v0.6.0.rst

v0.6.0 (___, 2018)

API Changes

• pvsystem.calcparams_desoto now requires arguments for each module model parameter.
• removed irradiance parameter from ModelChain.run_model and ModelChain.prepare_inputs

Enhancements

• Add sea surface albedo in irradiance.py (:issue:`458`)
• Implement :meth:`~pvlib.modelchain.ModelChain.first_solar_spectral_loss` in modelchain.py (:issue:`359`)
• Clarify arguments Egref and dEgdT for :func:`~pvlib.pvsystem.calcparams_desoto` (:issue:`462`)
• Add pvsystem.calcparams_pvsyst to compute values for the single diode equation using the PVsyst v6 model (:issue:'470')
• Extend :func:`~pvlib.pvsystem.singlediode` with an additional keyword argument method in ('lambertw', 'newton', 'brentq'), default is 'lambertw', to select a method to solve the single diode equation for points on the IV curve. Selecting either 'brentq' or 'newton' as the method uses :func:`~pvlib.singlediode_methods.bishop88` with the corresponding method. (:issue:`410`)
• Implement new methods 'brentq' and 'newton' for solving the single diode equation for points on the IV curve. 'brentq' uses a bisection method (Brent, 1973) that may be slow but guarantees a solution. 'newton' uses the Newton-Raphson method and may be faster but is not guaranteed to converge. However, 'newton' should be safe for well-behaved IV curves. (:issue:`408`)
• Implement :func:`~pvlib.singlediode_methods.bishop88` for explicit calculation of arbitrary IV curve points using diode voltage instead of cell voltage. If method is either 'newton' or 'brentq' and ivcurve_pnts in :func:`~pvlib.pvsystem.singlediode` is provided, the IV curve points will be log spaced instead of linear.
• Implement :func:`~pvlib.singlediode_methods.estimate_voc` to estimate open circuit voltage by assuming R_{sh} \to \infty and R_s=0 as an upper bound in bisection method for :func:`~pvlib.pvsystem.singlediode` when method is either 'newton' or 'brentq'.
• Add :func:`~pvlib.pvsystem.max_power_point` method to compute the max power point using the new 'brentq' method.
• Add new module pvlib.singlediode_methods with low-level functions for solving the single diode equation such as: :func:`~pvlib.singlediode_methods.bishop88`, :func:`~pvlib.singlediode_methods.estimate_voc`, :func:`~pvlib.singlediode_methods.bishop88_i_from_v`, :func:`~pvlib.singlediode_methods.bishop88_v_from_i`, and :func:`~pvlib.singlediode_methods.bishop88_mpp`.

Bug fixes

• Unset executable bits of irradiance.py and test_irradiance.py (:issue:`460`)
• Fix failing tests due to column order on Python 3.6+ and Pandas 0.23+ (:issue:`464`)
• ModelChain.prepare_inputs failed to pass solar_position and airmass to Location.get_clearsky. Fixed. (:issue:`481`)
• Add User-Agent specification to TMY3 remote requests to avoid rejection. (:issue:`493`)

Documentation

• Expand testing section with guidelines for functions, PVSystem/Location objects, and ModelChain.
• Updated several incorrect statements in ModelChain documentation regarding implementation status and default values. (:issue:`480`)
• Expanded general contributing and pull request guidelines.

Testing

• Add pytest-mock dependency
• Use pytest-mock to ensure that PVSystem methods call corresponding functions correctly. Removes implicit dependence on precise return values of functions
• Use pytest-mock to ensure that ModelChain DC model is set up correctly.

Contributors

• Will Holmgren
• Yu Cao
• Cliff Hansen
• Mark Mikofski
• Alan Mathew