Abstract

Due to their large power draws and increasing adoption rates, electric vehicles (EVs) will become a significant challenge for electric distribution grids. However, with proper charging control strategies, the challenge can be mitigated without the need for expensive grid reinforcements. This article presents and analyzes new distributed charging control methods to coordinate EV charging under nonlinear transformer temperature ratings. Specifically, we assess the tradeoffs between required data communications, computational efficiency, and optimality guarantees for different control strategies based on a convex relaxation of the underlying nonlinear transformer temperature dynamics. Classical distributed control methods, such as those based on dual decomposition and alternating direction method of multipliers (ADMM), are compared against the new augmented Lagrangian-based alternating direction inexact Newton (ALADIN) method and a novel low-information, look-ahead version of packetized energy management (PEM). These algorithms are implemented and analyzed for two case studies on residential and commercial EV fleets with fixed and variable populations. The latter motivates a novel EV hub charging model that captures arrivals and departures. Simulation results validate the new methods and provide insights into key tradeoffs.

Highlights

  • A S RENEWABLE generation is increasingly deployed, powering our transportation system from the electricManuscript received June 24, 2021; accepted September 20, 2021

  • We present a novel modeling framework for an EV charging (EVC) hub that enables the synchronous distributed EVC algorithms to apply to fleets of electric vehicles (EVs) with known, but time-varying arrivals and departures

  • A piecewise linear (PWL) approach is used to formulate the nonlinear problem as a quadratic program (QP), which improves the numerics of the problem significantly

Read more

Summary

INTRODUCTION

A S RENEWABLE generation is increasingly deployed, powering our transportation system from the electric. We compare the privacy offered by the classical algorithms of dual ascent and ADMM and new EVC algorithms, i.e., the augmented Lagrangian-based alternating direction inexact Newton (ALADIN) method [29] and the packetized energy management (PEM) [30]–[33] This comparison is based on protecting valuable customer information, such as personal travel schedules. This article leverages a new distributed optimization method with quadratic convergence, i.e., ALADIN [29], and it proposes the new iteration-free, packet-based coordination scheme [30]–[33] These different methods have hitherto not been developed or analyzed for the EVC problem under dynamic coupling constraints.

PROBLEM FORMULATION
Transformer Dynamics and Constraints
EV Dynamics and Constraints
EV Owner Preferences
EVC Control Objective
Centralized OCP
CONVEXIFICATION OF CENTRALIZED EVC PROBLEM
PWL Approximation
Centralized PWL Problem
NONCENTRALIZED IMPLEMENTATION
ALADIN
Dual Decomposition
PEM With Dynamic Constraints
CASE STUDY 1
Simulation Results
CASE STUDY 2
Hub System Model
Hub Energy Dynamics and Bounds
Objective Function With Hubs
Centralized OCP With Hubs
Noncentralized Hub Formulation
Simulation Setup for Case Study 2
Results
COMPARISON OF DISTRIBUTED METHODS
Selecting a Suitable Distributed Method
VIII. CONCLUSION AND FUTURE WORK
Primal Constraints and Dual Variables
KKT Stationarity Conditions
Proof of Theorem 1

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.