for Interleaved Three-Phase Three-Level DC-DC Converter

In this paper, a fault diagnosis method based on output current slope and switch drive signal is proposed for the diagnosis of switch open-circuit fault in interleaved three-phase three-level DC-DC converter. Firstly, the topology of the converter is equivalent through a virtual voltage source, and the inductor current and output current waveforms of the converter under normal operating conditions are analyzed. Secondly, the state of the converter after open-circuit fault is divided into two stages. The circuit state and current time-domain waveform characteristics are analyzed separately. Finally, by combining the drive signal of switch and current waveform characteristics, open-circuit fault diagnosis of the switch is achieved. The simulation results show that proposed fault diagnosis method can effectively detect switch open-circuit fault in interleaved three-phase three-level DC-DC converter.