As PV energy is clean and renewable, more and more PVG is connected to the grid. In this paper, PV grid connected is presented in a two-stage configuration. The first stage is a DC bus. It is composed by a BOOST converter with its MPPT control. This control is based on Perturb and observe method. This method is used under three scenarios, conventional method, optimized method by two PI controllers and modified method. The second stage is the AC bus. It is composed of a VSI inverter and LCL filter with its control, where there are three loops are figured such as outer current, voltage and inner current. The reactive power compensation and THD compensation are considered in order to improve energy flow between PVG and the three phase grid. Parameters PI controller are optimized by an easy analytical method. The theoretical study is tested and verified by simulation under MATLAB.Simulink.