Active damping for large-scale wind power systems with an LCL-filter using an improved DFT

Abstract

This paper proposes a simple active damping algorithm for a large-scale wind power system with an LCL-filter. Compared to an L-filter or an LC-filter, the LCL filter can decrease the harmonics induced by low switching frequency, and make a satisfactory grid side current using a comparatively low-inductance. Using the LCL filter, an additional active damping of the filter resonance is necessary. This paper introduces the active damping method using the improved DFT filter to improve performance without any additional sensors and complexities. The proposed algorithm is verified by simulations in comparison with the existing methods.