Department of Electrical Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

In this article, a new circulating current control architecture is proposed to suppress the submodule capacitor voltage ripple in a modular multilevel converter (MMC). The proposed cascaded control architecture uses the spatial repetitive controller (SRC) in both the outer voltage loop and the inner current loop, and can effectively suppress the second harmonic component of the submodule capacitor voltage ripple even under variable line frequency conditions. The dual SRC-based circulating current controller injects a second harmonic component into the circulating current to suppress the submodule capacitor voltage ripple. The SRC, which is a frequency-adaptive periodic digital controller, incorporates a phase sampling technique to achieve dynamic change in the sampling frequency, can adaptively tune its gain characteristics according to operating line frequency of the MMC. Unlike the existing techniques, the proposed controller uses the submodule capacitor voltage information for circulating current harmonic reference generation and, hence, does not require additional sensing of the output current. Detailed mathematical analysis and architecture of the proposed controller are presented in this article. A 400-V, 1-kW MMC laboratory prototype is developed and experimental results demonstrating the performance of the proposed circulating current control architecture for variable frequency and load conditions are also presented. © 1986-2012 IEEE.

World University root node

IEEE Transactions on Power Electronics

Capacitor Voltage Ripple Suppression in a Modular Multilevel Converter Using Frequency-Adaptive Spatial Repetitive-Based Circulating Current Controller

Air-conditioning and mechanical ventilation (ACMV), power distribution systems, elevators, and lighting systems are critical electrical assets of a smart building. Based on electrical components of these assets such as electrical motors, transformers, solid-state lighting and power electronic converters, a detailed analysis of failure mechanisms and statistics is presented in this paper. Further, suitable electrical and mechanical signals along with prevalent condition monitoring methods are suggested for condition monitoring of these assets based on the presented statistical analysis. This paper lays down the necessary foundation to understand the operating model of critical electrical equipment in buildings and provides a holistic picture for implementation of a predictive and preventive maintenance paradigm. This will enable the building operators to identify potential failures of building equipment and their evolution in real-time, driving decisions on scheduling repair or replacement of components to minimize downtime, save maintenance costs, improve occupant satisfaction, save energy, and maximize resilience. © 2020 IEEE.

IECON Proceedings (Industrial Electronics Conference)

A Survey of Failure Mechanisms and Statistics for Critical Electrical Equipment in Buildings

In this study, a distributed active noise control (DANC) system for spatial noise control in a network of acoustic sensor nodes based on the behavioural traits of felines is presented. An unified strategy based on incremental co-operative learning and cat swarm intelligence is proposed for noise mitigation in spatial region. The hybrid nature of the proposed incremental cat swarm optimisation (ICSO) algorithm provides efficient noise control without prior estimation of multiple secondary paths. In the developed ICSO-based DANC scheme, the individual sensor nodes communicate the intermediate solutions using incremental mode of cooperation to attain overall global noise mitigation over the distributed network. The performance of the proposed ICSO based DANC scheme is validated for tonal, broadband and practical air conditioner noise control test scenarios. Evaluation results show that the proposed system achieves faster convergence with computational efficiency of over 36% and ~2-9 dB improvement in noise cancellation for different noise cases and acoustic environments over genetic algorithm and particle swarm optimisation based DANC counterparts. © 2020 Cognitive Computation and Systems. All rights reserved.

Cognitive Computation and Systems

Bio‐inspired evolutionary computing approach for distributed active noise control problem

This study presents a passive islanding detection technique based on the approach of total variation filtering (TVF) for inverter-based distributed generation under noisy environment. Contamination of noise in the signal makes the islanding detection threshold less reliable. Therefore, the modal voltage signal is analysed through TVF-based decomposition procedure and several statistical features are obtained from its output. For decision making, the features are compared with the prespecified threshold. To tackle the challenge of islanding detection in the presence of the high-quality factor load, phase angle of the positive sequence voltage is considered as the second level of detection criterion. The proposed scheme is validated on IEEE 34-bus standard distribution system. The scheme is tested under islanding as well as all possible non-islanding network disturbances. Hardware-in-loop results are also presented in support of the theory. A comparative analysis of the proposed algorithm with the well-established S-transform is presented. The proposed scheme is found to be working effectively and can detect islanding condition within three cycles of its inception. © 2020 IET. All rights reserved.

IET Energy Systems Integration

Islanding detection using total variation‐based signal decomposition technique

Various gaseous constituents present in Venus atmosphere have been detected and measured using in situ and remote sensing instruments. However, the measurements of mesospheric constituents above the cloud level are still scarce and inadequate. This is because constituents above the cloud level have a low abundance and a high level of variability. However, millimeter and submillimeter (mm and sub-mm) frequencies can be used for Venus mesosphere measurements during prolonged Venusian day and night because several minor species in the upper atmosphere have emission/absorption bands in these frequencies owing to the rotational transitions. This study presents brightness temperatures and the corresponding sensitivity at the mm and sub-mm wave frequencies for a limb sounding radiometer. This will be useful in potential payload design, that is, instrument design, frequency, bandwidth selection, and satellite altitude as well as pointing accuracy determination for measurement above Venus clouds. For this study, a simulation based experiment has been performed and presented to determine the mm and sub-mm wave frequencies, optimum for estimation of concentration of water vapor, CO, CO2, SO2, HDO, and HCl present in the mesosphere. The simulations have been performed using a radiative transfer model called Atmospheric Radiative Transfer Simulator. The mm and sub-mm wave measurement frequencies have been determined for both day and night time of Venus. It has been determined that 183, 380, 448, and 556 GHz frequencies are most suitable for water vapor measurements, 115, 230, and 345 GHz are optimum for CO measurements, and 600, 621, and 690 GHz frequency measurements are sensitive for HCl detection. ©2020. American Geophysical Union. All Rights Reserved.

