A novel method to improve low voltage ride-through capability of DFIG

In order to prevent wind turbines departing from the grid when the grid fault occurs, the Crowbar circuit of the doubly-fed induction generator (DFIG) is often used to improve low voltage ride-through (LVRT) capability. Based on the analysis of the traditional Crowbar protection circuit, a modified Crowbar protection circuit with resistance in series with the capacitor was proposed. The double-fed induction wind power generator (DFIG) with the modified Crowbar protection circuit was simulated on MATLAB/Simulink platform. Compared with the traditional Crowbar protection circuit with the resistance, the modified Crowbar protection circuit not only restrains the rotor over current, but also shortens the transition process of the rotor over current. The simulation results show that the modified Crowbar protection circuit is reasonable and improves the low voltage ride-through capacity of DFIG effectively.