Solar Cell

Photovoltaic solar cell.

blockType: AcausalElectricPowerSystems.Sources.SolarCell

Path in the library:

/Physical Modeling/Electrical/Sources/Solar Cell

Description

Block Solar Cell The unit is a current source from a solar cell.

The solar cell model includes the following components:

The current induced by the solar cell;
Temperature dependence;
Thermal port.

The current induced by the solar cell

The unit simulates a single solar cell in the form of resistance , which is connected in series with a parallel combination of the following elements:

Current source ;
Two exponential diodes D1 and D2;
Parallel resistor .

The figure shows an equivalent electrical circuit:

solar cell 1

Output current defined as:

where

— the current induced by the solar cell:

where
- — illumination of the solar cell (intensity of incident radiation) in W/m2^;
- — the measured current generated by solar radiation in case of illumination ;
— saturation current of the first diode;
— saturation current of the second diode;
— thermal stress equal to , where
- — Boltzmann constant;
- — parameter value Device simulation temperature;
- — the elementary charge of an electron;
— the ideality coefficient (or emission coefficient) of the first diode;
— the ideality coefficient (or emission coefficient) of the second diode;
— voltage at the electrical terminals of the solar cell.

The coefficient of ideality varies for amorphous solar cells, and for polycrystalline cells it is usually equal to 2.

The block allows you to choose between two models.:

An 8-parameter model in which the above equation describes the output current.
A 5-parameter model in which the following simplifying assumptions are applied to the equation presented above:
- The saturation current of the second diode is zero.
- The total resistance of the parallel resistor is infinite.

If a model with 5 parameters is selected, then the unit can be parameterized in terms of the parameters of the equivalent circuit shown above or in terms of the short-circuit current and no-load voltage that the unit uses to obtain these parameters.

In all models, you can adjust the block resistance and current parameters depending on the temperature.

You can simulate any number of series-connected solar cells using a single unit. Solar Cell by setting for the parameter Number of series-connected cells per string The value is greater 1. The indoor unit still models only the equations for a single solar cell, but increases the output voltage depending on the number of cells. This method of modeling is more effective than individual modeling of equations for each element.

Temperature dependence

Some parameters of a solar cell depend on the temperature. The temperature of the solar cell is determined by the value of the parameter Device simulation temperature.

The unit provides the following relationship between the current induced by the solar cell, and the temperature of the solar cell :

where

— parameter value First order temperature coefficient for Iph, TIPH1;
— parameter value Measurement temperature.

The unit provides the following ratio between the saturation current of the first diode and the temperature of the solar cell :

where

— parameter value Temperature exponent for Is, TXIS1;
— the width of the forbidden zone, the value of the parameter Energy gap, EG.

The unit provides the following ratio between the saturation current of the second diode and the temperature of the solar cell :

where — parameter value Temperature exponent for Is2, TXIS2.

The block provides the following ratio between the series resistance and the temperature of the solar cell :

where — parameter value Temperature exponent for Rs, TRS1.

The block provides the following relationship between parallel resistance and the temperature of the solar cell :

where — parameter value Temperature exponent for Rp, TRP1.

Thermal port

A thermal port can be used to simulate the effect of the generated heat and the temperature of the device.:

If the check box is Enable thermal port If not installed, the unit does not contain a heat port and does not simulate heat generation in the device.
If the check box is Enable thermal port If installed, the unit contains a heat port that allows you to simulate heat generation due to heat loss. To ensure numerical efficiency, the thermal condition does not affect the electrical behavior of the unit.

The model of the thermal port shown in the following figure reflects only the thermal mass of the device. The thermal mass is directly connected to the thermal port of the H component. Indoor unit Controlled Heat Flow Rate Source provides heat flow to the port and the thermal mass. This heat flow is the internally generated heat.

solar cell 2

The internal heat generated in a solar cell is calculated according to the equivalent scheme given in the The current induced by the solar cell section. This is the sum of all losses on each of the resistors plus losses on each of the diodes.

The heat generated inside the device due to electrical losses is a thermal effect separate from solar radiation. To simulate thermal heating due to solar radiation, you must separately account for it in your model and add heat flow to the physical node connected to the thermal port of the solar cell.

