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Harmonics Reduction in a Wind Energy Conversion System with a Permanent Magnet Synchronous Generator
Abdulhakim Nasr,
Mohammed El-Hawary
Issue:
Volume 3, Issue 6, December 2017
Pages:
58-68
Received:
8 September 2017
Accepted:
10 October 2017
Published:
8 November 2017
Abstract: This paper is mainly doing simulation using Matlab to filter harmonics which are found in a Permanent Magnet Synchronous Generator (PMSG) Wind Energy Conversion System (WECS) connected to a three-phase load through a full converter (AC/DC/AC). Harmonics are caused by the converter system. To reduce these harmonics, an effective filter is needed. There are two types of filters that are usually used, active and passive filters. Among the types of passive filters are band pass which block lower harmonics orders such as 5th, 7th, 11th, and 13th, and high pass filters which are responsible to filter higher harmonics such as 24th. So, we use two stages of harmonic filtering. The first stage includes a c- type high pass filter (for lower orders), a double – tuned filter (for 11th and 13th) and high pass filter (for higher orders). Secondly, this stage includes a single – tuned filter instead of C- type filter with keeping the other filters. We applied Fast Fourier Transform (FFT) to determine the harmonics and purposes. In this thesis, we investigate and analyse the level of harmonic content of two AC/DC converters working at different wind speeds. Our findings indicate significant improvements in Total Harmonic Distortion (THD) with best results in the second method.
Abstract: This paper is mainly doing simulation using Matlab to filter harmonics which are found in a Permanent Magnet Synchronous Generator (PMSG) Wind Energy Conversion System (WECS) connected to a three-phase load through a full converter (AC/DC/AC). Harmonics are caused by the converter system. To reduce these harmonics, an effective filter is needed. Th...
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Piggyback Scheme over TCP in Very High Speed Wireless LANs: Review
Ali Ahmad Milad,
Saad Mohamed Lafi,
Mustafa Almahdi Algaet
Issue:
Volume 3, Issue 6, December 2017
Pages:
69-76
Received:
5 September 2017
Accepted:
8 October 2017
Published:
23 November 2017
Abstract: When the data packets transferred in duplex directions from part A to part B, and the data arrives at B, instead to sending a control frame from B to A, receiver B waits until the network layer at B send the next packet to A, and the Acknowledgment is attached in data frame from B to A using the field of Acknowledgment in the data frame header. so the acknowledgment got a free ride in the data frame, this technique known as piggybacking. One of the most advantages for piggyback scheme is improving the efficiency, which is reducing the overhead and increase system throughput. In this paper, we want to provide an overview of a research progress in piggyback scheme over wireless LANs. The research contributions are organised and summarized and it highlights the piggyback schemes that need to be investigated via high speed wireless LANs.
Abstract: When the data packets transferred in duplex directions from part A to part B, and the data arrives at B, instead to sending a control frame from B to A, receiver B waits until the network layer at B send the next packet to A, and the Acknowledgment is attached in data frame from B to A using the field of Acknowledgment in the data frame header. so ...
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Variativity of the Transport System at Intercity Passenger Transport from the Demand
Issue:
Volume 3, Issue 6, December 2017
Pages:
77-84
Received:
9 October 2017
Accepted:
30 October 2017
Published:
25 November 2017
Abstract: At this stage of development of intercity passenger transportion, there is a need to take into account fluctuations in demand for the services of carriers, which takes place over time. These fluctuations in demand are mostly tied to the onset of a period of nationwide or religious celebrations, the onset of a period of mass holidays, sports and cultural events of state or interstate significance, and so on. Therefore, such existing fluctuations in demand of passengers for the use of public routes in long-distance communication should be taken into account when planning the activity for the management of passenger traffic. In order to meet the needs of passengers for transportation, taking into account the available fluctuations in demand, certain decisions can be taken on the changes in the parameters of the components of the transport system. Such changes include changes in the number or type of rolling stock, timetables, changes in traffic patterns, the introduction of temporary routes, restrictions on the purchasing power of passengers with the help of changing the cost of travel, and so on.
Abstract: At this stage of development of intercity passenger transportion, there is a need to take into account fluctuations in demand for the services of carriers, which takes place over time. These fluctuations in demand are mostly tied to the onset of a period of nationwide or religious celebrations, the onset of a period of mass holidays, sports and cul...
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Bayes Estimation of Parameter of Laplace Distribution Under a New LINEX-Based Loss Function
Issue:
Volume 3, Issue 6, December 2017
Pages:
85-89
Received:
27 October 2017
Accepted:
29 November 2017
Published:
26 December 2017
Abstract: Loss function is one of the most topics in Bayesian analysis. The aim of this paper is to study the estimation of the shape parameter of Laplace distribution using Bayesian technique under a new loss function, which is a compound function of LINEX function. The Bayes estimator of the parameter is derived under the prior distribution of the parameter based on Gamma prior distribution. Furthermore, Monte Carlo statistical simulations illustrate that the Bayes estimators obtained under LINEX-based loss function is affected by the prior parameter and the value of the shape parameter of the LINEX-based loss function. But when the sample size is large, they have less influence on the estimation result.
Abstract: Loss function is one of the most topics in Bayesian analysis. The aim of this paper is to study the estimation of the shape parameter of Laplace distribution using Bayesian technique under a new loss function, which is a compound function of LINEX function. The Bayes estimator of the parameter is derived under the prior distribution of the paramete...
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