Maximum power extractions in a single stage PV sourced grid connected inverter during low irradiations and nonlinear loads

Grid connected PV systems are becoming increasingly popular due to an exponential energy demand and also due to depletion of fossil fuels and environmental concerns. However, extraction of peak power for such system which reduce cost has always been an area of concern. Many Maximum power point tracking (MPPT) algorithms were proposed for a two stage and single stage grid connected system with some limitations in system performance. A simple strategy to extract peak power from the grid connected PV with nonlinear load at Point of common coupling (PCC) is attempted. To achieve the same task in a single stage Photovoltaic (PV) grid system, two PV emulated virtual DC voltage sources are connected in series with the PV array. The operation of this strategy is tested under low irradiation and Voltage swell at the PCC connected to the grid. A control strategy to achieve dual mode control for MPPT and to regulate DC link voltage is achieved simultaneously by the proposed control. Analysis of the control strategy is carried out using MATLAB and experimentally validated with a TMS320F28335 controller.