Global MPPT Control of Photovoltaic Array Using SEPIC Converter under Partial Shading Condition

Abstract

The factors affecting the performance characteristics of a photovoltaic (PV) array are
temperature, solar insolation, shading and array configuration. The PV system exhibits a
non-linear I-V characteristic and its unique maximum power point on the P-V curve varies
with insolation and temperature. The passing clouds, neighbouring buildings and trees are
shadowing the PV arrays completely or partially as a result, it becomes more complex P-V
characteristics with multiple peaks in case of partially shaded conditions. Conventional
Maximum Power Point Tracking (MPPT) techniques fail to reach global peak power point
and tend to stay in local peak power point which significantly reduces the efficiency of the PV
system. This paper mainly focuses on extracting the maximum power from PV array under
partially shaded conditions by executing improved hill climbing algorithm to identify the
global maximum power point (GMPP) and SEPIC is used as a dc-dc interface. Simulation
results have been presented to verify the performance of the proposed GMPPT technique.