Model step
Inverter efficiency
DC to AC conversion loss
Inputs used: inverter.partload_fractions, inverter.voltage_curve_v, Max. efficiency, Power threshold
What it is
The inverter converts DC to AC with an efficiency that depends on the load and on the DC voltage. This step selects how the efficiency is read: interpolated in the inverter's measured curves, from the linear Sandia law set by its maximum efficiency, from the PVWatts part-load curve set by the same value, or as one flat efficiency.
Options
- Linear in power and voltage: linear in power along each curve, linear in voltage between curves
- Parabolic voltage blend: a parabola through the three curves in voltage
- Sandia, no voltage terms: the Sandia inverter model reduced to a straight line from the self-consumption to the nameplate
- Sandia, with voltage terms: the Sandia inverter model with its voltage terms, from the inverter's Sandia block or fitted from its curves
- Flat efficiency: one efficiency at every load
- PVWatts inverter (Dobos 2014): the PVWatts version 5 part-load curve set by a nominal efficiency
References
- King, Gonzalez, Galbraith & Boyson 2007, Performance Model for Grid-Connected Photovoltaic Inverters, Sandia report SAND2007-5036
- Driesse, Jain & Harrison 2008, Beyond the curves: modeling the electrical efficiency of photovoltaic inverters, IEEE 33rd Photovoltaic Specialists Conference
- Dobos 2014, PVWatts Version 5 Manual, NREL/TP-6A20-62641
API
inverter.efficiency_interpolation = bilinear | parabolic_voltage_blend | sandia | sandia_voltage, inverter.sandia