Fault Tolerant Hierarchical Control Strategy for Modular Multilevel Converter in HVDC Application
Translated title
Author
Term
4. term
Education
Publication year
2014
Submitted on
2014-05-27
Pages
95
Abstract
The Modular Multilevel Converter (MMC) has proven itself to be a good solution for High Voltage Direct Current Applications due to its high modularity, scalability and low output voltage harmonic distortion. One the main challenges of the MMC is the control. It is known that commercially available solutions use a centralized control topology, where a single controller is used to perform all the necessary calculations and processing of the MMC control. The aim of this thesis is to develop a control strategy using the hierarchical control topology approach. Using EtherCAT communication network a method for synchronizing the carrier waves of the MMC is developed and the resampled phase shifted PWM algorithm is implemented for different configurations of the MMC. In order to improve the reliability of the system an algorithm is developed to reconfigure the system in case of a fault in one of the MMC sub-modules. The averaging and balancing control of the MMC is studied through simulations.
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