Variable speed wind turbines are very sensitive to any disturbance， faults and grid voltage sags. They are disconnected from the grid whenever these conditions arise and reconnected once the grid is healthy. Maintaining the wind turbine connected to grid during disturbances is a real challenge. Future grid codes will require wind turbines（WTs） to be connected to the host grid even during the fault condition and to have voltage sag ride-through（VSRT） feature installed. VSRT feature is not available in most of the present WT and few do with hardware modification， thus increasing the cost of the system. In this paper， a control strategy and VSRT for WTs equipped with full-load converter connected asynchronous generators is presented to maintain the turbine connected to grid during fault and post fault condition without hardware modification. The controller of the electric subsystem of the WT is designed following the strategy of“predictive” deadbeat control. The transient behavior of a 300 kW WT during and after a 30% voltage sag， at which WTs are normally programmed to trip， has been simulated and the fault ride-through performances of the controller demonstrated.