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 ultrasound imaging, a non-linear beamforming algorithm called filtered delay multiply and sum (F-DMAS) has been demonstrated to provide improved contrast and resolution compared to the commonly employed delay and sum (DAS) algorithm. In F-DMAS, the delay compensated radio-frequency narrowband signals from the transducer channels is pairwise multiplied to generate baseband and higher-order harmonic components in the output spectrum. The final image is reconstructed by filtering the second harmonic component to provide better contrast and resolution. However, other generated harmonic components, which are not utilized in the standard F-DMAS could be employed for improved contrast and resolution. In this work, a modification to standard F-DMAS is proposed where the different frequency bands generated through pairwise multiplications are selectively combined through additive or difference compounding techniques to form the final image. The results show that the proposed approach outperforms the standard F-DMAS in terms of contrast and resolution. © 2020 IEEE.

World University root node

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Delay multiply and sum based selective compounding for enhanced ultrasound imaging

Perovskite-based solar cells are one of the most rapidly emerging photovoltaic devices in terms of their ability to convert sunlight into electrical energy. Although extensively researched upon, their efficiency is still less than the thermo-dynamic limit due to various electrical losses in the device and optical losses in the stack layers that make a perovskite solar cell (PSC). This work focuses on optimizing the thickness of the transport layers (electron and hole transport layers) in the stack for planar PSCs, by accounting for different optical losses in each layer analytically. © 2020 IEEE.

2020 5th IEEE International Conference on Emerging Electronics, ICEE 2020

Optimization of Transport Layer Thickness for Perovskite Solar Cells: An Optical Analysis

This paper proposes a Modular Solid-State-Transformer (SST) topology consisting of bidirectional Matrix-Based AC-DC Dual-Active-Bridge (DAB) submodules. Unlike the conventional SST topologies, the proposed topology offers a single stage Medium Voltage AC (MVAC) - Low Voltage DC (LVDC) conversion. The discussion is focused on the AC-DC DAB submodule of a 1 MVA SST for the Energy Control Centre (ECC) of a microgrid/nanogrid. The possible modulation modes along with the corresponding power transfer limits are presented and a suitable steady-state modulation scheme is identified for the required operating point. The modeling and small-signal analysis of the AC-DC submodule is comprehensively explained. Simulation results including the steady-state operation and the frequency response of the 17.6 kW submodule are presented. © 2020 IEEE.

IECON Proceedings (Industrial Electronics Conference)

A Bidirectional Matrix-Based AC-DC Dual-Active Bridge for Modular Solid-State-Transformers

Cascaded Modular Solid-State Transformer (CMSST) is proposed as an alternative to the conventional transformer for smart grids where controlled bidirectional power flow, provision to integrate distributed generation, grid support with ancillary services and feasibility for islanded operation have become absolute necessity. Even though CMSST is modular in design (both phase-wise and system-wise), voltage balance controllers (VBC) and power balance controllers (PBC) are still required to compensate the mismatches in passive elements of various modules. The design and control philosophy of VBC and PBC are well understood in the literature, however, influence of these balance controllers on steady-state and fault performance is less studied. In this paper, analysis of balance controllers during steady-state, transient and faulty conditions are studied interms of harmonics in grid current, bandwidth of system and choice of fault indicators. The presented analysis is substantiated with experimental results from a 1 kV A CMSST prototype. These findings can serve as a good starting guidelines while choosing appropriate balance controllers for CMSST. © 2020 IEEE.

IEEE PES Innovative Smart Grid Technologies Conference Europe

Analysis of balance controllers for cascaded modular solid-state transformer during steady-state, transient and fault conditions

We propose a framework to model ferroelectric negative capacitance: electrostatic Micro Electro Mechanical Systems (MEMS) hybrid actuators and analyze their dynamic (step input) response. Using this framework, we report the first proposal for reduction in the dynamic pull-in and pull-out voltages of the hybrid actuators due to the negative capacitance of the ferroelectric. The proposed model also reveals the effect of ferroelectric thickness on the dynamic pull-in and pull-out voltages and the effect of ferroelectric damping on the energy dissipated during actuation. We infer from our analysis that the hybrid actuators are better than the standalone MEMS actuators in terms of operating voltage and energy dissipation. Further, we show that one can trade-off a small part of the reduction in actuation voltage to achieve identical pull-in times in the hybrid and standalone MEMS actuators, while still consuming substantially lower energy in the former as compared to the latter. The circuit compatibility of the proposed hybrid actuator model makes it suitable for analysis and evaluation of various heterogeneous systems consisting of hybrid MEMS actuators and other electronic devices.

arXiv preprint arXiv:1904.12808

Dynamics of Ferroelectric Negative Capacitance - Electrostatic MEMS Hybrid Actuators

Here, a new decentralised approach-based wide-area back-up protection (WABP) scheme is proposed for faulted line identification (FLI). The scheme is divided into two sub-routines, i.e. possible faulted region (PFR) identification and FLI. Initially, the power system under study is divided into different coherent regions. The concept of centre of reactive power (CORP) is used to accomplish the task of PFR. Once the faulted region is identified, FLI is done by continuously monitoring the direction of reactive power flow (DORPF) of each line within the PFR. The proposed scheme is extensively tested on IEEE-39 bus test system for different types of faults. The performance of the scheme under stressed system conditions is also investigated. The obtained results show that the suggested algorithm is able to maintain the balance between dependability and security aspects of the protection logic. © The Institution of Engineering and Technology 2019.

