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Augmentation of Wind Farms Ride Through by DFIG-based Variable Speed Wind Generators
Okedu, K.E.,Muyeen, S.M.,Takahashi, R.,Tamura, J. Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1
Wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage has been recovered. Doubly Fed Induction Generator (DFIG) based wind farm is gaining popularity these days because of its inherent advantages like variable speed operation and independent controllability of active and reactive power over conventional Induction Generator (IG). This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs. Simulation analysis by using PSCAD/EMTDC shows that the DFIGs can effectively stabilize the IGs and hence the entire wind farm through the proposed control scheme by providing sufficient reactive power to the system.
Comparative Study between Two Protection Schemes for DFIG-based Wind Generator Fault Ride Through
Okedu, K.E.,Muyeen, S.M.,Takahashi, R.,Tamura, J. Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1
Fixed speed wind turbine generators system that uses induction generator as a wind generator has the stability problem similar to a synchronous generator. On the other hand, doubly fed induction generator (DFIG) has the flexibility to control its real and reactive powers independently while being operated in variable speed mode. This paper focuses on a scheme where IG is stabilized by using DFIG during grid fault. In that case, DFIG will be heavily stressed and a remedy should be found out to protect the frequency converter as well as to allow the independent control of real and reactive powers without loosing the synchronism. For that purpose, a crowbar protection switch or DC-link protecting device can be considered. This paper presents a comparative study between two protective schemes, a crowbar circuit connected across the rotor of the DFIG and a protective device connected in the DC-link circuit of the frequency converter. Simulation analysis by using PSCAD/EMTDC shows that both schemes could effectively protect the DFIG, but the latter scheme is superior to the former, because of less circuitry involved.
Rosyadi, Marwan,Takahashi, Rion,Muyeen, S.M.,Tamura, Junji Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.1
This paper present stabilization control of fixed speed wind generator by using variable speed permanent magnet wind generator in a wind farm connected with multi-machine power system. A novel direct-current based d-q vector control technique of back to back converter integrated with Fuzzy Logic Controller for optimal control configuration is proposed, in which both active and reactive powers delivered to a power grid system are controlled effectively. Simulation analyses have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is very effective to enhance the voltage stability of the wind farm during fault condition.
Performance Analysis of a Sliding Mode Control for Distributed Generations
Islam, Gazi,Al-Durra, Ahmed,Muyeen, S.M.,Caruna, Cedric,Tamura, Junji Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.1
This paper presents the performance analysis of a sliding mode based hybrid controller for three phase voltage source inverter. The main objective of this analysis is to observe the effectiveness of the controller for fault ride through (FRT) capability improvement of the distributed generations (DG). The performance of the conventional PI based cascaded controller is also presented for comparison purpose.
Stability Enhancement of a Hybrid Micro-grid System in Grid Fault Condition
Ambia, Mir Nahidul,Al-Durra, Ahmed,Caruana, Cedric,Muyeen, S.M. Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.2
Low voltage ride through capability augmentation of a hybrid micro-grid system is presented in this paper which reflects enhanced reliability in the system. The control scheme involves parallel connected multiple ac-dc bidirectional converters. When the micro-grid system is subjected to a severe voltage dip by any transient fault single power converter may not be able to provide necessary reactive power to overcome the severe voltage dip. This paper discusses the control strategy of additional power converter connected in parallel with main converter to support extra reactive power to withstand the severe voltage dip. During transient fault, when the terminal voltage crosses 90% of its pre-fault value, additional converter comes into operation. With the help of additional power converter, the micro-grid system withstands the severe voltage fulfilling the grid code requirements. This multiple converter scheme provides the micro-grid system the capability of low voltage ride through which makes the system more reliable and stable.
Small Signal Stability Analysis of Doubly Fed Induction Generator including SDBR
Shawon, Mohammad Hasanuzzaman,Al-Durra, Ahmed,Caruana, Cedric,Muyeen, S.M. Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.1
This paper presents small signal stability analysis of a doubly fed induction generator (DFIG) based wind farm including series dynamic braking resistor (SDBR) connected at the stator side. A detailed mathematical model of wind turbine, DFIG machine and converters and SDBR is presented in this paper to derive the complete dynamic equations of the studied system. Small signal stability of this system is carried out by modal and sensitivity analysis, participation factors and eigenvalue analysis. Finally, this paper presents an analysis of the dynamic behavior of DFIG based wind farm under voltage dip condition with and without SDBR.
Intelligent Virtual Impedance Based Control to Enhance the Stability of Islanded Microgrid
Jiang Enyu,Zhao Jikang,Shi Zhengjing,Mi Yang,Lin Shunfu,Muyeen S. M. 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5
This paper focuses on the voltage stability issue of an islanded microgrid in a cost-effective way adding the concept of adaptive virtual impedance. In the islanded microgrid structure, the mis-match of line impedance between the Distributed Generation (DG) units and imbalance of inverter local load are two critical factors to be dealt with carefully. These can result in serious circulating current and unreasonably reactive power sharing among DG units by using the conventional droop control method. In practical engineering, line inductance is often increased to eliminate the impedance mismatch. However, such a method would lead to an increase in cost, weight, and volume. To solve this problem, an adaptive virtual impedance droop control strategy based on fuzzy controller is proposed. Instead of DG units are equipped with series inductors, an adaptive virtual impedance is introduced to adaptively eliminate the reactive power error caused by the inconsistency of the line impedance through the fuzzy controller. At the same time, in order to deal with the droop control and the voltage drop at the inverter output caused by the addition of virtual impedance, a voltage compensation link is introduced to maintain the voltage within an acceptable range. The simulations were performed in Matlab/Simulink and RT-LAB experiments to verify the validity of the proposed control strategy.