H∞ repetitive current controller for grid-connected inverters

This paper proposes a current controller design based on H_∞ and repetitive control techniques for grid-connected inverters to reduce current total harmonic distortion (THD). The repetitive control, based on the internal model principle, offers an alternative for voltage tracking, as it can deal with a very large number of harmonics simultaneously. This leads to low harmonics distortion and improved tracking performance. The proposed controller is experimentally tested to validate its performance, with main focus on tracking error performance and total harmonics distortion.