Circulating Current Suppressing Control’s Impact on Arm Inductance Selection for Modular Multilevel Converter

Journal Article · Thu Oct 13 04:00:00 EDT 2016 · IEEE Journal of Emerging and Selected Topics in Power Electronics

DOI:https://doi.org/10.1109/JESTPE.2016.2617865· OSTI ID:1399423

Li, Yalong ^[1]; Jones, Edward A. ^[2]; Wang, Fred ^[2]

---

1. Univ. of Tennessee, Knoxville, TN (United States). Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks, Dept. of Electrical Engineering and Computer Science
2. Univ. of Tennessee, Knoxville, TN (United States). Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks, Dept. of Electrical Engineering and Computer Science

Arm inductor in a modular multilevel converter (MMC) is used to limit the circulating current and dc short circuit fault current. The circulating current in MMC is dominated by second-order harmonic, which can be largely reduced with circulating current suppressing control. By analyzing the mechanism of the circulating current suppressing control, it is found that the circulating current at switching frequency becomes the main harmonic when suppression control is implemented. Unlike the second-order harmonic that circulates only within the three phases, switching frequency harmonic also flows through the dc side and may further cause high-frequency dc voltage harmonic. This article develops the theoretical relationship between the arm inductance and switching frequency circulating current, which can be used to guide the arm inductance selection. The experimental results with a downscaled MMC prototype verify the existence of the switching frequency circulating current and its relationship with arm inductance.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; National Science Foundation (NSF)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1399423
• Journal Information: IEEE Journal of Emerging and Selected Topics in Power Electronics, Journal Name: IEEE Journal of Emerging and Selected Topics in Power Electronics Journal Issue: 1 Vol. 5; ISSN 2168-6777
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
Arm inductance selection
circulating current suppression control
modular multilevel converter (MMC)