Robust Current Control of Grid- Connected Photovoltaic Inverters

Development of distributed generations’ (DGs) technologies and their continuous increasing penetration has recently lead to a great tendency toward these resources, among which photovoltaic (PV) generations in power distribution systems are of great importance. Being cost-effective, PV resources which are directly connected to utility grids are studied in this paper where a new adaptive hysteresis current controller for single-phase single-stage PV central inverters is presented. The proposed scheme can be utilized in a diverse scope of PV technologies. Simulation results indicate that the suggested strategy improves the efficiency of the system by reducing the total harmonic distortion of the injected current to the grid; and, in addition to having the output current in phase with the voltage of the utility grid it is able to control switching frequency and to inject the current into power grid with good power quality. The simulated model of the system is developed in SIMULINK/MATLAB environment. The proposed scheme is found effective in obtaining the desired goal when the switching frequency is adequately high which leads to the synchronization of power grid voltage and inverter current and near to unity power factor.