Fault Tolerance of DFIG Wind Turbine with a Series Grid Side Passive Impedance Network

Due to the increase of the number of wind turbines connected directly to the electric utility grid, new regulator codes have been issued that require low voltage ride-through capability for wind turbines so that they can remain online and support the electric grid during voltage sags. Conventional ride-through techniques for the doubly fed induction generator (DFIG) architecture result in compromised control of the turbine shaft and grid current during fault events. In this paper, a series passive impedance network at the stator side of a DFIG wind turbine is presented. It is armed for easy to control, capable of off-line operation for high efficiency and economic in manufacturing and maintenance. The balanced and unbalanced fault responses of a DFIG wind turbine with a series grid side passive impedance network are examined using computer simulations and hardware experiments.