Abstract

There is a growing interest in using the flexibility of electric vehicles (EVs) to provide power system services, such as fast frequency regulation. Decentralized control is advocated due to its reliability and much lower communication requirements. A commonly used linear droop characteristic results in low average efficiencies, whereas controllers with 3 modes (idle, fully charging, fully discharging) result in large reserve errors when the aggregation size is small. To address these issues, we propose a stochastic, decentralized controller with tunable response granularity which minimizes switching actions. The EV fleet operator can optimize the chargers’ performance according to the fleet size, the service error requirements, the average switching rate and the average efficiency. We use real efficiency characteristics from EVs and chargers providing fast frequency regulation and we show that the proposed controller can significantly reduce reserve errors and increase efficiency for a given fleet size, while at the same time minimizing the switching actions."br

Abstract

The provision of ancillary services is an additional revenue stream for the owners of inverter-equipped storage systems, such as batteries and electric vehicles. As real demonstrations have shown, primary frequency control (PFC) is a suitable and economically viable service for small-scale energy storage (ES) systems. This paper proposes a decentralized stochastic control policy, which significantly reduces ES units’ losses when providing PFC. The proposed controller can be tuned to obtain the desired service reserve provision errors, while achieving a balance between tracking accuracy and efficiency. An extension of the algorithm significantly reduces the switching rate of the devices by up to 95%. Analytical expressions for the reserve errors and the switching rates, dependent on the aggregation size and the controllers’ settings, are derived and verified by simulations. Simulation results show that the proposed controller can significantly reduce ES units’ losses when they are providing PFC by 8–15.5%, while achieving the expected tracking performance.

Abstract

Decentralized feedback systems have long been of interest to the controls community [2], [3], [20]. In recent years, research in decentralized control has been re-invigorated by interest in such applications as cooperative control of autonomous vehicle teams, data fusion in sensor networks, air traffic management, and virus-spreading control, among many others, see the overviews [15]–[18] and also e.g. the articles [6], [19], [23]. These numerous network-control applications are widely varied: they have vastly different scales, may consist of autonomous-but-sensing agents (like vehicle teams) or may be hardwired (like electric power systems), and require a wide array of control and/or algorithmic capabilities. What these varying applications make clear, however, is that new tools for designing decentralized controllers are badly needed: ones that permit highly limited components subject to delay and variation to complete intricate tasks by exploiting the network's topological structure. As the need for topology-exploiting decentralized controllers has become clear, efforts to understand the role of a network's topology in its dynamics upon control have been initiated, but the core design problem remains to be addressed.

Abstract

@2017 Personal use of these materials is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating news collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works Inland navigation networks are large-scale systems with large dead times, nonlinearities and variable time delays. They are composed of interconnected reaches. The management goal is to maintain the water level of each reach around a certain value. In this paper, a decentralized control approach is addressed to fulfill this objective. It is based on IDZ models by considering connected reaches with distributaries. A real navigation sub-network in the north of France serves as the case study for this work. Peer Reviewed