Modeling and Experimental Evaluation of Z-Source Modular Multilevel Converter Using Reduced Inserted Cells Technique

• Published in: IEEE access 2021, Vol.9, p.133091-133101
• Main Authors: Khera, Fatma A., Klumpner, Christian, Wheeler, Pat
• Format: Article
• Language: English
• Subjects: Capacitors; Converters; Inductors; Modular multilevel converter; modulation technique; Multilevel; Multilevel converters; Rectifiers; reduced inserted cells; Resonant frequencies; Topology; Voltage; Voltage control; voltage step-up; Z-source network
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2021.3115634

The integration of a Z-source network with a modular multilevel converter (MMC) to provide voltage step-up function is proposed in this paper. The proposed Z-source modular multilevel converter (ZS-MMC) uses a Z-source network connected between the DC source and the DC-link terminals of the MMC. The operation principle of the ZS-MMC is presented utilising the reduced inserted cells (RICs) modulation technique. Compared to the quasi ZS-MMC previously developed by the authors, the ZS-MMC has small fundamental frequency component in the ZS inductor current which requires a smaller inductor size for the Z-source network and is also more efficient. The ZS-MMC is compared to other topologies that can accomplish buck and boost capabilities, such as the quasi Z-source MMC, the quasi Z-source cascaded multilevel converter and the full-bridge based MMC, to validate the viability of the proposed converter. The operation of the ZS-MMC employing the RICs technique is confirmed experimentally.