solve block error this variable is undefined

[ptc-5202952]

Hi everyone my name is jimmy from Mexico im student researcher my major is electromechanical engineer, i have a project for evaluation of PV modules, and one of my objectives is too use data-sheet information with 4 parameters Voc,Isc,Vmp,Imp from the PV module to extract another parameters (a,Iph,Io,Rs,Rp) that not included in the data-sheet. For that im using a five parameter model to solve that problem, im using the solve block (Given,Find) for a nonlinear systems, the method im using is the conjugate gradient. im attaching my file and you will see all the equations that i use, my problems is that when i put the solve command an error display appear saying that some variable is undefined and i check all the file to see what would be the problem and when i use the track error option put me in the first formula the saying that Iph is undefined. i will really appreciated if you can help me because im new on this software

Best regards to the PTC community.

[Werner_E · Accepted solution]

the five equations that i put it is from the model. It supposed works solving with the conjugated gradients method with mathcad solve block (Find,Given).

Nevertheless iot seems that Alan is right and you are missing a fifth equation. Or in other words, there is more you can wish.

Being an underdetermined system would perfectly explain the different results achieved with different methods.

Of course this does not mean that I think that there is mistake in the De Soto model, but maybe it needs some further inverstigation from your side.

[ptc-5202952]

Werner Exinger escribió:

the five equations that i put it is from the model. It supposed works solving with the conjugated gradients method with mathcad solve block (Find,Given).

Nevertheless iot seems that Alan is right and you are missing a fifth equation. Or in other words, there is more you can wish.

Being an underdetermined system would perfectly explain the different results achieved with different methods.

Hi Werner, perhaps youre right but as the way i see, the last equation is the proposed of the model, the author said that the fith equation replaced another one with out using experimental values.

[Werner_E]

Ok, so if you are happy, we should be, too 🙂

Just thought to post some links which may or may not be of interest.

http://www.ijetae.com/files/Volume3Issue3/IJETAE_0313_84.pdf
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=905309
http://services.eng.uts.edu.au/~venkat/pe_html/ch02s1/ch02s1p1.htm
http://jeldev.org/9Tayyan.pdf
http://journals.tubitak.gov.tr/physics/issues/fiz-13-37-1/fiz-37-1-13-1206-4.pdf

[ptc-5202952]

Werner Exinger escribió:

Ok, so if you are happy, we should be, too 🙂

Just thought to post some links which may or may not be of interest.

http://www.ijetae.com/files/Volume3Issue3/IJETAE_0313_84.pdf
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=905309
http://services.eng.uts.edu.au/~venkat/pe_html/ch02s1/ch02s1p1.htm
http://jeldev.org/9Tayyan.pdf
http://journals.tubitak.gov.tr/physics/issues/fiz-13-37-1/fiz-37-1-13-1206-4.pdf

Thx Werner but doesn't work when i click in the link

[Werner_E]

Somehow the links got melted together into one big (and nonworking) link.

Second try:

http://www.ijetae.com/files/Volume3Issue3/IJETAE_0313_84.pdf

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=905309

http://services.eng.uts.edu.au/~venkat/pe_html/ch02s1/ch02s1p1.htm

http://jeldev.org/9Tayyan.pdf

http://journals.tubitak.gov.tr/physics/issues/fiz-13-37-1/fiz-37-1-13-1206-4.pdf

[ptc-5202952]

Werner Exinger escribió:

Somehow the links got melted together into one big (and nonworking) link.

Second try:

http://www.ijetae.com/files/Volume3Issue3/IJETAE_0313_84.pdf

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=905309

http://services.eng.uts.edu.au/~venkat/pe_html/ch02s1/ch02s1p1.htm

http://jeldev.org/9Tayyan.pdf

http://journals.tubitak.gov.tr/physics/issues/fiz-13-37-1/fiz-37-1-13-1206-4.pdf

thanks Werner the last two is the author from the five parameter model and the de fourth one is the reference from the model and the first one give me a hint to modify the last two equations let see if we get a better result 😃

[AlanStevens]

Good set of references Werner. The following statement in the Tayyan paper: "The five reference parameters (a, Io, Iph, Rs, and Rp) can be obtained by simultaneously solving Eq. (7) through Eq.(11) ..." is simply wrong it seems to me!

Alan

[ptc-5202952]

AlanStevens escribió:

Good set of references Werner. The following statement in the Tayyan paper: "The five reference parameters (a, Io, Iph, Rs, and Rp) can be obtained by simultaneously solving Eq. (7) through Eq.(11) ..." is simply wrong it seems to me!

Alan

yes there are a good set of references and the first ones seems to me more understandable then the Tayyan paper, im doing the procedure of that paper i hope this works fine 😃

[VladimirN]

You can find these articles in attachment.