def calcparams_pvsyst(effective_irradiance, temp_cell,<EOL>alpha_sc, gamma_ref, mu_gamma,<EOL>I_L_ref, I_o_ref,<EOL>R_sh_ref, R_sh_0, R_s,<EOL>cells_in_series,<EOL>R_sh_exp=<NUM_LIT>,<EOL>EgRef=<NUM_LIT>,<EOL>irrad_ref=<NUM_LIT:1000>, temp_ref=<NUM_LIT>):
<EOL>k = <NUM_LIT><EOL>q = <NUM_LIT><EOL>Tref_K = temp_ref + <NUM_LIT><EOL>Tcell_K = temp_cell + <NUM_LIT><EOL>gamma = gamma_ref + mu_gamma * (Tcell_K - Tref_K)<EOL>nNsVth = gamma * k / q * cells_in_series * Tcell_K<EOL>IL = effective_irradiance / irrad_ref *(I_L_ref + alpha_sc * (Tcell_K - Tref_K))<EOL>I0 = I_o_ref * ((Tcell_K / Tref_K) ** <NUM_LIT:3>) *(np.exp((q * EgRef) / (k * gamma) * (<NUM_LIT:1> / Tref_K - <NUM_LIT:1> / Tcell_K)))<EOL>Rsh_tmp =(R_sh_ref - R_sh_0 * np.exp(-R_sh_exp)) / (<NUM_LIT:1.0> - np.exp(-R_sh_exp))<EOL>Rsh_base = np.maximum(<NUM_LIT:0.0>, Rsh_tmp)<EOL>Rsh = Rsh_base + (R_sh_0 - Rsh_base) *np.exp(-R_sh_exp * effective_irradiance / irrad_ref)<EOL>Rs = R_s<EOL>return IL, I0, Rs, Rsh, nNsVth<EOL>
Calculates five parameter values for the single diode equation at
effective irradiance and cell temperature using the PVsyst v6
model described in [1,2,3]. The five values returned by calcparams_pvsyst
can be used by singlediode to calculate an IV curve.

Parameters
----------
effective_irradiance : numeric
    The irradiance (W/m2) that is converted to photocurrent.

temp_cell : numeric
    The average cell temperature of cells within a module in C.

alpha_sc : float
    The short-circuit current temperature coefficient of the
    module in units of A/C.

gamma_ref : float
    The diode ideality factor

mu_gamma : float
    The temperature coefficient for the diode ideality factor, 1/K

I_L_ref : float
    The light-generated current (or photocurrent) at reference conditions,
    in amperes.

I_o_ref : float
    The dark or diode reverse saturation current at reference conditions,
    in amperes.

R_sh_ref : float
    The shunt resistance at reference conditions, in ohms.

R_sh_0 : float
    The shunt resistance at zero irradiance conditions, in ohms.

R_s : float
    The series resistance at reference conditions, in ohms.

cells_in_series : integer
    The number of cells connected in series.

R_sh_exp : float
    The exponent in the equation for shunt resistance, unitless. Defaults
    to 5.5.

EgRef : float
    The energy bandgap at reference temperature in units of eV.
    1.121 eV for crystalline silicon. EgRef must be >0.

irrad_ref : float (optional, default=1000)
    Reference irradiance in W/m^2.

temp_ref : float (optional, default=25)
    Reference cell temperature in C.

Returns
-------
Tuple of the following results:

photocurrent : numeric
    Light-generated current in amperes

saturation_current : numeric
    Diode saturation current in amperes

resistance_series : float
    Series resistance in ohms

resistance_shunt : numeric
    Shunt resistance in ohms

nNsVth : numeric
    The product of the usual diode ideality factor (n, unitless),
    number of cells in series (Ns), and cell thermal voltage at
    specified effective irradiance and cell temperature.

References
----------
[1] K. Sauer, T. Roessler, C. W. Hansen, Modeling the Irradiance and
 Temperature Dependence of Photovoltaic Modules in PVsyst,
 IEEE Journal of Photovoltaics v5(1), January 2015.

[2] A. Mermoud, PV modules modelling, Presentation at the 2nd PV
 Performance Modeling Workshop, Santa Clara, CA, May 2013

[3] A. Mermoud, T. Lejeune, Performance Assessment of a Simulation Model
 for PV modules of any available technology, 25th European Photovoltaic
 Solar Energy Conference, Valencia, Spain, Sept. 2010

See Also
--------
calcparams_desoto
singlediode