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A Modular Multilevel Series/Parallel Converter for Wide Frequency Range Operation

Li, Zhongxi and Lizana, Ricardo and Yu, Zhujun and Sha, Sha and Peterchev, Angel V. and Goetz, Stefan M. (2019) A Modular Multilevel Series/Parallel Converter for Wide Frequency Range Operation. IEEE Transactions on Power Electronics, 34 (10). pp. 9854-9865. ISSN 0885-8993.

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When providing ac output, modular multilevel converters (MMCs) experience power fluctuation in the phase arms. The power fluctuation causes voltage ripple on the module capacitors, which grows with the output power and inversely to the output frequency. Thus, low-frequency operations of MMCs, e.g., for motor drives, require injecting common-mode voltages and circulating currents, and strict dc voltage output relative to ground is impossible. To address this problem, this paper introduces a novel module topology that allows parallel module connectivity in addition to the series and bypass states. The parallel state directly transfers power across the modules and arms to cancel the power fluctuations and hence suppresses the capacitor voltage ripple. The proposed series/parallel converter can operate at a wide frequency range down to dc without common-mode voltages or circulating currents; it also allows sensorless operation and full utilization of the components at higher output frequencies. We present detailed simulation and experiment results to characterize the advantages and limitations of the proposed solution.

Item Type:Article
Related URLs:
URLURL TypeDescription
Li, Zhongxi0000-0002-4839-2045
Lizana, Ricardo0000-0001-8348-5258
Yu, Zhujun0000-0001-7427-1952
Peterchev, Angel V.0000-0002-4385-065X
Goetz, Stefan M.0000-0002-1944-0714
Additional Information:© 2019 IEEE. Manuscript received January 22, 2018; revised June 27, 2018 and August 27, 2018; accepted December 17, 2018. Date of publication January 4, 2019; date of current version June 28, 2019. This work was supported in part by the National Science Foundation under Grant 1608929, in part by the North Carolina Biotechnology Center under Grant 2016-CFG-8004, in part by a seed grant from the Duke University Energy Initiative, and in part by the FONDECYT Iniciación 2016 under Project 11160227.
Funding AgencyGrant Number
North Carolina Biotechnology Center2016-CFG-8004
Duke University Energy InitiativeUNSPECIFIED
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)11160227
Subject Keywords:Low-frequency operation, modular-multilevel converter, voltage ripple
Record Number:CaltechAUTHORS:20190201-153603349
Persistent URL:
Official Citation:Z. Li, R. Lizana F., Z. Yu, S. Sha, A. V. Peterchev and S. M. Goetz, "A Modular Multilevel Series/Parallel Converter for a Wide Frequency Range Operation," in IEEE Transactions on Power Electronics, vol. 34, no. 10, pp. 9854-9865, Oct. 2019. doi: 10.1109/TPEL.2019.2891052
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92596
Deposited By: George Porter
Deposited On:01 Feb 2019 23:58
Last Modified:08 Jul 2019 17:33

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