scholarly journals Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3316 ◽  
Author(s):  
Dong Wang ◽  
Xiaojie Zhang ◽  
Lei Yang ◽  
Yunhui Huang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Signal Model ◽  
Detailed Model ◽  
Weak Grid ◽  
Grid Connection ◽  
Sensitivity Studies ◽  
Stability Enhancement

Recent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to a weak grid. A reduced transfer function based small-signal model, which can allow for the interactions between PLL and converter outer power controls, is first proposed. Then, an improved net damping criterion is used to analyze the damping and stability characters of such system under various operating conditions and different controller configurations. Compared to the conventional net damping criterion, the used criterion has wider applicability in terms of stability judgment. Case studies show that the studied system tends to be unstable at weak-grid or heavy-loading conditions. The instability can be in the form of oscillations or monotonic divergence, in which, the latter is more likely to occur for the converters without grid voltage regulation capabilities. Besides, the net damping-based sensitivity studies can provide guidance on control tuning or design for stability enhancement. Detailed model-based time domain simulations are conducted to verify the analysis results.

Adaptive SRF-PLL Based Voltage and Frequency Control of Hybrid Standalone WECS with PMSG-BESS

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha
Keyword(s):  
Reactive Power ◽  
Frequency Control ◽  
Storage System ◽  
Synchronous Generator ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Control Scheme

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.

scholarly journals Coordinated Control System between Grid–VSC and a DC Microgrid with Hybrid Energy Storage System

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2699
Author(s):  
Miguel Montilla-DJesus ◽  
Édinson Franco-Mejía ◽  
Edwin Rivas Trujillo ◽  
José Luis Rodriguez-Amenedo ◽  
Santiago Arnaltes
Keyword(s):  
Control Strategy ◽  
Power Flow ◽  
Storage System ◽  
Coordinated Control ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Electrical Network ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Dc Microgrid

Direct current microgrids (DCMGs) are currently presented as an alternative solution for small systems that feed sensitive electrical loads into DC. According to the scientific literature, DCMG maintains good voltage regulation. However, when the system is in islanded mode, very pronounced voltage variations are presented, compromising the system’s ability to achieve reliable and stable energy management. Therefore, the authors propose a solution, connecting the electrical network through a grid-tied voltage source converter (GVSC) in order to reduce voltage variations. A coordinated control strategy between the DCMG and GVSC is proposed to regulate the DC voltage and find a stable power flow between the various active elements, which feed the load. The results show that the control strategy between the GVSC and DCMG, when tested under different disturbances, improves the performance of the system, making it more reliable and stable. Furthermore, the GVSC supports the AC voltage at the point of common coupling (PCC) without reducing the operating capacity of the DCMG and without exceeding even its most restrictive limit. All simulations were carried out in MATLAB 2020.

Adaptive Control Scheme for Grid Tied SPV System with DSTATCOM Capabilities: Review

2021 ◽  
Vol 23 (07) ◽  
pp. 678-689
Author(s):  
Bilal Ahmad Ganie ◽  
◽  
Dr. (Mrs.) Lini Mathew ◽  
Keyword(s):  
Adaptive Control ◽  
Stage Structure ◽  
Voltage Regulation ◽  
Control Technique ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Current Harmonics ◽  
Control Approach ◽  
Photovoltaic Array ◽  
Static Compensator

This study provides an adaptive control approach of VSC (voltage source converter) coupled with SPV (solar photovoltaic array), in a 3P3W (three-phase three-wire) system with three single-phase non-linear loads having Distributed Static Compensator (DSTATCOM) abilities using P and O (perturb & observe) methodology. The adaptive control technique converges quickly and has a low mean square error. For the correction of power factor and zero voltage regulation modes, the system is studied and simulated. The system’s great efficacy at high voltages is due to its one-stage structure. Grid current harmonics are significantly below the IEEE-519 norm. The suggested system is modeled and simulated with the available sim power system toolbox in MATLAB/Simulink, and the system’s behavior under different loads and environmental circumstances is confirmed.

PHC, Id-Iq and p-q Control Strategies for Mitigation of Current Harmonics in Three-Phase Three-Wire Shunt Active Filter with PI Controller

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Suresh Mikkili ◽  
Adinarayana Padamati
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Voltage Regulation ◽  
Active Filter ◽  
Electrical Network ◽  
Voltage Source ◽  
Complex Nature ◽  
Voltage Source Converter ◽  
Shunt Active Filter ◽  
Three Phase

Abstract In this research paper, the shunt active filter (SHAF) is used to improve the power quality of electrical network by mitigating the harmonics with the help of different control strategies (p-q control strategy, Id-Iq control strategy, PHC control strategy) for three phase three wire system. It is quite difficult to optimize the performance of power system networks using conventional methods, because of complex nature of the systems that are highly non-linear and non-stationary. Three phase reference current waveforms generated by the proposed schemes are tracked by three phase voltage source converter in a hysteresis band control scheme. The performance of proposed control strategies has been evaluated in terms of harmonic mitigation and DC link voltage regulation under various source voltage conditions. The proposed SHAF with different control strategies is able to eliminate uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/Simulink software are presented to support the feasibility of the proposed control strategy.

scholarly journals Modeling and Analyzing the Effect of Frequency Variation on Weak Grid-Connected VSC System Stability in DC Voltage Control Timescale

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4458 ◽  
Author(s):  
Yang ◽  
Yuan
Keyword(s):  
Voltage Control ◽  
System Stability ◽  
Voltage Source ◽  
Frequency Variation ◽  
Voltage Source Converter ◽  
Small Signal ◽  
Small Signal Stability ◽  
Dc Voltage ◽  
Weak Grid ◽  
Dc Voltage Control

The effect of frequency variation on system stability becomes crucial when a voltage source converter (VSC) is connected to a weak grid. However, previous studies lack enough mechanism cognitions of this effect, especially on the stability issues in DC voltage control (DVC) timescale (around 100 ms). Hence, this paper presented a thorough analysis of the effect mechanism of frequency variation on the weak grid-connected VSC system stability in a DVC timescale. Firstly, based on instantaneous power theory, a novel method in which the active/reactive powers are calculated with the time-varying frequency of voltage vectors was proposed. This method could intuitively reflect the effect of frequency variation on the active/reactive powers and could also help reduce the system order to a certain extent. Then, a small-signal model was established based on the motion equation concept, to depict the effect of frequency variation on the weak grid-connected VSC system dynamics. Furthermore, an analytical method was utilized to quantify the effect of frequency variation on the system’s small-signal stability. The quantitative analysis considered the interactions between the DC voltage control, the terminal voltage control, phase-locked loop, and the power network. Finally, case studies were conducted, and simulation results supported the analytical analyses.

scholarly journals Research on DC-link voltage stabiliser for voltage source converter as connected to weak grid

2017 ◽  
Vol 2017 (13) ◽  
pp. 2168-2172
Author(s):  
Yunhui Huang ◽  
Jinrui Tang ◽  
Guorong Zhu ◽  
Xianqiang Li ◽  
Haiyan Tang ◽  
...  
Keyword(s):  
Voltage Source ◽  
Voltage Source Converter ◽  
Weak Grid
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