The V-curves of a synchronous motor show relationship between Armature current (Ia) and Excitation current (If). The Inverted V-curves of a synchronous motor show relationship between power factor (pf) and field excitation (If).
For M no. of series configuration of solar cell, Open circuit voltage of PV module= M*Voc = 20*0.7 = 14 V Short circuit current of PV module = M*Isc = 20*4 = 80 A