An Overmodulation Algorithm With Neutral-Point Voltage Balancing for Three-Level Converters in High-Speed Aerospace Drives

• Published in: IEEE transactions on power electronics Vol. 37; no. 2; pp. 2021 - 2032
• Main Authors: Guo, Feng, Yang, Tao, Diab, Ahmed M., Yeoh, Seang Shen, Li, Chen, Bozhko, Serhiy, Wheeler, Patrick
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active control; Aircraft; Algorithms; Balancing; Capacitors; Control methods; Converters; Electric potential; Electric starters; Engines; High speed; High-speed motor drives; Modulation; more-electric-aircraft (MEA); Motor drives; neutral-point (NP) voltage; overmodulation; Power factor; three level; Trajectory; Voltage; Voltage control
• ISSN: 0885-8993; 1941-0107; 1941-0107
• DOI: 10.1109/TPEL.2021.3105752

In this article, a virtual space vector based overmodulation algorithm is presented for three-level neutral-point (NP) clamped converters in high-speed aerospace motor drives. With the proposed inscribed polygonal-boundary compression technique, the output voltage capability is enhanced under a lower crossover angle and compression coefficient. As a result, it brings an opportunity for the operation of the studied aircraft electric starter/generator (ESG) systems easily extending from the linear modulation range into the overmodulation region. Furthermore, an active capacitor voltage balancing control method is investigated to recover NP potential imbalance in the case of high modulation index and low power factor operating conditions. To simplify the digital implementation of the algorithm, a fast calculation approach is adopted in this work. The modulation performance of the proposed strategy is verified by both simulation and experimental results with a 45 kW, 32 k r/min ESG prototype system.