Connecting PXIe 4139 with solar PV

[Marzia]

We are trying to connect a PXIe4139 SMU with solar PV module with 270W using DC voltage pulse. We are having some queries in that regard.

1. To work with the remote sense do we need to connect both output HI, output LO and sense HI, sense LO with the PV terminal or we only need to connect sense HI and sense LO terminal? 
2. If we connect output HI, output LO and sense HI, sense LO all four with the PV panel, it shows the OLP (over load protection error). Why?
3. If we connect only sense HI and sense LO terminal with PV, the voltage reading it gives small single value of around 0.89V.What could be wrong? Is it because we did not connect the output HI and output LO with the PV or the DC pulse is just allowing to take a single measurement?
4. What would be the correct DC pulse source delay, aperture time, pulse on time, pulse off time and bias delay?
5. If we want to see the transient response of the DC pulse sweep using built in digitizer of the SMU, may I know how to do that?

Any feedback will be very helpful.

[santo_13]

Hi Marzia,

I would like to understand your test requirements better to guide you.

1. To use remote sense, all four wires need to be connected.
   
2. OLP occurs when there is a high inrush of current into the instrument, in this case, your PV is dumping into SMU and hence SMU protected itself.
3. It is not recommended to use only sense lines (NI SMU does not support such a mode)
4. Need test requirements to provide suggestions
5. You could try the example that comes with LabVIEW (combine below two example to get a pulse response)
   

[Marzia]

Hello.

Many thanks for your reply. The test requirement is to trace the I-V Sweep (every 1 minutes( for 2 solar panels (will be connected via mechanical switch) with a capacity of 270Wp each. However we have another test site which consists of 8 modules with 350Wp each and possibly will be connected via multiplexer.

To be noted, now we are only trying with a single module of 270Wp which could have maximum current of about 8A. But this OLP error occur even before we run any code to trace the I-V.

If I am not wrong, I believe as the SMU is in active mode so it is causing the in rush current from the PV to take it to the OLP mode even before the code is run. But I am concern about one thing is we are testing in a place where the climatic condition is such that the current was not probably even 3A. So I am afraid what might be causing this. 

I would request one more thing. There is a example which is called High Power LED pulsing with SMU. I tried to find the example but no where I could get it. That is recommended as suggested example for high power pulsing. Any idea on this?

[santo_13]

In your scenario, the possible cause would be, the output is connected and may be disabled. When the Output is disabled the SMU output is effectively 0V and current limit at 2% of the current range configured which may not be 3A.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019OQ0SAM&l=en-IN

From the overall circuit perspective, you've connected a short circuit (SMU) limited to 2% of 100mA and the SMU couldn't maintain 0V anymore since there is high current draining into the SMU from the Solar Panel.

A good option would be to source 0A from the SMU to match the voltage levels and use advanced sequencing to switch to Pulse current/voltage. I don't know if the intention of pulse mode is to test power sources (like battery or PV) but rather devices like LED/high power MOSFET/IGBT.