Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Operating wind power generation system at optimal power point is essential which is achieved by employing a Maximum Power Point Tracking (MPPT) control strategy. This literature focuses on developing a novel particle swarm optimization algorithm enhanced radial basis function neural network supported TSR based MPPT control strategy for Doubly Fed Induction Generator (DFIG) based wind power generation system. The proposed hybrid MPPT control strategy estimates the effective wind speed and estimates the optimal rotor speed of the wind power generation system to track the maximum power. The proposed controller extremely reduces the speed dissimilarity range of wind power generation system, which leads to rationalizing the pulse width inflection of DFIG rotor side converter. This in turn, increases the system's reliability and delivers an effective power tracking with reduced converter losses. Furthermore, by utilizing the proposed MPPT controller, the converter size can be reduced to 40%. Therefore, the overall cost of the system can be gradually decreased. To validate the performance of the proposed MPPT controller, an extensive simulation study has been carried out under medium and high wind speed conditions in MATLAB/Simulink. The obtained results have been justified using experimental analysis. © 2019 ISA

Department of Electrical Engineering

School of Electrical Engineering

Vellore Campus

Department of Communication Engineering

School of Electronics Engineering

World University root node

ISA Transactions

Adaptive hybrid intelligent MPPT controller to approximate effectual wind speed and optimal rotor speed of variable speed wind turbine

A novel compact wideband antenna with T-shaped strips inside square ring is proposed. By stacking a pair of T-shaped strip one above another, the antenna covers the WIMAX (3.3-3.8 and 5.25-5.85 GHz), WLAN (2.41-2.54, 5.15-5.35, and 5.72-5.85 GHz), and lower band of future 5G communications (3.6-6 GHz). The antenna is fabricated on 17 × 33 × 1.6 mm3 FR-4 substrate. UWB operation is achieved using a rectangular shaped slot in the ground plane. The designed antenna has been fabricated and measured. Simulation results and measured results are in good agreement. © 2019 Wiley Periodicals, Inc.

Microwave and Optical Technology Letters

Compact multiband CPW fed monopole antenna with square ring and T-shaped strips

Though the key technology for 5G communication is the massive Multiple input and multiple output (MIMO), it has a major drawback when the user generated inference signals are to be handled by several other users. When these interference signals are used in various users, issues concerning system ability, power management issues and QoS related issues arises with the involvement of MIMO channel. Though internet of things (IoT) making use of MIMO is still under development, the requirements of the IoT is quite different when compared to several other connections. Thus, taking into account the demands, the solutions were framed with the help of the proposed system. One such solution is the Partition Square and Cross-Processing method that can possess several antennas at the given destination. Based on this solution obtained the data rate can be drastically increased correspondingly reducing the power consumed thus producing the most desirable result with high signal to noise ratio (SNR). Best victory is another such solution that solves the issues relating to power reduction thereby providing the best solution with minimum SNR. These solutions produced by the proposed system still has some disadvantages with respect to the following case: when the number of destination antennas is less than the number of source antennas. This case is considered as most common in the model proposed. For the above-mentioned case, near optimal solution is produced by both the algorithms. In this article, the transmitters are represented by the source antenna and the receiver is represented by the destination antenna. Thus, with the help of IoT connectivity, major benefits can be bought to the massive MIMO channel. © 2020 John Wiley & Sons Ltd

Transactions on Emerging Telecommunications Technologies

Enhanced development of communication between the network and the end user by eliminating the interference signals in MIMO channel

A photonic crystal (PhC) based optical component paves a path to the upcoming all-optical computer processors. All the components can be realized with the help of PhCs. In particular, optical gates have played a major part in the development of all-optical half adders which has lead to the bloom of optical computing technology. In this paper, a PhC based optical half adder is proposed and a brief analysis is carried out for the different crystal structures and lattice patterns. The efficiency of the device is analyzed by providing proper distinct space in output power between logical '0' and '1' states and it operates well even in the reduced input power level. The error can be minimized while identifying the logical states (logic '0' and logic '1'), by setting a threshold limit for output power. The threshold level is fixed such that if it is greater than 0.7 µW, it is considered as logic '1', and if it is less than 0.35 µW, then it will be taken as logic '0'. The device with circular crystals in a hexagonal lattice provides a better contrast ratio of 12.55 dB and 9.29 dB for 'sum' and 'carry' respectively. The miniature size of the proposed device depicts that this device is compatible with photonic integrated circuit (PIC) applications. © 2020 Astro Ltd.

