Control Strategy for DFIG Wind Turbine to Enhance LVRT under Various Faults

This paper presents a new control method for both the rotor and grid side converters to enhance the low-voltage ride-through (LVRT) capacity of the DFIG WT. By providing suitable control for RSC and GSC converter switching circuit, the parameters voltage, current, real and reactive power, DC link voltage, rotor speed are controlled. In addition to this the pitch control is also provided. With the aid of the grid side control scheme the DC- link voltage fluctuation can been effectively reduced. The new control method for the grid side controller can effectively reduce the high transients that may occur during the faults. This new control can enable both active and reactive supports to the faulted grids from WT which is difficult for the crowbar based control. The new method is found to be very effective in achieving LVRT capacity during symmetrical and unsymmetrical fault.