FOFT Based Power Quality Improvement of the 3-phase Microgrid under Weak Grid Condition

A fourth-order filtering technique (FOFT) based control is used for the improvement in power quality of the single-stage three-phase grid-connected solar PV system. The filter is used to extract the fundamental in-phase component from the distorted grid voltage, which is contaminated by lower-order harmonics. In this paper, Perturb and Observe (P&O) MPPT technique is utilized to derive optimal power from the solar PV array. The FOFT based control for VSC is required to resolve several power quality issues like DC offset rejection, harmonics elimination, compensation of reactive power and the most important is to maintain the power factor near unity under abnormal grid condition. The system’s output is evaluated using the MATLAB/Simulink platform, and it is found to be satisfactory. The main purpose of the FOFT based control is to deliver sinusoidal current waveform to the three-phase weak AC grid. The system is tested under various abnormal grid conditions and the injected grid current is found to be sinusoidal having THD restricted to 5%, which satisfies the criteria mentioned in the IEEE-519 standard.