This component can be used to model a photovoltaic (PV) source. The PV source is assumed to consist of several strings of PV modules connected in parallel, where each string can consist of a number of PV modules connected in series. All PV modules in the array are assumed identical.
The PV cell model used in the components is based on [22]. A solar cell can be represented using the electrical equivalent circuit shown below:
Solar Photovoltaic Cell Model
The photo current, Ig, generated when the cell is exposed to light, varies linearly with solar irradiance. The current Id through the anti-parallel diode is largely responsible for producing the nonlinear I-V characteristics of the PV cell.
Application of the Kirchhoff’s current law to the circuit gives:
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(PV-1) |
Substitution of relevant expressions for the diode current Id and the shunt branch current Ish yields:
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(PV-2) |
In (PV-2), Ig is the photo current and it is a function of the solar radiation on the plane of the solar cell G and the cell temperature Tc:
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(PV-3) |
Where IscR is the short circuit current at the reference solar radiation GR and the reference cell temperature TcR. The parameter αT is the temperature coefficient of photo current (for Silicon solar cells αT = 0.0017 A/K).
The current Io in (PV-2) is called the dark (saturation) current, a function of cell temperature, and given by:
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(PV-4) |
Where IoR is the dark current at the reference temperature. The other parameters appearing in (PV-2) to (PV-4) are the electron charge q, the Boltzmann constant k, the band-gap energy of the solar cell material eg, and the diode ideality factor n which is between 1-2 (1.3 is typical for silicon solar cells).
Since a PV module is composed primarily of series-connected cells, and a PV array is composed of series- and parallel-connected modules, the single cell circuit can be scaled up to represent any series/parallel combination [22, 23].
G: Instantaneous value of solar radiation on the panel (W/m2).
T: Instantaneous value of cell operating temperature (°C).
More: |
PSCAD General Reference [22] PSCAD General Reference [23] |
PV Array ParametersPV Array Parameters
PV array name |
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Text |
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Name for the array (optional). |
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Number of modules connected in series per array |
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INTEGER |
Constant |
Number of PV modules connected in series in each of the module strings in the array. |
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Number of module strings in parallel per array |
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INTEGER |
Constant |
Number of PV module strings connected in parallel to form the array. |
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Number of cells connected in series per module |
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INTEGER |
Constant |
Number of PV cells connected in series in each of the cell strings in a PV module. |
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Number of cell strings in parallel per module |
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INTEGER |
Constant |
Number of parallel connected PV cell strings in a PV module. |
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Reference Irradiation |
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REAL |
Constant |
Reference irradiation at which the module parameters are specified [W/m2]. |
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Reference cell temperature |
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REAL |
Constant |
Reference temperature at which the module parameters are specified [oC]. |
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Graphics Display |
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Choice |
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Select Standard or Industry. |
PV Cell ParametersPV Cell Parameters
Effective area per cell |
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REAL |
Constant |
Effective cell area [m2]. |
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Series resistance per cell |
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REAL |
Constant |
PV cell series resistance, Rsr, [W]. |
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Shunt resistance per cell |
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REAL |
Constant |
PV cell shunt resistance, Rsh [W]. |
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Diode ideality factor |
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REAL |
Constant |
Diode ideality factor, n (usually in the range [1-2] ). |
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Band gap energy |
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REAL |
Constant |
Band gap energy of the PV cell material [eV].
It is assumed that the band gap energy remains approximately constant within the cell operating temperature range. |
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Saturation current at reference conditions per cell |
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REAL |
Constant |
The dark current (saturation current) of the cell at the reference irradiation and the reference temperature [kA]. |
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Short circuit current at ref. conditions per cell |
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REAL |
Constant |
The short circuit current of the PV cell at the reference irradiation and the reference temperature [kA]. |
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Temperature Coefficient of photo current |
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REAL |
Constant |
Temperature coefficient of photo current, aT, [A/K]. |
Photo current per module |
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Text |
Output |
Name for the photo current [kA] per module. |
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Internal diode current per module |
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Text |
Output |
Name for the internal diode current [kA] per module. |
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Internal diode voltage per module |
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Text |
Output |
Name for the internal diode voltage [kV] per module. |
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Internal power loss per module |
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Text |
Output |
Name for the internal power loss [MW] per module. |
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Output power per module |
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Text |
Output |
Name for the output power [MW] per module. |
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PV array output current |
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Text |
Output |
Name of the PV array output current [kA]. |
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PV array output voltage |
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Text |
Output |
Name for the PV array output voltage [kV]. |
