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Design and implementation of a DC fast charging system for electric vehicles
Author(s)
Zentani, Ahmed Taher Ahmed
Date Issued
2026
Type
doctoral thesis
Publisher
Cape Peninsula University of Technology
Abstract
The increasing penetration of electric vehicles (EVs) in the global transportation landscape has highlighted the importance of developing innovative charging infrastructure systems that meet the demands of modern EVs. Fast DC charging systems are key to reducing charging times and enhancing the user experience, particularly for EVs equipped with high-capacity batteries and extended driving ranges. This thesis presents a comprehensive study on the design and development of an off-board DC fast charging system that leverages renewable energy sources and advanced power electronics technologies to create a more sustainable and efficient charging solution. The integration of a photovoltaic (PV)-tied grid system as a primary supply source reflects a growing trend toward incorporating renewable energy in EV charging infrastructure. This approach not only reduces the load on traditional grid systems but also supports global efforts to minimize carbon emissions and transition to cleaner energy sources. At the core of the proposed system are the interconnection power electronics, consisting of bidirectional AC-DC and DC-DC converters. These converters are essential for managing the bidirectional power flow between the grid, the PV system, and the EV battery. By employing a Proportional Integral (PI) controller, the system can maintain a stable and efficient power transfer process, ensuring that the EV battery is charged quickly while avoiding unnecessary stress on the grid. The DC-DC step-up converter, which interfaces with the PV system, is designed with an advanced control algorithm based on Maximum Power Point Tracking (MPPT). The Perturb and Observe (P&O) MPPT method is chosen for its simplicity and effectiveness in optimizing energy extraction from the PV system, even under fluctuating environmental conditions. This ensures that the system operates at peak efficiency, maximizing the use of renewable energy while maintaining grid stability and power quality. Through rigorous testing and simulation in the MATLAB/Simulink environment, the study provides valuable insights into the performance and reliability of the proposed system under five case scenarios. These simulations not only validate the effectiveness of the control strategies but also offer practical guidelines for optimizing converter design, improvements in charging stability, reduced total harmonic distortion (<3%), efficient power transfer, and minimized current ripple, confirming the robustness of the proposed approach. The outcome of this research contributes to the growing body of knowledge on DC fast charging systems for EVs, offering practical solutions for enhancing charging efficiency, integrating renewable energy sources, and improving grid interaction. The findings also support the development of more robust, scalable, and energy-efficient EV charging infrastructures, addressing the evolving needs of the electric vehicle market.
Additional information
Thesis (DEng (Electrical Engineering))--Cape Peninsula University of Technology, 2026
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Zentani, ATA_217001882 (1).pdf
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