DFT-based controller for sag and harmonic mitigation with a series-connected compensator

Abstract

Voltage-quality  problems  in  power  distributionnetworks  include  harmonics,  voltage  sags  and  swells  andunbalances.  These  problems  may  seriously  affect  sensitiveindustrial loads causing production interruption or equipmentdamage. Now-a-days series voltage compensation using powerelectronics devices is a promising solution for these problemsand the design, control and application of this type of deviceshave  drawn  much  attention in the literature.  In fact,  compre-hensive  controllers  for  power  electronics  series  compensatorhave already been proposed in the literature to tackle all thoseproblems  simultaneously.  For  example,  repetitive  controllersshow  very  promising  performance  although  several  aspectsstill  need  closer  attention.  This  paper  proposes  a  differenttype  of  controller  based  on  a  Discrete  Fourier  Transform  tominimise voltage harmonic pollution using power electronicsseries  devices.  The  design  process  of  this  type  of  controlleris  straightforward  regardless  of  the  number  of  harmonics  tobe  tackled.  In  addition,  the  proposed  controller  uses  a  slowsampling rate and its computational effort is relatively low. Themain contributions of this paper are illustrated by simulation.