1,720,999 research outputs found
Modeling, Control and Prototyping of a Highly Integrated Battery-Ultracapacitor System for Microgrids
No full textA Highly-Integrated Battery-UltraCapacitor system (HIBUC) is presented in this paper. It consists of a battery pack and an ultracapacitor module, which are coupled to each other through a three-level neutral-point-clamped converter. The latter is connected to the point of common coupling between a microgrid and the main electric grid through a step-up transformer, which enables lower DC-link voltage rating and, thus, eases HIBUC prototyping without affecting its performances significantly. The DC-link is also connected to a dissipative voltage regulator, which has been designed with the dual purpose of preventing DC-link overvoltage and improving DC-link voltage regulation simultaneously. The effectiveness of the proposed configuration has been verified through a simulation study, which has been carried out in the Matlab-Simulink environment and refers to different HIBUC operating conditions
A Brief Overview on Commercial Aircraft Electrification: Limits and Future Trends
No full textThis paper presents a brief overview of aircraft electrification, particularly regarding the commercial aviation sector. At first, a technology overview is presented by focusing on aircraft design, propulsion, and energy storage systems. In this regard, hybrid-electric propulsion systems seem the most suitable solution at present due to technological limitations, especially the still low energy performance of electrochemical batteries. Subsequently, some prototypes are presented, which have been classified in long-range, medium-short range, and urban transportation; many of them are just at the concept stage as they rely on technologies not yet available. The most important issues to address are then resumed, together with future developments and concluding remarks
Electrification of Commercial Vessels: Pilot Projects and Open Issues
No full textThis paper presents a brief overview of some of the most recent pilot projects on vessel electrification, with particular reference to ferries and off-shore vessels. Firstly, the paper resumes the main technological improvements, which enable marine electrification and mainly regard power electronics and electric propulsion systems. Subsequently, the focus is on the description of some pilot projects, grouping them into two main categories, namely ferries and off-shore vessels, which are characterized by different usage and, thus, electrification needs. In conclusion, main features, challenges, and outcomes of each project are highlighted, as well as the overall pending issues, final remarks and future developments
Hybrid Energy Storage Systems for Smart Grids and Electric Propulsion Systems
No full textHybrid Energy Storage Systems (HESSs) represent a very promising and viable solution for the widespread diffusion of both Smart Grids (SGs) and Electric Propulsion Systems (EPSs). This is because an HESS benefits from two or more energy storage technologies that are characterized by complementary features, namely high energy and high power densities. Consequently, a number of energy and power services can be provided successfully, which are hardly deliverable by a single energy storage technology unless oversizing is concerned. Therefore, HESSs installed in SGs can provide multiple grid services, ranging from peak shaving to power quality, thus achieving an economic viability. While the employment of an HESS for supplying EPSs enables improved dynamic performances and energy efficiency during both acceleration and regenerative braking, thus extending the vehicle driving range. In this context, an HESS made up of batteries and supercapacitors is the most popular combination, it being suitable for both small-scale and large-scale applications due to its inherent modularity. However, HESS technical and economic viability strictly relies on management and control, which should enable the exploitation of the HESS inherent features to the maximum extent in accordance with the application requirements.
