OPTIMAL OPERATION OF ELECTRIC VEHICLE BATTERIES IN SMART GRIDS CONSIDERING VEHICLE-TO-GRID TECHNOLOGY

Abstract

ABSTRACT: The large-scale deployment of electric vehicles (EVs) is anticipated in the foreseeable future. Heavy intermittent charging and discharging reduce battery capacity and lifetime because of the vehicle-to-grid (V2G) technology employed in smart grids. Thus, modeling battery operation and maintenance is the key to assessing the adoption of EVs. In this study, the V2G application framework and generalized process for determining battery operation were analyzed. An operation and maintenance model was studied under three battery working states (i.e., charging, discharging, and traveling) and one failure state. The battery deteriorated over time and required corrective maintenance. For some given constraints, the long-run average cost was modeled and analyzed by increasing and decreasing geometric process. The analytical expression of the cost rate function was then derived based on the proposed operation and maintenance model. The corresponding optimal operation was also determined numerically or analytically to minimize the long-run average cost. The battery in the proposed operation and maintenance model was replaced with a new and identical battery following the Nth failure. A numerical simulation system was presented to illustrate the optimized operation model and method. Extensive simlulation results show significant performance improvements by using the proposed model and method compared with conventional coordinated charging/discharging in smart grids. It can be applied in battery management system and solve the cost problems caused by EVs. Keywords: Electric vehicle, Battery, Vehicle to grid, , V2G, Average cost rate, Geometric process