Mobility-Aware Electric Vehicle Fast Charging Load Models With Geographical Price Variations

Abstract

We study the traffic patterns as well as the charging patterns of a population of cost-minimizing EV owners traveling and charging within a transportation network equipped with fast charging stations (FCSs). Specifically, we study how the charging network operator (CNO) can influence where EV users charge in order to optimize the utilization of FCSs. These charging decisions of private EV owners affect aggregate congestion at stations (i.e., waiting time) as well as the aggregate EV charging load across the network. In this work, we capture the resulting equilibrium wait times and electricity load through a so-called traffic and charge assignment problem (TCAP) in an FCS network. Our formulation allows us to: 1) study the expected station wait times as well as the probability distribution of aggregate charging load of EVs in an FCS network in a mobility-aware fashion (an aspect unique to our work) while accounting for heterogeneities in users' travel patterns, energy demands, and geographically variant electricity prices; 2) analytically characterize the special threshold-based structure that determines how EV owners choose where to charge their vehicle at equilibrium, in response to the FCS's charging price structure, users' energy demands, and users' mobility patterns; and 3) provide a convex optimization problem formulation to identify the network's unique equilibrium. Furthermore, we illustrate how to induce a socially optimal charging behavior by deriving the socially optimal plug-in fees and electricity prices at the charging stations.