Experimental Validation of a quasi Z-Source Modular Multilevel Converter with DC Fault Blocking Capability

Khera, Fatma; Klumpner, Christian; Wheeler, Pat

Abstract

This paper considers the design methodology and the modulation of the quasi Z-source modular multilevel converter (qZS-MMC) with half bridge sub-modules and evaluates its performance in voltage boosting mode for medium voltage applications. The qZS-MMC consists of two quasi Z-source networks inserted between the two terminals of the DC input source and the DC-link terminals of a modular multilevel converter (MMC), which allows the generation of an output voltage larger than the input DC voltage. Two modulation schemes have been analysed based on a mathematical derivation for the converter internal voltages, currents, and stored energy. The quasi Z-source circuit is proven to provide the qZS-MMC with half bridge sub-modules to deal with DC-faults. The experimental results validate the performance of the proposed modulation schemes and the DC-fault blocking capability of the qZS MMC. Finally, the losses of the qZS-MMC is compared against a standard MMC using full bridge sub-modules that can also provide DC fault capability. The range in which the qZS-MMC is more efficient has been identified. Furthermore, the qZS-MMC can provide a significant reduction in number of semiconductor power devices with the same performance.

Citation

Khera, F., Klumpner, C., & Wheeler, P. (2021). Experimental Validation of a quasi Z-Source Modular Multilevel Converter with DC Fault Blocking Capability. IEEE Journal of Emerging and Selected Topics in Power Electronics, 9(2), 1951-1965. https://doi.org/10.1109/jestpe.2019.2955859

• Journal Article Type: Article
• Acceptance Date: Nov 12, 2019
• Online Publication Date: Nov 27, 2019
• Publication Date: 2021-04
• Deposit Date: Dec 4, 2019
• Publicly Available Date: Jan 9, 2020
• Journal: IEEE Journal of Emerging and Selected Topics in Power Electronics
• Electronic ISSN: 2168-6785
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 2
• Pages: 1951-1965
• DOI: https://doi.org/10.1109/jestpe.2019.2955859
• Keywords: Index Terms-DC faults; half bridge sub-modules; modular multilevel converter; modulation schemes; quasi Z-source
• Public URL: https://nottingham-repository.worktribe.com/output/3477155
• Publisher URL: https://ieeexplore.ieee.org/search/searchresult.jsp?newsearch=true&queryText=Experimental%20Validation%20of%20a%20quasi%20Z-Source%20Modular%20Multilevel%20Converter%20with%20DC%20Fault%20Blocking%20Capability
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