Research On Control Strategy Of DFIG For Wind Power Generation Under Distorted Grid Voltage Conditions

Recently, wind power has been an important part of our energy industry, it catches the world’s widely concern. However, for the capacity of wind power generation system increasing constantly, its penetration becomes higher and higher. For this, the ability to adapt the grid by wind power generation system has became one of the key issues in research.Due to the extensive use of power electronic devices and nonlinear loads, the grid usually contains a lot of harmonic voltage. This phenomenon threats the safety and stability of the wind power generation system seriously, its urgent for us to take some measures to improve the existing control strategies so that it can fulfills the grid-connecting conditions.In this paper, we take the Doubly-Fed Induction wind Generator(DFIG) which is widely used in the VSCF market as the target for research. After theoretical analysis of the DFIG under distorted grid, we found the current of DFIG both in the stator side and rotor side will be distorted. And it will also make against to the active power and reactive in stator side and output torque of DFIG, too.In order to eliminate these adverse effects effectively, this paper put forward three control strategies based on the multi-PI, the PR and the PIR regulator with a new Phase-Lock-Loop(PLL) firstly. Then build the simulation model by the matlab/simulink, verify the feasibility of the proposed control strategy theoretically. Finally, we simulate the actual wind farm by an induction motor for dragging the DFIG. After experiments, it can be seen that the waveform is in keeping with the simulations. All of this can prove the proposed control strategies is effective to suppress the adverse effects caused by the distorted grid voltage.