DFT-based repetitive control of a series active filter integrated with a 12-pulse diode rectifier

This paper considers the transient performance and stability of a recurrent discrete Fourier transform (DFT) based control method for a series active filter integrated with a 12-pulse diode rectifier. The control method targets specific harmonics and/or the negative sequence fundamental component of the supply current, and is intended for use with nonsinusoidal/unbalanced supply voltages. The proposed control method is based on DFTs instead of the dq-method, and a simple approach is used to account for small frequency variations found in practical power systems. Index Terms--Active filters, digital control, discrete Fourier transforms (DFTs).