An investigation of solar active power filter based on direct power control for voltage quality and energy transfer in grid-tied photovoltaic system under unbalanced and distorted conditions.

This paper discusses a renewable energy system connected to a dual-function power grid through a shunt active power filter to improve the power quality and inject photovoltaic (PV) energy to the power grid in the presence of nonlinear loads. Disturbance rejection for this electrical network is provided by the proposed direct power control (DPC) command. The DPC strategy combines a fractional order PID controller for the regulation of the DC bus voltage with an intelligent method of tracking the maximum power point articulated on the fuzzy logic, reserved to address dynamic weather conditions. The quality of energy is offered by the improved DPC resides in the elimination of the undesirable harmonics of the source currents. Thus, the studied system operates under a power factor near unity with acceptable harmonic distortion, in agreement with the international standard IEEE-519. The overall control of the presented system is assessed under different states of the power source behavior—balanced, unbalanced, and distorted—through simulation using MATLAB/Simulink software. The results demonstrate the performance, robustness, and feasibility of the proposed methods compared to the existing techniques in the literature. [ABSTRACT FROM AUTHOR]