i need to know the manufacture values for series, shunt resistance, and idealty factor for some solar cells to draw an actual curve for pv like in the data sheet and compare it to another estimated one.
You have to guess these parameters and fit the following equation to the manufacture IV curves
I=IL-I0((qV+IR)/nKT)-V/Rsh
You can tell from different parts of the curves if RS is too large or Rsh is too low. Check the following link for more details:
http://pveducation.org/pvcdrom/solar-cell-operation/series-resistance
i assum any values ?
so that there are alot of combinations of these values achieve these curve ?
You can start with ignoring Rs and Rsh. Ie RS=0 and Rsh=infinity. This simplifies the equation. q and k are constants, T=300K, set n (ideality factor) =1.
Use this website to try out different values.
http://pveducation.org/pvcdrom/solar-cell-operation/iv-curve
Rs and Rsh can be find taking Derivative of Isc at maximum voc
1/dv/dj for Rs and at V=0 , 1/dv/dj for Rsh
There is not something like the Rse in a PV cell. It often depends on the current and thus varies while varying the voltage. However, the parameters you mention are often used and can only be distracted from the diode equation by iterative fitting of the equation to the data. The energy centre of the Netherlands has developed a fitting tool for this. A trial license can be obtained via the following link: https://pvwebtools.ecn.nl . Another option is to build it yourself in e.g. matlab using a Lambert W function, see http://en.wikipedia.org/wiki/Lambert_W_function (2 Feb 2010) .
Dear Dalia,
Your questions are in the focus. I will introduce a simple but accurate method which needs very few calculations and which may be common in the model extraction literature. It is my proposal and i used it on my investigations of the solar cells.
-The first step is to plot Isc versus Voc in a semi logarithmic scale, The rsulting curve will be a straight line, and its slope can be used to determine the ideality factor n.
Delta V=[ nVt log I2 / I1] log10 exp with Delta V = V2-V1.
The reverse saturation current can be determined by extrapolating the straight lone to zero open circuit voltage. That is log I = log I0 at Voc=0.
For more details follow the Link: https://www.researchgate.net/publication/232710923_A._Zekry_and_G._El-Dllal__effect_of_MS_contact_on_the_electrical_behavior_of_solar_cells_Journal_of_solid-state_Electronics_Vol.31_No.1_1988
It is observed that the practical solar cell current remains constant in a relatively large range near the short circuit at V=0. If there is some shoring resistance Rsh it causes the the cell current to decrease slowly from its shortcurcuit value Ish with slope of 1/Rsh. So, one can read directly Ish and determine Rsh from the slope of the I-V characteristics in the vicinity of V=0.
The open circuit voltage can be directly picked up from the measured I-V curve at I=0. The open circuit condition can be practically good realized .Near open circuit the I-V curve of the solar cell. the slope of the slope of the I-V curve is = 1/Rs. That is Rs = delta I/ delta V. Here the range of delta V is really small and one one has to be cautious with the linear part near the opencircuit.
There are other methods to determine the reverse saturation current and the ideality factor. Please see for example the Link:
kdx.xidian.edu.cn/fj/a11.pdf
wish you success.
Article A. Zekry and G. El-Dllal, “ effect of MS contact on the elec...
Thanks A lor Prod , Dr for this great information
Thanks for your cooperation
Dear all,
In order to use datasheet to extract the unknown parameters, we need at least five equations, In the paper below presents a new method based on datasheet to determine the parameters:
Article A new method to extract the equivalent circuit parameters of...
New method for computing single diode model parameters of photovoltaic modules
- May 2018
- Renewable Energy 128:30-36
- DOI: 10.1016/j.renene.2018.05.065
Article A new method to extract the equivalent circuit parameters of...
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