Design of a charger/discharger for hybrid energy storage stations, intended for electric vessels used in river transportation

Abstract

Electric motor-powered river vessels are increasingly common in areas that prioritize sustainability and environmental protection. The use of electric motors enhances energy efficiency, reduces emissions, noise levels, operational costs, and maintenance frequency. These motors are powered by batteries previously charged at a charging station, which can be equipped with battery banks composed of new batteries, second-life batteries (SLBs), or hybrid systems integrating both types of batteries. The use of SLBs, which still retain a significant portion of their capacity after their first life, optimizes resources, reduces costs and waste, and extends their service life. Due to the heterogeneous degradation of cells in SLBs and the progressive reduction of capacity with each charge/discharge cycle, it is necessary to implement a specific control and monitoring strategy for these cycles to optimize their lifespan. This work describes the design of the power and control systems for a battery charger/discharger based on a Boost converter. The system employs a current controller that combines sliding-mode current control with a proportional-integral controller to ensure overall stability and limit current derivatives, thereby preventing accelerated battery degradation. This modular plug-and-play device enables the optimal connection and charging of both new and second-life batteries. Simulation results confirmed the validity of the proposed designs by meeting the established requirements in charge, discharge, and standby scenarios