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

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.

I. INTRODUCTION

The extreme dependence of mankind on non renewable fossil fuels is leading to the exhaustion of the fossil fuels. At the same time fossil fuels responsible for the deterioration of the environment. All these factors have forced the mankind to look for alternative, environmental friendly sources. Solar Photovoltaic (PV) has emerged as a major contender to serve as an alternative energy source and is currently playing a leading role in supporting the existing conventional power generation systems.