Electrical Engineering

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During a short circuit, the transformer's inner winding, which is supported by the inner support structure, may fail due to the buckling phenomenon. This occurs due to the generation of large radially inward electromagnetic force on the inner winding. In the literature, the effect of the number of axial supporting spacers on the critical buckling stress is reported, but there is no investigation about the effect of their circumferential width on the value of the critical buckling stress. In this letter, the effect of the circumferential width of the axial supporting spacers on the value of critical buckling stress of the transformer inner winding has been investigated. An algorithm has been given to calculate the critical buckling stress of the inner winding. A case study has been taken from the published work, and by varying the width of the spacers, the factor of safety against buckling has been determined. © 1986-2012 IEEE.

(SoE) School of Engineering

IEEE Transactions on Power Delivery

Effect of Width of Axial Supporting Spacers on the Buckling Strength of Transformer Inner Winding

Photoconductive antennae are one of the most common sources of terahertz radiation. Although extensive experimental and simulation work has been done to analyze the radiated fields, very limited theoretical analysis has been done to build elegant and compact models. This work presents the derivation of the radiated fields from a photoconductive antenna incorporating the effect of the semiconductor substrate. Additionally, an improved model of the semiconductor carrier dynamics has been proposed to analyze the radiation characteristics of the photoconductive antenna. The proposed carrier dynamics includes a novel analysis of the transient behavior of the substrate temperature and its effect on the parameters of the substrate material. It also incorporates the effect of the lifetime, polarization and velocities of the carriers as well as the effects of the radiated near zone fields and antenna geometry. The derived formulae and the proposed carrier dynamics model have been validated by comparing the results with the available experimental results in the literature. It has been found that the analytically calculated results closely follow the experimental results reported in the literature. © 2019 IOP Publishing Ltd.

World University root node

Semiconductor Science and Technology

Radiation field analysis of a photoconductive antenna using an improved carrier dynamics

In this letter, we study a few properties of Complex Conjugate Pair Sums (CCPSs) and Complex Conjugate Subspaces (CCSs). Initially, we consider an LTI system whose impulse response is one period data of CCPS. For a given input x(n), we prove that the output of this system is equivalent to computing the first order derivative ofx(n).Further, with some constraints on the impulse response, the system output is also equivalent to the second order derivative. With this, we show that a fine edge detection in an image can be achieved using CCPSs as impulse response over Ramanujan Sums (RSs). Later computation of projection for CCS is studied. Here the projection matrix has a circulant structure, which makes the computation of projections easier. Finally, we prove that CCS is shift-invariant and closed under the operation of circular cross-correlation. © 2019 IEEE.

Fulltext

IEEE Signal Processing Letters

On complex conjugate pair sums and complex conjugate subspaces

The paper analyses four types of DG (distributed generators) for their optimal placement in primary distribution system. They are sited and sized optimally to obtain maximum loss reduction. The ultimate objective of the adopted work in this paper is to identify the size and location of distributed generators for their placement in primary distribution network and to justify the economics of these placements. To serve the purpose, an analytical method is used in this paper for determination of sizes and sites for four DG types. The analytical method is considered suitable for the analysis purpose in proposed work. The paper presented a comprehensive analysis for four types of DGs for their placement in primary distribution system. The type 1 DG is capable of delivering real power only whereas type 3 DG is capable of providing real as well as reactive power to the distribution network. Out of other two types, type 2 can deliver only the reactive power whereas type 4 supplies active power but at the same time it consumes reactive power. The paper compares the economic feasibility of placement of four DG types in primary distribution system. © BEIESP.

International Journal of Innovative Technology and Exploring Engineering

Optimal integration of distributed generation in primary distribution system and its economics

In applications where heavy metal welding is performed, the short circuit welding current is very high. During these conditions, manual welding is difficult. Hence, using an automated welding system enhances the productivity and quality of welds, thus reducing dependency on skilled work force. In this manuscript one such mechanism of DC welding, where the welding electrode is automated with a voltage control algorithm is discussed. This algorithm is implemented by sensing the voltage across the electrodes and controls the welding action based on the logic implemented. Implementation of this automated system ensures, monitored time of contact between the job and electrode. © 2019 IEEE.

