Search results for "Electrical Circuits"
showing 10 items of 91 documents
Transverse flux generators a solution for stand-alone wind mill
2015
The transverse flux generator (TFG) proposed in the paper as a solution for stand-alone wind electric power plants has a topology derived from a reluctance one. This variant has a permanent magnet on the rotor derived for a well-known topology in literature. Consequently, the number of rotor poles becomes double compared with stator one. The paper analyses the possibility of using a multiple modules one phase structure in comparison with poly-phase topology. The costs, torque harmonic content and the different rotor poles' topology are discussed and the conclusions are useful for the plant designer.
Linear Types for Higher Order Processes with First Class Directed Channels
1995
Abstract We present a small programming language for distributed systems based on message passing processes. In contrast to similar languages, channels are one-to-one connections between a unique sender and a unique receiver process. Process definitions and channels are first class values and the topology of process systems can change dynamically. The operational semantics of the language is defined by means of graph rewriting rules. A static type system based on the notion of linear types ensures that channels are always used as one-to-one connections.
Video Streaming Distribution in VANETs
2011
Streaming applications will rapidly develop and contribute a significant amount of traffic in the near future. A problem, scarcely addressed so far, is how to distribute video streaming traffic from one source to all nodes in an urban vehicular network. This problem significantly differs from previous work on broadcast and multicast in ad hoc networks because of the highly dynamic topology of vehicular networks and the strict delay requirements of streaming applications. We present a solution for intervehicular communications, called Streaming Urban Video (SUV), that 1) is fully distributed and dynamically adapts to topology changes, and 2) leverages the characteristics of streaming applica…
OLS Identification of network topologies
2011
Abstract In many applications, it is important to derive information about the topology and the internal connections of more dynamical systems interacting together. Examples can be found in fields as diverse as Economics, Neuroscience and Biochemistry. The paper deals with the problem of deriving a descriptive model of a network, collecting the node outputs as time series with no use of a priori insight on the topology. We cast the problem as the optimization of a cost function where a set of parameters are used to operate a trade-off between accuracy and complexity in the final model. The problem of reducing the complexity is addressed by fixing a certain degree of sparsity and finding the…
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…
Bidirectional High-Efficiency Nonisolated Step-Up Battery Regulator
2011
The design and results of a high-efficiency high-power (5 kW) nonisolated bidirectional dc-dc converter is presented. High stability due to minimum phase behavior is an additional benefit of the topology. The converter is a new boost with output filter where input and output inductors are coupled. This converter is useful with any system that needs to charge and discharge backup batteries and can be applied in space, automotive, and telecom power systems.
Performance analysis and comparison of symmetrical and asymmetrical configurations of evanescent mode ridge waveguide filters
2009
[1] In this paper, the trade-offs between out-of-band performance, filter length, power-handling capability, and insertion loss of both symmetrical and asymmetrical evanescent mode ridge rectangular waveguide filters are investigated. As a result, clear design methodologies for optimizing such performances are proposed. The developed methodologies are then applied to design several evanescent mode filters, and a complete performance analysis of the symmetrical and asymmetrical structures is performed. From the performance analysis results, the designer can choose the more appropriate filter topology and design strategy to satisfy the prescribed specifications.
Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000
2016
Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good c…
A New ESO-Based Method to Find the Optimal Topology of Structures Subject to Multiple Load Conditions
2014
In the field of topology optimization problems, the Evolutionary Structural Optimization (ESO) method is one of the most popular and easy to use. When dealing with problems of reasonable difficulty, the ESO method is able to give very good results in reduced times and with a limited request of computational resources. Generally, main applications of this method are addressed to the definition of the optimal topology of a component subjected to a single load condition. In this work, a new methodology, based on the ESO approach, is introduced for the study of the optimal topology of a component subjected to multiple load conditions. The new procedure, entirely developed in the APDL programmin…
Designing Frame Relay WAN Networks with Trade-Off between Link Cost and Performance
2014
This paper is focused on the problem of designing a Wide Area Network topology with trade-off between link cost and response time to users. The L2 technology chosen for the research is a Frame Relay based solution. The link capacities in the network and the routes used by packets are determined in a way to minimize network cost and response time at the same time. In FR networks link capacity corresponds directly to CIR parameter which makes the presented numerical results very useful in practice, especially during preliminary network design in the Design Phase of the PPDIOO methodology.