SDBC-MMC STATCOM Control Under Unbalanced Grid Conditions Based on Different Sequence Extraction Methods

Meligy, Ahmed; Qoria, Taoufik; Ali, Waqas; Colak, Ilknur

doi:10.1109/iecon48115.2021.9589213

Cited by 1 publication

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DC offsets along with harmonics that come from non-linear loads may engender unwanted oscillations that affect the control operation [7] and lead to the malfunction of the overall system. On the other hand, the grid voltage unbalance resulting from single or bi-phase faults [11] gives rise to a negative sequence component that in turn results in the appearance of 2ω oscillations caused by the coupling between the positive and negative sequences [8], [12]- [14]. These oscillations affect the grid voltage and current, and consequently lead to an inaccurate estimation of the grid angle and frequency, a fluctuation of the injected reactive power, and an unbalance of the energy between the MMC legs [5].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Sequence Extraction Methods Applied to MMC-SDBC STATCOM Under Distorted Grid Conditions

Meligy

Qoria

Colak

2022

IEEE Trans. Power Delivery

Self Cite

View full text Add to dashboard Cite

Under grid distortions, Modular Multilevel Converters (MMC) must adopt proper control strategies to fulfill the power system requirements and ensure a stable operation. An inappropriate control under such conditions may lead to energy unbalances between the MMC legs, inaccurate current injection, and failure in the synchronization process. In this context, sequence extraction methods play a critical role in enhancing the performance of the control, firstly, by aiding the Phase-Locked Loop (PLL) to maintain the synchronization with the AC grid by following the positive sequence fundamental component of the voltage, secondly, by allowing an accurate active and reactive currents injection via the decoupled Voltage Oriented Control (dVOC), thirdly, by properly managing the internal energy of the MMC through the circulating current control. In prior researches, some sequence extraction methods have been used for MMC STATCOM. However, the sequence extraction was not the core of the performed studies and their impact on the system behavior has not been highlighted or tested in several grid conditions. This work fills this gap by first assessing the performance of a Single Delta Bridge Cell MMC (SDBC-MMC) STATCOM with four well-known sequence extraction methods (i.e., Decoupled Double Synchronous Reference Frame (DDSRF), Dual Second Order Generalized Integrator (DSOGI), Improved DSOGI, and Fortescue matrix-based (FMB) filter) under normal and abnormal grid conditions, then, finding the most suitable one in terms of stability, dynamics, and functionalities.

show abstract