Modeling and Current Control Strategy for a Medium-voltage Cascaded Multilevel STATCOM with LCL Filter

  • Xuehua Zhao China University of Mining & Technology
  • Liping Shi China University of Mining & Technology
  • Libing Chen China University of Mining & Technology
  • Zhenglong Xia Jiangsu Normal University
  • A. R. Bendre University of Wollongong

Abstract

The Static Synchronous Compensator (STATCOM a.k.a. SVG) is widely used to regulate dynamic reactive powerand to solve dynamic voltage stability problems. Modeling shows that a cascaded STATCOM, which is composedof several cascaded H-bridges, not only has strong coupling characteristics when an LCL filter is added but it is alsoa non-linear, multivariable system. Therefore, its practical design and application are dicult to implement. In thispaper an internal decoupling control algorithm is introduced to provide independent control of the active and reactivecurrents. Decoupling control algorithms are proposed, and models and simulation of the decoupling are provided. Wedescribe the setting up of a simulation and experiments with a cascaded STATCOM based on combined circuit topologywith a multi-field programmable gate array (FPGA), and double-loop control algorithms with a current inner loop, anda capacitor voltage outer loop. To provide control of the current inner loop, proportional-integral (PI) and resonantcontrollers are used, having the control ability to cancel harmonics while compensating for the reactive power. Thispaper presents new current-tracing control models that compensate for the fundamental current and eliminate selectiveharmonics by adopting a d-q synchronous reference frame, and a discrete Fourier transform (DFT). Voltage balanceis realized by introducing modulation wave distribution strategies. Furthermore, both simulation and experiments areemployed to verify the feasibility and eectiveness of the control strategy.

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Published
2015-03-27
How to Cite
ZHAO, Xuehua et al. Modeling and Current Control Strategy for a Medium-voltage Cascaded Multilevel STATCOM with LCL Filter. Journal of Power Technologies, [S.l.], v. 95, n. 1, p. 1--13, mar. 2015. ISSN 2083-4195. Available at: <https://papers.itc.pw.edu.pl/index.php/JPT/article/view/664>. Date accessed: 23 july 2021.
Section
Energy Engineering and Technology

Keywords

Cascaded H-bridge; Internal model decoupling; Resonant controller; Distribution of modulation; Double-loop control

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