Modified approach for global MPP finding under partial shading

Abstract

Today, despite the presence of well-developed and high efficient Maximum Power Point Trackers (MPPT) in all PV stations, remains the problem of their proper functionality during partial shading. Existing MPPT algorithms use sequential search procedures, therefore, they may falsely operate during partial shading. The reason of this obstacle is numerous local maximums appearing in the P-I or P-V characteristic curves. This impedes conventional MPPT systems to find the global maximum (GM) and significantly restricts the ultimate electric output of PV plants.The present article proposes the improved algorithm for MPPT functionality. The method based on a photo-current estimation of each PV panel. Owing this information, submitted algorithm provides permanent assessment of the upper and the low limits of regulating parameter (a current or a voltage) between which its optimal value that ensures GM is located. Further, conventional MPPT entering the work can easily find the nearest maximum that obviously is GM.Present work describes this new method to find more accurate and fast estimations of the GM boundaries and to keep GM even during fast changings partial shading conditions, which will cause the higher overall efficiency of MPPT.