Abstract
The strategies for handling sub-module (SM) faults in modular multilevel converters (MMCs) are essential for improving the reliability of HVDC grids. The SM faults are generally mitigated through the by-passing of faulty SMs. However, this results in an unbalance in three-phase voltages and currents, which is not desirable for the efficient operation of the MMC. Therefore, fault-tolerant strategies are required to compensate for the impact of the loss of SM. In this work, the unbalance introduced due to the by-passing of SMs has been studied by detailed simulation using the switched model of MMC. Further, a strategy to detect a by-passed SM based on arm-current analysis is presented. This paper also proposes an algorithm for restoring voltage balance during SM faults. In this algorithm, the number of healthy SMs in each arm is maintained equal, and the corresponding insertion indices are determined for symmetrical operation. The proposed algorithm is validated by simulating a simple circuit example of an MMC with fifty SM per arm using MATLAB/Simulink.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callSimilar Papers
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
