Control strategy of doubly-fed induction wind turbine

Abstract

Based on the principles of DFIG, this paper establishes a DFIG model in a synchronously rotating dq coordinate system. For the grid-side control system, the vector control technology facing the grid voltage is used to realize the decoupling of DFIG active power and reactive power. The methods of feedforward compensation and PI control are used to control the rotor side of the DFIG. When the voltage drops above the low voltage ride-through operating standard curve, DFIG should not leave the grid. When the grid voltage drops below 0.9 times the standard unit value, DFIG should also provide reactive power to the grid to support the grid voltage. Since the reactive power that can be provided by the stator side is much greater than the reactive power on the rotor side, when the grid voltage drop is small, the stator side first provides reactive power to the grid. When the grid voltage drops more, the stator side and the rotor side share power to the grid to provide reactive power. Finally, using MATLAB/Simulink software to simulate DFIG, verify the effectiveness of the control strategy proposed in this paper, and lay a foundation for fault characteristic analysis.