Design and Optimization of Grid-connected Solar Powered Electric Vehicle Charging Station (Case Study of Adama City)

Abstract

The rapid spread of electric vehicles (EVs) is a major step forward in addressing the ever increasing greenhouse gas emissions around the world. Grid-connected charging of electric vehicles based on renewable energy is recognized as one of the most suitable solutions for minimizing both oil consumption and greenhouse effect. Faster recharging using a public fast charging station (FCS) provides a quick charge for a shorter trip and alleviates the range anxiety for long-distance trips. Such “on-the-go” fast charging will eventually be as easy and convenient as refueling a gasoline vehicle. However, one of the biggest challenges facing EV owners is access to convenient charging infrastructure. This thesis proposes a method to design a grid-connected solar-powered fast charging station for electric vehicles. Taking the recorded minimum sunshine hour of 4.7 h/day, the hybrid system was designed and evaluated using HOMER and MATLAB Simulink software. The optimization process determines the best power generation system for the selected location. This allows electric vehicle loads to be powered despite radiation fluctuations. The selected system includes grid system, solar power, batteries and converters, resulting in a cost of energy (COE) of $0.09839/kWh and a total net present cost (NPC) of $264,737.4. The system has a payback period of 5 years. The charging station rectification stage uses voltage-oriented regulation to correct the power factor and minimize the total harmonic distortion of the system. In this thesis, a 50kW charger is designed for charging batteries with an output voltage of 200 V to 450 V and near to unity power factor.