Is the Pmax of inverters (acc. to temperature) taken in to account ?

[André Mermoud]

I already had contacts with some manufacturers about this subject.

This is not a simple problem as the procedures and specifications are not harmonized between manufacturers.

If a relation between the ambient temperature and the Pmax were specified, it would be possible to take this into account (but not done in PVsyst now). This applies only for inverters installed outdoor.

If the relation is given by respect to the device temperature (or the ambient around the inverter installed indoor) , this depends not only on the short "history" of the PV power, but also on the whole thermal behaviour of the building (ventilation, insulation, cooling mode of the inverter, etc). This is out of the scope of the software.

Therefore in the present time output AC powers above the Pnom value (up to a specified Pmax) are not implemented in PVsyst. This may give a little bonus by respect to the simulation, especially for installations with very under-sized inverters.

By the way, in highly undersized-sized systems the AC power limit is often motivated by a contractual limit with the grid manager (very rarely by the cost of the inverter). In these cases such a strategy of adapting PMax is obviously useless.