Short Circuit Fault Diagnosis for Interleaved DC-DC Converter Using DC-link Current Emulator

Switch fault diagnosis is an important design criterion for dc-dc converters, as it can improve system reliability, prevent converter damage, and production losses to end users. This paper proposes a short circuit fault (SCF) diagnosis method for interleaved dc-dc converters that can detect the fault and identify the faulty switch in less than one switching cycle. The dc-link current is utilized as the diagnostic signature. The main idea is to apply the derivative of the dc-link current based on the modulation of the converter, and to propose a predictive dc-link current emulator model. The measured dc-link current, and its corresponding predicted current, obtained from the available control signals, are used as the input to the fault diagnosis module. The entire fault diagnosis method, including the dc-link current emulator and fault diagnosis modules, is implemented on a DSP. The method has been analyzed, tested, and validated for a certain converter.