Aim of Experiment: Study of an equivalent model of a PV cell and its I-V and P-V characteristic under uniform solar insolation. Objective: To design an equivalent model of a PV cell To obtain I-V and P-V characteristic of a PV array under uniform solar insolation Circuit Diagram: Equivalent model of a PV cell Theory: Current generated from the PV array is directly proportional to the solar insolation. In the above figure PV generated current is governed by the following equations: I pv I m I sh Where I sh is the current through shunt resistor given by V I pv Rs I sh Rp Im I g Id Where I g is the generated PV current proportional to solar insolation given by I g I g ,n K1T Where I d is the diode current given by G Gn (V I pv Rs I d I 0 exp vt n 1 Where I 0 is the reverse saturation current of the diode given by I0 I sc ,n K I T V Kv T exp oc ,n 1 aV t Where vt is temperature equivalent voltage given by vt N s kT q Final expression for PV cell output current is given by: (V I pv Rs V I pv Rs I pv I g I 0 exp 1 vt n R p Description and values of different parameters mentioned above are given in the following table. Parameter Description Voc NP Open circuit voltage Short circuit current Boltzman’s Constant Number of cells in series Number of cells in parallel Description Value 301oK Tn Ambient Temperature Nominal temperature 1.38* 10-23 q Electron Charge 1.6*10-19 54 n 1 I0 Solar Insolation 800 I 0,n Diode Ideality factor Diode saturation current Diode nominal saturation current G Gn Nominal Solar insolation 1000 Eg Bandgap Energy 1.12eV KV Voltage coefficient -0.1230 I g ,n Nominal current at STC 8.214 KI Current coefficient R s & Rp Series and parallel resistance, respectively 0.221Ω, 414.5Ω I sc,n k Ns Value Parameter 32.9V T 8.21A 0.0032 3000K 2 9.85*10-8 By varying the load from zero to open circuit voltage of the PV array, I-V characteristic curve can be obtained.
