PV cell modelling

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:
pv m sh
I I I
Where
sh
I
is the current through shunt resistor given by
pv s
sh p
V I R
IR
m g d
I I I
Where
g
I
is the generated PV current proportional to solar insolation given by
,1g g n n
G
I I K T G
Where
d
I
is the diode current given by

0
(
exp 1
pv s
dt
V I R
II vn
Where
0
I
is the reverse saturation current of the diode given by
,
0
,
exp 1
sc n I
oc n v
t
I K T
IV K T
aV
Where
t
v
is temperature equivalent voltage given by
s
tN kT
vq
Final expression for PV cell output current is given by:
0(
exp 1
pv s pv s
pv g tp
V I R V I R
I I I v n R
Description and values of different parameters mentioned above are given in the following table.
Parameter
Description
Value
Parameter
Description
Value
oc
V
Open circuit
voltage
32.9V
T
Ambient
Temperature
301oK
,sc n
I
Short circuit
current
8.21A
n
T
Nominal
temperature
3000K
k
Boltzman’s
Constant
1.38*
10-23
q
Electron Charge
1.6*10-19
s
N
Number of cells
in series
54
n
Diode Ideality
factor
2
P
N
Number of cells
in parallel
1
0
I
Diode saturation
current
G
Solar Insolation
800
0,n
I
Diode nominal
saturation
current
9.85*10-8
n
G
Nominal Solar
insolation
1000
g
E
Bandgap Energy
1.12eV
,gn
I
Nominal current
at STC
8.214
V
K
Voltage
coefficient
-0.1230
I
K
Current
coefficient
0.0032
s
R
&
p
R
Series and
parallel
resistance,
respectively
0.221Ω, 414.5Ω
By varying the load from zero to open circuit voltage of the PV array, I-V characteristic curve can
be obtained.