Wind energy conversion systems as active filters: design and comparison of three control methods

Disturbances Rejection and Harmonics Reduction of Doubly Fed Induction Generator Based Wind Energy Conversion Systems

“…As observed in Figures 9 and 10, the proposed system not only has system-induced voltage harmonics compensated but lowered THD of the generated current as well. As a result, the proposed control helps a DFIG to satisfy grid integration codes [19] better and considerably weakens system distortion effects, as previously discussed. The injection of active power into the grid may cause an increase of PCC voltage, if no reactive power is produced.…”

“…One part is generated because of the existence of voltage harmonics, which is represented in Eq. (19), and the other part is caused by current harmonics, as represented in Eq. (20).…”

“…To address this subject, some authors have proposed using rotor-side converter (RSC) for the DFIG to compensate harmonic currents of the grid [16,17], but injecting harmonics to the DFIG rotor is harmful for the machine and deteriorates its performance. Some other authors have used a grid-side converter (GSC) for the same purpose [18,19], but since most of the DFIGbased WECSs are connected to grid by a long transmission line, using a GSC for the DFIG to compensate non-linear loads of the grid not only does not improve the situation, it also aggravates it by generating harmonic voltages and may cause some problems for the WECS itself that affect its performance. The harmonics that are generated by the DFIG itself was addressed in [20], but this work did not deal with disturbances imposed by grid harmonics.…”

Doubly Fed Induction Generator for Wind Energy Conversion Systems With Integrated Active Filter Capabilities

“…In all above methods [15][16][17], authors have used separate converters for compensating the harmonics and also for controlling the reactive power. But in later stages, some of the researchers have modified the control algorithms of already existed DFIG converters for mitigating the power quality problems and reactive power compensation [18][19][20][21][22][23][24][25][26]. The harmonics compensation and reactive power control are achieved with the help of existing rotor side converter (RSC) [18][19][20][21][22][23].…”

Wind Energy Interface to Grid with Load Compensation by Diode Clamped Multilevel Inverters

“…Wind generation is a renewable source and it is an important component of DG which has traditionally been used for energy conversion and is more recently being harnessed for grid support functions as well [1]. Different classes of power converters have been proposed for the integration of renewable energy resources into the distribution grid [2].…”