APLL-based Harmonic Compensation Scheme for DFIG-based Wind Power Generation System

With the current global energy crisis, the renewable energy shows a great development potential, in which the wind power generation is one of the most sophisticated means of power generation in technology. How-ever, for the doublyfed-induction-generator-based (DFIG-based) wind generation system, the grid voltage harmonics will result in the severe power oscillation, electromagnetic torque ripple and the grid current distortion since the stator is connected to the grid directly. In this paper, a novel control algorithm, which mainly includes two parts: one is the advanced phase-locked loop (APLL) and the other is the harmonics voltage compensation algorithm (HVCA), is proposed to eliminate the harmful effect caused by the grid voltage harmonic. The APLL part is applied to extract the amplitude and phase of each harmonic in the power grid, then the extracted amplitude and phase are fed to the HVCA part to control the LCL-type inverter to generate the harmonic compensation voltage, which shows the same amplitude but the opposite phase with the grid voltage harmonics. Finally, the harmonic compensation voltage is fed into the grid voltage through the series transformer which is cascaded between stator and grid. The simulation results are carried out to verify the effectiveness of the proposed control algorithm.