Fulltext

Radio Science

Millimeter-Wave Radiometric Information Content Analysis for Venus Atmospheric Constituents

This work presents microstrip and Substrate Integrated Waveguide (SIW) based monopulse comparators (MC) working at two different frequency bands for automated target detection. Center frequencies of the comparators are 3.5 GHz and 28 GHz with their operating bands fall in the sub-6 GHz and millimeter wave frequency range. Planar microstrip line based design is adopted for making the comparator at lower band. Simulation result shows simulated impedance matching of > 14.4 dB at the input ports over 3.4-3.6 GHz. The maximum phase deviation at the sum port of the comparator is 2.2°. At the millimeter wave range of 27.75-28.25 GHz, comparators are designed for working in a single plane and dual plane configuration. SIW is used to design these two comparators at millimeter wave. Single plane MC shows average differential phases at its sum and difference ports are -1.34° and 176.58°, respectively, with a minimum simulated return loss of > 16.26 dB at the input ports. The maximum simulated phase deviation at the sum port of dual plane SIW MC is 13.8° with impedance matching > 15.5 dB for the input ports of the comparator. © 2020 IEEE.

Proceedings of the 2020 International Symposium on Antennas and Propagation, APSYM 2020

Microstrip and SIW based Monopulse Comparators for Microwave and Millimeter Wave Applications

This work presents a broadband polarization insensitive circuit analog absorber from X to Ka-band applications. It consists of two different circular rings loaded with lumped resistors on two sides of the TLY-5 substrate, and the whole structure is terminated with the perfect electric conductor (PEC) through an air-spacer. It demonstrates 90% absorption bandwidth over 18.44 GHz with 116.8% fractional bandwidth. The proposed meta-surface is polarization insensitive due to the four-fold (circular) symmetry architecture, and it shows good angular stability for both TE and TM oblique incidences within the acceptable limit. The transmission line based equivalent circuit model shows near agreement with full-wave analysis. The novelty of this design lies in the usage of both sides of the substrate made this structure compact with a periodicity of 0.207\lambda and thickness 0.09\lambda, where \lambda is the free-space wavelength corresponding to the lowest frequency of the absorption band. Results from electromagnetic simulator prove the ability of proposed absorber in applications like electromagnetic shielding and energy harvesting. © 2020 IEEE.

Asia-Pacific Microwave Conference Proceedings, APMC

Design of Compact, Broadband Polarization Insensitive Dual-Circular Circuit Analog Absorber for X, Ku and Ka-Band Applications

This paper presents Substrate Integrated Waveguide (SIW) based beam scanning antenna array utilizing a Butler Matrix (BM). The proposed beamforming network is designed utilizing Electromagnetically coupled (EMC) four elements antenna array. BM has the feature of optimal amplitude and phase imbalance at its output ports. The four-beam array demonstrates wide scanning range from -42° to +42° with a peak gain of 11.1 dBi and peak side lobe levels (SLLs) of -10.12 dB over the frequency of 27.75-28.25 GHz for 5G cellular communication applications. © 2020 IEEE.

SIW Butler Matrix Driven Beam Scanning Array for Millimeter Wave 5G Communication

This work furnishes an Ultra-Wideband (UWB) Antipodal Vivaldi Antenna (AVA) utilizing a systematic approach. Initially, conventional AVA is designed for reference, and then periodic slit edges or corrugations are done at the edges of the AVA to get the desired frequency range of operation with increased gain. Moreover, periodic slots are done on the modified flares of the AVA to obtain the desired frequency range over a wider bandwidth (1.9 - 14 GHz). Finally, a tooth shaped dielectric director, with a higher dielectric constant is attached to the substrate to further improve the gain and directivity of the modified AVA. The proposed structure demonstrates a simulated gain of of 11.2 dBi, which is an improvement of 2.2 dBi over its non-dielectric counterpart. © 2020 IEEE.

High Gain Elliptically Tapered Antipodal Vivaldi Antenna with Tooth Shaped Dielectric Lens

In this paper, a reflective type wideband polarization converter is proposed. It can convert both linear to linear and linear to circular for different frequency bands. It consists of a simple dual-cut circular split ring resonator, printed on a thin FR-4 dielectric substrate terminated with the ground. Simulation result shows, an x/y polarized incident wave conversion to y/x reflected wave in three bands (4.49-4.63 GHz, 7.11-10.75 GHz, 14.94-16.93 GHz) and x/y polarized incident wave returns the circularly polarized reflected wave in three different bands (4.86-5 GHz, 6.09-6.46 GHz, 11.83-14.03 GHz). The proposed structure is compact with the unit-cell periodicity of 0.14λ and overall thickness 0.047λ, where λ corresponds to the lowest frequency of the operational band. The performance of the proposed structure is investigated under different oblique incidences. Surface current patterns are studied to analyze the reason behind the wideband response. Authors strongly believe that the proposed structure has the potential to be used in different applications where both linear-cross and linear-circular conversion are the primary concerns. © 2020 IEEE.