Villalva Algorithm Pull Request by JFrederico2022 · Pull Request #2878 · pvlib/pvlib-python

JFrederico2022 · 2026-10-03T02:30:34Z

Closes #xxxx
I am familiar with the contributing guidelines
I attest that all AI-generated material has been vetted for accuracy and is in compliance with the pvlib license
Tests added
Updates entries in docs/sphinx/source/reference for API changes.
Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
Pull request is nearly complete and ready for detailed review.
Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

github-actions · 2026-10-03T02:30:43Z

Hey @JFrederico2022! 🎉

Thanks for opening your first pull request! We appreciate your
contribution. Please ensure you have reviewed and understood the
contributing guidelines.

If AI is used for any portion of this PR, you must vet the content
for technical accuracy.

Finally, be sure the PR description includes the PR
checklist,
and complete the items you are able to.

cwhanse · 2026-10-04T15:35:57Z

@JFrederico2022 pvlib should get only the functions, not the notebook. It has been a while since we discussed that: #2754 (comment) "In pvlib, a calcparams_villalva function would go into pvlib.pvsystem. Code for fitting would go into pvlib.ivtools.sdm in a new module villalva.py"

If you want, you can convert the notebook to a python script and add to the Example Gallery. Just start the script name with "plot_" and use docstrings where you want text to appear.

JFrederico2022 · 2026-10-06T19:03:57Z

Hello, @cwhanse

I updated the docs. Please, let me know if they are all right.

Best regards,
João Frederico

Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

ramaroesilva · 2026-10-07T06:35:21Z

Hi @JFrederico2022, great initiative!

In my opinion, I think it would be nice for your PR to have a corresponding issue which includes a description of what you are adding to pvlib (e.g., what do you see is missing that a PR would add and include sources). That way reviewers and curious people can have a quick outlook of what's happening.

RDaxini · 2026-10-07T06:44:52Z

Hi @JFrederico2022, great initiative!

In my opinion, I think it would be nice for your PR to have a corresponding issue which includes a description of what you are adding to pvlib (e.g., what do you see is missing that a PR would add and include sources). That way reviewers and curious people can have a quick outlook of what's happening.

The issue exists (#2754) but, @JFrederico2022, please tag this in the PR template

echedey-ls · 2026-10-07T09:25:15Z

Remember to list the new functions in https://github.com/pvlib/pvlib-python/blob/main/docs/sphinx/source/reference/pv_modeling/sdm.rst?plain=1

RDaxini

I have suggested a few basic docstring revisions. You can implement changes recommended by reviewers either by committing them individually or, under the Files changed tab, adding the suggestions to a batch and committing them all at once.

Happy to look more in depth at the core implementation in the coming days

Co-authored-by: Echedey Luis <80125792+echedey-ls@users.noreply.github.com>

Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Updated references for M. G. Villalva's work in the documentation.

Added noqa comments to suppress E231 warnings for print statements and labels.

Added fit_villalva function to the list of fitting functions.

markcampanelli · 2026-10-11T20:27:03Z

@JFrederico2022 For the validation plot below, my understanding is that the Villalva model was fit to each temperature and irradiance condition separately. However, as I understand it, the original SDM paper describes using the Isc and Voc temperature coefficients to compute I0 away from STC (in particular, avoiding the need for a band gap parameter value). I am curious what the validation looks like using that extrapolation of the fit at STC, rather than separate "local" fits at different operating conditions. For PVfit, I have used IEC 61853-1 matrix measurements to assess how well a fit using STC conditions extrapolates to a wider set of conditions, and I have attached an example of that. (IIRC, this was a rather good fit, but other fits do not extrapolate so well away from STC.)

More pertinent to this PR, is the SDM using the Isc and Voc temperature coefficients ~~implemented~~ demonstrated here?

cwhanse

@JFrederico2022 any progress towards some unit tests for these new functions?

cwhanse · 2026-10-20T14:12:32Z

+    The finite-:math:`R_{sh}` open-circuit relation is used for the
+    temperature-dependent saturation current so that the operating-condition
+    equations remain consistent with the fitted reference parameters. The
+    fitted :math:`R_s` and :math:`R_{sh}` are held constant with operating
+    condition, following the Villalva modeling assumption used here.


This short paragraph leaves me wanting to see the equations that make up the model.

Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

Co-authored-by: Echedey Luis <80125792+echedey-ls@users.noreply.github.com>

Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Updated mathematical expressions and descriptions in the Villalva SDM parameters calculation for clarity.

Added test for calcparams_villalva to check operating-condition results and NaN propagation.

Add files via upload

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JFrederico2022 added 6 commits October 6, 2026 14:51

Merge branch 'pvlib:main' into main

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Delete pvlib/ivtools/sdm/Villalva.ipynb

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Add files via upload

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Update __init__.py

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Update pvsystem.py

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Add files via upload

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RDaxini added enhancement api labels Oct 6, 2026

cwhanse reviewed Oct 6, 2026

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JFrederico2022 and others added 3 commits October 6, 2026 21:09

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

Update pvlib/ivtools/sdm/villalva.py

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cwhanse added this to the v0.16.2 milestone Oct 7, 2026

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Comment thread pvlib/ivtools/sdm/__init__.py

JFrederico2022 and others added 7 commits October 9, 2026 09:11

Update pvlib/ivtools/sdm/villalva.py

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Update pvlib/ivtools/sdm/villalva.py

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Update pvlib/ivtools/sdm/villalva.py

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Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

JFrederico2022 and others added 10 commits October 9, 2026 09:17

Update pvlib/pvsystem.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update pvlib/ivtools/sdm/__init__.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update pvlib/pvsystem.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Update villalva.py

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Add Villalva parameters to PV modeling documentation

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Revise references in pvsystem.py documentation

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Updated references for M. G. Villalva's work in the documentation.

Suppress E231 warnings in plot_villalva.py

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Added noqa comments to suppress E231 warnings for print statements and labels.

Add fit_villalva function to parameters documentation

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Added fit_villalva function to the list of fitting functions.

Fix return statement indentation in pvsystem.py

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Import fit_villalva function in __init__.py

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JFrederico2022 and others added 9 commits October 21, 2026 14:23

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

Update pvlib/pvsystem.py

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

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Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

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echedey-ls reviewed Oct 22, 2026

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JFrederico2022 and others added 6 commits October 22, 2026 17:07

Update pvlib/ivtools/sdm/villalva.py

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Co-authored-by: Echedey Luis <80125792+echedey-ls@users.noreply.github.com>

Update pvlib/pvsystem.py

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Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Add files via upload

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Refine documentation for Villalva SDM parameters

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Updated mathematical expressions and descriptions in the Villalva SDM parameters calculation for clarity.

Implement test for calcparams_villalva function

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Added test for calcparams_villalva to check operating-condition results and NaN propagation.

Update title for Villalva model example

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