This paper suggest a control strategy to enhance the LVRT capability of doubly fed induction generator (DFIG) based wind turbine system using dynamic voltage restorer (DVR). Wind turbine generator should support the grid during the fault time. The method used here is series compensation method at the point of common coupling on the occurrence of fault to maintain the stator voltage constant. LVRT performance is improved by optimization of PI parameters using particle swarm optimization as compare to conventional DVR. This PI controller is used to regulate the IGBT pulses of the inverter fed by DC source. To validate the improved LVRT performance, a 9 MW grid integrated DFIG based wind plant is considered. The result shows that the voltage compensation of sag is greatly improved with PSO optimized DVR.
Robust current control of doubly fed wind turbine generator under unbalanced grid voltage conditions
