scholarly journals Base-Frequency Negative Sequence Impedance Modeling and Sensitivity Analysis of DFIG

2021 ◽  
Author(s):  
Simin Pang ◽  
Ruiyuan Jia ◽  
Qihui Liu ◽  
Linlin Wu ◽  
Hui Liu
Keyword(s):  
Sensitivity Analysis ◽  
Large Scale ◽  
Great Influence ◽  
Negative Sequence ◽  
Base Frequency ◽  
New Energy ◽  
Point Of Common Coupling ◽  
Impedance Modeling ◽  
Doubly Fed ◽  
Grid Side

The phenomenon of three phase voltage imbalance frequently occurs in large-scale new energy grid connected areas in China; in severe cases, a large number of wind turbines will be disconnected from the grid. To solve the problem of the voltage imbalance at the point of common coupling (PCC), analyze the influence of generator parameters change on negative sequence voltage under the background of unbalanced power grid, a modeling method of base-frequency negative sequence impedance of doubly fed induction generator (DFIG) which including phase locked loop (PLL), rotor side converter (RSC) and grid side converter (GSC) is proposed. By establishing the negative sequence equivalent circuit of grid-connected system of DFIG, the relationship between the negative sequence voltage of PCC and the negative sequence impedance of DFIG is listed, and analyzing the sensitivity of control parameters link to base-frequency impedance, the parameter that has great influence on base-frequency negative sequence impedance of PCC is found out. Finally, the accuracy of impedance modeling and sensitivity analysis is verified by simulation studies.

Power and Voltage Smooth Control of Doubly Fed Induction Generator

2014 ◽  
Vol 494-495 ◽  
pp. 1829-1832
Author(s):  
An Ren Ma ◽  
Cai Xia Wang ◽  
Zhi Wen Zhou ◽  
Tao Wu
Keyword(s):  
Decoupling Control ◽  
Induction Generator ◽  
Storage Device ◽  
Doubly Fed Induction Generator ◽  
Energy Storage Device ◽  
Good Characteristic ◽  
Smooth Control ◽  
New Energy ◽  
Doubly Fed ◽  
Grid Side

Doubly-fed induction generator (DFIG) is the leading in wind power technology currently. In this paper, decoupling control of DFIG is studied and a new energy storage device is used in the smooth control of DFIG system’s power and voltage. This new method has a good characteristic on stability of grid-side power and voltage when the wind speed changes rapidly. In this paper, a simulation system based on this method is designed using MATLAB, the experimental results of simulation show that the method is correct and has practical value.

scholarly journals Providing Ancillary Services with Wind Turbine Generators Based on DFIG with a Two-Branch Static Converter

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2490 ◽  
Author(s):  
Ernande Eugenio C. Morais ◽  
Francisco Kleber de A. Lima ◽  
Jean M. L. Fonseca ◽  
Carlos G. C. Branco ◽  
Lívia de A. Machado
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Power Converter ◽  
Ancillary Services ◽  
Nonlinear Loads ◽  
Turbine Generators ◽  
Point Of Common Coupling ◽  
Doubly Fed ◽  
Grid Side ◽  
Controller Board

This work aims to analyze and validate through mathematical modeling and experimental results, in a three-phase three-wire electrical system, the technical viability of a static power converter with a two-level topology with only two controlled branches (2L2B), operating as a grid-side converter (GSC) in a wind turbine generator based on a doubly fed induction generator (DFIG). With this reduced-switches topology, the GSC is able to regulate the DC-link voltage level from the generator back-to-back converter and provide ancillary services of harmonic filtering and reactive power compensation from linear/nonlinear loads connected to the point of common coupling. An 8-kVA experimental prototype was implemented in the laboratory to validate the proposal. The prototype control system was realized using the dSPACE DS1103 PPC Controller Board platform programmed via MATLAB/Simulink. The effectiveness of the proposed system is verified by comparing the results obtained with the 2L2B topology to the ones with the usual two-level three-branch topology.

The robustness assessment of doubly fed induction generator-wind turbine during short circuit

2019 ◽  
Vol 31 (4) ◽  
pp. 570-582 ◽  
Author(s):  
Muhammad Shahzad Nazir ◽  
Ahmed N Abdalla
Keyword(s):  
Short Circuit ◽  
Wind Farms ◽  
Superior Performance ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Point Of Common Coupling ◽  
Common Coupling ◽  
Doubly Fed ◽  
Grid Side ◽  
Grid Side Converter

Energy sources, such as wind, solar, hydro, etc., are an important source of energy, and wind power generators are important energy conversion machines. The doubly fed induction generator has wide industrial and commercial applications due to its superior performance, combined with fault and eco-friendly properties. However, the fault current dynamics of wind farms identify the potential impacts of fault currents and the voltage on the protection. This study focuses on wind farms (employing doubly fed induction generators) perturbation during symmetrical (three-phase) symmetrical short circuit (SSC) at different points. The detail of analyzing the doubly fed induction generator (DFIG) performance during transient conditions, control and modeling is studied in this paper. These two points are selected as grid-side converter and point of common coupling, respectively. These comparison results fetched the more precise understanding of the fault diagnosis reliability with reduced complexity, stability, and optimization of the system. The present findings illustrated the main difference between point of common coupling and grid-side converter under SSC faults and the robustness of these two mentioned points.

