PVsyst's forum

Welcome on PVsyst's forum.
It is currently Sun Oct 25, 2020 6:36 am

All times are UTC+02:00




Post new topic  Reply to topic  [ 1 post ] 
Author Message
PostPosted: Mon Mar 25, 2013 6:37 pm 
User avatar

Joined: Mon Apr 16, 2012 7:29 pm
Posts: 1680
Rshunt is the inverse of the slope of the I/V curve around Isc.
According to our measurements at sun, it has an exponential behaviour (increases when the irradiance diminishes).
For the crystalline modules that we have measured, this behaviour may be approached with an exponential paramater RshExp = 5.5, and an intercept Rsh(0 W/m²) = 4 times the Rsh(1000 W/m²).

Rserie is one of the 4 unknown parameters when establishing the one-diode model using a reference I/V curve (i.e. imposing that the curve passes through the 3 reference points (0,Isc), (Vmp, Imp), (Voc, 0) at STC). When we avail of a measured I/V curve, Rserie may be determined by minimizing the errors between the measurement and the modelled I/V curve.
NB: Rsmax is the maximun possible value allowing the curve to pass through the 3 reference points, i.e. to solve the equations.

Now for crystalline modules or CIS, the manufacturer's data don't specify an I/V curve, so that PVsyst has to do some hypothesis for proposing default values:
- 1/Rshunt is taken as a given fraction of the (Isc-Imp)/Vmp value,
- Rserie is chosen for getting a fixed value of the Diode Ideality factor Gamma in the equations.

These values have strong influence on the Low-light efficiency.
Therefore when we avail of reliable low-light efficiency data, the Rserie value may be chosen for approaching them at best.


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 1 post ] 

All times are UTC+02:00


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited