학술논문

EV Charging Scheduling Under Demand Charge: A Block Model Predictive Control Approach
Document Type
Periodical
Source
IEEE Transactions on Automation Science and Engineering IEEE Trans. Automat. Sci. Eng. Automation Science and Engineering, IEEE Transactions on. 21(2):2125-2138 Apr, 2024
Subject
Robotics and Control Systems
Power, Energy and Industry Applications
Components, Circuits, Devices and Systems
Electric vehicle charging
Costs
Stochastic processes
Optimization
Predictive control
Real-time systems
Power demand
Demand charge
demand side management
online scheduling
charging of electric vehicles
model predictive control (MPC)
Language
ISSN
1545-5955
1558-3783
Abstract
This paper studies the online scheduling of electric vehicle charging by a service provider subject to a demand charge in a distribution system. Demand charge imposes a penalty on the peak power consumption over each billing period, representing a substantial cost for the service provider with a large number of clients. Because the demand charge is calculated at the end of the billing period, it poses challenges in real-time scheduling when energy demand forecasts are inaccurate, resulting in either overly conservative power consumption or substantial demand charge. We propose a block model predictive control approach that decomposes the demand charge into a sequence of stage costs. Optimality conditions on demand patterns are also presented and analyzed. Numerical simulations demonstrate the efficacy of the proposed approach.Note to Practitioners—This paper addresses a significant practical problem of minimizing the demand charge on the real-time scheduling of deferrable demands. In particular, we consider a setting where a commercial electric vehicle (EV) charging service provider has to manage the online scheduling of a large number of arriving EVs at a charging facility subject to a maximum charging power constraint and a tariff with the demand charge. A major practical challenge is to balance the tradeoff between maximizing profit in scheduling as much EV charging as possible and the need to minimize penalty on the peak charging power. We propose a model predictive control strategy that decomposes the overall demand charge into a sequence of terminal costs. Also addressed is the practical constraint arising from the mismatched EV charging decision period and the power measurement period used to compute the demand charge. Using real data collected at the Adaptive Charging Network (ACN) testbed in simulations, the proposed approach yields 8-12% improvement in operational profit over existing benchmarks, while it has yet been tested in actual charging systems. In the future research, we will address the charging scheduling under demand charge over multiple charging stations.