Circuit design considerations for photovoltaic modules and systems

As part of the Jet Propulsion Laboratory's Low-Cost Solar Array Project, a program of module and array circuit-design studies has been carried out to improve the reliability of modules and to develop strategies for improving array system fault tolerance. Analyses to determine optimum element configuration and circuit design strategies, made with the use of a computer model that uses the measurable characteristics of cells and modules as input, are described and results are presented. Guidelines for implementing strategies to deal with specific module and array system circuit-design problems, involving use of series-paralleling and bypass diodes to reduce module and array system power losses resulting from anomalies, are offered. Several different power-loss conditions resulting from anomalies are considered.