IGBT Open-Circuit Fault Diagnosis for Modular Multilevel Converter With Reduced-Number of Voltage Sensor Measuring Technique

Insulated gate bipolar transistor (IGBT) open-circuit fault in the modular multilevel converter (MMC) can lead to waveform distortions, overcurrent and overvoltage problems, thus, affects the reliability of the converter system. This paper proposes an IGBT open-circuit fault diagnosis strategy for the MMC with reduced-number of voltage sensor measuring technique. The open-circuit fault can be isolated within several control cycles. The proposed method is applicable to both single and multiple faults conditions. Simulation results verify the effectiveness of the proposed strategy.