Optimal DFIG crowbar resistor design under different controllers during grid faults

To provide a DFIG-based wind turbine with good fault ride-through capability, the wind turbine and the power converter should have the ability to protect itself without disconnect during faults in the power grid. Hence, the crowbar for protection of the rotor side converter should be designed properly. The resistor value of the crowbar effects DFIG´s rotor current, reactive power output and electrical torque. Therefore, some indexes to assess the DFIG turbine fault ride-through capability are presented in this paper, and two DFIG controllers, current mode control (called PVdq controller) and flux magnitude and angle (called Fmac controller), are involved in the optimization the crowbar resistor. From simulation, it is found that system with optimal crowbar resistor value displays better fault ride-through capability and the use of different controllers have different optimal crowbar resistor values.