Marques, F., Santos, S., Junior, M., Nascimento, T. et al., "Advanced Management System for Lithium-ion Batteries in Hybrid Inverters Optimized for Photovoltaic Systems Connected to the Grid," SAE Technical Paper 2017-36-0047, 2017.
One main feature of the power demand profile is it varies time to time and its price changes accordingly. During the peak the less cost-effective and flexible power supplies must complement the base-load power plants in order to supply the power demand. Conversely, during the off-peak period when less electricity is consumed, those costly power plants can be stopped. This is a scenario which Energy Storage System (ESS) and photovoltaic (PV) generation plants could add flexibility and cost reduction to the customers and utilities. These aspects are only achieved due to the ESS, which enables the optimal use of energy produced by the photovoltaic modules through load management and discharge of the battery in the most convenient times. The battery, which for performance reasons is produced of lithium-ion technology, is an essential component of reliability and availability of PV systems and it is crucial to have a tool to identify its operational parameters, for example, State-of-Health (SoH) and State of Charge (SoC) in order to detect early failures, and allows the adoption of preventive/corrective maintenance and replacement. Therefore, advanced modeling is required and these models are part of the Battery Management System (BMS). The BMS is an embedded electronic system which accurately monitor and control the main parameters of the battery. As the central part of the BMS, advanced physics-based models need be embedded to offer more robust operation of the storage system. All these features allow the system to accomplish with safety and performance necessary for the application. This paper presents the results of the development of an energy management intelligence (BMS), methods for parameters estimation based on advanced modeling of battery and packaging of high-performance lithium-ion cells that were selected from results obtained in laboratory tests. Also it will be presented topologies and configurations of hybrid inverters currently studied in the academy, showing how its features are based on the union of grid-tie inverters and UPS (Uninterruptible Power Supply). The results obtained in the laboratory show the current state of project development. The BESS proposed is useful for PV systems maximizing the usefulness of solar panels and offering a variety of backup electricity supply solutions. The use of this system can extend the battery life, helps in the prediction for exchange of batteries and increase the system reliability.