Solar Cell
Description
The Solar Cell block represents a solar cell current
source.
The solar cell model includes the following components:
Solar-Induced Current
The block represents a single solar cell as a resistance
Rs that is connected in series
with a parallel combination of the following elements:
Current source
Two exponential diodes
Parallel resistor Rp
The following illustration shows the equivalent circuit diagram:
The output current I is
where:
Iph is the solar-induced
current:
where:
Ir is the
irradiance (light intensity), in
W/m2, falling on the
cell.
Iph0 is the
measured solar-generated current for the irradiance
Ir0.
Is is the saturation current
of the first diode.
Is2 is the saturation
current of the second diode.
Vt is the thermal voltage,
kT/q, where:
k is the Boltzmann constant.
T is the Device simulation
temperature parameter value.
q is the elementary charge on an
electron.
N is the quality factor (diode emission
coefficient) of the first diode.
N2 is the quality factor
(diode emission coefficient) of the second diode.
V is the voltage across the solar cell electrical
ports.
The quality factor varies for amorphous cells, and is typically
2 for polycrystalline cells.
The block lets you choose between two models:
If you choose the 5-parameter model, you can parameterize this block
in terms of the preceding equivalent circuit model parameters or in terms of the
short-circuit current and open-circuit voltage the block uses to derive these
parameters.
All models adjust the block resistance and current parameters as a function of
temperature.
You can model any number of solar cells connected in series using a single
Solar Cell block by setting the parameter
Number of series cells to a value larger than 1. Internally
the block still simulates only the equations for a single solar cell, but scales up
the output voltage according to the number of cells. This results in a more
efficient simulation than if equations for each cell were simulated
individually.
If you want to model N cells in parallel, you can do so for
single cells by scaling the parameter values accordingly. That is, multiply
short-circuit current, diode saturation current, and solar-generated currents by
N, and divide series resistance by N. To
connect solar cell blocks in parallel, where each block contains multiple cells in
series, make multiple copies of the block and connect accordingly.
Temperature Dependence
Several solar cell parameters depend on temperature. The solar cell temperature is
specified by the Device simulation temperature parameter
value.
The block provides the following relationship between the solar-induced current
Iph and the solar cell temperature
T:
where:
TIPH1 is the First order temperature
coefficient for Iph, TIPH1 parameter value.
Tmeas is the
Measurement temperature parameter value.
The block provides the following relationship between the saturation current of
the first diode Is and the solar cell
temperature T:
where TXIS1 is the Temperature
exponent for Is, TXIS1 parameter value.
The block provides the following relationship between the saturation current of
the second diode Is2 and the solar cell
temperature T:
where TXIS2 is the Temperature
exponent for Is2, TXIS2 parameter value.
The block provides the following relationship between the series resistance
Rs and the solar cell temperature
T:
where TRS1 is the Temperature
exponent for Rs, TRS1 parameter value.
The block provides the following relationship between the parallel resistance
Rp and the solar cell temperature
T:
where TRP1 is the Temperature
exponent for Rp, TRP1 parameter value.
Thermal Port
The block has an optional thermal port, hidden by default. To expose the thermal port,
right-click the block in your model, and then from the context menu select
> > .
This action displays the thermal port H on the block icon, and
exposes the Thermal Port parameters.
The thermal port model, shown in the following illustration, represents just the thermal mass
of the device. The thermal mass is directly connected to the component thermal port
H. An internal Ideal Heat Flow Source
block supplies a heat flow to the port and thermal mass. This heat
flow represents the internally generated heat.
The internally generated heat in the solar cell is calculated according to the equivalent
circuit diagram, shown at the beginning of the reference page, in the Solar-Induced Current section. It is
the sum of the i2 ·
R losses for each of the resistors plus the losses in
each of the diodes.
The internally generated heat due to electrical losses is a separate heating effect to that of
the solar irradiation. To model thermal heating due to solar irradiation, you must account
for it separately in your model and add the heat flow to the physical node connected to the
solar cell thermal port.
Ports
Input
expand all
Ir — Incident irradiance
physical signal
Physical signal associated with the solar cell incident
irradiance.
Conserving
expand all
+ — Positive voltage
electrical
Electrical conserving port associated with the solar cell positive
voltage
- — Negative voltage
electrical
Electrical conserving port associated with the solar cell negative
voltage
Parameters
expand all
Cell Characteristics
Parameterize by — Block parameterization
By s/c current and o/c voltage, 5
parameter (default) | By equivalent circuit parameters, 5
parameter | By equivalent circuit parameters, 8
parameter
Select one of the following methods for block parameterization:
By s/c current and o/c voltage, 5
parameter — Provide short-circuit
current and open-circuit voltage that the block converts to
an equivalent circuit model of the solar cell.
