Electric Vehicles Charging Management and Control Strategies F. J. Soares, D. Rua, C. Gouveia, J. A. Peças Lopes INESC TEC – INESC Technology and Science fsoares@inesctec.pt, cstg@inesctec.pt, drua@inesctec.pt, jpl@fe.up.pt Abstract—This paper presents a holistic framework for electric vehicles integration in electric power systems together with their charging management and control methodologies that allow minimizing the negative impacts in the grid of the charging process and maximize the benefits that charging controllability may bring to their owners, energy retailers and system operators. The performance of these management and control methods will be assessed through steady state computational simulations and then validated in a microgrid laboratory environment. Keywords—Communications; Electric Vehicles; Management and Control Strategies; Microgrids; Smart Grid Laboratory. I. INTRODUCTION The global warming is one of the environmental reasons leveraging the large scale adoption of Electric Vehicles (EV). According to the OECD, the transportation sector accounts for more than 50% of the world’s oil consumption and is responsible for ca. 20% of the world’s CO 2 emissions, being naturally one of the principal targets of countries’ policies to mitigate the climate change problematic. While the integration of moderate quantities of EV into the electric power system does not provoke any considerable impacts, their broad adoption would most likely create technical problems in what concerns the grid operation and management. To overcome them, two paths can be followed: reinforce the existing infrastructures and plan new networks in such way that they can fully handle the EV integration; or develop and implement enhanced charging management strategies capable of controlling EV charging according to the grids’ capabilities. While the former is a rather expensive solution that will require high investments in network infrastructures, the latter yields more benefits from the grid perspective once it provides elasticity to the EV loads. Given this context, and considering the expected growth in EV integration levels, detailed studies about the impacts of integrating EV in power systems should be performed to evaluate the best approaches to follow in the future. These studies will require the development of comprehensive and standardized EV models and simulation tools that can be used in a wide variety of scenarios, including different EV types and power systems with distinct characteristics. This paper addresses this topic by presenting a holistic EV integration framework and EV management and control methodologies. The effectiveness of these methodologies was assessed through steady state computational simulations and validated in a microgrid laboratory. II. ELECTRIC VEHICLE INTEGRATION ARCHITECTURE The technical management of an electric power system, having a large scale deployment of EV will require, for their battery charging, a combination of a centralized hierarchical management and control structure with a local control located at the EV grid interface based on the microgrid concept [1] [2]. The simple use of a smart device interfacing the EV with the grid does not solve all the problems arising from EV integration in distribution networks. These interfaces can be rather effective when dealing with the occurrence of voltage drops that may be caused by EV charging, by locally decreasing charging rates through a voltage droop control approach. However, this local solution fails to address issues that require a higher control level, such as managing branches’ congestion levels or enabling EV to participate in the electricity markets. For these cases, coordinated control is required and a hierarchical management and control structure responsible for the entire grid operation, including EV management, must be available. Therefore, the efficient operation of such a system depends on the combination and coordination of local and centralized control modes. The latter control approach relies on the creation of an adequate communications infrastructure [3] capable of handling all the information that needs to be exchanged between EV and the central control entities organized in a hierarchical structure. A. Normal System Operation When operating the grid in normal conditions, EV will be managed and controlled by a new (central) entity – the aggregator – whose main functionality will be grouping EV, according to the willingness of their owners, to exploit business opportunities in the electricity markets [4]. If EV would enter this market individually their visibility would be small and rather unreliable due to their stochastic behaviour. Nonetheless, if an aggregating entity exists, with the purpose of grouping EV to enter in the market negotiations, then the provided services would be more significant and the confidence on its availability much more accurate. It is important to stress that the aggregator should always take into account the drivers requests, which will provide information about power demand and connection period via the smart meters (SM). In the same regional area, several aggregators might co-exist and compete to gather as much clients as possible. This competition will be