Global Maximum Power Point Tracking of Photovoltaic Array Under Partial Shaded Conditions

Efficiency of the PV module can be improved by operating at its peak power point so that the maximum power can be delivered to the load under varying environmental conditions. This paper is mainly focused on the maximum power point tracking of solar photovoltaic array (PV) under non uniform insolation conditions. A maximum power point tracker (MPPT) is used for extracting the maximum power from the solar PV module and transferring that power to the load. The problem of maximum power point (MPP) tracking becomes a problem when the array receives non uniform insolation. Cells under shade absorb a large amount of electric power generated by cells receiving high insolation and convert it into heat which may damage the low illuminated cells. To relieve the stress on shaded cells, bypass diodes are added across the modules. In such a case multiple peaks in voltage-power characteristics are observed. Classical MPPT methods are not effective due to their inability to discriminate between local and global maximum. In this paper, Global MPPT algorithm is proposed to track the global maximum power point of PV array under partial shaded conditions.