A distributed SPICE-model of a solar cell

In this paper, a distributed SPICE-model for a solar cell is worked out. Special attention is paid to the problems of nonhomogeneous current distribution and the effective series resistance. Elaborate experimental techniques have been used to determine the model parameters. They are based on the I-V characteristics, the small signal impedance, and the open-circuit voltage decay measurements. The SPICE simulation results are compared with the measured static and dynamic characteristics of a solar cell. We found satisfactory agreement concerning the static characteristics, whereas there is discrepancy in the dynamic characteristics. This is because the SPICE-model of a p-n junction diode contains only one time constant. It is found that two time constants are necessary for accurate description of the dynamic performance. The techniques and methodologies developed here are applicable to other junction diodes operating at high frequencies or under transient conditions.