An Alternative Current-Error Based Control for VSC Integration to Weak Grid

Givaki, Kamyab; Dong, Chen; Xu, Lie; Xu, Yan

doi:10.1109/pesgm.2018.8586145

Cited by 5 publications

(2 citation statements)

References 16 publications

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“…The increasing penetration of power electronic converter interfaced distributed energy sources into the power grid, introduced new challenges to the monitoring, protection and control of the system [1]. The high amount of converter interfaced sources impacts the stability of the system, especially in a weak grid with high inductive impedance [2][3][4][5][6]. The knowledge of the grid impedance at the connection point of the converter to the grid (PCC) is essential for improving the control strategy and overall grid stability by either changing the control action or re-tuning the controller [7].…”

Section: Introductionmentioning

confidence: 99%

Machine learning based impedance estimation in power system

Givaki

Seyedzadeh²,

Givaki³

2019

8th Renewable Power Generation Conference (RPG 2019)

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A passive machine learning based technique to estimate the impedance of the power grid at the point of common coupling of a converter interfaced distributed generation source is proposed. The proposed method is based on supervised learning and provides a fast and accurate estimation of the grid impedance without adversely impacting the power quality of the system. This method does not need an injection of additional signals to the grid and provides an accurate estimation of the grid impedance. Multi-objective NSGA-II algorithm is used for optimisation and tuning the random forest model for accurate estimation of both R and X The resistive and inductive reactance of grid is estimated using Random Forest model due to its capability in the prediction of multiple output values simultaneously.

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Section: Introductionmentioning

confidence: 99%

Machine learning based impedance estimation in power system

Givaki

Seyedzadeh²,

Givaki³

2019

8th Renewable Power Generation Conference (RPG 2019)

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“…system damping, [13] introduces current-error based compensators to the VSC voltage reference, while gainscheduling and cross-coupling terms in the outer loop were proposed in [21] to decouple the d-and q-axis control. Each of these strategies performs better than conventional VCC but, as with the PLL-focused controllers, these works do not consider multiple controller operating points.…”

mentioning

confidence: 99%

Analysis of Controller Bandwidth Interactions for Vector-Controlled VSC Connected to Very Weak AC Grids

Morris

Ahmed

Egea‐Àlvarez

2021

IEEE J. Emerg. Sel. Topics Power Electron.

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Stability assessment of conventional vector current control (VCC) of voltage-source converters (VSCs) in weak grids has not been standardized. In this paper, a small signal model is derived to quantify the maximum active power transfer in a very weak grid across a much wider range of controller bandwidths than has previously been investigated. A novel investigation of the VCC-VSC controller bandwidth interactions between inner and outer control loops, including the phase-locked loop (PLL) dynamics, is demonstrated and a stability bubble of safe operating points is established. Robustness of the stability bubble under different SCRs is investigated and dynamic performance considerations are introduced to form a reduced operating region with good transient performance. The controller gains within this region allow rated power transfer in inverting mode and good dynamic performance with no modifications to the conventional VCC structure. For very weak grids, it is recommended that PLL bandwidths between 5 and 30 Hz are avoided. If a slow PLL bandwidth is chosen, the outer loop q-axis should have a fast bandwidth; with a fast PLL, the outer loop q-axis control bandwidth should be reduced. In all cases, the outer loop d-axis should be slowed down to reach the power transfer limit.

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Power-Synchronization Control for Ultra-Weak AC Networks: Comprehensive Stability and Dynamic Performance Assessment

Morris

Ahmed

Egea‐Àlvarez

2021

IEEE Open J. Ind. Electron. Soc.

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Power-synchronization control (PSC) is a promising control strategy to improve the stability and performance of voltage-source converters (VSCs) in ultra-weak AC grids. However, evaluation of PSC to date has investigated performance only at single controller operating points, rather than holistically varying multiple controller gains. This paper develops a new methodology, based on small-signal eigenvalue analysis, to comprehensively analyze PSC-VSC stability. The maximum active power transfer of PSC is established across a broad range of controller tunings and the two-way and three-way couplings between the powersynchronization control, AC voltage control and high-pass current filter gains are quantified. A new stable tuning region is introduced, which represents the controller parameter space for stable operation. It is shown that PSC can achieve rated power transfer into an AC grid (short circuit ratio(SCR)=1) at multiple controller operating points, but dynamic performance varies significantly within this region. The robustness of this operating region to SCR changes is also investigated. The stability boundary and dynamic performance are validated using control hardware-in-the-loop experiments with a real-time digital simulator. Practical recommendations arising from this work are a set of controller gains that provide stability and good dynamic performance at high power transfer for ultra-weak grid-connected VSCs employing PSC. INDEX TERMSPower-synchronization control, VSC, weak grids, small signal analysis Khaled H. Ahmed (M'09, SM'12) received the B.Sc. (Hons.

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An Alternative Current-Error Based Control for VSC Integration to Weak Grid

Cited by 5 publications

References 16 publications

Machine learning based impedance estimation in power system

Machine learning based impedance estimation in power system

Analysis of Controller Bandwidth Interactions for Vector-Controlled VSC Connected to Very Weak AC Grids

Power-Synchronization Control for Ultra-Weak AC Networks: Comprehensive Stability and Dynamic Performance Assessment

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