Determination of Polycrystalline Photovoltaic Module Degradation Rate Based on Electrical Parameters Estimation

Abstract

The aim of this paper is to determine the degradation rate of electrical parameters of a PHOTOWATT BPX 47500 polycrystalline photovoltaic module that was exposed to outdoor conditions in a temperate climate in Morocco for about 30 years. The degradation rate is determined using the estimated parameters of the single diode model, based on I-V characteristic measurements. The Levenberg-Marquardt (LM) and Particle Swarm Optimization (PSO) algorithms based optimization fitting methods were investigated to estimate three main parameters: series resistance, shunt resistance, and ideality factor. Furthermore, a step to correct electrical parameters to standard test condition is performed. From the results, we noticed a correlation between the value of series resistance and the degradation in the open circuit voltage and maximum output power parameters, which are reduced annually by 0.33% and 1.16%, respectively. In addition, the algorithms are coded using Python environment.