Impedance based stability analysis of single-phase PV inverter connected to weak grid with voltage feed forward control

This paper presents techniques to shape the output impedance of single phase PV inverter tied to the grid. In the proposed approach, the single phase PV Inverter is controlled by means of double loop current control with PLL is considered. When the Voltage feed forward is added into the control System (VFFC). The overall system becomes unstable under certain bandwidths. In order to improve the system performance, the Phase lead compensation is added in the feed forward path of the control system to make the system stable. The system stability is studied by means of the Impedance based stability criteria. The overall system stability is analyzed by means of the graphical approach and it is validated in Matlab Simulation. The quality of the grid current in terms of the THD is improved.