Multi-function control of small-scaled grid-connected PV systems

The installation capacity of the grid-connected small-scaled PV systems in distribution grids is remarkable. Therefore, the capacity of these systems can play an important role in distribution grids. By applying a proper control, these systems can, in addition to their energy source, be used as a harmonic and voltage compensators at the point of common coupling (PCC). This paper presents a multi-functions control scheme for small-scaled PV systems. In the presented approach, the control system, in addition to delivering the energy of the panels to the grid, will put the solar system in the harmonic and voltage compensation process at the PCC. Both the voltage and harmonic compensation strategies are implemented by on-line analysing the PCC voltage. The structure in the proposed approach is a single-phase transformerless HERIC inverter with the LCL filter at the output. Finally, the results will be evaluated by MATLAB simulator and verified by experimental prototype.