Minimum DC Voltage

This condition arises either at very high temperatures, and/or when a mistake has been made in the design of an array - it represents one of the most common design problems.

At each time step, all points in \(IV_{\text{array,inv}}(t)\) where v is less than the inverter minimum MPPT DC voltage are removed, and an additional I-V point is calculated to correspond to operting exactly at the limit. This new curve is denoted \(IV_{\text{array,VDCmin}}(t)\).

The Effect associated with inverter minimum DC voltage for array at time t is calculated as:

$$\Delta_{inv,VDCmin}\left( t \right) = \left( \frac{MPP(IV_{array,VDCmin}\left( t \right))}{MPP(IV_{array,inv}\left( t \right))} - 1 \right) \bullet 100%$$

To calculate monthly or annual values for this effect over multiple inverters, the individual MPP values should be averaged:

$$\Delta_{inv,VDCmin} = \left( \frac{\sum_{i = 1}^{N_{\text{arrays}}}{\sum_{t}^{}{MPP(IV_{array,VDCmin}\left( t \right))}}}{\sum_{i = 1}^{N_{\text{arrays}}}{\sum_{t}^{}{\text{MPP}\left( IV_{array,inv}\left( t \right) \right)}}} - 1 \right) \bullet 100%$$

Where an annually-representative result is to be calculated, it is important to de-season.