Synchronous Flux Weakening Control With Flux Linkage Prediction for Doubly-Fed Wind Power Generation Systems
Under grid-voltage dips, there exist dc and negative sequence components in the stator and rotor flux of doubly-fed induction generator (DFIG). As a result, higher transient overcurrent is generated in the rotor. To enhance the low-voltage ride-through (LVRT) ability of the DFIG, a synchronous flux weaken control strategy with flux linkage prediction is proposed to suppress the transient overcurrent. In the proposed control strategy, the deadbeat predictive control is used to realize rapid synchronization and weak interaction between the stator and rotor flux by flux linkage prediction under grid-voltage dips. A series of research is carried out on a typical 1.5-MW DFIG system, and comparisons are made with the LVRT control strategy based on proportional-resonant (PR) controller to validate the proposed control strategy. The results indicate that the proposed control strategy is effective in suppressing overcurrent in the stator and rotor and reducing oscillations in torque, which largely improves the performance of the DFIG during grid-voltage dips.