Sure. You can model the PV cells using one of the equivalent circuit models known in literature. For example, the model shown below is called a single diode equivalent circuit model, of which detailed description can be found in this link. It is made of a current source producing the light-generated current I_ph, a diode modeling the voltage-dependent current I_D lost due to recombination, and resistors with equivalent shunt and series resistances, R_shunt and R_series, respectively. The I_D-V_D characteristics of the diode is governed by the Shockley’s exponential model: I_D = I_S ·exp(V_D/nV_T) where I_S is the reverse saturation current, V_T is the thermal voltage (=kT/q), and n is the diode’s ideality factor. When this model is describing a set of N_S serially-connected PV cells, the equivalent ideality factor n may increase with N_S.

Writing this equivalent circuit model in XMODEL is straightforward using the circuit primitives. The schematic cellview 'sandbox.pvcell:schematic' shown below describes this PV cell model using the 'isource', 'diode', and 'resistor' primitives. Among them, the 'diode' primitive is selecting the exponential model, which can specify the reverse saturation current and ideality factor directly using the parameters 'Is' and 'N', respectively. Its series resistance parameter 'Rs' is set to 1% of the PV cell’s series resistance R_series, because the value of 'Rs' must be greater than 0.

This schematic cellview 'sandbox.tb_pvcell:tb_meas_iv' describes a testbench to measure the I-V characteristics of the PV cell model. Basically, it is using the 'probe_dc' primitive to measure the current 'IL' delivered by the PV cell while sweeping the voltage 'VL' across its two terminals.

The testbench view 'sandbox.pvcell:tb_meas_iv' configures the simulation and plotting commands for this testbench as shown below. Basically, it adds a '--sweep' option to repeat the simulation while varying the 'Iph' parameter for the PV cell representing the light-generated current (i.e., the irradiance level), and overrides the simulation and plotting commands using the 'meas_dc' script. A more detailed explanation on the use of '--sweep' option and 'meas_dc' script can be found in this Q&A posting.

Below are the I-V characteristic curves of the PV cell model simulated using the described testbench. The assumed parameters for the PV cell model are I_S=10^-8A, n=20, R_series=0.5Ω, and R_shunt=200Ω, and the plotted I-V curves are for I_ph=1, 3, and 5A.

Using a similar approach, the schematic cellview 'sandbox.tb_pvcell:tb_meas_pv' shown below measures the power-voltage (P-V) characteristics of the PV cell model. The only difference with the 'tb_meas_iv' testbench is that the 'probe_dc' primitive is measuring the power 'PL' computed as a product between 'IL' and 'VL' as a function of 'VL'.

Finally, the simulated P-V characteristic curves of the PV cell assuming the same set of parameter values are shown below. There exists an optimal voltage level that maximizes the power delivered to the output, called the "maximum power point (MPP)". The maximum power point may change depending on the irradiance level, temperature, and so on.

Attachment: pvcell_20221130.tar.gz

Sure. You can model the PV cells using one of the equivalent circuit models known in literature. For example, the model shown below is called a single diode equivalent circuit model, of which detailed description can be found in this link. It is made of a current source producing the light-generated current I_ph, a diode modeling the voltage-dependent current I_D lost due to recombination, and resistors with equivalent shunt and series resistances, R_shunt and R_series, respectively. The I_D-V_D characteristics of the diode is governed by the Shockley’s exponential model: I_D = I_S ·exp(V_D/nV_T) where I_S is the reverse saturation current, V_T is the thermal voltage (=kT/q), and n is the diode’s ideality factor. When this model is describing a set of N_S serially-connected PV cells, the equivalent ideality factor n may increase with N_S.

Writing this equivalent circuit model in XMODEL is straightforward using the circuit primitives. The schematic cellview 'sandbox.pvcell:schematic' shown below describes this PV cell model using the 'isource', 'diode', and 'resistor' primitives. Among them, the 'diode' primitive is selecting the exponential model, which can specify the reverse saturation current and ideality factor directly using the parameters 'Is' and 'N', respectively. Its series resistance parameter 'Rs' is set to 1% of the PV cell’s series resistance R_series, because the value of 'Rs' must be greater than 0.

This schematic cellview 'sandbox.tb_pvcell:tb_meas_iv' describes a testbench to measure the I-V characteristics of the PV cell model. Basically, it is using the 'probe_dc' primitive to measure the current 'IL' delivered by the PV cell while sweeping the voltage 'VL' across its two terminals.

The testbench view 'sandbox.pvcell:tb_meas_iv' configures the simulation and plotting commands for this testbench as shown below. Basically, it adds a '--sweep' option to repeat the simulation while varying the 'Iph' parameter for the PV cell representing the light-generated current (i.e., the irradiance level), and overrides the simulation and plotting commands using the 'meas_dc' script. A more detailed explanation on the use of '--sweep' option and 'meas_dc' script can be found in this Q&A posting.

Below are the I-V characteristic curves of the PV cell model simulated using the described testbench. The assumed parameters for the PV cell model are I_S=10^-8A, n=20, R_series=0.5Ω, and R_shunt=200Ω, and the plotted I-V curves are for I_ph=1, 3, and 5A.

Using a similar approach, the schematic cellview 'sandbox.tb_pvcell:tb_meas_pv' shown below measures the power-voltage (P-V) characteristics of the PV cell model. The only difference with the 'tb_meas_iv' testbench is that the 'probe_dc' primitive is measuring the power 'PL' computed as a product between 'IL' and 'VL' as a function of 'VL'.

Finally, the simulated P-V characteristic curves of the PV cell assuming the same set of parameter values are shown below. There exists an optimal voltage level that maximizes the power delivered to the output, called the "maximum power point (MPP)". The maximum power point may change depending on the irradiance level, temperature, and so on.

Attachment: pvcell_20221130.tar.gz