TEAM ASTROS

Solar Cell Performance Measurement System

ANDY CASTELLANOS

ALBERTO CHICO

ENRIQUE FERNANDEZ

Objective

Team Astros has undertaken the task of designing and implementing a Solar Cell performance measurement system for Dr. David Zubia, assistant professor in the Electrical and Computer Engineering (ECE) Department at the University of Texas at El Paso (UTEP). This system will measure current and voltage (IV) characteristics of test solar cells and will perform analysis and data logging.

Abstract

The system is comprised of the following subsystems:

A bipolar data acquistion board connected to a computer
A program to operate the system (GUI) using National Instrument's Laboratory Virtual Instrument Engineering Workbench software (LabVIEW)
A Xenon lamp-based light source

The program will provide the user with a GUI to enter the appropriate test parameters to obtain the IV characteristics of a test solar cell. This cell, illuminated by the light source, will be subjected to a voltage sweep via the LabVIEW program in conjunction with the data acquisition board. During this voltage sweep, measurements of the voltage across the cell and the current generated by it will be acquired, analyzed, plotted and saved to a tab-delimited file for later importation into 3rd party software (e.g. Microsoft Excel, Access, etc.) for later analysis.

Method of Completion

The work was divided among the three team members in the following manner:

Enrique Fernandez was responsible for the research of a bipolar power supply and purchase of a bipolar data acquisition board based on his research, consultations with Dr. Zubia and budget limitations. Fernandez was also responsible for the development and implementation of a current-measuring circuit designed to eliminate current loss from the test cell and compatible with the data acquisition board.
Andy Castellanos was co-responsible with Fernandez in the research of the power supply and responsible for the programming of the GUI using LabVIEW.
Alberto Chico was responsible for the research and purchase of all the lighting-related components, as well as the integration of these to the rest of the modules.

Issues

The current issues that the team must deal for the completion of this project are:

Due to the very small current from the test cell being measured (in the range of a few mA), noise is being picked up by the system when the xenon lamp-based light source is turned on. This problem does not occur when the light source is off. This issued is currently being worked on.
Due to a different configuration desired by the end user of the system, the single halogen lamp of the original stressing light enclosure design might not be enough to uniformly illuminate with new number of cells desired. Options are being evaluated for the resolution of this problem.

Schematics

Conclusion

Test solar cells shall be characterized the week of November 18th, 2002. These cells will be stressed under certain lighting conditions and re-characterized in order to evaluate any performance degradation. Once the system is proven reliable to the Senior Project coordinators, Teaching Assistant, Dr. Zubia and the end user, the system will be turned over to the end user for full use.