Battery charge and discharge control for energy management in EV and utility integration

Electric drive vehicles (EDVs) have got many benefits as compared to normal petrol or gas cars. Moreover, the electrification of transportation systems would enable increased electricity generation from carbon-free and renewable energy sources, such as wind, solar, and hydro. However, due to highly distributed and mobile nature as well as high charge and discharge power demand of EDVs, it is important to investigate how to manage EDV charge and discharge to enhance the usage of renewable resources in the future smart grid framework. This paper presents an energy control study in a charging station, a typical integrated EDV and utility system. The charging station consists of an ac/dc converter for grid interface and multiple dc/dc converters for EDV battery management. For the grid-side converter, a direct-current control mechanism is employed for reactive power, ac system bus voltage, and dc-link voltage control. For the EDV-side converters, constant-current and constant voltage control mechanisms are developed for charging and discharging control. The paper considers energy management need for charge and discharge of multiple EDVs simultaneously as well as V2G and G2V requirements. A realtime simulation system is developed and the performance of the integrated EDV and utility system is investigated.