Design And Control of a Photovoltaic-Based Standalone Off-Grid Electric Vehicle Charging Station

Abstract

The use of petroleum for transportation has resulted in significant environmental concerns such as fuel shortages and price surges, air pollution, climate change, etc. Consequently, many governments worldwide are promoting eco-friendly and low-emission alternatives such as electric vehicles (EVs), to reduce the dependence on fossil fuels and limit greenhouse gas (GHG) emissions. However, achieving sustainable transportation requires the integration of renewable energy sources and EVs, and a reliable and efficient charging infrastructure is crucial.

The exclusive reliance of EV charging systems on the grid as the sole power source poses a significant ecological challenge. Off-grid EV charging stations that depend on standalone renewable energy sources such as photovoltaic (PV) panels for power supply are gaining attention. However, uncontrolled charging can have a negative impact on the operation of the utility grid. Therefore, developing an effective and reliable off-grid EV charging infrastructure that can be deployed in remote areas or regions with limited access to the utility grid is necessary.

This study aims to design an efficient off-grid EV charging system powered by solar energy. The system will also achieve Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS) by incorporating snubber circuits in bidirectional DC-DC converters (BDC). The research involves developing an optimal system for charging and discharging the standalone PV-based EV charging station, identifying problems to enhance the efficiency of standalone EV charging station, and exploring control techniques to optimize the performance of the charging station.

The off-grid EV charging system proposed in this work incorporates a BDC with the snubbers, a solar array, a boost converter, and an energy storage unit (ESU). This charging station uses droop and master-slave control techniques to manage the charging of multiple EVs while maintaining stable voltage and frequency levels. The combination of these control techniques simplifies the operation and maintenance of the charging system, resulting in a more cost-effective solution. The results show that the proposed system achieves ZVS and ZCS, improving the efficiency of the charging system while reducing switching losses.

The results of the study are essential for creating a reliable and efficient off-grid EV charging infrastructure, particularly in remote locations or areas with limited grid access. Additionally, the results from this study support the shift towards a more sustainable future by decreasing reliance on fossil fuels and reducing GHG emissions.