Coordinated Control For Variable Pitch And Variable Speed In Doubly Fed Induction Generation

Recently,wind power as a renewable and no pollution energy resource is paid great attention by more and more countries. The development and utilization of wind energy has achieved an unprecedented degree.Ac excitated generator to implement VSCF is popular technical scheme currently in wind power generation. Doubly fed induction generator(DFIG) has been mainstream generator in wind farm. The wind farm based on DFIGs connects to the local grid, which produces impacts on the grid because the power flow distribution of the original gird is changed. Especially, active power fluctuation reduce the operation safety of power grid. By using vector control technology and coordinated control for variable pitch and variable speed, the smooth control of active power has been achieved in decouping reactive power and active power of DFIG and improving the utilization ratio of wind power.The model of DFIG establish under synchronization reference frame in this paper Build simulation model of active and reactive decoupling control with the stator flux oriented vector control is built in MATLAB/SIMULINK.Two kinds of smoothing control scheme for active power are proposed. That are torque deviation and variable pitch and variable speed collaborative control strategy for the active power smooth. In realizing the maximum wind power captured premise, suppressed active power fluctuations. Below the rated wind adopt the based on torque deviation for active power smooth control, calculating the best corresponding relation between the generator speed and the wind speed with the purpose output smooth active power, adjust generator speed with changed wind speed; Detection and control electromagnetic torque error, adjusting generator speed to maintain the best corresponding relation with the wind speed ; In all operating regions, combined the variable pitch control of wind turbine with the variable speed control of the generator, designed Fuzzy Controller for variable pitch and PI Controller for controlling output active power of DFIG, based on above ,proposed power error control strategy for output active power of generator. Through controlling the voltage of rotor suppressing the fluctuation of active power. This improvement scheme, can provide to the grid more smooth active power, improve operating stability of the grid. The simulation results show that the active power control strategy is effective...