Operation of Dual-T-Type Modular Multilevel Converter for Uninterrupted Power Supply Under Bridge Failures

Cheng Wang, Hongkang Yang, Hongting Hua, Yaosuo Xue

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Dual-T-type modular multilevel converter (DTMMC) is an alternative to the existing uninterrupted power supply (UPS) due to its advantage in flexible leg reusing, multiple power ports, and high operating efficiency. In this article, a DTMMC-UPS, which has series configurations on both input/output ac sides, obtains high-voltage grid/load accessing interfaces is presented. In the described system, the fact that copies of T-type legs are employed makes semiconductor failure common to happen. Moreover, both the coupling between rectifier and inverter conversions and the confliction between intercell and inner-cell voltage balancing make fault-tolerant control a tough issue. In this article, the switch fault types are first clarified and diagnosed by the different impacts on normal operation. An improved voltage vector modulation is then deduced to facilitate the planning of proper primary switching patterns, to achieve rectifier side normal operation. The secondary alternated level-shifted pulsed-width modulation (LS-PWM) is also modified to achieve inverter side normal operation. The experiment results are supplied to verify the validity of the modulation-coordinated fault toleration strategy.

Original languageEnglish
Pages (from-to)11876-11886
Number of pages11
JournalIEEE Transactions on Industrial Electronics
Volume70
Issue number12
DOIs
StatePublished - Dec 1 2023

Funding

This work was supported by the Natural Science Foundation of Jiangsu Province under Grant BK20190461.

FundersFunder number
Natural Science Foundation of Jiangsu ProvinceBK20190461

    Keywords

    • Cascaded multilevel converter
    • T-type power converter
    • fault toleration
    • modulation strategy

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