A single-phase single-stage, high power factor grid-connected PV system, with maximum power point tracking

This paper proposes a single-phase, grid connected non-isolated, very compact photovoltaic (PV) processing system, which is able to inject a low-distortion current into the grid while tracks the maximum power point (MPPT) of the PV array. The arrangement is based on a buck full-bridge inverter, whose switches are gated to provide an almost sinusoidal current into the grid keeping the PV panels voltage near constant, using what is known as the simplest method of MPPT available to date. The concept is validated by a comprehensive set of theoretical equations and digital simulation results concerning a 720W PV power injected to a 127V, 60 Hz line grid. A solar radiation step response case is considered to prove the feasibility of the idea. The small number of components of the complete system confers to it a great efficiency and reliability.