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Analysis on Circulating Current and Split Capacitor Voltage Balance for Modular Multilevel Converter Based Three-phase Four-wire Split Capacitor DSTATCOM
- Source :
- Journal of Modern Power Systems and Clean Energy, Vol 9, Iss 3, Pp 657-667 (2021)
- Publication Year :
- 2021
- Publisher :
- IEEE, 2021.
-
Abstract
- We propose a modular multilevel converter (MMC) based three-phase four-wire (3P4W) split capacitor distribution static synchronous compensator (DSTATCOM), aiming at compensating unbalanced and reactive load currents. Due to the zero-sequence current compensation, the circulating current characteristics of 3P4W MMC-DSTATCOM are different from conventional MMCs. Moreover, the distinct working principle of MMC would affect the features of split capacitor voltage. The decoupled positive-, negative- and zero-sequence second-order and DC components of the circulating current are deduced explicitly. Two proportional-integral controllers with dual dq transformation are employed to suppress the positive- and negative-sequence components of second-order circulating current, while quasi proportional-resonance controller is designed to eliminate the zero-sequence component. Besides, the phenomenon of the unbalanced split capacitor voltages is revealed, and fast-tracking balancing method by controlling zero-sequence current flowing through the split capacitors is provided. Digital simulation results verify the accuracy of the analysis and the feasibility of the suppression methods.
Details
- Language :
- English
- ISSN :
- 21965420
- Volume :
- 9
- Issue :
- 3
- Database :
- Directory of Open Access Journals
- Journal :
- Journal of Modern Power Systems and Clean Energy
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.0ae9051d5dc34801afe491059b229d18
- Document Type :
- article
- Full Text :
- https://doi.org/10.35833/MPCE.2019.000213