2019 Global Conference for Advancement in Technology, GCAT 2019

Design and Implementation of Automatic Welding Machine

This abstract reports very high (&gt;1014 cm−2) sheet carrier density (ns)in Zinc Oxide (ZnO) based heterostructure for low Magnesium (Mg) compositions (&lt;0.15) in barrier layer, achieved by alloying Cadmium (Cd) in buffer layer ZnO, grown by Dual Ion Beam Sputtering (DIBS) deposition technique. © Springer Nature Switzerland AG 2019.

Springer Proceedings in Physics

Enhanced sheet carrier density in zno based heterostructure by alloying cadmium in buffer layer zno

Air pollution monitoring systems with energy-intensive sensors cannot afford to sample frequently in order to maximize time between successive recharges. In this paper, we propose an energy-efficient machine learning based sensor duty-cycling method for a sensor hub receiving data from the air-pollution sensors. In particular, we demonstrate that temporal correlation of pollutant concentration can be exploited to select optimum sampling period of an energy-intensive sensor to reduce sensing energy consumption without losing much information. Support Vector Regression is used to predict the missing samples during the period sensor is turned off. © 2018 IEEE.

2018 24th National Conference on Communications, NCC 2018

Energy-Efficient Air Pollution Monitoring with Optimum Duty-Cycling on a Sensor Hub

A new method of power control for wireless power transmission (WPT) system has been proposed and analysed. The circuit and method suggested in this study holds good promise of reducing switching loss in the high-frequency converter of WPT. The effect of misalignment between transmitter and receiver coils has been analysed and a simple remedial method has been proposed. The desirability of frequency tuning of converter's output voltage under varying degrees of misalignment has been highlighted. The conventional perturb and observe method for maximum power point tracking has been gainfully employed here to achieve the required frequency tuning of the proposed converter. The proposed methods are implemented and tested on laboratory scale. Some suggestions have been given for augmenting driver assistance system aimed at limiting lateral misalignment in dynamic WPT system. The suggested algorithm is tested in a laboratory environment using a simple communication system. © The Institution of Engineering and Technology 2019

IET Electric Power Applications

Methods for overcoming misalignment effects and charging control of a dynamic wireless electric vehicle charging system

This letter introduces a real valued summation known as complex conjugate pair sum (CCPS). The space spanned by CCPS and its one circular downshift is called complex conjugate subspace (CCS). For a given positive integer N ≥ 3, there exists φ(N)/2 CCPSs forming φ(N)/2 CCSs, where φ(N) is the Euler's totient function. We prove that these CCSs are mutually orthogonal and their direct sum form a φ(N) dimensional subspace sN of ℂN. We propose that any signal of finite length N is represented as a linear combination of elements from a special basis of sd, for each divisor d of N. This defines a new transform named as complex conjugate periodic transform (CCPT). Later, we compared CCPT with discrete Fourier transform (DFT) and Ramanujan periodic transform (RPT). It is shown that, using CCPT, we can estimate the period, hidden periods, and frequency information of a signal. Whereas, RPT does not provide the frequency information. For a complex valued input signal, CCPT offers computational benefit over DFT. A CCPT dictionary based method is proposed to extract non-divisor period information. © 2018 IEEE.

A New Signal Representation Using Complex Conjugate Pair Sums

In resource allocation for secure cooperative communication systems, along with power allocation, relay placement also has equal importance in improving the system performance. In this paper, we study the joint optimization of relay placement and power allocation to minimize the secrecy outage probability (SOP) for a four- node cooperative system with a trusted randomize- and-forward relay in the presence of an external eavesdropper. Initially, we derive the expression of SOP, and then formulate an optimization problem to minimize SOP under given power budget and relay placement (RP) constraints. By providing analytical insights on power allocation (PA) between source and relay, we obtain closed form expressions of optimal PA (OPA) for a given RP that minimizes the SOP. Next, we propose a low complexity algorithm to obtain the near-optimal RP (ORP) for a given PA. Finally, we obtain optimal SOP with joint RP and PA. Numerical results present validation of analytical SOP through Monte Carlo simulations, optimal PA for a given RP, optimal RP for a given PA, and joint PA and RP for a given secrecy threshold rate. Finally, we highlight the significant performance gains achieved by the joint design over the conventional scheme. © 2019 IEEE.