Optimizing Electric Vehicle Charging Schedules under Unknown Price-based Demand Response

Core Concepts

An end-to-end learning and optimization framework that combines price-based demand response modeling and charging station operation optimization to efficiently schedule electric vehicle charging under unknown customer demand patterns.

Abstract

The paper proposes an end-to-end learning and optimization framework for electric vehicle (EV) charging station operation. The key aspects are:

Modeling the price-based demand response (PBDR) of EV customers as unknown functions of the charging price. Two examples of PBDR models are provided - utility-maximization and piecewise quadratic.

Formulating the charging station operation as a constrained quadratic programming problem, where the objective is to minimize the overall operation cost while satisfying customer charging demands.

Developing an end-to-end framework that jointly learns the PBDR model and optimizes the charging schedules. This is in contrast to the standard two-step approach of first fitting a PBDR model and then using it in the optimization.

Deriving the gradients of the optimization problem with respect to the PBDR model parameters, allowing backpropagation of the optimization objective through the PBDR model during training.

Evaluating the proposed framework on a simulation of a charging station with synthetic PBDR patterns. The results show that the end-to-end approach outperforms the two-step method, especially when the training dataset is small, leading to over 20% reduction in operation costs.

The key innovation is the integration of demand response modeling and charging optimization in an end-to-end differentiable framework, which allows the demand forecasting model to be trained directly on the ultimate optimization objective rather than just prediction accuracy.

Stats

The total electricity demand of the 5 EV customers varies in the range of 5-20 kW.
The charging station has 3 Level-2 charging ports with 6.6 kW maximum power and 2 Level-2 charging ports with 3.6 kW maximum power.
The real-world hourly commercial electricity purchase price data from Anaheim City, California is used in the simulation.

Quotes

"Our formulation makes it possible to backpropagate from the ultimate charging task-based objective to the learning of individual PBDR model."
"Experimentally, our method is evaluated on noisy demand response samples based on varying charging prices. The results demonstrate that our framework can lead to a considerable decrease in the operation costs by more than 20% compared to the standard two-step (predict-then-optimize) method."

Key Insights Distilled From

Learning and Optimization for Price-based Demand Response of Electric Vehicle Charging

by Chengyang Gu... at arxiv.org 04-17-2024

https://arxiv.org/pdf/2404.10311.pdf

Deeper Inquiries

How can the proposed end-to-end framework be extended to handle stochastic EV arrivals and real-time implementation

To extend the proposed end-to-end framework to handle stochastic EV arrivals and real-time implementation, several adjustments and enhancements can be made. Firstly, the framework can incorporate probabilistic models to account for the uncertainty in EV arrival patterns. By utilizing techniques from stochastic optimization, such as scenario-based approaches or robust optimization, the framework can generate charging schedules that are resilient to variations in EV arrival times. Additionally, real-time data streams can be integrated into the model through continuous learning algorithms that update the demand forecasting module in response to new information. This would enable the framework to adapt to changing conditions and make dynamic charging decisions in real-time. By incorporating these elements, the framework can effectively handle stochastic EV arrivals and operate in a real-time implementation setting.

What are the potential challenges in generalizing the PBDR modeling to capture more realistic, noisy customer behavior

Generalizing the Price-Based Demand Response (PBDR) modeling to capture more realistic and noisy customer behavior poses several challenges. One key challenge is the need to account for the diverse and complex nature of customer responses to pricing signals. Real-world customer behavior may exhibit non-linear and unpredictable patterns, requiring more sophisticated modeling techniques. Incorporating machine learning algorithms that can handle noisy data and capture intricate relationships between pricing signals and charging demands is essential. Moreover, ensuring the robustness and generalizability of the model across different customer segments and market conditions is crucial. Validating the model with extensive and diverse datasets that reflect the variability in customer behavior will be necessary to enhance its accuracy and reliability in capturing noisy customer responses.

How can the co-optimization of time-varying pricing assignments and charging schedules for individual customers be incorporated into the framework

Incorporating the co-optimization of time-varying pricing assignments and charging schedules for individual customers into the framework can be achieved through a multi-objective optimization approach. By formulating the problem as a multi-objective optimization task, the framework can simultaneously optimize pricing assignments to incentivize desired customer behavior and charging schedules to minimize operational costs. This involves defining appropriate objective functions that balance the trade-offs between maximizing profits, ensuring demand satisfaction, and promoting efficient charging practices. Additionally, the framework can leverage reinforcement learning techniques to learn optimal pricing strategies and charging schedules through interactions with the environment. By integrating these components, the framework can achieve co-optimization of pricing assignments and charging schedules to enhance overall system efficiency and customer satisfaction.