where i and v are the array’s terminal current and voltage, and Isc and Voc are its short-circuit current
and open-circuit voltage, respectively.
The thermal voltage of the array is Vth = mkT/q, where there
are m
cells in series, k is Boltzmann’s constant, T is the absolute temperature and q is the électronic charge.
Eqn. 1 (Fig. 2a) gives a
unimodal v-p characteristic (Fig. 2b);
the MPP (V*, P*) is
where ∂ p/∂ v = 0,
p = vi being the power.
The characteristic can be modelled electrically by a current source Isc
shunted by m diodes, as in Fig. 1.
Quality Fill Factor : FF
Maximal Power Point : MPP
Short Circuit Courant : Isc
Open Circuit Voltage : Voc
FF = (Impp * Umpp) / (Isc * Voc) ≈ [ Voc - Ln(Voc + 0.72) ] / (Isc * Voc)
