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

This work presents a study where a Sinusoidal Corrugated Antipodal Vivaldi Antenna (SC-AVA) operating in the Ultra-Wideband (UWB) region is employed as a transducer for microwave imaging of a cancerous breast. The functionality of the antenna within the UWB range is initially confirmed through thorough testing of performance parameters, including return loss, gain, radiation pattern, and group delay. Subsequently, its practical application in biomedical imaging is evaluated by measuring Specific Absorption Rate (SAR) readings at multiple frequencies within the operational range. The SAR readings are obtained from an EM simulator by modelling both homogeneous and heterogeneous breast phantoms and placing them in close proximity to the transducer. The SAR values are recorded at various frequencies, and it is determined that these readings comply with the Federal Communication Commission (FCC) regulations. The modelled SC-AVA is further utilized in the detection of a single tumor in a homogeneous breast phantom and multiple tumors in a realistic heterogeneous breast phantom. These phantoms are developed in a laboratory environment and imaged using an in-house developed monostatic microwave imaging setup. To gather preliminary information about the target, a homogeneous phantom with one tumor is imaged initially. Subsequently the heterogeneous phantom with two embedded tumors is imaged in this study. The imaging results demonstrate that tumors of different sizes can be clearly visualized in both breast phantoms using the SC-AVA, employing image reconstruction algorithms such as Delay and Sum (DAS) and iterative Delay and Sum (it-DAS). Furthermore, a comparison of the reconstructed images reveals that the it-DAS reconstruction algorithm produces images with improved clarity compared to the DAS algorithm. © 2023, Electromagnetics Academy. All rights reserved.

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Progress In Electromagnetics Research C

Systematic Performance Evaluation for the Detection of Breast Tumors with Sinusoidal Corrugated Antipodal Vivaldi Antennas Utilizing DAS and It-DAS Methodologies

In literature, the use of passive electromagnetic interference (EMI) filters is extensively researched to not only restrain the common-mode (CM) noise but also the differential-mode (DM) noise. Although the CM and DM chokes are simple to design, reliable, and do not need an auxiliary power supply, they increase the overall volume and reduce the power density of a power converter. Hence, this paper presents a novel integrated choke that offers higher DM impedance than the traditional CM choke by maintaining the same volume, when compared to the traditional CM choke. The calculation of CM inductance, as well as DM inductance of the proposed integrated filter topology, is presented along with a small signal measurement using an impedance analyzer. The proposed EMI filter performance is verified on a three-phase silicon carbide (SiC) fed brushless dc (BLdc) motor. © 2023 IEEE.

2023 IEEE IAS Global Conference on Renewable Energy and Hydrogen Technologies, GlobConHT 2023

Toroidal-EE-Based Integrated Common-mode Choke for dc-side EMI filter

Atrial fibrillation (AF), a complex arrhythmia with substantial morbidity and mortality implications, demands timely detection to preempt chronic cardiac complications. The need for continuous AF monitoring rises the demand for an automatic, fast and reliable detection approach that ensures low computational complexity in terms of model size and processing time. This study presents an AF detection method using a fast straightforward RR interval extraction method and Shannon entropy (ShE). The method utilizes symbolic dynamics from electrocardiogram (ECG) segments' heart rate sequences to calculate ShE. When tested on two datasets (2-lead and 12-lead) of 10 s and 30 s durations, the method achieves an accuracy of 99.958% and 100%, respectively, utilizing five machine learning classifiers. Furthermore, it showcases an exceptionally fast detection time of 0.286 μs with multilayer perception neural network. The best performance is achieved with 10 s ECG segments with Naive Bayes classifier. The classifier obtained an accuracy of 99.958% with model size of 1.5 kB and processing time of 2.13 μs. In comparison to previous studies, the evaluation results demonstrate the superior sensitivity, specificity, accuracy and speed of this newly developed AF detection method with low computational complexity. It is clear from the experimental results that the proposed methodology is highly suitable for implementation in real-time health monitoring systems. © 2023 IEEE.

