Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
PV cells can be arranged in a series
configuration to form a module, and modules
can then be connected in parallel-series
configurations to form arrays. When
connecting cells or modules in series, they
must have the same current rating to produce
an additive voltage output, and similarly,
modules must have the same voltage rating
when connected in parallel to produce larger
currents.
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
Theory of I-V Characterization
PV cells can be modeled as a current source in
parallel with a diode. When there is no light
present to generate any current, the PV cell
behaves like a diode. As the intensity of
incident light increases, current is generated by
the PV cell, as illustrated in Figure 1
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
I-V Curves for Modules
For a module or array of PV cells, the shape of
the I-V curve does not change. However, it is
scaled based on the number of cells connected
in series and in parallel. When n is the number
of cells connected in series and m is the
number of cells connected in parallel and ISC
and VOC are values for individual cells, the I-V
curve shown in Figure 10 is produced.
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
Understanding cell connection
Current (A)
•The PV module is the basic unit in a complete
PV system
4
•Understanding how the module is designed
and assembled provides key understanding to
designing a system
•Towards this end consider the following IV
characteristics of a single cell
JP TEASEL 01/02/11
Voltage (V) 0.6
Photovoltaic modules
Session 6
•With three cells
connected in series the
combined characteristics
are shown
•Connecting the cells in
series maintains the same
current, only the voltage
of each cell is added
together
Current (A)
4
Voltage (V)
0.6
1.2
The combined IV characteristics of three
identical cells connected in series
JP TEASEL 01/02/11
1.8
Photovoltaic modules
Session 6
Current (A)
C
• If two cells with
different
characteristics
(dissilimar) are
wired together in
series, the result is
shown in following
figures
• Series connected
dissimilar cells
produce an added
voltage output, but
series current is
equal to the lowest
value of the two
Current (A)
Voltage (V)
A B
Voltage (V)
A B
The individual IV characteristics of two dissimilar cells
Current (A)
C
D
Voltage (V)
A+B
The combined IV characteristics of the two
dissimilar
cells
connected in series
JP TEASEL
01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11
Photovoltaic modules
Session 6
JP TEASEL 01/02/11