Laser Physics

Photonic crystal based all-optical half adder: A brief analysis

A four-port optical circulator based on two-dimensional square lattice photonic crystals is reported. It is simple besides the brief framework. The crystalline geometrical structure of the circulator makes 90° non-reciprocal transmissions of electromagnetic waves with low insertion loss and high levels of isolation by the diligence of magneto-optic crystals. The structure is novel because it uses a resonant cavity with a simple design. Also, in comparison to prior models, the proposed four-port circulator utilizes a two-dimensional square lattice crystal structure with a cylindrical ferrite section of the π/4 Faraday angle. The finite element method is used for this anisotropic medium to get the tensor elements in this simulation. The importance of the gyromagnetic properties of ferrite crystals for the non-reciprocal transmission is investigated. Furthermore, the corresponding S-parameters for this circulator are analyzed and reported. Due to the compact size and ease of fabrication, this device can be realized for applications such as splitting and isolation in photonic integrated circuits. © 2019 Astro Ltd.

Compact four-port circulator based on 2D photonic crystals with a 90° rotation of the light wave for photonic integrated circuits applications

Microelectronic technology has possibly reduced the power consumption rate of portable electronic devices and has led to harvest its energy from the environment through Piezoelectric Energy Harvesting Systems (PEHS). The PEHS remains promising sources for the development of self-powered microelectronic applications. This literature discusses the PEHS for powering microelectronic applications with improved efficiency and also briefly reviews the different piezoelectric material which is best suitable for the PEHS's. To validate the best piezoelectric material, an extensive experimental study has been carried out using the piezo materials such as; Lead Zirconate Titanate, Macro Fibre Composites, Quick Pack and Polyvinyl di-Fluoride in terms of vibrating frequencies, tip mass, and load resistance. The experimental results helps to understand the capability of the piezoelectric materials for energy generation when subjected to different stress and strain. The outcome of the experimental aids to choose the best piezoelectric material for the PEHS to power microelectronic applications. © 2019 IOP Publishing Ltd.

Materials Research Express

Analysis on smart material suitable for autogenous microelectronic application

Abstract: The effect of alloying additions, such as copper, carbon, and molybdenum with carbonyl iron powder, on the densification behavior, microstructural evolution, and mechanical properties of spark plasma sintered (SPS) compacts have been investigated in this work. The sintering temperature, pressure, and time during SPS were 1120°C, 30 MPa, and 5 min, respectively. Fe–2Cu–0.8C–0.6Mo was found to exhibit the highest density, hardness, and also tensile strength among all the compositions attempted. The microstructural examination of fractured surfaces of the sintered samples revealed the evidence of a mixed mode of fracture in all the alloy compositions. © 2018, Pleiades Publishing, Ltd.

Department of Manufacturing Engineering

School of Mechanical Engineering

Physics of Metals and Metallography

Microstructural Evolution of Iron Based Alloys Produced by Spark Plasma Sintering Method

In this paper, a layered tabu search (LTS) algorithm for a complex-valued channel matrix (LTS-C) is developed to provide optimal detection in large MIMO systems. The proposed LTS-C algorithm works directly on the complex-valued channel matrix rather than converting it to a real-valued matrix. The contribution of this paper is twofold. First, we propose a novel neighborhood approach based on a signal constellation graph to obtain a set of neighborhoods for the given complex-valued initial vector. Second, the tabu matrix structure is changed to track complex-valued moves. The proposed structure significantly reduces the size of the tabu matrix. Our simulation results show that the complexity reduction is substantial in the LTS-C algorithm over the LTS algorithm. In particular, LTS-C is able to achieve approximately 45–50% and 93–94% of complexity reduction in terms of the number of real operations for 16×16 and 32×32 MIMO systems, respectively. © 2017 Elsevier GmbH

