Optmizer boost current above Isc of the Panel?

[ignacio.sanchis]

I have modeled a simple installation with some shados using optimizers. 

What i can not understand is why the optimizers are boosting current OVER the Isc of the solar Panel. Could someone help me reason this? 

PvSyst 7.1 

 

Thank you very much. 

[André Mermoud]

The optimizer is basicaaly a DC:DC converter, which can increase the current of the source (PV module) by diminishing the voltage.

It may deliver "any" current, independently of the source current.

[ignacio.sanchis]

Sorry for the insistance but i do not undertand:

Quote

 t may deliver "any" current, independently of the source current.

Solar Pales has Isc=10.2A why after appliying a Optimizer the Isc increases to 14A!!!! 

I understand how optimizers work, they lower voltage to increase a modules Current, BUT not over Isc.

Like were does those 4A come from? 

 

Thankyou for your answer! 

[ignacio.sanchis]

I think i was having incorrect results by not using same model equipment. 

 

After simulating with Huawei Inverter-L1 and Huawei optimizers the results are as expected: 

While heavy shadows are applied, current is boosted to Isc BUT NOT OVER IT.

[André Mermoud]

Why not over Isc ???

The optimizer operates at the Maximum power point of the module.  This is completely independent on the Isc.

The optimizer is a DC-DC converter, i.e. an electronic device which is able to transform any voltage signal into another voltage, by keeping the available power, i.e. Iout = Pout / Vout.  The maximum available current is a property of the optimizer.

See the behaviour of the optimizer in the software (open the dialog of the concerned optimizer, and look at the page "Output I/V behaviour").

[ignacio.sanchis]

So if i understand correctly: 

The solar panel while shadowed with optimizers has for example:

-->93.5W of power produced, it can adjuts voltage to boost current right while mantaining Power. 

(A) Iout = Pout / Vout   = 93,5V / 12V = 7,78A   "Upper limmit"

(B) Iout = Pout / Vout   = 93,5V / 42V = 2,22A "Lower limmit"

 

So its just a DC-DC converter, it could set voltage to 1V and current to 93,5A right?

 

Guess upper limit of tension is set by the maximun Un of the solar panel?

Guess the lower limit of tension (highest current posible) is set by the maximun current that the other paneles are producing right?  (probably there is a limit also to not burn cables?) 

 

I think i finally understood it??!! 

 

Thank you André!!

 

 

[André Mermoud]

No, each optimizer has a maximum output current parameter.

You have the following output curve  (this inverter is defined with a max. output current of 15A).

NB: this curbe is part of the Optimizer definition dialog. However sorry, there is a bug in the versions 7.2 and 7.3, the maximum current is not applied correcly. This will be corrected in the next version 7.4.

 

[ignacio.sanchis]

Ahhhh, that current value was the only thing putting me off!! 

I'll wait for 7,4.

Thank you for your time André!!