Roads equipped with a wireless recharging system equipped with a energy storage system These are solutions that show promise for the future of electric mobility. They provide important advantages related to the saving time when recharging and in the reduced pressure on wired charging infrastructure conventional. The integration of this charging system and the management of the corresponding storage system are the subject of a Cornell University study which has been published in the magazine Applied Energy.
The electric vehicle industry has undergone remarkable expansion and technical development over the last decade. By 2030, electric vehicles are estimated to comprise 48%, 42% and 27% of light vehicle sales in China, Europe and the United States, respectively. This is indicated by H. Oliver Gao, Howard Simpson Professor of Engineering and Jie Shi, a former systems postdoctoral researcher at Cornell, co-authors of the study.
The main advantages of inductive and dynamic charging is that it allows reduce the size and the capacity of the traction batteries. This implies a lower vehicle weight and also the use of fewer materials, which makes them more sustainable and economical. On the other hand, it also reduces the pressure on conventional charging infrastructuresince the need to stop at them is reduced and also the waiting times are shorter.
Therefore, the integration of wireless charging on the roads along with a efficient management of the supporting energy storage system are crucial for the successful implementation of these systems. “In this work, we develop a coupled transport and energy system for the incorporation of a road wireless charging system in the electricity market in real time,” explains Gao, director of Cornell’s Systems Engineering Program. “In addition, we propose a control strategy based on Lyapunov optimization to operate the energy storage system cost-effectively.”
The simulation study shows that the efficient storage system control not only reduces the energy costs of the entire road wireless charging system, but also relieves the pressure produced by wireless charging on the existing electrical network. In two numerical examples, energy costs are reduced by 2.61% and 15.34%, respectively.
“We designed a control strategy based on Lyapunov optimization to cost-effectively manage the energy flow between the wireless charging roads and the energy storage system,” adds Gao. “The proposed framework is made up of three main modules: Hybrid Traffic Mapping, Extended DCOPF, and Controller.”
The hybrid traffic mapping calculates traffic flow on specific trips through a road network made up of wireless charging lanes and normal traffic lanes. The optimal power flow of extended direct current (DCOPF) determines the optimal electrical power flows between generation resources, load centers and wireless charging highways in a given electrical network. The control approach seeks to minimize the energy costs of wireless charging highways by efficiently managing the output of the energy storage system.
“Our control strategy is computationally efficient and does not require forecasting of system states, which makes it attractive for practical applications,” Jie concludes.