Research On Harmonic Suppression Of Doubly-fed Wind Turbine

The stator windings of the doubly-fed wind turbines are directly connected to the grid.This feature makes the output current susceptible to the disturbance of the power grid.the harmonic problem is one of these problem,which will have a great negative impact on the safe and stable operation of the wind turbine.In order to solve the harmonic problem caused by doubly-fed wind power generator,this paper adopted the active filter on the stator side of the doubly-fed generator,and the harmonic suppression measures of the PIR resonant controller are adopted on the rotor side to achieve the purpose of improving the power quality of wind power.First,analyzing the principle of double-fed wind turbine and the source of harmonic.On the basis of this,the active filter with dynamic suppression of the harmonics is carried out on the stator side for harmonic suppression,and analyzed the harmonic detection algorithm of the active filter.On the basis of the traditional i_p-i_q harmonic detection algorithm,using the optimized Butterworth filter and the mean algorithm replace the traditional low-pass filter to improve the dynamic response speed of the harmonic detection algorithm and reduce the ripple of filter effectively.The improved hysteresis control strategy is used to active filter,optimize the parameters,solve the contradiction between the hysteresis loop width and the precision,and quickly compensate the harmonic current.Secondly,the method of optimizing the control strategy is used to suppress the main harmonics of 5,7 times,and establish the back-to-back converter model.According to the control target,deduced the basic control strategy of the converter and PIR Resonant controller,added PIR controller in the stator side converter and the network side converter control strategy to enhance the control of harmonic current capability.In the MATLAB / SIMULINK simulation environment,a doubly fed power generation system model is established,and the harmonic detection algorithm and the harmonic compensation strategy are simulated and analyzed respectively.The simulation results show that the harmonic suppression strategy can effectively reduce the harmonic distortion rate of the doubled wind power generator and make some research significance to improve the power quality work.