Optimal design of dynamic wireless charging electric bus system

Abstract

Dynamic wireless charging (DWC) is an emerging technology that enables the batteries of electric vehicles (EVs) to charge while the vehicles are in motion. The DWC-EV system addresses the challenges inherent in battery technology, such as the short driving range, long recharging time, and high price of EVs. The DWC system enables to reduce a size of the on-board battery and extend a driving range. Also, EVs do not need to spend a lot of recharging time since the charging is done when EVs pass over the wireless charging infrastructure, "power track", embedded along the road. This thesis presents methodologies for the optimal design of a DWC-EV system, specifically focusing on the mass public transit bus system in terms of economics. We obtain the most economic battery size and the optimal allocation of power tracks along a given bus route, minimizing total cost of the system. For this, we first introduce the DWC system and present power dynamics model of the DWC system. The optimal design model is proposed for a single route transportation such as shuttle system. Then we expand the single route design model to multiple routes which represent a mass public transportation system in urban area. Specifically, we proposed a heuristic approach to deal with the large-scale problems for the multiple routes. We consider the driving uncertainty issue for design problem. The robust optimization is presented to find the optimal design of DWC-EV system, which is immune to the uncertainties of energy demand and charge. The robust solution suggests a mathematical basis of safety factors for designing the system

battery size and the allocation of power tracks. At the end, we investigate a battery degradation model to account for a quantitative relation between power track installation and battery life extension. A mathematical formulation is presented to identify the optimal design of the DWC-EV system at minimum long-term cost, which includes the power track installation and battery life costs. This thesis reports various mathematical approach and properties for designing the DWC system with numerical results. The DWC system has been successfully developed and now in the commercialization stage. Hence, the optimal design of the DWC-based transportation system presented in this thesis will prove increasingly important.