Current Issue : January - March Volume : 2014 Issue Number : 1 Articles : 5 Articles
The three-phase synchronous reluctance motor (SynRM) is presented as a possible alternative in all-electric ship applications. The\r\nbasic features of this motor with regard to the other types of motors are shown. The structure of the motor and specifically the\r\nstructure of its rotor are analyzed, while the basic operating principles are presented and references on commonly used control\r\nstrategies are made. In this paper, a demonstration of a reluctance motor fed by a voltage source inverter (VSI) takes place. To\r\ndemonstrate the operation of the motor fed by a VSI, an example using a scalar control method is implemented, where harmonic\r\ninjection PWM (HIPWM) is used to drive the VSI. Experimental results on a commercially available motor are shown, focusing\r\non the harmonic content of the current....
This review paper reveals the broadband potential of overhead and underground low-voltage (LV) and medium-voltage (MV)\r\nbroadband over power lines (BPL) networks associated withmultiple-inputmultiple-output (MIMO) technology.Thecontribution\r\nof this reviewpaper is fourfold. First, the unified value decomposition (UVD)modal analysis is introduced.UVDmodal analysis is a\r\nnewtechnique that unifies eigenvalue decomposition (EVD) and singular value decomposition (SVD)modal analyses achieving the\r\ncommon handling of traditional SISO/BPL and upcoming MIMO/BPL systems. The validity of UVD modal analysis is examined\r\nby comparing its simulation results with those of other exact analytical models. Second, based on the proposed UVD modal\r\nanalysis, theMIMOchannels of overhead and underground LVandMVBPL networks (distribution BPL networks) are investigated\r\nwith regard to their inherent characteristics. Towards that direction, an extended collection of well-validated metrics from the\r\ncommunications literature, such as channel attenuation, average channel gain (ACG), root-mean-square delay spread (RMS-DS),\r\ncoherence bandwidth (CB), cumulative capacity, capacity complementary cumulative distribution function (CCDF), and capacity\r\ngain (GC), is first applied in overhead and underground MIMO/LV and MIMO/MV BPL channels and systems. It is found that\r\nthe results of the aforementioned metrics portfolio depend drastically on the frequency, the power grid type (either overhead or\r\nunderground, either LV or MV), the MIMOscheme configuration properties, the MTL configuration, the physical properties of the\r\ncables used, the end-to-end distance, and the number, the electrical length, and the terminations of the branches encountered along\r\nthe end-to-end BPL signal propagation. Third, three interesting findings concerning the statistical properties of MIMO channels of\r\ndistribution BPL networks are demonstrated, namely, (i) the ACG, RMS-DS, and cumulative capacity lognormal distributions;\r\n(ii) the correlation between RMS-DS and ACG; and (iii) the correlation between RMS-DS and CB. By fitting the numerical\r\nresults, unified regression distributions appropriate for MIMO/BPL channels and systems are proposed. These three fundamental\r\nproperties can play significant role in the evaluation of recently proposed statistical channelmodels for various BPL systems. Fourth,\r\nthe potential of transformation of overhead and underground LV/BPL and MV/BPL distribution grids to an alternative solution\r\nto fiber-to-the-building (FTTB) technology is first revealed. By examining the capacity characteristics of various MIMO scheme\r\nconfigurations and by comparing these capacity results against SISO ones, a new promising urban backbone network seems to be\r\nborn in a smart grid (SG) environment....
Conformal antennas and antenna arrays (arrays) have become necessary for vehicular communications where a high degree of\r\naerodynamic drag reduction is needed, like in avionics and ships. However, the necessity to conform to a predefined shape (e.g.,\r\nof an aircraft�s nose) directly affects antenna performance since it imposes strict constraints to the antenna array�s shape, element\r\nspacing, relative signal phase, and so forth. Thereupon, it is necessary to investigate counterintuitive and arbitrary antenna shapes\r\nin order to compensate for these constraints. Since there does not exist any available theoretical frame for designing and developing\r\narbitrary-shape antennas in a straightforward manner, we have developed a platformcombining a genetic algorithm-based design,\r\noptimization suite, and an electromagnetic simulator for designing patch antennas with a shape that is not a priori known (the\r\ngenetic algorithm optimizes the shape of the patch antenna). The proposed platform is further enhanced by the ability to design\r\nand optimize antenna arrays and is intended to be used for the design of a series of antennas including conformal antennas for\r\nshipping applications. The flexibility and performance of the proposed platform are demonstrated herein via the design of a highperformance\r\nGPS patch antenna....
An important tool for the energy management system (EMS) is state estimation. Based on measurements taken throughout the\r\nnetwork, state estimation gives an estimation of the state variables of the power system while checking that these estimates are\r\nconsistent with the measurements. Currently, in the Cameroon power system, state estimates have been provided by ad hoc\r\nsupervisory control and data acquisition (SCADA) systems. A disadvantage is that the measurements are not synchronised,\r\nwhich means that state estimation is not very precise during dynamic phenomena in the network. In this paper, real-time phasor\r\nmeasurement units (PMUs) that provide synchronised phasor measurements are proposed for integration into the power system.\r\nThis approach addresses two important issues associated with the power system state estimation, namely, that of measurement\r\naccuracy and that of optimization of the number of measurement sites, their location, and the importance given to their\r\nmeasurements on the dynamic state estimation....
The significant advances in power electronics have permitted the implementation of sophisticated methods for control of electric\r\nmotors. Each innovative electrical apparatus for industrial and automotive application must be correctly and exhaustively tested,\r\nboth during the developing process and finally for the compliance test. The development of a new electrical system should be\r\nassociated with a parallel design of an ad hoc measurement system, whose performance should be defined according to the features\r\nof the system under test. In recent years, the increasing interest for sensorless electric motor drives involved the development and\r\nimplementation of a wide set of control techniques. This paper reviews the state and the trends of measurement techniques and\r\ninstruments applied for the experimental characterization of variable speed drives....
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