Control scheme for grid-tied distributed generation inverter under unbalanced and distorted utility conditions with power quality ancillary services

This study proposes a control scheme with a new fundamental sequence components extractor for grid interfaced distributed generation inverter under polluted grid conditions. The proposed sequence extractor is realised using third-order sinusoidal signal integrator-based frequency adaptive filters. It has an excellent ability to decompose the three-phase voltage and current signals into positive and negative sequence components under distorted grid scenario. The proposed control scheme is immune to frequency variations and is capable of providing power quality ancillary services such as reactive power compensation and harmonics rejection in addition to basic power injection. The performance of the proposed system under various grid disturbances and loading conditions is evaluated through simulation and experimental studies.