The Sandia Inverter Model provides a means to predict AC output power ($P_{AC}$) from DC input power ($P{_{DC}}$).

The form of the model is as follows:

$P_{AC}=\left&space;\{&space;\frac{P_{AC0}}{A-B}&space;-C\left&space;(&space;A-B&space;\right&space;)\right&space;\}\left&space;(&space;P_{DC}-B&space;\right&space;)+C\left&space;(&space;P_{DC}-B&space;\right&space;)^{2}$

where

$A=P_{DC0}\left&space;\{&space;1+C_{1}\left&space;(&space;V_{DC}-V_{DC0}&space;\right&space;)&space;\right&space;\}$,

$B=P_{s0}\left&space;\{&space;1+C_{2}\left&space;(&space;V_{DC}-V_{DC0}&space;\right&space;)&space;\right&space;\}$, and

$C=C_{0}\left&space;\{&space;1+C_{3}\left&space;(&space;V_{DC}-V_{DC0}&space;\right&space;)&space;\right&space;\}$

Parameters:

• $V_{DC}$ : DC input voltage (V).  This is typically assumed to be the array’s maximum power voltage.
• $V_{DC0}$ : DC power level (W) at which the AC power rating is achieved at reference operating conditions.
• $P_{AC}$ : AC output power (W)
• $P_{AC0}$ : Maximum AC power rating for inverter at reference conditions (W).  Assumed to be an upper limit.
• $P_{s0}$ : DC power required to start the inversion process (W)
• $C_{0}$ : Parameter defining the curvature of the relationship between AC output power and DC input power
• $C_{1}$ : empirical coefficient allowing $P_{DC0}$ to vary linearly with DC-voltage input, default value
is zero, (1/V)
• $C_{2}$ : empirical coefficient allowing $P_{S0}$ to vary linearly with DC-voltage input, default value
is zero, (1/V)
• $C_{3}$ : empirical coefficient allowing $C_{0}$ to vary linearly with dc-voltage input, default value is
zero, (1/V)