A Variable Step Size Logarithmic Hyperbolic Cosine Adaptive Filtering-Based Control Scheme for Grid-Tied PV-DSTATCOM to Enhance Power Quality

variable step size logarithmic hyperbolic cosine adaptive filtering (VSS-LHCAF)-based control scheme is proposed for a grid-tied multifunctional photovoltaic-distribution static compensator (GTPVD) having single-stage topology for solar energy conversion with maximum power extraction from the PV array. The proposed VSS-LHCAF control scheme is utilized to estimate the fundamental weight components of nonlinear load current accurately in generating the driving pulses for the three-phase two-level voltage source converter (VSC) switches employed in GTPVD, thus enhancing the power quality by mitigating the harmonics produced by nonlinear loads, providing a reactive power compensation, unbalanced load compensation, and maintaining grid currents sinusoidal at unity power factor (UPF). The multifunctional GTPVD system is developed in MATLAB/Simulink. The response of GTPVD is observed under solar irradiance variation and unbalanced loading conditions with a nonlinear load. Further, the proposed control scheme is compared with existing adaptive filtering-based algorithms like least mean square (LMS) and least mean fourth (LMF)-based control schemes, and it is observed that proposed control scheme offers better performance in terms of convergence, oscillations, steady-state error, and grid current total harmonic distortion (THD).