Sliding Mode Control of a Photovoltaic Based Shunt Active Power Filter in Islanding Operation

Renewable energy sources (RES) are constantly evolving nowadays due to the ever-increasing energy needs and the depletion of fossil fuel reserves. This, together with power quality problems, has led to the development of photovoltaic-based shunt active power filter (PV-SAPF) systems. However, the performance of these systems is linked to the control strategy used. Hence, to enable the PV system to perform the functions of power quality improvement, load supply, low THD current injection into the grid, and to avoid damage to connected loads during islanding operation, this paper proposes a control strategy for PV-SAPF in islanding operation. This control strategy is based on the optimal operating point tracking of the PV system. Multi-variable filter harmonic identification method is used for the determination of the harmonic and fundamental components of the reference currents of the grid-connected inverter. The islanding algorithm is used to detect a voluntary or involuntary disconnection from the grid. The performances of the proposed control strategy are evaluated for different operating scenarios by numerical simulations performed in MATLAB/Simulink software. The simulation results obtained show the good adaptation of the system in the different operating scenarios with harmonic distortion rates lower than the 5% recommended by the IEEE Std. 519-2014 standard, even during islanding. The responsiveness of the proposed control strategy is observed with the adaptation of the modulation coefficients of the fundamental components of the reference currents in the different operating modes.