In this regard, the presentation will focus on most recent advancements in management and control of HESS for both SG and EPS. Particularly, the most popular HESS configurations, management and control approaches will be introduced at first, highlighting their most important advantages and drawbacks. Subsequently, a highly-integrated HESS configuration will be presented, which is well suited for SGs, but especially for EPSs. This is because it benefits from the advantages of both passive and active HESS configurations due to its inherent flexibility. An Optimal HESS Power and Energy Management (OPEM) for SGs will be presented as well; this has been developed analytically in order to achieve an optimal trade-off between peak shaving and reduced grid energy buffering, providing power quality and preventing an excessive battery cycling at the same time. Preliminary and advanced results will be presented and discussed extensively, which highlight the effectiveness of the proposed solutions in terms of HESS configuration, management and control
A Real-Time Energy Management System for Operating Cost Minimization of Fuel Cell/Battery Electric Vehicles
No full textThis paper presents a Real-Time Energy Management System (RT-EMS) for minimizing the operating costs of a Fuel Cell/Battery Electric Vehicle (FCBEV). Particularly, a suitable cost function is considered, which accounts for battery and fuel cell degradation, as well as for fuel consumption and battery charging reinstatement. The cost function is thus minimized in real-time by a suitable energy management strategy, which is designed based on an appropriate model of the overall electric propulsion system. In this regard, a suitable power split criterion is determined, based on which the proposed RT-EMS shares the propulsion power between fuel cell and battery. As a result, the cost function can be minimized whatever the driving cycle is. The effectiveness of the proposed RT-EMS has been assessed by numerical simulations, which have been performed in Matlab-Simulink considering different driving cycles and a hysteresis-based EMS for comparison purposes
Design of a 10 MW multi-phase PM synchronous generator for direct-drive wind turbines
No full textThis paper presents the preliminary design of a 10 MW permanent magnet synchronous generator (PMSG) for offshore direct drive wind turbines (DDWT). In order to improve the DDWT torque quality, energy efficiency, power management, fault tolerance and reliability a twelve-phase PMSG made of four independent three-phase star connected subsystems has been considered. With the aim of satisfying the several constraints related to cogging torque reduction, stator and rotor diameter limitation, low speed operation and magnetic decoupling of four three-phase subsystems, a multi-star fractional-slot tooth concentrated winding PMSG has been designed. The analytical results have been validated by means of Finite Element Analysis (FEA) highlighting the worth and effectiveness of the proposed configuration
The Plug-in Electric Vehicles Role in Smart Grid Development: a Survey
No full textAn overview of the Vehicle-to-Grid technology (V2G) is presented in this paper. It aims to highlight V2G main features, opportunities and requirements. Thus, after briefly resuming the most popular charging strategies for Plug-in Electric Vehicles (PEVs), the V2G concept is introduced, especially highlighting its potentiality as a revenue opportunity for PEV owners; this is mainly due to the V2G capability to provide ancillary services, such as load levelling, regulation and reserve. Such solutions have been deeply investigated in the literature by both economic and technical point of views and here reported. In addition, V2G requirements are properly taken into account, such as mobility needs, charging stations availability and appropriate PEV aggregative architectures. In conclusion, future developments and scenarios have been also reported
Vehicle-to-Grid Technology: State-of-the-Art and Future Scenarios
No full textAn overview of V2G (vehicle-to-grid) technology is presented in this paper. It aims to highlight the main features, opportunities and requirements of V2G. Thus, after briefly resuming the most popular charging strategies for PEVs (plug-in electric vehicles), the V2G concept is introduced, especially highlighting its potentiality as a revenue opportunity for PEV owners; this is mainly due to the V2G ability to provide ancillary services, such as load leveling, regulation and reserve. Such solutions have been thoroughly investigated in the literature from both the economic and technical points of view and are here reported. In addition, V2G requirements such as mobility needs, charging stations availability and appropriate PEV aggregative architectures are properly taken into account. Finally, future developments and scenarios have also been reported
Development of a Characterization Tool for Innovative Batteries for Aerospace Applications
No full textThis paper presents the development of a characterization tool for innovative batteries intended for space applications. i.e. an innovative Lithium-Ion battery equipped with a nanostructured germanium anode. Particularly, a second-order equivalent circuit model and the test campaign required to identify all model parameters are introduced. Subsequently, the battery characterization tool developed on LabVIEW environment for the automatic implementation of the test campaign is described. The battery characterization tool has been experimentally tested on a battery prototype
Design, Control and Prototyping of a Bidirectional Dual Active Bridge Converter for integrating a Sodium Metal Halide Battery into a Telecom Station
No full textThe paper presents the design, control and prototyping of a Dual Active Bridge converter (DAB) devoted to interface a Sodium Metal Halide Battery (SMHB) to the DC grid of a telecom station. The design process is accomplished starting from telecom DC supply and SMHB specifications, especially power and voltage ratings and their corresponding variation ranges. Furthermore, DAB components are selected carefully based on an extensive performance analysis to maximise the energy efficiency, by enabling Zero-Voltage Switching (ZVS) over wide power and voltage operating ranges. The effectiveness of the proposed configuration is guaranteed also by a nested PI-based control system, which avoids unsuitable DC-bias current components by a proper management of phase-shift variations. Both simulations and experiments are presented and discussed, which corroborate the validity of all the design solutions
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