Control of a bidirectional DC-DC converter for grid-connected electric vehicles

Abstract

Due the increasing concerns about air pollution which contributes for the global warming growth, there is a vast dissemination of Electric Vehicle (EV) worldwide, considering that those vehicles are not polluting gases emitters and are pondered as clean means of transportation. With an increasing projection for those vehicles on next years, and due to the big amount of EV unities spread around the globe, numerous researches have been studying the utilization of those vehicles as a distributed energy storage system that, if connected with the electric grid, can provide many services for the power system. Hence, considering a promising future for EV and that the connection with the grid will be essential, studies concerning the interconnection between the electric network and the vehicles have been proved necessary. Therefore, the main objective of this thesis consists of developing a control technique for a Bidirectional DC-DC Converter (BDC), which is part of a bidirectional interface, that is responsible for connecting an EV battery with the grid. The bidirectional interface works with two operating modes, the Vehicle-to-Grid (V2G) mode - which can provide ancillary services for the utility grid, as the power supply - and the Grid-to-Vehicle (G2V) mode - which the main target is the battery charging process. The system has been validated not only by computational simulations, with Mathlab and Simulink softwares, but also experimentally, by using a realtime interface from dSPACE. The latter is in charge of interconnecting the power structure and the control algorithm developed on the Simulink environment. The experimental validation of the system was succesfully achieved.