1. A Flexible and Decoupled Space Vector Modulation Scheme With Carrier-Based Implementation for Multilevel Converters
- Author
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Qingle Sun, Zhifu Wang, Suleiman M. Sharkh, and Wenmei Hao
- Subjects
Electrical and Electronic Engineering - Abstract
This article proposes a novel space vector pulse width modulation (SVPWM) scheme for multilevel converters in abc coordinate system, in which the reference vector is decomposed into an offset vector and a remainder vector thatcan be synthesized using two-level SVPWM. The switching state satisfying a specific relationship is first selected as the offset vector such that the common-mode components are eliminated and therefore the phase voltages are decoupled. A dynamic reference point mechanism establishes a one-to-one correspondence between all available vector combinations and one unique variable, i.e., the number of level shifts. This feature further facilitates a general approach to determining the optimum switching states to satisfy different control objectives, such as common-mode voltage rejection. Besides, phase decoupling enables the introduction of carrier-based modulation to simplify implementation, where theduty cycle of the zero vector can be flexibly adjusted while the non-zero vectors remain the same to generate an equivalent output. Consequently, two-level SVPWM-based method and carrierbased PWM are combined to exploit their respective strengths. The proposed scheme achieves overmodulation operation, and provides more flexibility, i.e., redundant switching states and adjustable duty cycles, to optimize switching patterns. Simulation and experimental results validate the proposed algorithm.
- Published
- 2023