A review on modeling and control of grid-connected photovoltaic inverters with LCL filter

This paper deals with the modeling and control of the grid-connected photovoltaic (PV) inverters. In this way, the paper reviews different possible control structures that can be used for grid-connected inverters and then examines their capabilities. The controllers that are used are classic PI controllers and inverter is working in current control mode. A low pass filter is used for interconnection of inverter to the grid which is mainly LCL filter and depending on control way, there are four control strategies. In this paper, at first, control design methodology for each strategy is proposed and then performance comparison between these strategies is carried out. The performance analysis is carried out from different point of view such as grid voltage disturbance rejection and stability under different grid short circuit levels. The inverter output impedance is used as a criterion for inverter performance evaluation which has an important role in grid voltage disturbance rejection and system stability in different grid short circuit levels. Finally the best strategy will be introduced by using the simulation results in Matlab/Simulink software.