Shay Mathews with Roger French, Timothy Peshek, and Yang Hu
Photovoltaic Degradation Analysis and Two Diode Simulated Models
An understanding of the degradation process of photovoltaic modules during real world use is crucial to extending their lifetime and reliability. The degradation that occurs during normal use of a panel can be due to unpredictable conditions of the weather and surroundings. Large amounts data collected over long periods of time is most helpful to understanding degradation. Over the course of 4 months, large data sets containing minute by minute IV curves of the panels were collected using the Daystar MultiTracer. These data, in conjunction with minute by minute climactic and insolation data, will be analyzed using R Analytics using time series analysis and cross sectional studies of the semiconductor device performance under varying degrees of irradiance and for different brands of modules. Understanding the performance over varying conditions, can help identify degradation modes and gain a better understanding of how and why PV modules degrade in the real world. The results will be compared with results from an electrical simulation of the modules electrical performance using NGSPICE, using a two diode SPICE model of the PV module to predict electrical performance. By comparing real and simulated data, a theoretical interpretation of device performance will be created. Theoretical interpretations linking processes on the semiconductor device and cell string scale to real world data trends may prove helpful to improving the lifetime of PV modules.