A comparative analysis of the one, two and three - diode photovoltaic (PV) models

Abstract

This study presents a comparative analysis of the one, two and three – diode mathematical models of photovoltaic (PV) cells. It is shown that for an n-diode (n > 1) PV cell model, the open circuit voltage and maximum power decreases by n % when compared with a one diode model. The non-linear equations that governs the current – voltage and power - voltage characteristics are presented and simulated using an iterative looping method in Matlab. All the mathematical model simulations were performed at manufacturers standard test conditions (25 °C, 1000W/m²) and compared with the manufacturer parameter values from the KC200GT datasheet. Results obtained are presented for two cases: models without shunt resistance and models with shunt resistance. For models without shunt resistance, the one diode has the highest values of the open circuit voltage and maximum power. The two diode model values of maximum power and open circuit voltage differed from values of the single diode model with a 2 % decrease. The three diode model values were reduced by 3 %. Similarly, for models with shunt resistance, the one diode has the highest values of the open circuit voltage and maximum power. The two diode model values of maximum power and open circuit voltage differed from values of the single diode model by 2 % decrease. The three diode model values were decreased by 3 %. The findings indicate that the one-diode model offers the best trade-off between simplicity and accuracy, making it suitable for simulation tasks where computational efficiency is critical. This comparative framework provides valuable insights for selecting appropriate PV models based on application-specific requirements.