Vanadium Redox Flow Battery Modelling and PV Self-Consumption Management Strategy Optimization

Abstract

This work aims to maximize the photovoltaic solar electricity’s self-consumption, through the development and validation of an equivalent electric model of a vanadium redox flow battery and its implementation in an energy management strategy. The first phase of the work presents the modelling of the 5.0 kW/60 kWh VRFB integrated in a solar photovoltaic microgrid - 3.5 kWp monocrystalline plus 3.2 kWp polycrystalline technology - at the University of Évora. The model is based in the equivalent electric circuit model built upon the consulted bibliographic references allowing to calculate the battery parameters on the desired power. It considers the auxiliary power consumption and operational parameters and despite its simplicity attains for a good match with experimental results. Upon its validation, the model is further enhanced as to better describe the VRFB real response in its regular operating conditions. Assessment of the enhanced model is based on key performance indicators such as selfconsumption rate, rate of battery usage or electric grid independence. In this work an approach to best fit the battery modelling and simultaneously the energy management strategy for a PV+VRFB system is presented, based on actual operating conditions and on a prescribed EMS goal.