Optimal power dispatch in solar‐assisted uninterruptible power supply systems

Abstract

Many countries in the developing world undergo regular power outages (scheduled and nonscheduled) due to lack of sufficient generation capability or transmission and distribution bottlenecks. Therefore, uninterruptible power supply (UPS) systems are commonly installed to critical power loads during daily power outages. While the integration of solar photovoltaic (PV) with these UPSs has seen rapid growth in recent years, their incorporation in conventional topologies is highly suboptimal. Therefore, in this work, we formulate a mathematical framework for optimal solar PV integration with domestic UPS systems for minimum cost solution incorporating all relevant system constraints and requisite system losses. We also propose and develop a retrofitting technological solution to integrate solar PV with typical UPS systems for optimal system operation. Results show that the proposed methodology and system implementation can achieve cost savings of up to 40.6% compared with conventional UPS system (without solar) in typical scenarios. In addition, with the proposed optimized utilization of PV, the grid utilization is decreased by 75% compared with the conventional case where UPS is integrated with solar using standard maximum power point charge controllers. This work is therefore highly useful for many developing regions with intermittent grids.