A Simplified Method for Parameter Determination of a Photovoltaic Module using Manufacturer’s data

Robinson Ndegwa; Elijah Ayieta; Justus Simiyu; Nicodemus Odero

Robinson Ndegwa Department of Physics, University of Nairobi
Elijah Ayieta Department of Physics, University of Nairobi
Justus Simiyu Department of Mathematics and Physical Sciences, Maasai Mara University
Nicodemus Odero Department of Electrical and Electronic Engineering, Machakos University

Keywords: Ideality factor, Photocurrent Saturation current, Series resistance, shunt resistance

Abstract

Accurate and fast modelling and simulation of Photovoltaic module requires careful determination and identification of the unknown parameters required in fitting the voltage-current and power-voltage curves to replicate an actual system. The main objective of this study is to determine ideality factor (A), saturation current (I_o), photocurrent (I_ph), series resistance (R_s) and shunt resistance (Rsh), the five unknown parameters using I_sc, I_mpp, V_mpp, and Voc available from manufacturer's datasheet. A single diode equivalent circuit has been used to formulate a simple method for evaluating ideality factor (A), saturation current (I_o) and photocurrent (I_ph) by first assuming that the photovoltaic array has negligible series resistance (R_s) and infinite parallel resistance (R_sh). Additional analysis of series and parallel resistance have been carried out for fine tuning the voltage-current and power-voltage curves to fit the experimental data. The model presented in this work has been simulated using the GNU Octave open-source software. The photovoltaic modules with International Electrotechnical Commission (IEC) 61215 standards have been selected from Solarex-MSX60, BP- SX150 and Kyocera-KK280P. The extracted parameters produced results for the output power with an error of less than 0.5% for all the modules.