Fulltext

IET Generation, Transmission and Distribution

Decentralised wide-area back-up protection scheme based on the concept of centre of reactive power

Sound Source Localization is the technique to exactly locate the position of a sound emitting source with the help of the audio data only. Its applications are audio surveillance, security monitoring where visual data is not available, robotics such as robots acting as a waiter, etc. It is also an initial stage of signal processing for the fields of speech enhancement, speech separation and Automatic Speech Recognition (ASR). Localization is usually carried out using array of microphones. The scenario of locating a sound source can be different such as single source localization, multiple source localization, moving source localization, source localization in noisy environment, etc. Extensive research progress is there in this field due to its multidimensional applications. This paper attempts to address some of the existing challenges in this field. Work in this paper deals with designing of a real-time, automatic target monitoring framework based on sound source localization. A comparative study of our results with other standard localization algorithm is also presented. The studies presented in this paper leads to the fact that the designed sound source localization framework is indeed low cost, small, real-time and able to locate multiple sources satisfactorily even in office environment where level of noise and reverberation is higher than standard anechoic rooms. © 2019 IEEE.

Proceedings - 2019 7th International Conference on Digital Information Processing and Communications, ICDIPC 2019

Design of a Real-Time Automatic Source Monitoring Framework Based on Sound Source Localization

This work investigates the application of zero-frequency resonator (ZFR) for detecting systolic peaks of photoplethysmogram (PPG) signals. Based on the authors' studies, they propose an automated noise-robust method, which consists of the central difference operation, the ZFR, the mean subtraction and averaging, the peak determination, and the peak rejection/acceptance rule. The method is evaluated using different kinds of PPG signals taken from the standard MIT-BIH polysomnographic database and Complex Systems Laboratory database and the recorded PPG signals at their Biomedical System Lab. The method achieves an average sensitivity (Se) of 99.95%, positive predictivity (Pp) of 99.89%, and overall accuracy (OA) of 99.84% on a total number of 116,673 true peaks. Evaluation results further demonstrate the robustness of the ZFR-based method for noisy PPG signals with a signal-to-noise ratio (SNR) ranging from 30 to 5 dB. The method achieves an average Se = 99.76%, Pp = 99.84%, and OA= 99.60% for noisy PPG signals with a SNR of 5 dB. Various results show that the method yields better detection rates for both noise-free and noisy PPG signals. The method is simple and reliable as compared with the complexity of signal processing techniques and detection performance of the existing detection methods. © 2019 Institution of Engineering and Technology. All rights reserved.

Healthcare Technology Letters

Use of zero-frequency resonator for automatically detecting systolic peaks of photoplethysmogram signal

The design, development and characterization of microelectromechanical systems (MEMS) based lateral single-pole-four-throw (SP4T) and single-pole-seven-throw (SP7T) switching networks are presented in this paper. Switches are fabricated using surface micromachining process on alumina substrate. SP4T and SP7T switches demonstrate measured average return loss of better than 22 dB and 12 dB, worst case average insertion loss of 0.3 dB and 5.89 dB at 3.5 GHz and 28 GHz, respectively. The average isolation is better than 22 dB up to 30 GHz. Switching networks are operational &gt; 1 billion cycles even with 1 W of RF power. Maximum fabricated switch (SP7T) area is ~ 0.89 mm2 including bias lines and pads. © 2019 IEEE.

2019 IEEE MTT-S International Microwave and RF Conference, IMARC 2019

Broadband, reliable and compact lateral MEMS SP4T and SP7T switching networks for 5G applications

A carrier based hybrid pulse width modulation (PWM) strategy for dual inverter with reduced switching loss is proposed in this paper. The proposed hybrid modulation scheme clamps each phase 60° continuously to the DC bus mid-point at all load power factors and results in reduced switching loss for lower modulation range. The hybrid scheme is obtained after comparing different combinations of level shifted and decoupled PWM methods based on average switching energy loss, current harmonic distortion, common mode and differential mode voltage switchings. All PWM methods are analysed on a dual inverter fed induction motor (IM) drive operated with open loop v/f control. From the analysis, it is observed that the proposed carrier based hybrid PWM scheme results in upto 20% reduction in switching loss as compared to the conventional bus clamping PWM methods for low speed operations. The hybrid PWM also has improved performance in terms of common mode and differential mode voltage switchings. The performance of PWM methods are experimentally validated on an open end winding IM drive. The PWM methods are generated using triangle carrier comparison with synchronous sampling. © 2019 IEEE.