Improving LVRT for DFIG used in WPCS under voltage dip

This work presents the crowbar active circuit protection method in case of voltage dips on the grid affecting the DFIG based wind power conversion system (WPCS). The sudden voltage drop produces high values of stator and rotor currents which also leads to an increase of the DC bus voltage. Without protection, the rotor side converter (RSC) can be destroyed and the DFIG can be damaged. With the proposed method, the currents will be limited to prescribed values at the onset and at the disappearance of the fault, which will allow to keep the DFIG connected to the grid during the voltage dip and to recover its normal operation after the fault disappearance.