Research on influence between photovoltaic power and module temperature and ambient temperature

摘要

The photovoltaic (PV) module temperature (Tm) and ambient temperature (Ta) are both important factors to PV power output (P), but are often confused with each other or even ignored. In this paper, the physical analysis methods and mathematical analysis methods are utilized to research the differences and similarities of two temperatures in effecting of PV power output. Firstly, based on PV effect theory, energy balance equation and heat transfer theory, the relationship between three variables is analyzed in physical. Secondly, in mathematical aspect, correlation coefficient and information entropy are utilized to analyze the correlation between Tm and P as well as Ta and P in the whole year and four kinds of weather types based on actual data of a grid-connected 500kW PV system. The results indicate that, other things equal, Tm is a more direct and stronger factor than Ta.