Hybrid behaviors analysis of photovoltaic array performance

Photovoltaic cells would operate as a load when local solar irradiation declines in series connection, which would result in damage easily. Nowadays modules are often configured with bypass diodes to provide energy releasing route. Furthermore, blocking diode is connected in series before parallel connection in order to prevent inverse power injection. Based on such configurations, this paper was mainly devoted to present a simplified method for characterizing hybrid photovoltaic performance. Newton-Raphson method was adopted for numerical simulations. It was proven to be suitable and effective in model validation coinciding with manufacturer specification. Furthermore, MPP peak positions were reviewed roundly via simulations of the total characteristic curves, especially the operation mismatches caused by random shadows. Different abilities under diverse series/parallel patterns were also investigated for comparison. Researches indicate that: firstly, traditional monotone algorithms of MPPT could be invalid for detecting false maximum only; secondly, the "doorsill effect" of local irradiation intensities, namely that global power output might not be influenced by changes of local shadows; finally, suggestions are put forward that parallel connection should be ranked prior consideration with whole array design, to boost power output relatively. © 2009 IEEE.