DEVELOPMENT OF DC FAST MOBILE CHARGERS FOR EV APPLICATIONS

Abstract

This thesis unveils the comprehensive development of a DC Mobile Fast Charger (MFC) for EV applications. The focus was on integrating a communications controller and power electronics equipment within the charger for seamless power transfer and communication. The research also addressed the growing demand of a more flexible and accessible charging solution to counteract obstacles such as range anxiety within consumers and lack of infrastructure for charging stations. The MFC was partially designed on the system level, by carefully working on each component and merging them together through electrical and communication links. A robust and versatile power converter and power meter were integrated to facilitate reliable power transfer. Furthermore, various power topologies were also presented to account for different types of MFCs. A totempole converter was used and tested on to present solutions for the two main types of MFCs. Its DC-DC stage could be used in a battery-backed MFC and the AC-DC stage in a grid-connected MFC. Although this exact converter was not used in charging session testing, its knowledge was still utilized to select an off-the-shelf industrial converter to integrate. A core contribution of this work was the development of a complete Supply Equipment Charging Controller (SECC) using programming concepts such as Linux and C++. The missing links such as communication with the power converter were developed through the implementation of software drivers. These drivers ensured proper communication between on-board components and Electric Vehicle Supply Equipment (EVSE) to EV. For practical implementation, these SECC drivers were fully integrated with the industrial converter, enabling complete digital communication and embedded energy management. Both the industrial power electronics hardware and SECC controller were experimentally tested through an EV emulator load. Performance metrics for communication and electrical were both tested to ensure the MFC could function in various operating conditions. Communication response time, power transfer efficiency, and charging times were all tested, validating the power electronics-SECC link in the EVSE. This research provides a regulatory and portable MFC prototype that allows for more EV charging flexibility while addressing obstacles such as lack of infrastructure and consumer range anxiety. Future work will focus on re fining the prototype by exploring new semi-conductor technology for higher efficiency, a smarter hardware-software integration for quicker communication through artificial intelligence, and allowing more thermal and bidirectional operation for even higher power applications.