An Improved Strategic Analysis on Fault Diagnosis in Modular Multilevel Converter

Modular multilevel converters are most popular among all converters due to not only their modular structure but also the power handling capacity. To ensure continuous availability and energy security, these converters are designed with fault diagnosis techniques. This paper presents a strategic review on key theories, models, and techniques utilized in the fault diagnosis strategies proposed by previous researchers till recently. In this paper, a detailed critical, comparative analysis of fault diagnosis strategies, and the major research gaps has been presented. A new classification of fault diagnosis methods based on system parameters which reveal fault characteristics and thus the presence of faults is also suggested. An experimental study was conducted to determine, understand the causes, sources, and effects of short circuit, and open circuit faults developed by the MOSFETS/IGBTs during their operation. Finally, the paper suggests a possible automated, fault diagnosis system that can not only be used in modular multilevel converters but also in any converters or systems.