1,720,990 research outputs found
A Hybrid Control System for LC filters that couple Energy Storage Systems with AC grids
No full textA hybrid control system for LC network filters is proposed in this paper, which enables coupling energy storage systems with the main grid suitably. The proposed control system is developed by combining both linear and predictive control approaches: particularly, the outer grid current loop is designed by means of PI regulators, whereas the intermediate capacitor voltage and the inner inductor current loops are designed in a deadbeat predictive control fashion. As a result, three nested loops have been achieved, whose performance can be set properly through dynamic decoupling and multi-rate sampling. The effectiveness of the proposed solution is verified through numerical simulations, which refer to different grid operating conditions in terms of active/reactive power exchanges
An MPC-based Energy Management System for a Hybrid Electric Vehicle
Full text linkA real-time Energy Management System (EMS) is presented in this paper, which aims at minimizing the operating costs of a Hybrid Electric Vehicle (HEV) equipped with different energy storage units (fuel cell, supercapacitors, batteries). The proposed EMS manages all HEV operating constraints properly through a Model Predictive Control (MPC) approach, which identifies the allowable ranges of each variable based on system modelling and actual HEV operating conditions. The optimization is then carried out by means of suitable look-up tables, which are accessed in accordance with the variable ranges previously computed. The effectiveness of the proposed MPC-based EMS is verified through numerical simulations, which also regard a rule-based EMS for comparison purposes
Photovoltaic spectroscopy of exciton structures in Zn(1-x)Cd(x)Se/ZnSe multiple quantum wells
No full textA Genetic Algorithm Approach for Sizing Integrated PV-BESS Systems for Prosumers
Full text linkA procedure for properly sizing integrated configurations of photovoltaic (PV) and battery energy storage systems (BESSs) is presented in this paper. Specifically, an energy management strategy oriented to maximise the electricity self-consumption has been used. In this regard, the energy management of Li-ion BESS is optimised by means of a specific tool based on a Genetic Algorithm (GA). In order to determine the best rated power and capacity of integrated PV-BESS system for residential and commercial users, the optimisation has been performed for different combination of PV and BESS rated powers and capacities, evaluating, for each of them, the annual self-consumption. The analysis of the results permits the proper choice of the PV-BESS system for a specific prosumer end for a given self-consumption target. Moreover, the proposed design approach highlights that the increase of BESS size for a defined electricity demand may lead to weak benefits in terms of increased self-consumption and, thus, to an unsuitable oversizing of the PV-BESS system
Design of High-Speed/High-Power PM Synchronous Machines for an Adiabatic Compressed Air Storage System
No full textThis paper presents the design of NdFeB-based high-speed/high-power surface-mounted Permanent Magnet Synchronous Machines (PMSMs) for an Adiabatic Compressed Air Storage system (ACAES). A preliminary PMSM configuration is presented at first, which aims at complying with all electromagnetic, mechanical and thermal constraints, by guaranteeing the specifications and target imposed by ACAES. Subsequently, due to limited maximum speed and weak flexibility, a second modular PMSM configuration is proposed, which consists of identical PMSMs mechanically series-connected. In this way, all PMSMs share the same mechanical speed and contribute to the high overall power required by ACAES, ensuring higher maximum speed and flexibility compared to the first configuration. The modular PMSM configuration is validated through extensive finite element analyses, also in comparison with the first PMSM configuration in terms of performance, efficiency and losses
Design and Performance Assessment of an Integrated Flywheel Energy Storage Systems based on an Inner-Rotor Large-Airgap SPM
Full text linkAn integrated flywheel energy storage system topology is presented in this paper, which is based on an inner rotor large-airgap surface-mounted permanent magnet synchronous machine and which aims at achieving a unity energy to power ratio. The proposed synchronous machine is equipped with a thick carbon-fiber cylindric layer that acts as both the flywheel and the sleeve; as a result, this layer ensures permanent magnet containment and storing/delivering the required amount of energy simultaneously. In order to comply with all the design targets and constraints, a two-step design procedure is employed: a preliminary design is achieved analytically, by using an integrated mechanical-electromagnetic-energy modelling. Subsequently, the preliminary configuration is refined and validated through finite element analyses, which regard a performance assessment on mechanical, electromagnetic, energy, and thermal aspects at different operating conditions
Flux-Weakening Space Vector Control Algorithm for Permanent Magnet Brushless DC Machines
No full textA Flux-Weakening Space Vector Control algorithm (FW-SVC) for Permanent Magnet Brushless DC Machine (PMBDCM) is presented in this paper. It is developed referring to a novel ft reference frame, which enables distinguishing field and torque current components clearly. Therefore, a voltage follower PI regulator has been introduced in order to synthesize the reference field current based on the DC-link voltage deficit. This goal requires coping with non-linearities of the PMBDCM model in order to achieve a suitable trade-off between dynamic and steady-state performances. The effectiveness of the proposed solution is verified through numerical simulations, which regard the comparison between the proposed FW-SVC and both a conventional Current Commutation Control (CCC) and an SVC with no field current injection
Absorption spectrum of Ge-doped silica samples and fiber preforms in the vacuum ultraviolet region
No full textWe report absorption measurements in the vacuum ultraviolet (VUV) spectral region on Ge-doped silica samples grown through chemical vapor deposition (CVD) and fiber preforms grown through modified chemical vapor deposition (MCVD) with GeO2 doping concentration from 0.3 to 4.0 mol%. We observed in all spectra an absorption band at 5.15 eV and a structure at about 7.0 eV. We observed differences in the absorption spectrum between Ge-doped silica samples and fiber preforms in the shape and relative amplitude of optical absorption bands. The intensity of defect-related bands depends on the Ge concentration and distribution. Differences in Ge concentration and distribution are due to the preparation methods and growing condition
A Combined Planning and Design Approach of a Public Charging Infrastructure for Electric Vehicles
No full textA Combined Planning and Design approach (CPD) for a Public Charging Infrastructure (PCI) for Electric Vehicles (EVs) is presented in this paper. The aim is defining the displacement of charging infrastructures for easing early EV diffusion. The proposed CPD consists in a traffic/parking model that estimates the charging demand of potential EV owners for a given scenario. A coarse distribution of Charging Stations (CSs) over the selected Zones of Interest (ZOIs) is achieved at first, by taking into account the charging demand coverage. Subsequently, PCI structure is further and sequentially refined in order to comply with both urban and power system constraints, by minimizing installation cost at the same time. The proposed CPD is being employed for designing the PCI of the Italian island of Sardinia in order to support the adoption of EVs for commuting; its effectiveness is shown by some preliminary results that refer to a portion of the overall PCI
A multistage design procedure for planning and implementing public charging infrastructures for electric vehicles
Full text linkPresented in this paper is a Multistage Design Procedure (MSDP) for planning and implementing Public Charging Infrastructures (PCIs) to satisfy intracity charging demand of Electric Vehicles (EVs). The proposed MSDP splits planning and design processes into multiple stages, from macroscale to fine-scale levels. Consequently, the preliminary results achieved at each stage can be refined at the subsequent stages, leading to determine the accurate number and precise geographical location of each charging point. The main advantage of the proposed approach is that it splits a very complicated procedure into multiple and simpler stages, at each of which appropriate goals, targets and constraints can be included. As a result, the iterative interactions among all the stakeholders involved in the PCI design process are significantly simplified. The proposed MSDP has been employed in the planning and design of the PCI of the Italian island of Sardinia, accordingly to all the public bodies
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