EFFECTS OF MISMATCH LOSSES IN PHOTOVOLTAIC ARRAYS

Experimental and modeling results on the effects of mismatch losses in photovoltaic arrays are presented. Field tests conducted on each of t he 192 modules are used to describe the variation in the properties of production run photovoltaic modules. Module specific estimates of a f ive-parameter module model are obtained by nonlinear regression. Mathe matical models of four-module parallel string and series block photovo ltaic array performance based on the five-parameter module model are d eveloped and used to evaluate the variation in maximum output power an d mismatch loss of arrays with random module orderings. Module maximum output power averaged 14% below the nameplate rating and exhibited a coefficient of variation of 2.1%. Mismatch losses were very small, nev er exceeding 0.53%. No differences between parallel string and series block arrays in array maximum output power were observed.