By equivalent circuit parameters, 5
parameter — Provide electrical
parameters for an equivalent circuit model of the solar cell
using the 5-parameter solar cell model that makes the
following assumptions:
By equivalent circuit parameters, 8
parameter — Provide electrical
parameters for an equivalent circuit model of the solar cell
using the 8-parameter solar cell model.
Short-circuit current, Isc — Short-circuit current
7.34
A (default)
Current that flows when you short-circuit the solar cell.
Dependencies
This parameter is visible only when you select By s/c
current and o/c voltage, 5 parameter for the
Parameterize by parameter.
Open-circuit voltage, Voc — Open-circuit voltage
0.6
V (default)
Voltage across the solar cell when it is not connected.
Dependencies
This parameter is visible only when you select By s/c
current and o/c voltage, 5 parameter for the
Parameterize by parameter.
Diode saturation current, Is — First diode saturation current
1e-6
A (default)
Asymptotic reverse current of the first diode for increasing reverse
bias in the absence of any incident light.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 5 parameter or
By equivalent circuit parameters, 8
parameter for the Parameterize
by parameter.
Diode saturation current, Is2 — Second diode saturation current
0
A (default)
Asymptotic reverse current of the second diode for increasing reverse
bias in the absence of any incident light.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 8 parameter for the
Parameterize by parameter.
Solar-generated current for measurements, Iph0 — Solar-generated current for measurements
7.34
A (default)
Solar-induced current when the irradiance is
Ir0.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 5 parameter or
By equivalent circuit parameters, 8
parameter for the Parameterize
by parameter.
Irradiance used for measurements, Ir0 — Irradiance used for measurements
1000
W/m2 (default)
Irradiance that produces a current of
Iph0 in the solar
cell.
Quality factor, N — First diode emission coefficient
1.5 (default)
Emission coefficient of the first diode.
Quality factor, N2 — Second diode emission coefficient
2 (default)
Emission coefficient of the second diode.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 8 parameter for the
Parameterize by parameter.
Series resistance, Rs — Series resistance
0
Ohm (default)
Internal series resistance.
Parallel resistance, Rp — Parallel resistance
inf
Ohm (default)
Internal parallel resistance.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 8 parameter for the
Parameterize by parameter.
Configuration
Number of series cells — Series-connected solar cells
1 (default) | positive scalar
Number of series-connected solar cells modeled by the block. The value
must be greater than 0.
Temperature Dependence
First order temperature coefficient for Iph, TIPH1 — First order temperature coefficient for Iph
0
1/K (default) | nonnegative scalar
Order of the linear increase in the solar-generated current as
temperature increases. The value must be greater than or equal to
0.
Energy gap, EG — Energy gap
1.11
eV (default)
Solar cell activation energy. The value must be greater than or equal
to 0.1.
Temperature exponent for Is, TXIS1 — Temperature exponent for Is
3 (default) | nonnegative scalar
Order of the exponential increase in the current from the first diode
as temperature increases. The value must be greater than or equal to
0.
Temperature exponent for Is2, TXIS2 — Temperature exponent for Is2
3 (default) | nonnegative scalar
Order of the exponential increase in the current from the second diode
as temperature increases. The value must be greater than or equal to
0.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 8 parameter for the
Parameterize by parameter.
Temperature exponent for Rs, TRS1 — Temperature exponent for Rs
0 (default)
Order of the exponential increase in the series resistance as
temperature increases. The value must be greater than or equal to
0.
Temperature exponent for Rp, TRP1 — Temperature exponent for Rp
0 (default) | nonnegative scalar
Order of the exponential increase in the parallel resistance as
temperature increases. The value must be greater than or equal to
0.
Dependencies
This parameter is visible only when you select By
equivalent circuit parameters, 8 parameter for the
Parameterize by parameter.
Measurement temperature — Measurement temperature
25
degC (default) | positive scalar
Temperature at which the solar cell parameters were measured. The
value must be greater than 0.
Device simulation temperature — Device simulation temperature
25
degC (default) | positive scalar
Temperature at which the solar cell is simulated. The value must be
greater than 0.
Thermal port
This tab is visible only if you expose the thermal port on this block.
Thermal mass — Thermal mass
100
J/K (default)
The heat energy required to raise the temperature of the solar cell by
one degree. When modeling more than one cell in series, specify the
thermal mass for a single cell. This value gets multiplied internally by
the number of cells to determine the total thermal mass.
Initial temperature — Initial temperature
25
degC (default)
The temperature of the solar cell at the start of simulation.
References
[1] Gow, J.A. and C.D. Manning. “Development of a
Photovoltaic Array Model for Use in Power-Electronics Simulation Studies.”
IEEE Proceedings of Electric Power Applications, Vol. 146,
No. 2, 1999, pp. 193–200.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
See Also
Introduced in R2008a
