Control of transformerless grid-connected PV system using average models of power electronics converters with MATLAB/Simulink

This paper presents the analysis, modeling and control of a grid connected photovoltaic (PV) system supplying two local loads. For this purpose, the average models of both boost converter and three-phase voltage source inverter (3-ph VSI) are used. Their advantage in term of computational speed allows simplifying and accelerating the simulation in order to develop their control laws. A Fractional Open Circuit Voltage (FOCV) algorithm based Maximum Power Point Tracking (MPPT) control technique is modified and combined with a DC-DC boost converter. The Watt-Var control approach is presented for the 3-ph VSI control. The Both proposed control algorithms are thereafter validated in detailed (switching) models. The proposed model is implemented in the MATLAB/Simulink software and simulation studies are presented. The simulation results show the advantage of using Power Electronics Converters (PEC) in their average versions. They also demonstrate the high performance and feasibility of the proposed system with its control strategy.