Harmonic Currents Suppression for Full Size Power Grid-connection Converters Used for Wind Power Generation

The low order harmonic in grid voltage combined with the nonlinear characteristics of the power electronics devices will cause great amount of harmonic currents from the grid-connection converter used for wind power generation system,this will degrade the operational performance of the generation system.In order to improve the power quality of the full size power converter for the wind power generation system,a method was proposed to suppress the harmonic currents of the grid-side converter(GSC) in this paper.The harmonic mathematic model of the GSC was investigated in detail,and the cross-coupling control strategy was proposed to suppress the low order(5th,7th,11th,13th) harmonic current components.In the proposed control scheme,the DC components of each order harmonic currents could be detected in the multiple synchronous rotating reference frames,and they could be accurately controlled to be zero with the cross-coupling current controller which was analyzed and designed.Taking into account the cross-coupling influence of the each order harmonic current circuit,the proposed control strategy can effectively reduce the interactive effects among the each order harmonic currents and fundamental current,which improving the operation stability of the system.Both the simulation and experiment results verify the proposed control scheme.