Search results for "bandwidth"
showing 10 items of 250 documents
Scalable and Privacy-Preserving Admission Control for Smart Grids
2015
International audience; Energy demand and production need to be constantly matched in the power grid. The traditional paradigm to continuously adapt the production to the demand is challenged by the increasing penetration of more variable and less predictable energy sources, like solar photovoltaics and wind power. An alternative approach is the so called direct control of some inherently flexible electric loads to shape the demand. Direct control of deferrable loads presents analogies with flow admission control in telecommunication networks: a request for network resources (bandwidth or energy) can be delayed on the basis of the current network status in order to guarantee some performanc…
Secondary substation power line communications for medium voltage smart grids
2012
In this paper a performance analysis is carried out, in order to evaluate the possibility to employ power line communication (PLC) between secondary substations of a medium voltage (MV) distribution networks in a smart grid. The study is focused on the analysis of PLC technologies and the evaluation of the influence quantities on the communication performance in the most common case of by-pass connection at MV bus-bars of secondary substations. Different quantities have been analyzed as modulation techniques, requested bandwidth and bitrate, coupling device and system attenuation versus frequency in order to find the best solution for a reliable communication system. A complete model of a r…
A portable instrument for the location and identification of defects generating PD
2011
A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…
Kalman filtering applied to Profibus-DP systems. Multirate control systems with delayed signals
2008
In networked control systems several devices (controllers, sensors and actuators) share a common communication resource. This feature can introduce variable and even random delays when those devices try to transmit information through the shared medium. The limited bandwidth capabilities of the transmission medium also can restrict the freedom to set the sampling periods in the control loop. An attempt to reduce the significance of the signal delays and save to some bandwidth can be based on high values of sampling periods. Usually this solution has remarkable effects in the system performance because with higher sampling periods closed loop response capabilities are decreased. This paper p…
Design of a configurable multispectral imaging system based on an AOTF.
2011
In this paper, we present a configurable multispectral imaging system based on an acousto-optic tunable filter (AOTF). Typically, AOTFs are used to filter a single wavelength at a time, but thanks to the use of a versatile sweeping frequency generator implemented with a direct digital synthesizer, the imager may capture a configurable spectral range. Experimental results show a good spectral and imaging response of the system for spectral bandwidth up to a 50 nm.
New distributed model for synthesis of classical dual mode filters
2010
Up to now, distributed models for classical dual mode filters have not been developed. In this paper, the whole procedure to derive such distributed models is shown step by step. The resulting formulas are very similar to those standard ones used for in-line filters since the 1960s. Model limitations, very similar to those related to classical formulas, in terms of precision and bandwidth, are pointed out. Finally, two practical examples of distributed models of dual mode filters for satellite transponders with different orders have been extracted.
Modeling the Sequential Switching Shunt Series Regulator
2005
This letter characterizes, in terms of the bandwidth and limit cycle frequency of its constituent subsystems, the sequential switching shunt series regulator -S/sup 4/R, a high-efficiency, low-mass and volume power cell devised to power the next generation of regulated power buses in telecommunication spacecrafts. Transconductance power source modeling is used to obtain linear and nonlinear models. These are used to establish a design control strategy which involves the dynamic response in large load requirements or at the end of the satellite life. Simulations and experimental results are also given to demonstrate the validity of the model.
Efficient CAD of Optimal Multi-Port Junctions Loaded with Partial-Height Cylindrical Posts using the 3D BI-RME Method
2005
A rigorous full-wave technique based on the 3D BI-RME (Boundary Integral-Resonant Mode Expansion) method for the analysis and design of compensated waveguide junctions is presented. This method is used to investigate the electrical performance of right-angled bends and rectangular waveguide T-junctions loaded with partial-height cylindrical posts, with the aim of extending the typical usable bandwidths of such components. It is found that the electrical performance of a two-way power divider can be significantly improved by considering a post displaced along the symmetry plane of the structure. Therefore, this contribution reveals a new crucial design parameter not considered in previous wo…
A low-cost compact uniplanar Quasi–Yagi printed antenna
2008
A low cost directive uniplanar broadband printed Quasi–Yagi antenna design is presented. As a particular realization, some prototypes have been designed to operate in the 2.45 GHz band. They have been then modeled, fabricated onto standard printed circuit dielectric substrate and tested successfully. For the design and the modeling processes, we have make use of FDTD based in-house developed algorithms. The obtained bandwidth is, for all the considered cases, better than 15%. The main radiation characteristics are 2–5.5 dBi gain, depending on the number of director elements, and better than 25 dB front-to-back ratio. Overall antenna size was, in any case lesser than 1 λ × 0.5 λ. © 2008 Wile…
Two Methods to Broaden the Bandwidth of a Nonlinear Piezoelectric Bimorph Power Harvester
2017
We propose two methods to broaden the operation bandwidth of a nonlinear pinned–pinned piezoelectric bimorph power harvester. The energy-scavenging structure consists of a properly poled and electroded flexible bimorph with a metallic layer in the middle, and is subjected to flexural vibration. Nonlinear effects at large deformations near resonance are considered by taking the in-plane extension of the bimorph into account. The resulting output powers are multivalued and exhibit jump phenomena. Two methods to broaden the operation bandwidth are proposed: The first method is to extend the operation frequency to the left single-valued region through optimal design. The second method is to exc…