Photovoltaic (PV) systems are solar energy supplySystems which either supply power directly to an electrical equipment or feed energy into the public electricity grid. It focuses on the latest development of modelling and control of grid connected photovoltaic energy conversion system. In the photovoltaic system, power electronic conversion is necessary to improve the efficiency of PV panels and system stability. In these systems, the backstage power circuit consists of a high step-up DC to DC converter and a full-bridge inverter to convert DC to AC, as the grid voltage is AC in nature. Modelling of photovoltaic systems include modelling of SPV array, power electronics inverter/converter based on MATLAB/SIMULINK. This present control algorithm of a three-phase and single phase grid-connected photovoltaic (PV) system including the PV array and the electronic power conditioning (PCS) system, based on the MATLAB/Simulink software. It also discusses advances in MPP tracking technologies, the synchronization of the inverter and the connection to the grid.