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

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.

2013 ◽  
Vol 373-375 ◽  
pp. 1287-1293
Author(s):  
Jian Wei Liang ◽  
Tao Wang

The paper is based on PSCAD/EMTDC. The basic structure and operation principle of DFIG are analyzed and the mathematical model of DFIG is established, based on which the control system of rotor-side and grid-side converters is set up. The stator flux-oriented vector control is adopted for rotor-side converter. The no-load grid connection is realized before cutting in and control strategy is switched after grid connection successfully. DFIG can meet grid connection condition quickly with the control strategy and is connected to grid with no current shock nearly. The output of active and reactive power can be regulated respectively.


2014 ◽  
Vol 1070-1072 ◽  
pp. 224-227
Author(s):  
Li Lin ◽  
Kai Li

Current control strategy of reactive power and voltage for wind power integration is separate control of single wind farm (WF), which cannot achieve the optimal allocation of reactive power and is not beneficial for the optimization of voltage stability and network loss. In this paper, a coordinated control strategy of reactive power and voltage for wind farm cluster is proposed, which takes the voltage stability at point of common coupling (PCC) and economic operation as the optimization goals. The coordinated control strategy is realized through the platform of Cybercontrol industrial configuration, and the application testing verifies the effectiveness of the proposed strategy.


Author(s):  
Zakieldeen M. E. Elhassan ◽  
Abusabah I. A. Ahmed ◽  
Othman Hassan Abdalla

Abstract. This paper presents an approach frequency coordinated control of Doubly Fed Induction Generator (DFIG) applying in the Rotor Side Converter (RSC) using an order reference active power (Pref ). Pref is obtained from the frequency deviation, speed regulation and kinetic energy stored in the DIFG. The Pref is employed as a main controller parameter of the dq-axis currents in the RSC under two case studies. In case1 study, the Pref is used to regulate the q-axis reference current and the grid reactive power controlled d- axis reference current. Whilst in case2 study, the d- axis reference current is produced by Pref , and the rotormechanical speed responsible to generate the q-axis reference current. The modified vector control method is used to control the Grid Side Converter (GSC) in two case studies. The transient performance of two case studies is simulated by PSCAD/EMDTC program under constant, step and variable wind speeds. A comparative result between two case studies shown that the frequency coordinated control has an ability to control both rotor dq-axis currents, and it enhancing the system frequency as well as improved DFIG voltage stability.However, case2 study has a better response than case1 study during system operated under random wind speed.


Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7685
Author(s):  
Xiangwu Yan ◽  
Wenfei Chang ◽  
Sen Cui ◽  
Aazim Rassol ◽  
Jiaoxin Jia ◽  
...  

A large-scale power system breakdown in the United Kingdom caused blackouts in several important cities, losing about 3.2 percent of the load and affecting nearly 1 million power users on 9 August 2019. On the basis of the accident investigation report provided by the UK National Grid, the specific reasons for the sub-synchronous oscillation of Hornsea wind farm were analyzed. The Hornsea wind power system model was established by MATLAB simulation software to reproduce the accident. To solve this problem, based on the positive and negative sequence decomposition, the control strategy of grid-side converter of doubly-fed induction generator is improved to control the positive sequence voltage of the generator terminal, which can quickly recover the voltage by compensating the reactive power at the grid side. Consequently, the influence of the fault is weakened on the Hornsea wind farm system, and the sub-synchronous oscillation of the system is suppressed. The simulation results verify the effectiveness of the proposed control strategy in suppressing the sub-synchronous oscillation of weak AC wind power system after being applied to doubly-fed induction generator, which serves as a reference for studying similar problems of offshore wind power.


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