Title:  Control and Fault Tolerance Improvement of the Class of Modular Multilevel Converters

Committee:

Dr. Maryam Saeedifard, ECE, Chair , Advisor

Dr. Tom Habetler, ECE

Dr. Lukas Graber, ECE

Dr. Sakis Meliopoulos, ECE

Dr. Mehdi Narimani, McMaster Univ

Dr. Santiago Grijalva, ECE

Abstract:

The family of the modular multilevel converters (MMCs) has become the most promising class of converters for medium/high-power energy conversion systems, because of salient features including modularity, scalability, high efficiency, superior harmonic performance, easy realization of the redundancy, and absence of DC-link capacitors. The salient features of the MMCs can potentially be exploited for various applications at medium- and high-voltage levels including adjustable speed drives, solid-state transformers, grid integration of renewable energy resources, etc. However, for each application, unique operational and control challenges are imposed. As a result, unique control strategies and design considerations are required to guarantee proper operation of the MMCs, achieve high power density, efficiency, and reliability. Over the past decade, significant research has been performed to address the technical challenges associated with control and operation of various MMC topologies and to unveil their full promises. This thesis is in continuation of this endeavor.