ICSIMA 2023 - 9th IEEE International Conference on Smart Instrumentation, Measurement and Applications

Fast Straightforward RR Interval Extraction Based Atrial Fibrillation Detection Using Shannon Entropy and Machine Learning Classifiers for Wearables

Three-phase matrix-based ac-dc power conversion has recently gained popularity, considering its higher conversion efficiency and power density compared to the conventional two stage solutions. In the literature, several modulation strategies have demonstrated improved total harmonic distortion (THD) of the ac current in the matrix converters through independent control of the anti-series combination of active devices that form a matrix switch (i.e., two gate drivers per matrix switch). In this article, a matrix-based ac-dc power converter that utilizes only one gate driver per matrix switch is proposed without compromising the quality of ac current. Managing energy stored in high-frequency (HF) transformer's leakage inductor is an issue while utilizing single driver per matrix switch. An additional short-circuit (SC) leg is proposed to circulate stored energy in the leakage inductance during zero vector periods of the proposed converter, thereby ensuring continuous path for the leakage inductor's energy flow. Steady-state analysis of the proposed ac-dc converter along with its loss modeling is presented with necessary mathematical expressions. The presented analysis and design of the proposed converter are experimentally validated on a 2 kW hardware prototype in the laboratory environment. A pertinent comparison of the proposed matrix-based conversion methodology with the conventional matrix-based conversion strategy is also provided. © 2013 IEEE.

IEEE Journal of Emerging and Selected Topics in Power Electronics

A Modulation Strategy With Transformer Leakage Inductance Energy Management for a Three-Phase Matrix-Based Isolated AC-DC Converter

Human emotion recognition plays a vital role in brain-to-brain communication, human-machine interactions and affective computing interfaces. This paper presents electroencephalogram (EEG) based emotion recognition using variational mode decomposition (VMD) and convolutional neural network (CNN) by finding optimal hyperparameters for recognizing three emotional classes: positive, neutral and negative. The two-stage VMD based EEG processing is proposed for effectively removing artifacts and noises from the EEG signal and also for decomposing EEG signal into five brain waves such as delta, theta, alpha,beta and gamma. The CNN based emotion recognition is presented based on the differential entropy feature extracted from 1 second brain waves instead of using brain waves directly in order to reduce size of CNN model. In this study, we created twelve CNN models using three number of layers (2, 5 and 7) and four activation functions with major objective of finding best CNN model(s). The standard SEED database is used to obtain trained CNN models and test their performance. Evaluation results show that the CNN architecture with rectified linear unit (ReLU) yielded higher accuracy of 90.33% among four activation functions. For predicting emotions of positive, negative and neutral, the CNN model with 2-layer and ReLU achieves an accuracy of 100%, 94.44% and 78.2%, respectively whereas the CNN model with 7-layer results in accuracy of 100%, 94.40% and 89.13%, respectively. This study also demonstrates significance of selecting optimal hyperparameters and best activation function. © 2023 IEEE.

2023 11th International Conference on Control, Mechatronics and Automation, ICCMA 2023

EEG Based Emotion Recognition Using Variational Mode Decomposition and Convolutional Neural Network for Affective Computing Interfaces

High gain broadband reflectarray antenna (RA) using novel frequency selective surface (FSS) has been shown here for millimeter (mm) wave band wireless communication. A 25×25 array of the FSS is arranged periodically to realize the reflecting surface. The geometry of the FSS consists of edge-connected dipoles (ECDs) at the unit cell's bounday and a cross-loop resonator (CLR) at the center. The Filter characteristic is evaluated for normal and oblique angles through numerical simulation. FSS exhibits bandstop resonance at 28 GHz with s_2l < -10dB stopband bandwidth (BW) between 25.28 to 29.62 GHz (4.34 GHz or 15.8 %). A conventional Ka-band pyramidal horn antenna is placed in a prime focus position to illuminate the reflecting surface. Radiation from the horn makes a plane wave after being reflected from the FSS and enhances the directivity of the primary feed. The designed antenna displays a broadside pencil beam radiation pattern with a gain of 21.8 dBi at 28 GHz. In two ortho-normal planes (: E and H-plane)., 3 dB beamwidth of the antenna is < 7.4°. © 2023 IEEE.

