Smart Hybrid Charging Station Example for Electric Vehicles

Abstract

The present study aims to design a smart hybrid station for electrical vehicles using solar energy as a renewable energy source. The designed system consisted of a charging station, photovoltaic module, smart inverter, storage unit, direct current-direct current converter, and micro controller. In the charging process, smart inverter settings were designed for the photovoltaic modules to supply energy primarily in case of insufficient energy from the storage unit when both sources were insufficient or when the batteries in the storage units were overloaded. For current and voltage control, signal width modulation output of microcontroller and direct current-direct current buck type converter were used. The parameters of the converter were calculated and simulated on Matlab/Simulink. The converter circuit was designed by considering the compatibility of the calculated values with the simulation. Electrical vehicle batteries were charged in a controlled manner by choosing a constant current or constant voltage charging method according to the battery charge. The charging process was performed by comparing the current and voltage with the references values using their feedback and adjusting the signal width modulation duty ratio. The charging process continued until the electrical vehicle batteries dropped below the threshold current value. The system was programmed to terminate the charging process when the battery temperature exceeded 55oC. In addition, changes in the system parameters were displayed by using a 2x16 liquid crystal screen.