change name from mppt -> mpp

* add mpp tests for float, array and series
*

Author: mikofski

pvlib/pvsystem.py

@@ -1821,11 +1821,11 @@ def singlediode(photocurrent, saturation_current, resistance_series,
     return out
 
 
-def mppt(photocurrent, saturation_current, resistance_series, resistance_shunt,
-         nNsVth, method='gold'):
+def mpp(photocurrent, saturation_current, resistance_series, resistance_shunt,
+        nNsVth, method='gold'):
     """
-    Max power point tracker. Given the calculated DeSoto parameters calculates
-    the maximum power point (MPP).
+    Given the calculated DeSoto parameters, calculates the maximum power point
+    (MPP).
 
     :param numeric photocurrent: photo-generated current [A]
     :param numeric saturation_current: diode one reverse saturation current [A]
@@ -1837,13 +1837,13 @@ def mppt(photocurrent, saturation_current, resistance_series, resistance_shunt,
         and ``p_mp``
     """
     if method.lower() == 'fast':
-        mppt_func = singlediode_methods.fast_mppt
+        mpp_fun = singlediode_methods.fast_mpp
     else:
-        mppt_func = singlediode_methods.slow_mppt
+        mpp_fun = singlediode_methods.slow_mpp
     try:
         len(photocurrent)
     except TypeError:
-        i_mp, v_mp, p_mp = mppt_func(
+        i_mp, v_mp, p_mp = mpp_fun(
             photocurrent, saturation_current, resistance_series,
             resistance_shunt, nNsVth
         )
@@ -1852,7 +1852,7 @@ def mppt(photocurrent, saturation_current, resistance_series, resistance_shunt,
         out['v_mp'] = v_mp
         out['p_mp'] = p_mp
     else:
-        vecfun = np.vectorize(mppt_func)
+        vecfun = np.vectorize(mpp_fun)
         ivp = vecfun(photocurrent, saturation_current, resistance_series,
                      resistance_shunt, nNsVth)
         if isinstance(photocurrent, pd.Series):

pvlib/singlediode_methods.py

@@ -171,8 +171,8 @@ def fast_v_from_i(i, photocurrent, saturation_current, resistance_series,
     return bishop88(vd, *args)[1]
 
 
-def slow_mppt(photocurrent, saturation_current, resistance_series,
-              resistance_shunt, nNsVth):
+def slow_mpp(photocurrent, saturation_current, resistance_series,
+             resistance_shunt, nNsVth):
     """
     This is a slow but reliable way to find mpp.
     """
@@ -188,8 +188,8 @@ def slow_mppt(photocurrent, saturation_current, resistance_series,
     return bishop88(vd, *args)
 
 
-def fast_mppt(photocurrent, saturation_current, resistance_series,
-              resistance_shunt, nNsVth):
+def fast_mpp(photocurrent, saturation_current, resistance_series,
+             resistance_shunt, nNsVth):
     """
     This is a possibly faster way to find mpp.
     """
@@ -216,7 +216,7 @@ def slower_way(photocurrent, saturation_current, resistance_series,
     args = (photocurrent, saturation_current, resistance_series,
             resistance_shunt, nNsVth)
     v_oc = slow_v_from_i(0.0, *args)
-    i_mp, v_mp, p_mp = slow_mppt(*args)
+    i_mp, v_mp, p_mp = slow_mpp(*args)
     out = OrderedDict()
     out['i_sc'] = slow_i_from_v(0.0, *args)
     out['v_oc'] = v_oc
@@ -243,7 +243,7 @@ def faster_way(photocurrent, saturation_current, resistance_series,
     args = (photocurrent, saturation_current, resistance_series,
             resistance_shunt, nNsVth)  # collect args
     v_oc = fast_v_from_i(0.0, *args)
-    i_mp, v_mp, p_mp = fast_mppt(*args)
+    i_mp, v_mp, p_mp = fast_mpp(*args)
     out = OrderedDict()
     out['i_sc'] = fast_i_from_v(0.0, *args)
     out['v_oc'] = v_oc

pvlib/test/test_pvsystem.py

@@ -625,6 +625,56 @@ def test_PVSystem_i_from_v():
     assert_allclose(output, 3.0, atol=1e-5)
 
 
+@requires_scipy
+def test_mpp_floats():
+    """test mpp"""
+    IL, I0, Rs, Rsh, nNsVth = (7, 6e-7, .1, 20, .5)
+    out = pvsystem.mpp(IL, I0, Rs, Rsh, nNsVth)
+    expected = {'i_mp': 6.1362673597376753,  # 6.1390251797935704, lambertw
+                'v_mp': 6.2243393757884284,  # 6.221535886625464, lambertw
+                'p_mp': 38.194210547580511}  # 38.194165464983037} lambertw
+    assert isinstance(out, dict)
+    for k, v in out.items():
+        assert np.isclose(v, expected[k])
+    out = pvsystem.mpp(IL, I0, Rs, Rsh, nNsVth, method='fast')
+    for k, v in out.items():
+        assert np.isclose(v, expected[k])
+
+
+@requires_scipy
+def test_mpp_array():
+    """test mpp"""
+    IL, I0, Rs, Rsh, nNsVth = ([7, 7], 6e-7, .1, 20, .5)
+    out = pvsystem.mpp(IL, I0, Rs, Rsh, nNsVth)
+    expected = {'i_mp': [6.1362673597376753] * 2,
+                'v_mp': [6.2243393757884284] * 2,
+                'p_mp': [38.194210547580511] * 2}
+    assert isinstance(out, dict)
+    for k, v in out.items():
+        assert np.allclose(v, expected[k])
+    out = pvsystem.mpp(IL, I0, Rs, Rsh, nNsVth, method='fast')
+    for k, v in out.items():
+        assert np.allclose(v, expected[k])
+
+
+@requires_scipy
+def test_mpp_series():
+    """test mpp"""
+    idx = ['2008-02-17T11:30:00-0800', '2008-02-17T12:30:00-0800']
+    IL, I0, Rs, Rsh, nNsVth = ([7, 7], 6e-7, .1, 20, .5)
+    IL = pd.Series(IL, index=idx)
+    out = pvsystem.mpp(IL, I0, Rs, Rsh, nNsVth)
+    expected = pd.DataFrame({'i_mp': [6.1362673597376753] * 2,
+                             'v_mp': [6.2243393757884284] * 2,
+                             'p_mp': [38.194210547580511] * 2},
+                            index=idx)
+    assert isinstance(out, pd.DataFrame)
+    for k, v in out.items():
+        assert np.allclose(v, expected[k])
+    for k, v in out.items():
+        assert np.allclose(v, expected[k])
+
+
 @requires_scipy
 def test_singlediode_series(cec_module_params):
     times = pd.DatetimeIndex(start='2015-01-01', periods=2, freq='12H')