Characterization of a small amorphous photovoltaic panel and derivation of its SPICE model

Abstract

This paper presents a simple method to resolve the parameters of the single-diode equivalent circuit for small amorphous photovoltaic (PV) panels. It is based on a precise measurement using a test bench that allows the characterization of PV panels at different illumination levels from 10 lx to 3000 lx. The measurement under different illumination conditions allows the calculation of the model parameters using only a standard polynomial, logarithmic and exponential functions - no numerical approach or Lambert W function is required. The solved parameters are later used in LTspice simulations, which are compared with the real measurements. The Spice model presented in this paper is based on the single diode model, but is modified to be more reliable at low illumination levels. The Spice model can be used for the design of MPPT systems or for various indoor IoT applications, where it allows to predict the available energy under different conditions.