MSOGI-FLL based Robust Harmonics Compensation under Distorted Grid Voltage Condition

In the presence of a non-linear load, the grid Power Quality (PQ) is seriously affected due to harmonic current demand. To compensate these harmonics to the non-linear load, shunt active power filter (SAPF) is generally used. Among several approaches of control of SAPF, Synchronous reference frame (SRF) based control is most common and simple. Further, the performance of SRF based control depends on the unit vector generation methodology. Particularly under distorted voltage condition at the grid, estimation of unit template seriously gets affected, that further marred the performance of SRF control. In this paper, Multiple Second-Order Generalized Integrator-Frequency Locked Loop (MSOGI-FLL) is used to generate the unit template for SRF based SAPF operation under distorted grid condition. The effectiveness of the proposed control technique based on MSOGI-FLL is verified using MATLAB simulation and OPAL-RT real-time simulation. The total harmonics distortion (THD) level of grid current is maintaining as per the IEEE-519 standard.