Operation and Control of a Hybrid Seven-Level Converter

• Published in: IEEE transactions on power electronics Vol. 27; no. 2; pp. 652 - 660
• Main Authors: Saeedifard, M., Barbosa, P. M., Steimer, P. K.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active neutral point clamped (ANPC) converter; Applied sciences; Capacitors; Circuit properties; Control algorithms; Controllers; Dielectric, amorphous and glass solid devices; Direct current networks; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical power engineering; Electronic circuits; Electronic mail; Electronics; Exact sciences and technology; FCC; Integrated circuits; Modulation; multilevel converters; Power electronics, power supplies; Power networks and lines; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; space vector modulation (SVM); Support vector machines; Switches; Switching; Topology; Transformers; Vector space; voltage balancing; Performance evaluation; Power converter; Electric energy transportation; space vector modulation (SVM); MATLAB software; Control system; Direct current line; Voltage regulation; Power system stability; Active neutral point clamped (ANPC) converter; Power electronics; Support vector machine; Switching; Operating conditions; multilevel converters; High power; Neutral point connection; Modulation; Power factor; Voltage drift; voltage balancing; Capacitor; Multilevel system; Power transmission line
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2011.2158114

This paper introduces a novel hybrid seven-level converter that is based on the upgrade of the five-level active neutral-point-clamped converter concept and is suitable for high-power applications. The paper provides a comprehensive analysis for the operation of the converter. Based on the analysis, a space vector modulation (SVM)-based switching strategy that takes advantage of redundant switching vectors of the SVM strategy to counteract the voltage drift phenomenon of the proposed converter is proposed. The limit to the range of operation of the seven-level converter based on the proposed SVM strategy is also presented. It is shown that the ability to stabilize the dc-link capacitor voltages and the per-phase flying capacitors is a function of the converter operating indices, i.e., the load power factor and modulation index. The salient feature of the proposed SVM-based control strategy is that it enables proper operation of the converter with no requirements for additional controls or auxiliary power circuitry, within the specified range of operation. Performance of a converter under various operating conditions, based on the proposed SVM strategy, in the MATLAB/Simulink environment, is evaluated and experimentally demonstrated.