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PV Panel modulation

Hello,

I would like to know if it's possible to configure a matrix of various strings of PV panels in parallel in Solar Module (Physical model)? If I multiply the parameters related to the current, will the program assume that the panels are in parallel?

Thank you.

Gonçalo Simão

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English

PSIM

v2023.1

Accepted answers

NikosDimitrakopoulos

Hello Nikos,

I think it is not correct because the voltage calculated at MPPT continues to be higher for 500 W/m2 than for 1000 W/m2 as you can see below:

For 500 W/m2:

Vmax=39.97V

For 1000 W/m2:

Vmax=36.56V

The IV and PV curves seems also sharper than the ones in the catalogue. What I sould obtain is something like the curves of the image below:

I also don't undestand why I can't change all the values in solar panel utility since they are copied to the block of the PV Panel.

Thank you very much.

Best Regards,

Gonçalo Simão

Hi Gonçalo,

You are right, the max voltage should increase with Light Intensity. Upon examining the datasheet once more I made the observation that this is either a 24V or 12V PV depending on how you connect the cells.

The panel has 66 cells. I believe it has two 33s1p arrays. If you connect them in series (66s1p) you have a 24V panel. If you connect them in parallel (33s2p) you have a 12V that can provide double the current of the 24V case. So it's not a 11s6p connection as initially thought.

The graphs of the datasheet should apply to the 24V case, so 66s1p connection:

That being said, I tried to model this with the utility. Made some key changes:

1. I digitized the datasheet graphs and recalculated the correct dv/di to -0.276

2. I changed the Ideality Factor A to 1.8 as this is a crystalline silicone panel. The PSIM manual suggest :" A good initial guess of the ideality factor A is around 2 for crystalline silicon, and is less than 2 for amorphous silicon. "

These changes gave me some logical results across different levels of Lights Intensity. Please consider that 100% will not be achieved. As both the panel datasheet and the PSIM manual suggest, the given values and calculation techniques respectively are only trying to approximate the panel's behavior.

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That being said, you can use these values to approximate the behavior along a spectrum of different intensities. If accuracy to the datasheet graphs across all intensity is the main interest, I would create different models, each one parameterized for a specific intensity.

BR,

Nikos Dimitrakopoulos

Community-Pasted-Attachment-1727262867567.png

All comments

NikosDimitrakopoulos

Dear Gonçalo Simão,

I believe your question should be answered from the "Solar Module Physical Model" tutorial inside PSIM.

You can find this tutorial by navigating to "Help" >> "Tutorials" >> "Solar Module Physical Model.pdf" pages 7-8.

Another tip when looking for tutorials, examples or materials in general is to navigate to "Help" >> "Index" >> Type the topic of interest in the search bar:

Hope this helps!

Best regards,

Nikos Dimitrakopoulos

Gonçalo Simão

Dear Nikos Dimitrakopoulos,

Thank you for your answer. I have already tried to multiply and divide the parameters as described in the Psim manual, but I continue to have some issues with my simulation.

Starting fot the beginning, I used the datasheet in this link ( https://cdn.solarpowersupply.eu/files/_166 Mono 400W-66 Technical Data Sheet1906X1043X35-compressed-20221227.pdf ), and I obtained the following results for one PV Panel, tested with 500 W/m2:

I put 11 in the parameter of a number of cells but I don't know where I should put the number of cells in parallel of each PV Panel, since the PV Panel of the datasheet have 6 strings of 11 cells in series and Ns is only the number of cells in series and doesn't account for the cells in parallel. I noticed that the PV and IV curves seem little weird.

I also tested the PV Panel for 1000 W/m2 and I obtained the following results:

I noticed that the voltage for the maximum power point is lower for the 1000W/m2 test than for the 500 W/m2, which do not make sense since the voltage of the maximum power point should increase with the increase of the irradiance.

When I tried to multiply the parameters in order to have 4 strings in parallel of 6 PV Panels in series, I obtained the following results:

The calculations that I did are described below and take in account what is said in Psim Manual:

Pmax= 400*24=9600W

Voltage at Pmax=37.62*6=225.72V

Current at Pmx=10.64*4=42.56A

Voc=45.52*6=273.12V

Isc=11.27*4=45.08A

Slope at Voc=-0.6921*1.4=-1.03815 V/A

Rs=0.001576/4=0.000394 Ohm

Isc0=11*4=44A

Is0=(2.24*10^-9)*4=8.96*10^-9

Ct=0.006492*4=0.025968 A/K

It do not make sense for me to manually change the values of Rs, Isc0, Is0 and Ct, since they are calculated with the values above. As it is possible to see the curve do not make any sense, so I also tried to put 66 in the number of cells and I obtained the following results:

It is possible to notice that the results still do not make sense.

Can you help me to emulate the PV Panel in the datasheet in a configuration of 6 PV in series and 4 PV in parallel, please?

Thank you very much.

Best regards,

Gonçalo Simão

1_Parametros multiplicados 11.PNG

2_Parametros multiplicados 11.PNG

NikosDimitrakopoulos

Dear Nikos Dimitrakopoulos,

Thank you for your answer. I have already tried to multiply and divide the parameters as described in the Psim manual, but I continue to have some issues with my simulation.

Starting fot the beginning, I used the datasheet in this link ( https://cdn.solarpowersupply.eu/files/_166 Mono 400W-66 Technical Data Sheet1906X1043X35-compressed-20221227.pdf ), and I obtained the following results for one PV Panel, tested with 500 W/m2:

I put 11 in the parameter of a number of cells but I don't know where I should put the number of cells in parallel of each PV Panel, since the PV Panel of the datasheet have 6 strings of 11 cells in series and Ns is only the number of cells in series and doesn't account for the cells in parallel. I noticed that the PV and IV curves seem little weird.

