Fundamental-Frequency Reactive Circulating Current Injection for Capacitor Voltage Balancing in Hybrid-MMC HVDC Systems During Riding Through PTG Faults

Journal Article · Thu Sep 21 00:00:00 EDT 2017 · IEEE Transactions on Power Delivery

DOI:https://doi.org/10.1109/TPWRD.2017.2755505· OSTI ID:1474569

Lu, Maozeng  ^[1]; Hu, Jiabing  ^[1]; Zeng, Rong  ^[2]; He, Zhiyuan ^[3]

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1. Huazhong Univ. of Science and Technology, Wuhan (China). School of Electrical and Electronic Engineering
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Power Electronics and Electric Machine Group
3. Global Energy Interconnection Research Inst., Beijing (China)

Here, this article presents a comprehensive analysis and a novel solution for the discharge problem on the half-bridge submodules' (HBSMs') capacitors in the hybrid modular multilevel converter (MMC)-based high-voltage direct current transmission systems under a long-term (e.g., several minutes or longer) pole-to-ground fault condition. The mechanism of this issue is analyzed, and then a solution based on fundamental-frequency reactive circulating current (FFRCC) injection is proposed. The influence of FFRCC injection is analyzed in terms of the fluctuated arm capacitor energy and the current stress of semiconductors. Moreover, an enhanced arm voltage modulation method based on HBSMs and full-bridge submodules coordinate control is proposed to accelerate the capacitor voltage balance of HBSMs. Finally, the performance of the proposed control strategy is verified by the simulation results.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725; 2014CB247400
• OSTI ID: 1474569
• Journal Information: IEEE Transactions on Power Delivery, Vol. 33, Issue 3; ISSN 0885-8977
• Publisher: IEEE
• Country of Publication: United States
• Language: English

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