Reliability enhancement of modular multilevel converter by applying fault tolerant control

Modular Multilevel Converters (MMC) are considered very suitable for the transmission of bulk power. Increasing the reliability of MMCs forms a real challenge since they are built from series connection of sub-modules. Applying the concept of fault tolerance to the MMC control system can significantly increase the reliability of the MMC as it will be available in normal as well as faulty conditions. This paper presents an analysis of the MMC reliability enhancement gained from applying different fault tolerant control techniques. The reliability is investigated through solving differential equations generated from Markov chains.