Design and Analysis of a Bidirectional TNPC Converter-Cased Electric Vehicle Charging Station with Photovoltaic Support

Photovoltaic (PV)-powered electric vehicle (EV) charging stations are a sustainable and innovative way to meet mobility demands emphasizing reduced carbon footprint. This paper proposesthe design and analysis of a grid-connected EV charging station with renewable energy integration utilizing a bidirectional T-type NPC (TNPC) converter. The system aims to provide a sustainable charging solution by integrating a 27 kW PV system with a 160 kW TNPC converter, allowing bidirectional power flow for charging and discharging of the EV battery. The system also includes two DC-DC converters and 77 kWh EV battery having a charge power of up to maximum 100 kW. This configuration supports various operating modes, including grid-to-vehicle (G2V) and vehicle-to-grid (V2G), as well as standalone operation with PV support during grid failures. Modeling is conducted at the semiconductor converter level to accurately capture the dynamic behavior and performance of the EV charging station. The system's control strategy employs conventional PI-based control loops to manage power electronic converters, ensuring stable and efficient operation. The dynamic behaviors of four different operating modes, namely off-grid, off-PV, V2G, and PV+grid feeding modes of the EV charging station are analyzed with detailed simulations. The simulation results confirm the EV charging station's ability to function effectively and demonstrate smooth control of the variables. The simulations have confirmed that the charging infrastructure parameters, including voltage, current, power, and SOC, within a specified time frame, comply with the DC Level-1 and DC Level-2 chargingmodes of the SAE J1772 standards in certain operating scenarios.