ANALYSIS OF GLOBAL AND LOCAL MAXIMUM POWER POINTS IN PV ARRAYS UNDER PARTIAL SHADING CONDITION

Abstract

Partial shading (PS) has a significant impact on the decrease in efficiency of photovoltaic (PV) array and performance of maximum power point tracking (MPPT) that must be addressed. We conduct an analysis and evaluation of local maximum power point (LMPP) in terms of quantity, and global maximum power point (GMPP) in terms of magnitude and diversity. Simulation is carried out using single diode ideal model and nine generic PS patterns that are specifically designed to bring up the substantial characteristics of the LMPP and GMPP and applied to series-parallel (SP) and total cross-tied (TCT) configurations. The SP configuration has LMPP with two, three, and four peaks, appearing three times each. The TCT configuration has two peaks that appear six times, three peaks that appear once, and four peaks that appear twice. The SP configuration experiences power losses ranging from 56% to 72%, while the TCT configuration has power losses ranging from 52% to 64%. The SP configuration generates a maximum voltage of 76.64 volts and a minimum of 39.20 volts, while the TCT configuration generates a maximum voltage of 77.62 volts and a minimum of 58.21 volts. With a smaller number of LMPP, a larger magnitude of GMPP parameters, and lower diversity, TCT exhibits better characteristics and performance compared to SP.