Comparison of two power flow control strategies for photovoltaic inverters

High penetration levels of distributed photovoltaic inverters on electrical distribution grids and due to the main points demanded in the latest issues of grid codes such as the reactive power injection during transient grid faults (voltage sags) and their disconnection in order to avoid the islanding phenomena, a suitable control algorithm combination is needed to provide an optimum operation at the electrical grids where they are connected, improving the power quality and the power supply continuity. This paper is devoted to the comparison through simulation of two power flow control strategies for 100 kW photovoltaic inverters in order to analyze the advantages and disadvantages of each one. The first one is based on the modulation index and the disphase controls of the reference signal face to the point of common coupling voltage. The second one is based on a synchronous reference frame with the voltage at the point of common coupling using i_d and i_q current component controllers.