International Conference on Microwave, Antenna and Communication, MAC 2023

Coupled Resonators Based Miniaturized Bandstop FSS for Broadband High Gain Reflectarray Antenna at Millimeter Wave 5G Communication Band

An aperture coupled feeding technique based dual band high gain 4 × 4 microstrip antenna array has been presented here for X-band radar and satellite communication. The designed array consists of three layers which are corporate feed network, 2D array of radiating patches, and coupling apertures on the ground plane. The novelty of the work is the designing of a new asymmetric H-shaped slot for the aperture coupled antenna (ACA) element. The antenna exhibits dual resonances in X-band at frequencies 8.45 and 11.15 GHz, those are altered by changing ACA's physical dimensions. The three layers of the array are printed on two Taconic TLY-5 dielectric materials, which are stacked over each other. The designed array is realized on overall size of 100×100×2.09 mm3 and having return loss bandwidth (BW) of 3.2 % in both bands that covers frequencies 8.53 to 8.81 GHz and 10.8 to 11.15 GHz. In two bands array radiates with gain of 17.1 and 19.34 dBi, and efficiencies of 90.7 % and 94.1 % respectively. The array exhibits considerable low cross-polarization of < - 14.2 dB and <- 36.2 dB at two operating frequencies. © 2023 IEEE.

Novel Dual Band High Gain Antenna Array Using Aperture Coupled Feeding for X-Band Radar

Energy generation is stepping on to the integration of more renewable sources as it is environment friendly and poses less ecological impact. Practical feasibility of such technologies has to be studied well before it is implemented on a system. Large scale integration of Renewable Energy Sources (RES) will reduce the total system inertia and can have adverse effects on power system transient stability. The objective of this paper is to find the impact of renewable energy penetration on one of the power system stability indicators called critical clearing time (CCT). The study is carried out on the well known IEEE 9 bus system considering different penetration of type-IV wind turbine generators (WTG). CCT is calculated for different fault locations using Dynamic Security Assessment Tools (DSA Tools) software of Powertech Labs. Furthermore, the correlation between inertia distribution index (IDI) and CCT is also explored. The results shows that the RES can have positive as well as negative impact on CCT. © 2023 IEEE.

5th International Conference on Power, Control and Embedded Systems, ICPCES 2023

Critical Clearing Time Revisited in an Inverter Dominated Power Systems

Flexible power point tracking (FPPT) control algorithms have been introduced in the literature to provide frequency support in low-inertia grid-connected photovoltaic (PV) systems. This is achieved by regulating the PV output power to a power reference obtained from the energy management system. Partial shading of PV arrays is a frequent phenomena that needs to be investigated for FPPT operation of PV systems. This paper proposes a simple and improved secant-based global FPPT algorithm that tracks the power reference during partial shading conditions. Guaranteed and fast convergence with flexibility to operate on both sides of the global maximum power point are the main contributions of the proposed algorithm. Experimental validation is carried out to demonstrate the efficacy of the proposed algorithm. IEEE

IEEE Transactions on Power Electronics

Improved Secant-Based Global Flexible Power Point Tracking in Photovoltaic Systems Under Partial Shading Conditions

In ultrasound (US)-guided interventions, accurately tracking and visualizing needles during in-plane insertions are significant challenges due to strong directional specular reflections. These reflections violate the geometrical delay and apodization estimations in the conventional delay and sum beamforming (DASB) degrading the visualization of needles. This study proposes a novel reflection tuned apodization (RTA) to address this issue and facilitate needle enhancement through DASB. The method leverages both temporal and angular information derived from the Radon transforms of the radio frequency (RF) data from plane-wave imaging to filter the specular reflections from the needle and their directivity. The directivity information is translated into apodization center maps through time-to-space mapping in the Radon domain, which is subsequently integrated into DASB. We assess the influence of needle angulations, projection angles in the Radon transform, needle gauge sizes, and the presence of multiple specular interfaces on the approach. The analysis shows that the method surpasses conventional DASB in enhancing the image quality of needle interfaces while preserving the diffuse scattering from the surrounding tissues without significant computational overhead. The work offers promising prospects for improved outcomes in US-guided interventions and better insights into characterizing US reflections with Radon transforms.