Electric Vehicle Charging Station with Solar-Grid Interactive System for Maximum Power Exchange

This article introduces a solar grid-tie integrated (GTI) Electric Vehicle (EV) charging station with high-frequency-link (HFL) Full-Bridge Photovoltaic Converter (FBPC). Due to its ease of use and low cost, a step-down transformer with rectifier running at line frequency is the most popular method for charging electric three-wheelers (ETW). This conventional charging system cannot regulate output voltage or current which leads the batteries to charge inconsistently, resulting in overcharging, overheating, and most significantly, energy waste and accelerated battery life degeneration over time. On the other hand, the solar-grid interface can ensure maximum power generation and exchange throughout the system. This paper presents the design, development, and performance analysis of a locally developed HF H-bridge DC-DC converter-based solar charging solution with integrated GTI to exchange the power (in/out) from the utility grid. The main functions of the GTI are to synchronize the grid and the FBPC enables batteries to be efficiently charged at predetermined voltage and current levels according to the charging profile dependent on state of charge (SOC). Various operational scenarios were examined through calculations and prototype trials with a photovoltaic (PV) array to confirm the proposed system's performance.