Comparative Study of Robust RSC Control of Doubly Fed Induction Generator Based Wind Turbine under Grid Frequency and Voltage Variations

The configuration of a grid-connected doubly fed induction generator (DFIG) for wind energy generation systems consists of direct coupling of the generator stator windings with the grid and partial coupling of the rotor through power converters. This structure makes the system sensitive to the fault grid. Thus, robust control techniques are required to deal with the undesirable transient sequences in the network. In this paper, two robust controllers have integrated to regulate the stator active and reactive power of DFIG based wind turbine. Then, they have been tested and compared to verify their performances when abnormal grid networks have occurred. Firstly, we used high order sliding mode (HOSM) based Super Twisting, which keeps the same conventional sliding mode performances, such as fast dynamic response and redundancy to the extern disturbances, with a simple design and chattering reduction. Secondly, we implement the backstepping control approach which is known for its robustness in transient sequences. A number of simulations have carried out to evaluate the ride-through performance of both control strategies in case of low grid voltage dips and grid frequency variations.