P/Q Control of Grid-Connected Inverters.

For several years, the focus of recent research has been on solar power and distributed generation (DG) systems, these systems have been widely used in various applications. In photovoltaic grid-connected (GC) and DG systems, one of the objectives that the grid-connected inverters (GCI) is the control of current coming from the photovoltaic modules or DG units. In this way, this paper describes a simple P/Q control strategy for three-phase GCI. Initially, the proposed control of the grid side is introduced. Secondly, to synchronize the grid side voltage with grid current, a synchronous reference frame (SRF) based phase locked loop (PLL) is applied. Finally, the simulation of grid-connected inverters using PSIM is presented to illustrate concepts and results.