Development of an instantaneous real power tracking control scheme for a single-phase grid-tied photovoltaic inverter with minimum DC-Link capacitance

In this paper, an instantaneous maximum power point tracking (MPPT) control is first adopted to achieve fast tracking response for the photovoltaic (PV) power generation system. Then an instantaneous real power tracking control is proposed to overcome the dilemma of the inherent double line frequency ripple without adding an additional circuit so that one can replace the large electrolytic capacitor with small bipolar film-type capacitors to achieve longer lifetime of the single-phase grid-tied inverter. Furthermore, the mathematical model of the PV system is derived and the minimum capacitance for a specified allowable DC-link capacitor voltage swing is obtained. Finally, simulation results are given for verifying the feasibility of the proposed control strategy.