Power sharing in Multi-MPPT setting

[Asim]

Dear PVsyst Team,
I am writing to inquire about the Multi-MPPT feature in PVsyst and its practical implications for string inverters.
I understand that this feature allows for the simulation of different power setpoints for each MPPT input based on sub-array power. However, in practice, most string inverters do not have the capability to independently adjust power setpoints for individual MPPTs.
Given this discrepancy, I would like to understand how the simulation results obtained through the Multi-MPPT feature in PVsyst translate to real-world scenarios with string inverters.
Specifically, I am interested in knowing:

1. How does PVsyst account for the limitations of string inverters when simulating different MPPT setpoints?
In what ways can the simulation results obtained through this feature be applied to optimize system design and performance, considering the practical constraints of string inverters?
2. Are there any specific recommendations or best practices for using the Multi-MPPT feature in PVsyst when working with string inverters?
3. Any insights or clarification you could provide on this matter would be greatly appreciated.
Thank you for your time and attention.

Sincerely,
Asim Aslam

[André Mermoud]

The "Powr setpoints" that you mention here is indeed the limit nominal power for this MPPT input. This is not fixed in the inverter. This is the result of the "Power sharing" calculation by PVsyst, for ensuring that the PNom of the whole inverter is the sum pf the PNom of each MPPT input  (according to their own number of PV modules). 

Answers to your questions:

1.  During the simulation, each MPPT input is supposed to have a PNom corresponding to the value listed here. In the real system the limitation will be the Pnom for the whole inverter.

2.  If you have MPPTs with, for example, 1 and 2 strings, you should always make sure that the Power sharing is activated. If all MPPT inputs of an inverter are within a same subarray, you should uncheck the option "Use Multi-MPPT feature". If the inverter inputs are distributed on several subarrays, you should use this tool for Power sharing.