Comparison of active crowbar protection schemes for DFIGs wind turbines

The doubly fed induction generators (DFIGs) are used in almost 50% of the offshore and onshore wind power plants. The DFIGs offer advantages compared to fix speed induction generators. The DFIGs are sensitive to grid voltage disturbances and require additional protection for the rotor side power electronic converter, like crowbar protection. In the present paper two active crowbar topologies are compared, IGBT with bypass resistor and rectifier with IGBT, which were the most studied in the scientific literature. A DFIG model with analyzed crowbar protections was implemented in Matlab/Simulink. The simulation results reveal that both solutions can limit the rotor current and the dc link voltage values. However, the solution with rectifier offers better results