IEEE_Paper_PD21.pdf (2.11 MB)
Download fileAssessment of Sequence Extraction Methods Applied to MMC-SDBC STATCOM Under Distorted Grid Conditions
preprint
posted on 2021-11-09, 01:21 authored by Taoufik QORIATaoufik QORIA, Ahmed Meligy, Ilknur ColakUnder 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.
History
Email Address of Submitting Author
T.qoria@reinhausen.comSubmitting Author's Institution
Maschinenfabrik Reinhausen, Medium Voltage Power Electronics R&D DepartmentSubmitting Author's Country
- Germany