Search results for "supply"
showing 10 items of 1190 documents
La alimentación en los viajes espaciales tripulados: desde el Programa Gemini hasta la ISS/Shuttle
2014
Los alimentos espaciales han tenido una gran importancia en el desarrollo de las misiones espaciales tripuladas ya que constituyen la única fuente de energía y nutrientes para el ser humano fuera del planeta Tierra. Dichos alimentos han experimentado una gran evolución desde el inicio del Programa Mercury hasta las actuales misiones a la International Space Station (ISS). En un primer momento eran diseñados para ofrecer una gran densidad energética y nutritiva y actualmente se da prioridad a las características organolépticas y psicológicas, ya que contribuyen a un mayor consumo y un mejor estado nutricional de los astronautas. El objetivo del presente estudio es hacer un análisis retrospec…
Optimized design of high power density EMI filters for power electronic converters
2016
Nowadays, power density of power converters and related EMI filters is gaining more and more attention. This severely impacts on the design constraints in several application domains. A conventional design of the EMI filter does not guarantee the selection of components/configuration leading to the best power density. For this reason, an optimized design procedure of discrete EMI filters in terms of power density is proposed in this paper. It is based on a previously developed rule-based design procedure, introducing here additional features to obtain a more effective optimization of EMI filter's power density. The proposed approach has been validated in terms of EMI filter's performance an…
Medium Voltage Smart Grid: Experimental Analysis of Secondary Substation Narrow Band Power Line Communication
2013
This paper is focused on the possibility of employing narrow band power line communication (PLC) in medium voltage (MV) distribution networks. The topic is investigated by means of both simulations and experimental tests, which were carried out in the distribution network of Ustica Island. In detail, a two-way MV communication was tested between two secondary substations connected by an MV cable power line. Each substation has a by-pass connection at MV bus-bars and an MV/LV oil filled power transformer. In this paper, the MV and the PLC systems under test are described and the experimental tests are presented, which were carried out to evaluate the parameters of the simulation model. The a…
Dynamic performance enhancement of AC/DC PFC boost converters by means of MRAS observers
2015
Controlling a Power Factor Corrected (PFC) boost converter is not a trivial task, because the higher the dynamic performance, the higher is the input current distortion. On the other hand, recent applications of these converters require fast transients in response to disturbances, such as sudden variations of load power, reference voltage and input voltage. Better performance can be obtained adding a feedforward action to the traditional control scheme, using observers to estimate the input voltage and the output current. However, the actual improvement depends on the dynamic performance of the chosen observers. This paper aims at evaluating the applicability and the performance of differen…
Comparison of power quality impact of different photovoltaic inverters- the viewpoint of the grid
2005
This paper presents the results of an experimental analysis performed with the aim of evaluating the effect of many photovoltaic plants on power quality of the grid. Several parameters as voltage and current distortion, flicker, voltage variations at fundamental frequency and power factor have been observed. The measured values have been compared with the limits reported in the standards and, when possibiIe, their dependence on the characteristics of the grid in terms of its impedance has been pointed out.
Soft switched interleaved boost converters used as high-power battery discharge regulator for space power systems
2004
In the following years the telecommunication satellites will have a much greater power demand than nowadays. One reason for this is that the geostationary orbit required by this kind of satellites is becoming too crowded. Probably power levels of l0 kW to l00 kW will be the standard and with life duration of 25 years. It is not possible to keep 0.5 kW modules with more than 100 in parallel and therefore higher power modules (5 kW) must be used. A higher bus voltage seems also necessary and keeping a safety limit of 150 V, any voltage below it and above 100 V could meet the needs. In this paper we will propose a topology that fits the application: two soft switched interleaved boost converte…
Controlled Fault-Tolerant Power Converters for Power Quality Enhancement
2013
Power quality depends generally on the interaction of electrical power with electrical equipments. If electrical equipments operate correctly and reliably without being damaged or stressed, a suitable level of power quality is assured. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, power quality is poor and probably the economical loss could be important like the technical one. In the scenario of the Distributed Generation, power quality issues will be moreover important because an higher dissemination of power conditioning equipment will be requested and this obviously increases the sources of vulnerability of the electrical s…
Water losses dynamic modelling in water distribution networks
2015
In the last decades, one of the main concerns of the water system managers have been the minimisation of water losses, that frequently reach values of 30% or even 70% of the volume supplying the water distribution network. The economic and social costs associated with water losses in modern water supply systems are rapidly rising to unacceptably high levels. Furthermore, the problem of the water losses assumes more and more importance mainly when periods of water scarcity occur or when not sufficient water supply takes part in areas with fast growth. In the present analysis, a dynamic model was used for estimating real and apparent losses of a real case study. A specific nodal demand model …
Hydraulic Dynamic Calculation and Simulation
2021
Hydraulic dynamics is emerging as a basic concept with applications and important implications for many industrial, civil, and environmental engineering problems [...]
Leveraging BIM and Big Data to deliver well maintained highways
2017
The Highway infrastructure is one of the most valuable assets for any state or national Government. Efficient operations of Highways lead to success of national and local economies as well as improve the quality of life of the general public dependent on it. In order to ensure aging road networks continues to move with its ever increasing number of users, requires maintenance and improvements to the road network at the highest standard. Increasing scrutiny over the cost of maintenance along with increasing pressure from Government and the public for transparency over road network spending, has made a strong case for more efficient management of the Highway road asset and traffic management…