Calculates the parameters that are not available in the datasheet of photovoltaic modules. In order to do so, equations derived from the diode model are used. Due to the complexity of the equations, numerical method is used to get the parameters.

Also calculates the values for I-V curve and P-V curve based on single diode model. Can draw I-V curve and P-V curve graphs as well.

• numpy

• scipy

• matplotlib

Automatically installed when this package is installed.

Use pip3:

pip3 install photovoltaic-modeling-python

• Python 3.5 and 3.6.

It's not tested on Python 2.6 or 2.7 yet.

• Unit of temperature voltage coefficient: [V/ºC] not [%/ºC].

  Different datasheets use different unit (either one of these units). If it's given in [%/ºC] in datasheet, make sure to convert it to [V/ºC].

• Unit of temperature current coefficient: [A/ºC] not [%/ºC].

  Different datasheets use different unit (either one of these units). If it's given in [%/ºC] in datasheet, make sure to convert it to [A/ºC].

• Definition of thermal voltage:

      Vt = (AkT) / q
  
      where, Vt: Thermal voltage, A: Diode quality factor, k: Boltzmann constant, T: Temperature at Standard Test Condition (STC),  q: charge of electron
  

  This is the definition from reference [1]

  Some literatures use

      Vt = (nkT) / q
  
      where, n: number of cells in series
  

  For example, reference [2]

  But this project uses the first definition above and all the equations are adjusted accordingly.

1. Parameter Extraction

   Example:

   from photovoltaic_modeling.parameter.parameter_extraction import ParameterExtraction
   
   short_circuit_current = 3.87 
   open_circuit_voltage = 42.1 
   maximum_power_point_current = 3.56 
   maximum_power_point_voltage = 33.7 
   number_of_cells_in_series = 72
   
   parameter_extraction = ParameterExtraction(short_circuit_current, open_circuit_voltage, 
                                              maximum_power_point_current, maximum_power_point_voltage, 
                                              number_of_cells_in_series = number_of_cells_in_series)
   
   series_resistance_estimate = 1
   shunt_resistance_estimate = 1000
   diode_quality_factor_estimate = 1
   
   parameter_estimates = [series_resistance_estimate, shunt_resistance_estimate, diode_quality_factor_estimate]
   parameter_extraction.calculate(parameter_estimates)
   
   print('series_resistance=', parameter_extraction.series_resistance)
   print('shunt_resistance=', parameter_extraction.shunt_resistance)
   print('diode_quality_factor=', parameter_extraction.diode_quality_factor)
   

2. Single diode model

   Note: Use series_resistance, shunt_resistance, and diode_quality_factor obtained by "1. Parameter Extraction" above.

   Example:

   from photovoltaic_modeling.diode_model.single_diode_model import SingleDiodeModel
   import matplotlib.pyplot as pyplot
   import photovoltaic_modeling.diode_model.report_helper as report_helper
   
   short_circuit_current = 5.75
   open_circuit_voltage = 22.5
   temperature_current_coefficient = 0.04
   series_resistance = 0.115820201147
   shunt_resistance = 37173.5612907
   diode_quality_factor = 1.27873896365
   
   number_of_series_connected_cells = 36
   
   number_of_voltage_decimal_digits = 1
   
   single_diode_model = SingleDiodeModel(short_circuit_current, 
                                         open_circuit_voltage, 
                                         number_of_series_connected_cells, 
                                         number_of_voltage_decimal_digits = number_of_voltage_decimal_digits,
                                         temperature_current_coefficient = temperature_current_coefficient, 
                                         series_resistance = series_resistance, 
                                         shunt_resistance = shunt_resistance, 
                                         diode_quality_factor = diode_quality_factor)
   
   operating_temperature = 35 + 273
   actual_irradiance = 1000
   
   single_diode_model.calculate(operating_temperature, 
                                actual_irradiance)
   
   voltages = single_diode_model.voltages
   currents = single_diode_model.currents
   powers = single_diode_model.powers
   
   report_helper.write_result_to_csv_file(single_diode_model, 'single_diode_model_rng-100d_one_module_no_shading')
   report_helper.plot_result(single_diode_model)
   

1. Parameter Extraction:

   Example:

   $ photovoltaic_modeling parameter_extraction --short_circuit_current 3.87 --open_circuit_voltage 42.1 --maximum_power_point_current 3.56 --maximum_power_point_voltage 33.7 --number_of_cells_in_series 72
   

Bug reports and pull requests are welcome on GitHub at https://github.com/tadatoshi/photovoltaic_modeling_python. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The project is available as open source under the terms of the MIT License.

[1] D. Sera, R. Teodorescu, and P. Rodriguez, "PV panel model based on datasheet values," in Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on, 2007, pp. 2392-2396.

[2] M. G. Villalva and J. R. Gazoli, ”Comprehensive approach to modeling and simulation of photovoltaic arrays,” Power Electronics, IEEE Trans- actions on, vol. 24, pp. 1198-1208, 2009.

[3] A. Bellini, S. Bifaretti, V. Iacovone, and C. Cornaro, ”Simplified model of a photovoltaic module,” in Applied Electronics, 2009. AE 2009, 2009, pp. 47-51.