Online PV panel characterisation for PV system diagnostic

Photovoltaic PV systems are widely installed to produce green electrical energy in recent years due to its high reliability, installation simplicity, and zero fuel costs. Many research works prove that PV cells and modules are influenced by climatic conditions perturbations. In this way, many diagnosis methods have been developed, among them that based on the PV current and voltage analysis. In this paper, an online PV system I-V characterization using two-diode model has been investigated to study the health of an operating PV system. An iterative algorithm to extract the online real I-V characteristic is explored in this paper. The proposed method is validated on an experimental setup composed of a PV panel, a DC/DC converter and a resistive load. The DC/DC duty cycle ratio variation allows to extract experimental I-V curve portion for 60%V
OC
≤ V
PV
≤ V
OC
. The implemented algorithm allows the estimation of the short circuit current for a given irradiance and temperature through the adjustment of internal parameters, if needed, of the PV two-diode model. The obtained results are used to study the health state of the PV system.