Study of Failure Rate Model for a Large-Scale Water Supply Network in Southern China Based on Different Diameters

2012 ◽  
Vol 260-261 ◽  
pp. 1200-1205
Author(s):  
Peng Jun Yu ◽  
Jin Xu Nie ◽  
Gang Xu ◽  
Zhi Hong Long ◽  
Zhi Hong Wang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Large Scale ◽  
Southern China ◽  
Paper Analysis ◽  
Current Control ◽  
Transient Model ◽  
Grid Voltage ◽  
Doubly Fed ◽  
Grid Side ◽  
Different Diameters

This paper studies on the electromagnetic transient model of doubly-fed wind turbinegrid-side converter under the imbalanced grid condition. And on this basis, the paper analysis theimpact of doubly-fed converter when grid voltage asymmetric drop. It puts forward a dual PLL anddual current control combination of doubly-fed converter grid side control strategy. This strategyachieves grid voltage positive and negative sequence fast separation when asymmetric grid voltagedrop occur, achieves the active output power secondary fluctuate suppression under the imbalancedgrid voltage condition, avoids DC voltage rise at the fault moment and also achieves converterreactive power support under the imbalanced grid fault. The simulation and experimental resultsshow that the proposed control strategy is correct and with the application value of engineering.

scholarly journals Research on Zero-Voltage Ride Through Control Strategy of Doubly Fed Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2287
Author(s):  
Kaina Qin ◽  
Shanshan Wang ◽  
Zhongjian Kang
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Control Strategy ◽  
Large Scale ◽  
Sliding Mode ◽  
Stable Operation ◽  
Wide Range ◽  
Dc Bus ◽  
Doubly Fed ◽  
Zero Voltage

With the rapid increase in the proportion of the installed wind power capacity in the total grid capacity, the state has put forward higher and higher requirements for wind power integration into the grid, among which the most difficult requirement is the zero-voltage ride through (ZVRT) capability of the wind turbine. When the voltage drops deeply, a series of transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur in the motor, which will seriously endanger the safe operation of the wind turbine itself and its control system, and cause large-scale off-grid accident of wind generator. Therefore, it is of great significance to improve the uninterrupted operation ability of the wind turbine. Doubly fed induction generator (DFIG) can achieve the best wind energy tracking control in a wide range of wind speed and has the advantage of flexible power regulation. It is widely used at present, but it is sensitive to the grid voltage. In the current study, the DFIG is taken as the research object. The transient process of the DFIG during a fault is analyzed in detail. The mechanism of the rotor overcurrent and DC bus overvoltage of the DFIG during fault is studied. Additionally, the simulation model is built in DIgSILENT. The active crowbar hardware protection circuit is put into the rotor side of the wind turbine, and the extended state observer and terminal sliding mode control are added to the grid side converter control. Through the cooperative control technology, the rotor overcurrent and DC bus overvoltage can be suppressed to realize the zero-voltage ride-through of the doubly fed wind turbine, and ensure the safe and stable operation of the wind farm. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy.

scholarly journals Coordinated Control of RSC and GSC for DFIG System under Harmonically Distorted Grid Considering Inter-Harmonics

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 28 ◽  
Author(s):  
Bo Pang ◽  
Hui Dai ◽  
Feng Li ◽  
Heng Nian
Keyword(s):  
Theoretical Analysis ◽  
Control Strategy ◽  
Coordinated Control ◽  
Delay Compensation ◽  
Pass Filter ◽  
Grid Connection ◽  
Distorted Grid ◽  
Negative Impacts ◽  
Doubly Fed ◽  
Grid Side

For improving the performance of a doubly fed induction generator (DFIG) system under a harmonically distorted grid, this paper proposes a coordinated control strategy which is effective for grid inter-harmonics as well as grid integer harmonics. In order to suppress the negative impacts caused by grid harmonics, including inter-harmonics, this paper introduces an additional harmonics suppression controller, which contains a Chebyshev high-pass filter and a modified lead element considering the delay compensation. The proposed controller is employed in the rotor side converter (RSC) and grid side converter (GSC). Based on the proposed harmonics suppression controller, a coordinated control strategy between RSC and GSC is developed, in which the control targets, including the sinusoidal output current, constant power, or steady generator torque, can be achieved for DFIG, while GSC is responsible for maintaining the sinusoidal total current to guarantee the power quality of the grid connection. The effectiveness of the proposed method is verified by the theoretical analysis, and the experimental results derived using a 1 kW DFIG system validate the correctness of the theoretical analysis.

scholarly journals Analysis and Mitigation of Sub-Synchronous Resonance for Doubly Fed Induction Generator under VSG Control

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1582
Author(s):  
Yingzong Jiao ◽  
Feng Li ◽  
Hui Dai ◽  
Heng Nian
Keyword(s):  
Reactive Power ◽  
Synchronous Generator ◽  
Impedance Analysis ◽  
Damping Factor ◽  
Renewable Power ◽  
Induction Generators ◽  
Parameter Configuration ◽  
Impedance Modeling ◽  
Doubly Fed ◽  
Series Capacitor Compensation

This paper presents the analysis and mitigation of sub-synchronous resonance (SSR) for doubly fed induction generators (DFIG) under virtual synchronous generator (VSG) control, based on impedance methods. VSGs are considered to have grid-supporting ability and good stability in inductance-based weak grids, and are implemented in renewable power generations, including DFIG systems. However, stability analyses of VSGs for DFIG connecting with series capacitor compensation are absent. Therefore, this paper focuses on the analysis and mitigation of SSR for DFIG under VSG control. Impedance modeling of DFIG systems is used to analyze SSR stability. Based on impedance analysis, the influence of VSG control parameters and the configuration of damping factor of reactive power are discussed. Next, a parameter configuration method to mitigate SSR is proposed. Finally, time-domain simulation and fast fourier transform (FFT) results are given to validate the correctness and effectiveness of the impedance model and parameter configuration methods.

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