Open Circuit Fault Diagnosis of Modular Multilevel Converter Based on Local Outlier Factor Detection

The modular multilevel converter is a kind of ac-dc converter with high power level and high efficiency, which contains a large number of submodules (SMs) and insulated gate bipolar transistors (IGBT). The open-circuit fault of IGBT will not affect the system operation in a short time, but will cause damage to the system, which needs to be detected and located in time. This paper presents an IGBT open fault diagnosis algorithm based on local outlier factor (LOF) detection, which can locate the open circuit fault of MMC in a short time and improve the reliability of the system.