Global Asymptotic Stability of Current-Controlled Modular Multilevel Converters

• Published in: IEEE transactions on power electronics Vol. 30; no. 1; pp. 249 - 258
• Main Authors: Harnefors, Lennart, Antonopoulos, Antonios, Ilves, Kalle, Nee, Hans-Peter
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-01-2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Asymptotic methods; Asymptotic properties; Asymptotic stability; Control systems; Converters; Current control; Current measurement; Damping; Electric currents; Harmonic analysis; Integrated circuits; Lyapunov methods; Measurement; Modular; Multilevel; Multilevel systems; On-line systems; SRA - Energi; SRA - Energy; Stability; Stability analysis; Voltage control
• ISSN: 0885-8993; 1941-0107; 1941-0107
• DOI: 10.1109/TPEL.2014.2298560

In this paper, previously developed stability results for open-loop sum-capacitor-voltage control of modular multilevel converters are extended. To give improved damping, circulating-current feedback is included in the control law. With the output-current control loop and a first-order measurement lag taken into account, global asymptotic stability is proven. Careful consideration of the on-line sum-capacitor-voltage reference computation is given, since this is the most critical part of the control system.