Thevenin's equivalent of photovoltaic source models for MPPT and power grid studies

The model of a photovoltaic (PV) source is needed for Maximum Power Point Tracking (MPPT) and power grid studies. The single diode model can fairly emulate PV's characteristic. The only nonlinear element in this model is the single diode. This paper proposes Thevenin's equivalent model for a PV source by piecewise linearization of the diode characteristic. The variation of the parameters with the change in temperature and irradiance is also studied. It is shown that Thevenin's equivalent model of PV produces a voltage-current characteristic which represents the PV source operation fairly well.