A solar PV system controlled by least sum of exponentials algorithm

This study proposes a new control for grid-connected solar PV (Photovoltaic) system which simultaneously injects active power and improves the quality of power of a three-phase distribution grid. The system comprises of a solar PV array, a VSC (Voltage Source Converter), a RC ripple filter and interfacing reactors connected to the three-phase distribution grid and linear/nonlinear balanced/unbalanced loads. The proposed control for the VSC in addition to harmonics mitigation, reactive compensation and balancing of three-phase loads concurrently extracts the maximum available power from the PV array by means of a MPPT (Maximum Power Point Tracking) algorithm. Besides the MPPT algorithm, the VSC is controlled by the least sum of exponentials algorithm. The THDs (Total Harmonic Distortions) of grid currents and the voltages at the PCC (Point of Common Coupling) are found to be within the limits given by IEEE 519 and IEEE 929 standards. The system performance is experimentally tested for a variety of loads and solar insolation levels on a prototype developed in the laboratory.