CACS: controle adaptativo climático do estado de carga para sistemas fotovoltaicos off-grid

Abstract

This dissertation assesses the potential of integrating climatic data into the operation of off-grid photovoltaic (PV) systems, with emphasis on balancing energy supply, system reliability, and battery-bank preservation. A Climatic Adaptive State-of-Charge Control (CACS) strategy is proposed, which dynamically adjusts the lower SOC limit based on a climatic index r(t), thereby aligning energy storage utilization with the anticipated risk of generation shortfalls. A simulation framework was developed to couple PV generation, load demand, and battery aging, using ten years of hourly meteorological data (INMET/BDMEP) for Maria da Fé, Minas Gerais, Brazil. The comparison between control strategies followed a full 2! factorial design combining control approach (conventional vs. CACS), maximum depth of discharge (DoD"#$ = 20% vs. 40%), and system sizing (baseline vs. oversized), totaling eight scenarios. The results show a reduction in mean annual unmet energy from 500.68 kWh/year (C2) to 169.04 kWh/year (C8), with the served energy fraction increasing from 0.850 to 0.951. Mean daily reliability increased from 0.228–0.239 (C1–C2) to 0.730–0.737 (C8–C7). Regarding aging, annual throughput ranged from 66 to 79 kAh/year, and the annual consumed life fraction ranged from 0.132 to 0.140, corresponding to an estimated lifetime of 7.15 to 7.58 years. Overall, the performance of CACS is conditioned by the operating regime, providing an objective basis for design and operational decision-making in off-grid PV systems.