Modulation Methods for 3L-NPC Converter Power Loss Management in STATCOM Application

• Published in: IEEE transactions on industry applications Vol. 55; no. 5; pp. 4965 - 4973
• Main Authors: Zhou, Jiuyang, Cheng, Po-Tai
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Automatic voltage control; Converters; Electric potential; Electric power distribution; Modulation; neutral-point (NP) voltage; Neutral-point clamped (NPC); Portfolio management; Power factor; Power loss; power loss distribution; Pulse width modulation; pulsewidth modulation (PWM); Reactive power; Semiconductor devices; static synchronous compensator (STATCOM); Static synchronous compensators; Switches; Switching loss; thermal; Tin; Voltage
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2019.2924407

The uneven power loss distribution among the semiconductor devices is one critical issue of the three-level neutral-point clamped converter. Besides, different operating conditions will result in different loss distribution profiles. The case with low power factor and high modulation usage, which is common in the static synchronous compensator (STATCOM) application, has not been paid much attention to in the literature. In this paper, the power loss distribution under this condition is discussed. And a novel carrier-based modulation technique is proposed to balance the power loss distribution and reduce the power loss in the most stressed device. In addition, an active neutral-point (NP) voltage balancing control strategy is also proposed based on the proposed modulation scheme. Simulation and laboratory results are presented to verify the performances of the proposed modulation technique in power loss redistribution and NP voltage control. Its influence on the output current harmonic performance is also evaluated.