Impact of active front end topology on wind farm resonance

This paper analyzes the advantages of utilizing the True Unity Power Factor (TUPF) converter topology as the full power active-front end for wind turbines in comparison to conventional two-level voltage source converters (2L-VSC) as a means to avoid resonance excitation in wind farms. The True Unity Power Factor topology is described and comparisons between the frequency-scan impedance and harmonic distortion of a wind farm comprised by 2L-VSC and TUPF converter are presented at simulation level, considering grid characteristics from a wind power plant installed in southern Brazil. The use of TUPF converters results in resonances at higher frequencies, with lower amplification and less distortion in the grid.