Single phase shunt active filter with digital control

Abstract

This  paper  presents  a  single-phase  shunt  active  filter designed to minimize problems related to power quality in electrical systems. The power stage of the active filter is based on  a  two-leg  full-bridge  inverter,  with  a  single  capacitor  in  the  dc side, and a filter inductor in the ac side. The control system is   based   on   the   instantaneous   power   theory   in   the   α-β-0reference  frame  (pq-theory),  derived  to  be  applied  in  single-phase systems. In essence, the shunt active filter is designed to drain, from the electric grid, harmonic and reactive components of  the  load  currents,  such  that  the  system  current  will  become,  basically, a sinusoidal waveform, with low harmonic distortion, and in phase with the system voltage. Simulation results of the shunt  active  filter  operating  with  three  different  loads  are  presented in order to verify its performance.