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Doubly fed induction generator (DFIG) is significantly affected by various faults occurring in the grid as they are directly connected to the grid. In order to realize the low voltage ride through (LVRT) capability, the DFIG must remain connected to the system for a certain period of time according to the grid code requirement. In order to achieve this, the high rotor current must be reduced in DFIG against faults occurring on the grid side. In this study, a decoupled feed-forward control model was developed for the LVRT capability. Positive, negative, natural, and forced methods were used for the decoupled feed-forward control (FFC) model. In addition to this developed model, while the stator electromotive force (EMF) model was developed for simulation study performance and ease of calculation, the rotor EMF model was also developed to predict the transient rotor current quickly. The developed models and the conventional model were used and compared in detail. According to the results obtained, it was observed that the system became stable owing to the developed model, while the oscillations formed as a result of the transient stability were damped. [ABSTRACT FROM AUTHOR]

Low-voltage ride-through is important for the operation stability of the system in balanced- and unbalanced-grid-fault-connected doubly fed induction generator-based wind turbines. In this study, a new LVRT capability approach was developed using positive–negative sequences and natural and forcing components in DFIG. Besides, supercapacitor modeling is enhanced depending on the voltage–capacity relation. Rotor electro-motor force is developed to improve low-voltage ride-through capability against not only symmetrical but also asymmetrical faults of DFIG. The performances of the DFIG with and without the novel active–passive compensator–supercapacitor were compared. Novel active–passive compensator–supercapacitor modeling in DFIG was carried out in MATLAB/SIMULINK environment. A comparison of the system behaviors was made between three-phase faults, two-phase faults and a phase–ground fault with and without a novel active–passive compensator–supercapacitor modeling. Parameters for the DFIG including terminal voltage, angular speed, electrical torque variations and d–q axis rotor–stator current variations, in addition to a 34.5 kV bus voltage, were investigated. It was found that the system became stable in a short time and oscillations were damped using novel active–passive compensator–supercapacitor modeling and rotor EMF. [ABSTRACT FROM AUTHOR]

Low voltage ride through (LVRT) is one of the most popular methods to protect doubly fed induction generator (DFIG) against balanced and unbalanced voltage dips. In this study, a novel LVRT capability strategy is enhanced using forcing demagnetization controller (FDC) in DFIG-based wind farm. Moreover, not only stator circuit but also rotor circuit were developed by electromotor force (EMF) for LVRT in DFIG-based wind farm. The transient stability performances of the DFIG with and without the FDC and EMF were compared for three- and two-phase faults. In addition to variations such as 34.5 kV bus voltage and terminal voltage of DFIG, speed of DFIG, electrical torque of DFIG and d-q axis rotor-stator current variations of DFIG were also evaluated. It was seen that the system became stable within a short time using the FDC and EMF. [ABSTRACT FROM AUTHOR]