Parameters missing from ivtools.sdm.fit_desoto_sandia returns statement

[RDaxini]

Is your feature request related to a problem? Please describe.
In addition to the parameters already listed in the returns statement in the docs of pvlib.ivtools.sdm.fit_desoto_sandia, this function also returns a_ref and dEgdT, which are two parameters required for the De Soto module performance model.

Describe the solution you'd like
Add descriptions of a_ref and dEgdT to the returns statement in the docs

Describe alternatives you've considered
Have I missed something here...?

[kandersolar]

@cwhanse I notice a possible sign error: fit_desoto_sandia returns dEgdT=0.0002677 while calcparams_desoto defaults to dEgdT=-0.0002677. Is this a bug?

If so, it may affect the matlab version as well: https://github.com/sandialabs/MATLAB_PV_LIB/blob/master/pvl_desoto_parameter_estimation.m#L276

[cwhanse]

@cwhanse I notice a possible sign error: fit_desoto_sandia returns dEgdT=0.0002677 while calcparams_desoto defaults to dEgdT=-0.0002677. Is this a bug?

Yes it is. New issue or fix here?

If so, it may affect the matlab version as well: https://github.com/sandialabs/MATLAB_PV_LIB/blob/master/pvl_desoto_parameter_estimation.m#L276

Technically, no, since the Matlab function doesn't return dEgdT.

[kandersolar]

Opened #2321 so we can close this one with #2317.