1,721,057 research outputs found
Ultrafast charging station for electrical vehicles: Dynamic modelling, design and control strategy
No full textThe paper deals with mathematical modelling and the control system for UltraFast Charging Stations (UFCS) based on DC micro-grid concept and Energy Storage System Integration to feed new Electrical Vehicles (EVs) at 800V DC in order to reach the EVs power requirement for charge-time less than 10 min. The UFCS integrates a battery energy storage system (BESS) to reduce the peak power of AC main grid, decoupling the dynamics of the DC charging station from the AC grid by means of its dedicated control system. Designing procedure and Control Strategy, based on Load Levelling power management, are dealt with numerical simulation results in Matlab-Simulink software, presented in order to verify UFCS performance and the charging station's dynamics
Power Control Strategy of a Delta-Connected Photovoltaic Cascaded H-Bridge Converter for Low Voltage Distribution Networks in Energy Community
No full textThe paper deals with the power control of a delta connected Cascaded H-Bridge (CHB) converter equipped with photovoltaic (PV) modules. A hierarchical architecture of energy management is proposed: A 'Module level' controller performs a Maximum Power Point Tracking (MPPT) algorithm to achieve the optimal utilization of each PV module; a 'Leg level' controller manages the power flow control within the modules of a single CHB phase leg, and a 'System' level controller manages the active power flow between the three CHB phases and the reactive power generation towards the grid. The active power control is aimed at the compensation of the mismatches between the different PV-powered modules, which may come from partial shadowing phenomena. A power unbalance compensation between cascaded modules is implemented through the Pulse Width Modulation (PWM) algorithm, while the unbalance compensation between the phases is implemented through the phase currents control. To compensate the active power unbalance due to PV module mismatches, the obtained effect is equivalent to the injection of a zero sequence current. A reactive power control has been implemented to perform a power factor (PF) correction, too. A set of numerical simulations validate the effectiveness of the algorithm, which can simultaneously achieve the desired active power generation from all the PV panels and the desired PF control towards the grid
Exploring the global scientific literature on urban metabolism
Full text linkUrban ecosystems can be conceptualized like living organisms supported by material and energy flows that allow the generation of ecosystem structures and functions and the production of goods and services. Urban metabolism accounts for the flows of materials, energy, resources, food, and people in cities, providing a framework for the study of the interactions between natural and socio-economic systems. In this paper, the global scientific literature on urban metabolism was explored to identify knowledge gaps and emerging research areas over the last decades. A bibliometric network analysis was implemented to generate maps based on network data of scientific publications displaying relationships among scientific journals, researchers, countries, and keywords. The total number of publications on urban metabolism from 1990 to 2019 resulted in 498 documents. USA and China resulted the first countries publishing on urban metabolism while among the journals, the Journal of Industrial Ecology and Journal of Cleaner Production resulted the first in the ranking. The co-occurrence network map of keywords showed that, over the last decade, the main focus of research on urban metabolism has shifted from environmental issues to environmental accounting and socio-economic aspects. Considering the importance of urban systems for the achievement of local and global sustainability goals, it is likely that the scientific literature on urban metabolism will continue growing over the next years. Being cities characterized by complex relationships between natural and socio-economic systems, it is desirable that future studies will explore the multidimensional features of urban metabolism through multi-criteria assessment frameworks
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