Ports

Conserving

# + — positive voltage
electricity

Details

The electrical port connected to the positive voltage of the solar cell.

Program usage name

p

# – — negative voltage
electricity

Details

The electrical port connected to the negative voltage of the solar cell.

Program usage name

n

# H — thermal port
warm

Details

Thermal non-directional port.

Dependencies

To enable this port, check the box Enable thermal port.

Program usage name

thermal_port

Input

# Ir — illumination
scalar

Details

The illumination of the solar cell.

Data types	`Float64`
Complex numbers support	No

Parameters

Cell Characteristics

# Parameterize by — parameterization of the block
By s/c current and o/c voltage, 5 parameter | By equivalent circuit parameters, 5 parameter | By equivalent circuit parameters, 8 parameter

Details

Select one of the following block parameterization methods:

By s/c current and o/c voltage, 5 parameter — specify the short-circuit current and the no-load voltage that the unit converts into an equivalent solar cell circuit.
By equivalent circuit parameters, 5 parameter — Specify the electrical parameters for the equivalent solar cell circuit model using the 5-parameter solar cell model, which uses the following assumptions:
- The saturation current of the second diode is zero.
- The parallel resistor has infinite resistance.
By equivalent circuit parameters, 8 parameter — Specify the electrical parameters for the equivalent solar cell circuit model using the 8-parameter solar cell model.

Values	`By s/c current and o/c voltage, 5 parameter` \| `By equivalent circuit parameters, 5 parameter` \| `By equivalent circuit parameters, 8 parameter`
Default value	`By s/c current and o/c voltage, 5 parameter`
Program usage name	`model_type_and_parameterization`
Evaluatable	No

# Short-circuit current, Isc — short-circuit current
A | pA | nA | uA | mA | kA | MA

Details

The current that occurs when a solar cell is short-circuited.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By s/c current and o/c voltage, 5 parameter.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`7.34 A`
Program usage name	`I_sc`
Evaluatable	Yes

# Open-circuit voltage, Voc — No-load voltage
V | uV | mV | kV | MV

Details

The voltage on the solar cell when it is not connected.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By s/c current and o/c voltage, 5 parameter.

Units	`V` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`0.6 V`
Program usage name	`V_oc`
Evaluatable	Yes

# Irradiance used for measurements, Ir0 — illumination used for measurements
W/m^2

Details

The illumination at which a current is generated in a solar cell equal to .

Units	`W/m^2`
Default value	`1000.0 W/m^2`
Program usage name	`irradiance0`
Evaluatable	Yes

# Quality factor, N — the emission coefficient of the first diode

Details

The emission coefficient of the first diode.

Default value	`1.5`
Program usage name	`N_diode1`
Evaluatable	Yes

# Series resistance, Rs — consistent resistance
Ohm | mOhm | kOhm | MOhm | GOhm

Details

Internal sequential resistance.

Units	`Ohm` \| `mOhm` \| `kOhm` \| `MOhm` \| `GOhm`
Default value	`0.0 Ohm`
Program usage name	`R_s`
Evaluatable	Yes

# Diode saturation current, Is — saturation current of the first diode
A | pA | nA | uA | mA | kA | MA

Details

Asymptotic reverse current of the first diode to increase the reverse bias in the absence of any incident radiation.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 5 parameter or By equivalent circuit parameters, 8 parameter.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`1.0e-6 A`
Program usage name	`I_diode1_sat`
Evaluatable	Yes

# Solar-generated current for measurements, Iph0 — the current generated by solar radiation for measurements
A | pA | nA | uA | mA | kA | MA

Details

The current induced by solar radiation when the illumination of the element is equal to .

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 5 parameter or By equivalent circuit parameters, 8 parameter.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`7.34 A`
Program usage name	`I_ph0`
Evaluatable	Yes

# Diode saturation current, Is2 — saturation current of the second diode
A | pA | nA | uA | mA | kA | MA

Details

Asymptotic reverse current of the second diode to increase the reverse bias in the absence of any incident radiation.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 8 parameter.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`0.0 A`
Program usage name	`I_diode2_sat`
Evaluatable	Yes

# Quality factor, N2 — the emission coefficient of the second diode

Details

The emission coefficient of the second diode.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 8 parameter.

