# pvlib.inverter.fit_sandia¶

pvlib.inverter.fit_sandia(ac_power, dc_power, dc_voltage, dc_voltage_level, p_ac_0, p_nt)[source]

Determine parameters for the Sandia inverter model.

Parameters
• ac_power (array_like) – AC power output at each data point [W].

• dc_power (array_like) – DC power input at each data point [W].

• dc_voltage (array_like) – DC input voltage at each data point [V].

• dc_voltage_level (array_like) – DC input voltage level at each data point. Values must be ‘Vmin’, ‘Vnom’ or ‘Vmax’.

• p_ac_0 (float) – Rated AC power of the inverter [W].

• p_nt (float) – Night tare, i.e., power consumed while inverter is not delivering AC power. [W]

Returns

dict – A set of parameters for the Sandia inverter model 1. See pvlib.inverter.sandia() for a description of keys and values.

Notes

The fitting procedure to estimate parameters is described at 2. A data point is a pair of values (dc_power, ac_power). Typically, inverter performance is measured or described at three DC input voltage levels, denoted ‘Vmin’, ‘Vnom’ and ‘Vmax’ and at each level, inverter efficiency is determined at various output power levels. For example, the CEC inverter test protocol 3 specifies measurement of input DC power that delivers AC output power of 0.1, 0.2, 0.3, 0.5, 0.75 and 1.0 of the inverter’s AC power rating.

References

1

D. King, S. Gonzalez, G. Galbraith, W. Boyson, “Performance Model for Grid-Connected Photovoltaic Inverters”, SAND2007-5036, Sandia National Laboratories.

2

Sandia Inverter Model page, PV Performance Modeling Collaborative https://pvpmc.sandia.gov/modeling-steps/dc-to-ac-conversion/sandia-inverter-model/

3

W. Bower, et al., “Performance Test Protocol for Evaluating Inverters Used in Grid-Connected Photovoltaic Systems”, available at https://www.energy.ca.gov/sites/default/files/2020-06/2004-11-22_Sandia_Test_Protocol_ada.pdf