Adaptive bidirectional droop control for electric vehicles parking with vehicle-to-grid service in microgrid

Abstract

With the popularity of electric vehicles (EVs), a large number of EVs will become a burden to the future grid with arbitrary charging management. It is of vital significance to the control of the EVs charging and discharging state appropriately to enable the EVs to become friendly to the grid. Therefore, considering the potential for EVs seen as energy storage devices, this paper proposes a multiport DC-DC solid state transformer topology for bidirectional photovoltaic/battery-assisted EV parking lot with vehicle-to-grid service (V2G-PVBP). Relying on the energy storage function of EVs, V2G-PVBP is able to not only satisfy the normal requirements of EVs' owner, but also provide the function of load shifting and load regulation to the microgrid. In this paper, EVs are categorized into limited EV and freedom EV. Limited EVs are always kept in charging state and freedom EVs can take part in the load regulation of the microgrid. The proposed adaptive bidirectional droop control is designed for freedom EVs to make them autonomously charge or discharge with certain power which according to each EV's state of charge, battery capacity, leaving time, and other factors to maintain the stability of the future microgrid. Eventually, the simulation and experiment of the adaptive bidirectional droop control based V2G-PVBP are provided to prove the availability of V2G-PVBP.