I also tested the PV Panel for 1000 W/m2 and I obtained the following results:

I noticed that the voltage for the maximum power point is lower for the 1000W/m2 test than for the 500 W/m2, which do not make sense since the voltage of the maximum power point should increase with the increase of the irradiance.

When I tried to multiply the parameters in order to have 4 strings in parallel of 6 PV Panels in series, I obtained the following results:

The calculations that I did are described below and take in account what is said in Psim Manual:

Pmax= 400*24=9600W

Voltage at Pmax=37.62*6=225.72V

Current at Pmx=10.64*4=42.56A

Voc=45.52*6=273.12V

Isc=11.27*4=45.08A

Slope at Voc=-0.6921*1.4=-1.03815 V/A

Rs=0.001576/4=0.000394 Ohm

Isc0=11*4=44A

Is0=(2.24*10^-9)*4=8.96*10^-9

Ct=0.006492*4=0.025968 A/K

It do not make sense for me to manually change the values of Rs, Isc0, Is0 and Ct, since they are calculated with the values above. As it is possible to see the curve do not make any sense, so I also tried to put 66 in the number of cells and I obtained the following results:

It is possible to notice that the results still do not make sense.

Can you help me to emulate the PV Panel in the datasheet in a configuration of 6 PV in series and 4 PV in parallel, please?

Thank you very much.

Best regards,

Gonçalo Simão

Hi Gonçalo,

In my understanding, your solar panel has a 11s6p configuration. In the Solar Panel utility, I would suggest modeling only one 11s cell array as11s(1p). There is no option to add Np (parallel) here.

In the first picture you showed, you have the values of the complete solar panel. 400W correspond to all 11s6p cells - not 11s(1p). One string of 11s cells should have 400/6=66.67W of power. Also, all current related values should be divided by six in the solar panel utility like this:

Data sheet values for 11s6p panel:

Pmax = 400W
Voltage at Pmax = 37.62V
Current at Pmax = 10.64A
Open-circuit voltage = 45.52V
Short-circuit current = 11.27A
dv/di = -0.6921

Values you should input to the Solar panel utility:

Ns = 11
Pmax = 400 / 6
Voltage at Pmax = 37.62V
Current at Pmax = 10.64 / 6
Open-circuit voltage = 45.52V
Short-circuit current = 11.27 / 6
dv/di = -0.6921 * 6
..... the others can stay the same

This will calculate the 11s(1p) string of the solar panel.

Then you can either put 6 of them in the schematic and connect them in parallel or use a similar approach to this:

*For the block you but in the schematic and considering 6 in parallel instead of 2.

-Nikos

Gonçalo Simão

Hi Nikos,

Thank you for your fast answer.

I tried to do what you said and I obtained the following results for 500 W/m2 and 1000 W/m2.

As you can see, the voltage at MPPT continues to be higher for 500 W/m2 than for 1000 W/m2. Do you know why this happens?

I also noticed that the curvature in MPPT seems a little sharp.

Thank you!

Best Regards,

Gonçalo Simão

NikosDimitrakopoulos

Hi Nikos,

Thank you for your fast answer.

I tried to do what you said and I obtained the following results for 500 W/m2 and 1000 W/m2.

As you can see, the voltage at MPPT continues to be higher for 500 W/m2 than for 1000 W/m2. Do you know why this happens?

I also noticed that the curvature in MPPT seems a little sharp.

Thank you!

Best Regards,

Gonçalo Simão

Dear Gonçalo,

Please review my latest response again. What I suggested is the following for the utility:

This results make sense for one 11s(1p) string.

And the multiplying part holds for the block only, not the utility. The values in this block:

BR,

Nikos

Gonçalo Simão

Hello Nikos,

I think it is not correct because the voltage calculated at MPPT continues to be higher for 500 W/m2 than for 1000 W/m2 as you can see below:

For 500 W/m2:

Vmax=39.97V

For 1000 W/m2:

Vmax=36.56V

The IV and PV curves seems also sharper than the ones in the catalogue. What I sould obtain is something like the curves of the image below:

I also don't undestand why I can't change all the values in solar panel utility since they are copied to the block of the PV Panel.

Thank you very much.

Best Regards,

Gonçalo Simão

NikosDimitrakopoulos

Hello Nikos,

I think it is not correct because the voltage calculated at MPPT continues to be higher for 500 W/m2 than for 1000 W/m2 as you can see below:

For 500 W/m2:

Vmax=39.97V

For 1000 W/m2:

Vmax=36.56V

The IV and PV curves seems also sharper than the ones in the catalogue. What I sould obtain is something like the curves of the image below:

I also don't undestand why I can't change all the values in solar panel utility since they are copied to the block of the PV Panel.

Thank you very much.

Best Regards,

Gonçalo Simão

Hi Gonçalo,

The graphs of the datasheet should apply to the 24V case, so 66s1p connection:

That being said, I tried to model this with the utility. Made some key changes:

1. I digitized the datasheet graphs and recalculated the correct dv/di to -0.276

----------------------------------------------------------------

-----------------------------------------------------------------

------------------------------------------------------------------

BR,

Nikos Dimitrakopoulos

Community-Pasted-Attachment-1727262867567.png

Gonçalo Simão

Thank you so much! It worked using that data.

Gonçalo Simão