Behaviour assessment of DFIG based wind turbine generator while coupling to the grid using a new and practical connection technique

This paper proposes an easy, new and practical technique for connecting a Doubly Fed Induction Generator (DFIG) based Wind Turbine Generator (WTG) to the distribution grid. In fact, a DFIG can be assimilated to a synchronous generator except for an AC supply in the rotor windings. Therefore, eventually, the DFIG can be coupled to the grid in a similar way to the synchronous machine through rotor windings supply control. Actually, this technique is found practical, as it does not require any type of control loops, but in contrast, the DFIG is ready for any type of control (Flux Oriented Control, Direct Torque Control...) once starting is completed with this technique. In addition to steps of this procedure, a state model of the system is given including two DFIG models (before and after connection). These models were simulated on a 300 kW wind generation system using Matlab/SIMULINK environment. According to the simulation results, a behaviour assessment of the generator before, during and after connection is given so to evince benefits and drawbacks of this procedure.