In October 2020, research paper of Chengzhang Wang entitled “Hybrid of fixed and mobile charging systems for electric vehicles: system design and analysis” is accepted by ISTTT 24 (The 24th International Symposium on Transportation and Traffic Theory). ISTTT is recognized as the highest-level international conference in the field of transportation. The conference is held every 2-3 years, and only no more than 36 papers are accepted and invited to deliver academic reports.  

Charging facilities are required to support the fast popularization of electric vehicles. In addition to widespread fixed charging piles, a new charging service that allows mobile chargers to charge electric vehicles has recently been proposed and studied. This study aims to quantitatively analyze and design a charging system with both fixed and mobile charging services. We first develop an equilibrium model in a homogeneous plane to capture customer behaviors, to examine the existence and uniqueness of the equilibrium state, and to propose a convergent algorithm to solve the model. Then, we establish a model to formulate the optimal design of service providers on a homogeneous plane as a mixed-integer program (MIP) problem and further extend the model that enables it to solve the case with a heterogeneous plane. Numerical tests of the equilibrium model show that the algorithm can quickly converge to the equilibrium solution, and some managerial insights for the hybrid charging system design are identified from the numerical tests of the optimal design model.