Comparison and Analysis of Algorithms for Coordinated EV Charging to Reduce Power Grid Impact

Electric vehicle (EV) adoption has been increasing rapidly, posing new challenges for integrating EV charging infrastructure with the existing electrical grid. Uncoordinated charging of EVs can cause transformers to overload, leading to instability and unreliability in the grid. This article introduces two smart charging coordinators for EV charging pools designed to manage EV charging while considering transformer power limits. The first strategy aims to minimize operational costs, while the second maximizes the charger flexibility. Both coordinators account for uncertainties in EV arrival time and state of charge, as well as inflexible demands on transformers. The strategies are evaluated and compared using grid-aware and grid-unaware methods regarding transformer power limits. Real-world datasets are utilized to assess the performance of the proposed strategies through simulation studies across three scenarios: single charging station behavior, average parking lot occupancy, and worst-case occupancy scenarios. Comparative analysis against uncoordinated and coordinated strategies from the literature reveals that the flexibility maximization strategy provides the most uniform response, effectively mitigating transformer overload events by optimizing charging power and scheduling flexibility. The study underscores the importance of accurate, innovative charging strategies for seamless EV integration and emphasizes the necessity of coordinated charging pools for reliable EV charging operations.