Non-linear control and transient stability of SCAG connected to unbalanced AC network

The wind turbines generator connected to grid are frequently subjected to grid faults. When fault occur in grid, a large current of stator increases and may cause damage to stator winding, converters, DC link capacitor or cause mechanical oscillations in the generator speed. This paper studies the transient behavior of a large squirrel cage asynchronous generator (3MW) connected to the grid, during faults such as short circuit and voltage sags. The system is controlled by sliding mode control associated with maximum power point tracking (MPPT) and a pitch control strategies. The side-generator converter is used to generate the maximum power from wind turbine generator. The grid side converter is used to maintain the DC link voltage constant and to achieve unity power factor. The results of simulation show that the sliding mode control is efficient, gives good performance and keeps the wind turbine connected to the network during grid faults.