Efficient fault-ride-through control strategy of DFIG-based wind turbines during the grid faults

• A comparative review of DFIGs fault-ride-through improvement approaches is presented.
• An efficient control strategy is proposed to improve the FRT capability of DFIG.
• The rotor overcurrent, DC-link overvoltage and torque oscillations are decreased.
• The RSC, DC-link capacitor and mechanical parts are kept safe during the grid faults.
• The DFIG remains connected to the grid during the symmetrical and asymmetrical faults.

As the penetration of wind power in electrical power system increases, it is necessary that wind turbines remain connected to the grid and contribute to the system stability during and after the grid faults. This paper proposes an efficient control strategy to improve the fault ride through (FRT) capability of doubly fed induction generator (DFIG) during the symmetrical and asymmetrical grid faults. The proposed scheme consists of active and passive FRT compensators. The active compensator is carried out by determining the rotor current references to reduce the rotor over voltages. The passive compensator is based on rotor current limiter (RCL) that considerably reduces the rotor inrush currents at the instants of occurring and clearing the grid faults with deep sags. By applying the proposed strategy, negative effects of the grid faults in the DFIG system including the rotor over currents, electromagnetic torque oscillations and DC-link over voltage are decreased. The system simulation results confirm the effectiveness of the proposed control strategy.