Informatics Publishing Limited

B. Karunamoorthy ¹, D. Somasundareswari ², P. Renuka ³

Affiliations
1 Department of Electrical and Electronics Engineering, Kumaraguru College of Technology, Coimbatore, IN
2 Department of Electronics and Communication Engineering, Adithya Institute of Technology, Coimbatore, IN
3 Kumaraguru College of Technology, Coimbatore, IN

Abstract

This paper analyses the stability problem of grid connected inverter. Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time. The unused or remaining capacity of the converters could be used to provide some ancillary functions like harmonic and unbalance mitigation of the power distribution system. As some of these DG sources have wide operating ranges, they need special power converters for grid interfacing. Being a single-stage buck-boost inverter, recently proposed Z-source inverter (ZSI) is a good candidate for future DG systems. This paper presents a controller design for a ZSI-based DG system to improve power quality of distribution systems. Due to the variation of grid impedances, the system gets affected by stability problems. Since the grid impedance varies, the system tends to be unstable. In this control strategy, the inverter is controlled by means of robust H^∞ controller along with stability is analyzed. An inner inverter-output-current loop with high bandwidth is also designed to get better disturbance rejection capability. The selection of weighting functions, inner inverter-output-current loop design, and system disturbance rejection capability are discussed in detail in this paper. The proposed control method is tested with simulation results obtained using Matlab/Simulink. In this paper the performance of the grid model is compared when it is connected from renewable energy sources through traditional and Z-Source inverter.

Keywords

Distributed Generation (DG), Grid Impedance, Nqyuist Stability Criterion, Voltage Source Inverter (VSI).

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D. Jeyakumari ¹, D. Somasundareswari ²

Affiliations
1 R.V.S. College of Engineering and Technology, ECE Department, Coimbatore, IN
2 Electrical Sciences, Adithya Institute of Technology, Coimbatore-641107, IN

Abstract

Image segmentation is a key technology in image processing and computer vision application. It is used to enhance the capabilities of image, computer processing application and improve the feature of color image, the color image segmentation. Color image segmentation methods as an extension of the gray scale image segmentation method in the color images, but a lot of the original gray scale image segmentation method cannot be applied to the color images. It is necessary to improve the method according to the color image which improves the feature of information used in color image segmentation. This paper proposes a Color image segmentation method with the combination of watershed algorithm and edge detection algorithm and can obtain superior results than other segmentation methods.

Keywords

Image Segmentation, Watershed Algorithm, K-Means Algorithm.

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V. Shanthi ¹, D. Somasundareswari ²

Affiliations
1 Department in Park College of Engineering and Technology, Coimbatore, IN
2 Department of Electronics of Communication Engineering, Adithya Institute of Technology, Coimbatore, IN

Abstract

In mobile scenarios, location dependent data can be provided by an infrastructure, or, in case an infrastructure is not available or feasible, by opportunistic networking among mobile devices populating the region of interest. Caused by node mobility, data availability within the region of interest relies on replication and forwarding techniques. Our approach associates data with a geo-address describing the Point of Interest (POI) of the data and proposes a decentralized al-gorithm for data dissemination. Mobile devices replicate data to increase data availability within a circular area around the POI. To avoid unnecessary communication overhead, the distributed algorithm Sector Heads Aided Flooding Technique (SHAFT) restricts the number of mobile nodes that forward data by arranging data placement geometrically in the area. Hereby, each mobile node decides whether to become a forwarding node based on its geo-location and the known scheme for data arrangement. Additionally, the algorithm adapts to the locally measured density of mobile de-vices in range. By applying the approach to a cooperative parking lot management system based on the Manhattan mobility model we demonstrate its usefulness. Simulation results are provided show-ing that SHAFT reaches similar data availability as flooding by re-ducing the number of packets transferred by a factor of up to newly created data and by up to 81:1% for data updates in scenarios of high node density.

Keywords

MANETs, Mobile Data, Geo-based Data Dissemination, Replication.

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