Efficiency interpolation

What it is

Selects how the inverter's AC output is read from its efficiency curves at each DC power and voltage.

Typical values and how to get it

Chosen on the Model tab.

Values

Linear in power and voltage = bilinear (default): the output is linear in the DC power along each voltage curve and linear in the voltage between the curves · Parabolic voltage blend = parabolic_voltage_blend: the output follows a parabola in voltage through the three curves; with two curves it is the linear blend · Sandia, no voltage terms = sandia: the output is a straight line from the self-consumption to the AC nameplate, reached at the nameplate divided by the maximum efficiency; no curve and no voltage effect · Sandia, with voltage terms = sandia_voltage: King's Sandia model with its voltage terms: the output is quadratic in the DC power, and its reference DC power, start power and curvature change linearly with the DC voltage; the parameters come from the inverter's Sandia block, else they are fitted from its efficiency curves · Flat efficiency = flat: the output is the DC input above the threshold times the maximum efficiency at every load; the curves are not read · PVWatts inverter (Dobos 2014) = pvwatts: the PVWatts version 5 part-load curve with the maximum efficiency as the nominal efficiency; the curves are not read

References

1. Driesse, Jain & Harrison 2008, Beyond the curves: modeling the electrical efficiency of photovoltaic inverters, IEEE 33rd Photovoltaic Specialists Conference
2. King, Gonzalez, Galbraith & Boyson 2007, Performance Model for Grid-Connected Photovoltaic Inverters, Sandia report SAND2007-5036

API

inverter.efficiency_interpolation