Fault-tolerant controller architecture for cascaded multi-level converters

Voltage source multi-level converters (MC) are one of the options for rectifying and inverting in high power applications. Each converter consists of several modules connected together to form a single converter. Power rating of the converter is usually more than the desired rating and it is possible to continue operation by bypassing the failed modules. This capability increases the reliability of this category of converters compared to other type of converters. In this paper, a distributed controller has been proposed that implements hot standby techniques to increase reliability and availability of the converter. Each slave controller is directly connected to the power electronic module with data link to neighbor controllers and all of the controllers are being synchronized through a master controller. At the end, reliability assessment of the proposed controller based on Markov modeling has been represented and experimental result approves the feasibility of the control method.