A novel control strategy for stand-alone solar PV systems with enhanced battery life

Abstract

This paper proposes a novel control scheme for a stand-alone PV application. A two power stage approach has been used that consists of a front end high gain DC-DC converter followed by a 3φ H-bridge inverter. A general reactive load has been considered. The control scheme uses abc to dq reference frame transformation. The active power demand is controlled by regulating the dc link voltage. Reactive power is controlled by varying the inverter output voltage magnitude. Provision for MPPT has been incorporated in the control scheme. As battery is involved due to MPPT and for providing power during the night time, special attention has been given to enhancing the battery life by ensuring that it is neither overcharged nor deep discharged. Yet, a dump load is not required to dissipate excess energy. A bidirectional converter is used to realize the battery interface with the dc link. All the analytical, simulation and experimental results of this work are included.