Looking for some technical insight regarding Voc and Isc of panels

[Deee]

Pretty much as the topic suggests. Having seen many a graph regarding open circuit voltage and short circuit voltage on panel data sheets I am keen to fully understand exactly what this means. Thanks

 

[yellowvanman]

You've seen the graph but the only points you can test at on that graph is Isc (where V = 0) and Voc (where I=0), all points in between you can't get access to - only the inverter and that is trying to keep to the 'knee' of the curve where you get max power.

 

[Stevesolargill]

I believe the graph you are referring to is the IV Curve. This shows the relationship between the open circuit voltage (voc) and short circuit current (isc). The point at the top of the the arc is known as the maximum power point (mpp).

Hope this helps

 

[Deee]

Yes the IV curve. I've been looking a little more into it and started getting an idea now. I see there are standard test conditions for all panels with set amounts off irradiance, module temp, angle etc.
I am not an electrician but an engineer so I am okay with electrical principles but always looking to learn a little more. Yes so the knee of the curve is where we want the panel to be performing and is where the manufacturers get their power figures from then?
Interesting point about the inverter, yellowvanman, so the inverter has the ability to modulate in order to try and optimise the IV curve towards the MPP point?

Apologies if this seems dumb! Its a learning curve. Thanks for the replies guys.

 

[yellowvanman]

Interesting point about the inverter, yellowvanman, so the inverter has the ability to modulate in order to try and optimise the IV curve towards the MPP point?

I guess so.

Not only that, on the ac side it varies its terminal voltage to ensure it kicks out the power it needs to and can overcome voltage drop of supply cables etc.

No such thing as a dumb question, we're all here to learn off each other!

 

[Deee]

So common sense is telling me then that the inverter must regulate the voltage in order keep the current from dropping off, quite steeply from the graphs I have seen!