Coordinated power sharing in a low voltage direct current microgrid with photovoltaic and hybrid energy storage system for two-wheeler electric vehicle charging

Abstract

The increasing popularity of electric vehicles (EVs), driven by technological advances and a heightened awareness of environmental sustainability, has led to the commercial production of solar-powered battery charging stations. This shift is further supported by the declining costs of photovoltaic (PV) systems. This study presents a solar-powered EV charging station equipped with a 100 V Direct Current (DC) bus, incorporating a PV system and a hybrid energy storage system (HESS). The HESS integrates batteries and supercapacitors to efficiently regulate charging demand changes and stabilize local loads. A unique State of Charge (SoC)-based current-sharing coefficient and voltage error feed-forward loop facilitate accurate DC bus voltage regulation, reducing battery stress by using supercapacitors for transient load management. The proposed system achieves DC bus voltage regulation within 30–45 ms, reducing undershoot and overshoot by 74.3 % and 78.9 %, respectively, compared to conventional methods. Additionally, the voltage ripple is minimized to 0.9 %, representing an 80.0 % improvement. Two two-wheeler EVs are charged using multi-rate constant current charging, which optimizes SoC levels and enhances the State of Health (SoH) of EV batteries. The power management system is meticulously assessed under various operating conditions, reflecting different levels of PV power availability and load demands. The model is simulated using MATLAB/SIMULINK and validated through OPAL-RT OP-4510 real-time simulator, with results confirming the system's efficiency, stability, and reliability.