Comparative Study B etween Lognormal and Weibull Distributions in Modeling Commercial Concentrator III – V Triple - Junction Solar Cells Lifetimes

Abstract

In this paper, we show that modeling the accelerated lifetime of commercial concentrator lattice match triple-junction GaInP/GaInAs/Ge cells by a lognormal distribution is better fitted than by Weibull distribution has been adopted by most of the research literature in the field. A fair number of statistical tests are used to analyze real-time datasets from accelerated life testing that significantly favors the lognormal distribution. For comparison purposes, the Arrhenius-Weibull and lognormal stress relationships are used to predict the lifetime model under nominal conditions. They provide comparable estimates to the nominal meantime to failure and activation energy of the cells, yet, the two models possess different behaviors, especially at their tails and peaks. Moreover, an intensive Monte Carlo simulation is conducted to examine the distribution robustness towards the censoring scheme. The results again affirm that type I censored samples of Lognormal are more efficient than those of Weibull in estimating the distribution parameters.