A LVRT control strategy based on flux tracking for DFIG-based wind power systems

For doubly-fed induction generator (DFIG) based wind power systems, when a grid voltage dip happens, a large electromotive force (EMF) will be induced in the rotor circuit. Without proper control for protection, over current will appear in the rotor circuit, and it may lead to the destruction of the rotor-side converter (RSC). To mitigate this problem, a new low voltage ride-through (LVRT) control strategy based on flux tracking is proposed. With the proposed control strategy, once the voltage dip is detected, the rotor flux is controlled to track the changing stator flux by controlling the RSC. The validity of the proposed method is verified using the full order model of a typical 1.5 MW DFIG in the SIMULINK/SimPower Systems simulation environment. The proposed control strategy is proven to be able to effectively reduce the rotor current during both symmetrical and asymmetrical grid faults without any additional hardware circuit.