Research on Grid-friendly Control Methodology of Direct-drive Wind Turbine Set

Rapid development of power electronics technology has boosted the development of clean energy to a new height, but also brought a series of power quality problems which even threat the stable operation of power grid. Resonance caused by grid-connected wind turbines and the lag problem of discrete control systems gradually intensify with the increase of number of grid-connected units. Thus, a grid friendly control methodology of direct-drive wind turbine is researched in this paper. Considering the delay of capacitor current feedback and discretization control system, a repetitive predictive control strategy is proposed to improve its stability and controllability, whose effectiveness is verified by simulation and physical test.