An Improved Control Strategy for Double Feed Induction Generator in Low Frequency Resonant Power Grid

When the grid contains sub-synchronous oscillations below 50Hz, corresponding power pulsations will occur on both the DFIG side and the grid side. The traditional PI control strategy can hardly restrain sub-synchronous oscillations. If long-term operation lasts in this condition, sub-synchronous oscillations will affect the life of the unit and the power quality of the grid, In this paper, the mechanism of sub-synchronous resonance is analyzed first, then an improved PIR control strategy is proposed to suppress SSR, and the effectiveness of the proposed strategy is validated by Matlab / Simulink simulation. The results showed that compared with PI control, PIR control has better SSR inhibitory effect.