Power voltage characteristics and global mppt algorithms for any severe partial shading condition

Abstract

The power-voltage curves of conventional series-parallel photovoltaic (PV) arrays under partial shading conditions show multiple peaks. The multiple peaks make the classical algorithms of maximum power point tracking (MPPT) ineffective. Thus, Global MPPT (GMPPT) algorithms are needful to track those curves global maximum power point (GMPP). Initially, this paper presents a statistical simulations study of the P-V characteristics of series-parallel arrays for any PS condition in a range of usual temperatures. This study has as contributions a set of GMPP distribution characteristics graphics and a set of P-V curves that exposes as false the continuously decreasing behavior of the power peaks in both sides of the GMPP, since this hypothetical behavior is claimed by several papers in literature to build GMPPT algorithms. Furthermore, as several GMPPT algorithms in literature have been also built and tested for simple, in a second moment this paper presents a comparative of two GMPPT algorithms found in literature that can track the GMPP in any PS condition. For this, simulations and experiments of these algorithms tracking the GMPP of three series-parallel arrays are carried for several severe PS condition in a range of usual temperatures and performance parameters as tracking time and voltage track are evaluated.