Limitation of pan file for BC and HJT module

[Chen]

Hi PVsyst team：

Since the modules of new technologies (IBC / HJT) exhibit a very high Fill Factor. so the main contribution to this increase is the VMPP/  VOC ratio more than 86% , and resulting in lower RS（MAX） and poor low light performance. 

Will your team consider high fill factor module technology in future PVsyst versions？ thanks！

[Luca Antognini]

Dear Chen,

We are currently investigating how to adapt our model to such technologies.

It will take some times, as we want our modification to be backed-up by high quality experimental data and be applicable to the whole of our PV module database. 

We will present an update of our research at the upcoming EU-PVSEC.

 

[Chen]

Okay, thanks.

[Myron]

Hi PVsyst Team,

Has any progress been made with modeling the new technology modules?

[Luca Antognini]

We research the topic (see our abstrac from EUPVSEC) but no new implementation at this stage. For the moment we still propose the following workaround:

 

 

Problem for one diode model parameter determination with High fill factor PV modules:

 

When entering a PV module in the database with a very high Fill Factor (above ~ 82-83%), or equivalently very high Vmp/Voc (above ~86%), PVsyst might not be able to find suitable parameters for the one diode problem and the following messages might appear:

 

 

 or 

 

This comes from the fact that PVsyst needs to find parameters that simultaneously reproduce several constraints and there might not exist a mathematical solution.

This is a known mathematical problem, and more information is available in our dedicated publication : https://www.pvsyst.com/en/company/publications/

 

The solution we propose at the moment is to increase slightly Voc until PVsyst is able to find a solution.

Note well that this does not impact the MPP, therefore the simulation results remain mostly unchanged by this small work around.

 

PVsyst will find the minimum increase of Voc required if you do the following:

1) Go in the Tab "Model Parameters"

2) Check the box to get the default value of Rshunt: A pop-up will appear informing you of the impact on the relative low-light efficiency. Click Yes to close it.

3) Check the box to get the default value of Series resistance. Another pop-ip will appear informing you that in order to find a series resistance suitable with a relative low-light efficiency of -3% (the default value we suggest), PVsyst will need to increase the shunt resistance and possible the Voc value. Again click Yes to accept