I want to confirm some equations of a new IV curves translation method that I propose.
You can find good IV curve in Green et al. "Solar cell efficiency table (ver.49).
Most of them are cell result, but you can find new module result from Trina and Kaneka in Fig.1.
http://onlinelibrary.wiley.com/doi/10.1002/pip.2855/epdf
Dear Kunta,
Thank you very much, but what I need to know are the pairs (V, I) of the IV curve to do something similar to what appears in the attached article. I will try to work with the article that you attached. Thanks again.
Dear Victor,
Thank you for the reply. For such calculation, you may need details of the module (like cell size and numbers). I think you can find suitable data from the datasheet provided by PV mudule maker which can be found in the website. They often show IV curves at different irradiance and temperature. I have attached one example. It may be interesting to see for different types of PV module (mono Si, multi Si, CIGS, CdTe).
The I(V)-curve for Crystalline Silicon PV-battery is pretty good described by Spice-model with Photo-Current Source and Shunt Diode. But the I(V)-curve for Amorphous Silicon PV-battery is very differ from I(V)-curve for Crystalline Silicon PV-battery. So simplest model with Photo-Current Source and Shunt Diode (classic Spice-model) is not suitable for Amorphous Silicon PV-battery.
Does Your translation method can describe this difference?
Dear Vladimir
I do not use spice-model but I think that your problem is that you must to find the correct ideality factor of the diode (m).
This is the third method I want to develop but now I will refer to the second one.
I attached a file with some graphics done with Labview and I will explain it.
Using the formula for the ideal solar cell you can plot the IV curve of an ideal solar cell (black curve), from it, adding the effects of Rs and Rsh you can get a IV curve look like IV curve of a real solar cell (green curve). In figure 1 an ideality factor of 1 was used and in figure 2 an ideality factor of 2 was used.
For crystalline silicon, the ideality factor of the diode is near to 1 (figure 3: m= 1,16, Sharp NU245: monocrystalline Silicon) and for thin film cells the ideality factor of the diode is near to 2 (figure 4: m= 1,57, Avancis Powermax: CIS). In figure 3 and 4 the black curve is the calculated IV curve and the red curve is the measured IV curve (or real curve)
I developed this method with data of the University of Jaen of Spain but now I need data with more precision for my new method.
Regards
My own opinion that single diode model with two resistors is not suitable for all types of PV-cells. Any manipulation with ideality factor and resistance cann't help. The complex model of Amorphous PV-cell needs two different diodes in parallel connection.
Dear Vladimir
Two-diode model offers better results than one-diode model, but I think it is not worth doing a more complex calculation for a little more of precision.
Of course, you should calculate Rs and Rsh, I can't explain it here because I use my own method and it's a little hard to explain in the answer box, but I think that you can find a way to calculate it.
After that, you can find the value of m keeping in your mind that the value of the maximum power point (MPP) depends almost linearly on the value of m. If you consider that dependency like a linear dependency I think that you can get good results ("Physics is the science of approximations"). I attached a file with a simulation made in labview. All curves have the same value of Rs and Rsh but different value of m (1,00 , 1,25 , 1,50 , 1,75 , 2,00). Figure 2 is a zoom of figure 1. The blue line is a least squares regression.
For example, you can plot an ideal IV curve with m=1 and other with m=2, then add the effects of Rs and Rsh. Your measured IV curve will be between the others two. Because you know the value of the MPP of each IV curve you can find the value of m of your measured IV curve.
Regards
Here is I(v) data for Amorphous Si on glass.
Data Amorphous Si on glass PV-battery I(V) data
Dear Vladimir
In your diodes parameters adjustment, you're adjusting (indirectly) the value of m ("N" in your case). dV is the thermal voltage (mkT/q) for values of m differents from 1 and VT is the thermal voltage when m is equal to 1 (kT/q), then dV/VT = m, but you can't use that equation immediately, you must first eliminate the effects of Rs and Rsh using the Kirchoff's laws in the equivalent circuit for a real solar cell (attached file).
In your data, I can't find the temperature value. Any combination of m and T could get the same results, for example, if you use m=1 and T=300K, dV would be equal to 300.K/q=25.85mV, but if you use m=2 and T=150K, dV would be equal to 300.k/q=25.85mV again, but the value of m is wrong.
Regards
I have data for I-V curve and looking for suitable software to plot curves.
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