AEU - International Journal of Electronics and Communications

Low complexity layered tabu search detection in large MIMO systems

High penetration of wind power generation system into grid network has satisfied enormous energy demand and has necessitated the wind power generation system to remain connected with grid network to maintain essential grid stability, even during grid fault conditions. This paper presents a novel hybrid genetic algorithm optimized Elman neural network controller for proton exchange membrane fuel cell supported customized Dynamic Voltage Restorer (DVR) to improve the fault ride-through capability of Doubly Fed Induction Generator (DFIG) based wind power generation systems. The outstanding aspect of the proposed customized DVR is that it has low heat transmission losses, therefore has a better efficiency up to 3% when compared with the conventional energy storage based DVR. The proposed shrewd DVR adequately rides through the fault by improving voltage regulation and prevents wind turbine termination during grid faults. The effectiveness of the customized DVR and proposed control strategy is analyzed for doubly fed induction generator based wind power generation system under symmetrical and unsymmetrical fault conditions. The operation of customized DVR is confirmed using time-domain simulation study carried out in MATLAB/Simulink environment. © 2018 Elsevier Ltd

Sustainable Cities and Society

Improved fault ride through capability of DFIG-wind turbines using customized dynamic voltage restorer

In this paper, we propose a modified lattice reduction (LR) for parallel decoding (PD) in multiple input and multiple output (MIMO) systems. Compared with the conventional methods, without any performance loss, the symbols can be estimated in parallel using this LR-PD algorithm. This parallel decoding is achieved through the proposed postrotation matrix. Among the various LR algorithms, LLL has been considered in the analysis of this postrotation matrix. However, this can be applied to any other LR algorithms without any modifications. In simulations, we show that with a minimal number of extra arithmetic operations and without any significant loss in orthogonal defect and bit error rate performance, the parallel decoding becomes possible in a real as well as complex-valued MIMO system model. © TÜBITAK.

Fulltext

Turkish Journal of Electrical Engineering and Computer Sciences

Parallel decoding for lattice reduction-Aided MIMO Receiver

The use of multiple antennas at both the transmitter and the receiver is the key technology for future wireless communications since it achieves higher spectral efficiency. Symbol decoding at the receiver for such a system is still a challenge. We propose a new enumeration technique, termed as probabilistic threshold-based Schnorr-Euchner (PSE) enumeration, to reduce the complexity of sphere decoding (SD). The conventional SE-SD algorithm visits all nodes satisfying the sphere constraint in ascending order of their branch metric values. However, this algorithm is computationally expensive in real-time scenarios. Therefore, we use a threshold limit for the branch metric values in the Schnorr-Euchner (SE) enumeration which is based on the noise statistics, to reduce the overall complexity. In each layer of the decoding process, the proposed PSE-SD technique performs a threshold test before visiting the next candidate in an SE ordered list. As a result, unlikely nodes, which do not satisfy the threshold test, are pruned earlier than in the conventional SE-SD algorithm. From the simulation results, we examine the influence of the proposed probabilistic threshold for various MIMO configurations and witness that the PSE-SD technique achieves a significant complexity reduction over existing methods with only a negligible performance loss. © 2016 Elsevier GmbH. All rights reserved.

Reduced complexity sphere decoding using probabilistic threshold based Schnorr-Euchner enumeration

Sphere decoding (SD) for multiple-input and multipleoutput systems is a well-recognized approach for achieving near-maximum likelihood performance with reduced complexity. SD is a tree search process, whereby a large number of nodes can be searched in an effort to find an estimation of a transmitted symbol vector. In this paper, a simple and generalized approach called layer pruning is proposed to achieve complexity reduction in SD. Pruning a layer from a search process reduces the total number of nodes in a sphere search. The symbols corresponding to the pruned layer are obtained by adopting a QRM-MLD receiver. Simulation results show that the proposed method reduces the number of nodes to be searched for decoding the transmitted symbols by maintaining negligible performance loss. The proposed technique reduces the complexity by 35% to 42% in the low and medium signal-to-noise ratio regime. To demonstrate the potential of our method, we compare the results with another well-known method - namely, probabilistic tree pruning SD. © 2014 ETRI.

ETRI Journal

Performance analysis of layer pruning on sphere decoding in mimo systems

A threshold based Schnorr-Euchner (TSE) sphere decoder (SD) is presented in this paper to reduce the high computational burden incur in multiple input multiple output (MIMO) decoding. The proposed method makes use of the probabilistic threshold for SE enumeration to remove the nodes which are most unlikely to be an ML solution. The threshold is chosen using the pruning probability based on noise statistics. By increasing the pruning probability, the higher level of complexity reduction can be achieved at the cost of slight performance loss. Simulations illustrate that the proposed TSE-SD achieves an improvement in performance through complexity reduction over conventional SE-SD. © 2014 IEEE.