Distributed Coordination of Charging Stations Considering Aggregate EV Power Flexibility

TL;DR

This paper introduces a two-stage distributed scheme for EV charging station management that preserves privacy, reduces computational load, and ensures convergence to optimal coordination considering network constraints.

Contribution

It develops a novel two-stage approach that derives an aggregate flexibility region and a distributed coordination mechanism with convergence guarantees.

Findings

Flexibility region accurately represents feasible EV dispatch strategies.

The distributed mechanism converges to the centralized optimal solution.

Case studies validate the effectiveness and advantages of the proposed scheme.

Abstract

In recent years, electric vehicle (EV) charging stations have witnessed a rapid growth. However, effective management of charging stations is challenging due to individual EV owners' privacy concerns, competing interests of different stations, and the coupling distribution network constraints. To cope with this challenge, this paper proposes a two-stage scheme. In the first stage, the aggregate EV power flexibility region is derived by solving an optimization problem. We prove that any trajectory within the obtained region corresponds to at least one feasible EV dispatch strategy. By submitting this flexibility region instead of the detailed EV data to the charging station operator, EV owners' privacy can be preserved and the computational burden can be reduced. In the second stage, a distributed coordination mechanism with a clear physical interpretation is developed with consideration of AC power flow constraints. We prove that the proposed mechanism is guaranteed to converge to the centralized optimum. Case studies validate the theoretical results. Comprehensive performance comparisons are carried out to demonstrate the advantages of the proposed scheme.