Default value	`2.0`
Program usage name	`N_diode2`
Evaluatable	Yes

# Parallel resistance, Rp — parallel resistance
Ohm | mOhm | kOhm | MOhm | GOhm

Details

Internal parallel resistance.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 8 parameter.

Units	`Ohm` \| `mOhm` \| `kOhm` \| `MOhm` \| `GOhm`
Default value	`Inf Ohm`
Program usage name	`R_p`
Evaluatable	Yes

Panel Configuration

# Number of series-connected cells per string — the number of sequentially connected solar cells in each chain

Details

The number of sequentially connected solar cells in each chain modeled by the unit. The value must be higher 0.

Default value	`1.0`
Program usage name	`series_cell_count`
Evaluatable	Yes

# Number of parallel-connected strings — number of parallel connected chains

Details

The number of solar cell chains connected in parallel. The value must be higher 0.

Default value	`1.0`
Program usage name	`parallel_cell_count`
Evaluatable	Yes

Temperature Dependence

# Enable thermal port — turning on the heat port

Details

To enable thermal effects modeling, select the checkbox for this option.

Default value	`false (switched off)`
Program usage name	`has_thermal_port`
Evaluatable	No

Details

The order of linear increase in the current generated by a solar cell as the temperature increases. The value must be greater than or equal to 0.

Units	`1/K` \| `1/degR` \| `1/deltaK` \| `1/deltadegC` \| `1/deltadegF` \| `1/deltadegR`
Default value	`0.0 1/K`
Program usage name	`K0`
Evaluatable	Yes

# Energy gap, EG — the width of the forbidden zone
J | mJ | kJ | MJ | mW*hr | W*hr | kW*hr | MW*hr | eV | cal | kcal | Btu_IT

Details

The activation energy of the solar cell. The value must be greater than or equal to 0.1.

Units	`J` \| `mJ` \| `kJ` \| `MJ` \| `mWhr` \| `Whr` \| `kWhr` \| `MWhr` \| `eV` \| `cal` \| `kcal` \| `Btu_IT`
Default value	`1.11 eV`
Program usage name	`E_g`
Evaluatable	Yes

# Temperature exponent for Is, TXIS1 — temperature indicator for I_s

Details

The order of exponential increase of the current on the first diode with increasing temperature. The value must be higher 0.

Default value	`3.0`
Program usage name	`K1`
Evaluatable	Yes

# Temperature exponent for Rs, TRS1 — temperature indicator for R_s

Details

The order of exponential increase of the series resistance with increasing temperature. The value must be greater than or equal to 0.

Default value	`0.0`
Program usage name	`K3`
Evaluatable	Yes

Details

The temperature at which the parameters of the solar cell were measured. The value must be higher 0.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`25.0 degC`
Program usage name	`T_measurement`
Evaluatable	Yes

Details

The temperature at which the solar cell is modeled. The value must be higher 0.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`25.0 degC`
Program usage name	`T_device_fixed`
Evaluatable	Yes

# Temperature exponent for Is2, TXIS2 — temperature indicator for I_s2

Details

The order of exponential increase of current on the second diode with increasing temperature. The value must be greater than or equal to 0.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 8 parameter.

Default value	`3.0`
Program usage name	`K2`
Evaluatable	Yes

# Temperature exponent for Rp, TRP1 — temperature indicator for R_p

Details

The order of exponential increase in parallel resistance with increasing temperature. The value must be greater than or equal to 0.

Dependencies

To use this parameter, set for the parameter Parameterize by meaning By equivalent circuit parameters, 8 parameter.

Default value	`0.0`
Program usage name	`K4`
Evaluatable	Yes

Thermal Port

# Thermal mass per cell — thermal mass per cell
J/K | kJ/K

Details

The thermal energy required to increase the temperature of one solar cell by one degree. When simulating more than one cell sequentially, specify the thermal mass for one cell. This value is multiplied by the number of elements to determine the total thermal mass.

Units	`J/K` \| `kJ/K`
Default value	`100.0 J/K`
Program usage name	`thermal_mass`
Evaluatable	Yes

Details

The temperature of the solar cell at the beginning of the simulation.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`25.0 degC`
Program usage name	`T_start`
Evaluatable	Yes

Literature

J.A. Gow J.A., 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.