Control strategy of a transformerless three phase shunt hybrid power filter using a robust PLL

This paper deals with a shunt hybrid active power filter (SHAPF) based on a advanced control algorithm consisting of synchronous reference frame (SRF) rotating at fundamental angular speed using a Multi-Variable Filters (MFV) based robust PLL to determine the reference current for the SHAPF in order to improve the power quality and compensate reactive power required by nonlinear load. The SHAPF is formed by a single 7^th tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series without any matching transformer. The required rating of the active filter is much smaller than that of a conventional standalone active filter be. All simulations are performed by using Matlab-Simulink Power System Blockset and validated with an experimental test bench developed in the LIAS laboratory, University of Poitiers. Various simulation and experimental results of the proposed control algorithm are presented under steady state and transient conditions to confirm his validity and effectiveness.