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 wide range of compact and reliable single-pole-multi-throw (SPMT) radio frequency (RF) microelectromechanical system (MEMS) switches where the M (output) varies from 3 to 14 throws. The single dc-contact switch dimensions are 0.144 mm × 0.29 mm which are fabricated on 635 m alumina substrate using a surface micromachining process. SPMT switching networks demonstrate a measured return loss of more than 14 dB, a worst case insertion loss of ∼1.76 dB and isolation of ∼14.5 dB up to 12 GHz. The maximum area of the fabricated SPMT switch is ∼1.2 mm2. The SPMT switches are capable of handling 1 W of RF power up to &gt;1 billion cycles at 25 °C, and sustained even up to &gt;80 million cycles with 0.5 W at 85 °C. To the best of our knowledge, this is the first reported wide range of MEMS SPMT switches and their respective performance evaluations in the literature that has undergone extensive measurement stages. © 2016 IOP Publishing Ltd.

World University root node

Journal of Micromechanics and Microengineering

Extensive performance evaluations of RF MEMS single-pole-multi-throw (SP3T to SP14T) switches up to X-band frequency

Heart sound segmentation is the process of identifying the various events like S1, S2, S3, S4, and murmurs present in the phonocardiogram (PCG) signal. In this paper, a heart sound segmentation algorithm for segmenting S1 and S2 heart sound which corresponds to the systolic and diastolic activity of the heart is presented. The proposed method is based on variational mode decomposition (VMD) algorithm. The recorded PCG is decomposed into various modes using VMD. A novel criterion is proposed to select an appropriate mode which is based on center frequency and relative energy. Then the Shannon entropy envelope of the selected mode is computed. S1 and S2 heart sound is segmented by applying dynamic threshold on the Shannon entropy envelope. The segmentation algorithm is tested on both available standard database (Physionet, Pascal, Michigan, and eGeneralMedical) and recorded signal. The simulation results demonstrate that the proposed method achieved the sensitivity, positive predictivity, and the accuracy of above 95% with detection error rate of below 6%. © 2017 IEEE.

IEEE Region 10 Annual International Conference, Proceedings/TENCON

S1 and S2 heart sound segmentation using variational mode decomposition

In this paper, we present a new method based on sparse signal decomposition for effectively removing baseline wander (BW) noise from the ECG signal. Our proposed method not only eliminates BW noise from ECG signal but also preserves the morphological shape of local waves of the signal. Our proposed method is tested and validated on real ECG signals taken from MIT-BIH arrhythmia database. Comparative results depict the superior performance of the proposed method over the state of art methods. © 2016 IEEE.

A robust sparse signal decomposition framework for baseline wander removal from ECG signal

Objective: Automatic detection and classification of noises can play a vital role in the development of robust unsupervised electrocardiogram (ECG) analysis systems. This paper proposes a novel unified framework for automatic detection, localization, and classification of single and combined ECG noises. Methods : The proposed framework consists of the modified ensemble empirical mode decomposition (CEEMD), the short-term temporal feature extraction, and the decision-rule-based noise detection and classification. In the proposed framework, ECG signals are first decomposed using the modified CEEMD algorithm for discriminating the ECG components from the noises and artifacts. Then, the short-term temporal features such as maximum absolute amplitude, number of zerocrossings, and local maximum peak amplitude of the autocorelation function are computed from the extracted high-frequency and low-frequency signals. Finally, a decision rule-based algorithm is presented for detecting the presence of noises and classifying the processed ECG signals into six signal groups: noise-free ECG, ECG+BW, ECG+MA, ECG+PLI, ECG+BW+PLI, and ECG+BW+MA. Results: The proposed framework is rigorously evaluated on five benchmark ECG databases and the real-time ECG signals. The proposed framework achieves an average sensitivity of 99.12%, specificity of 98.56%, and overall accuracy of 98.90% in detecting the presence of noises. Classification results show that the framework achieves an average sensitivity, positive predictivity, and classification accuracy of 98.93%, 98.39%, and 97.38%, respectively. Conclusion: The proposed framework not only achieves better noise detection and classification rates than the current state-of-the-art methods but also accurately localizes short bursts of noises with low endpoint delineation errors. Significance: Extensive studies on benchmark databases demonstrate that the proposed framework is more suitable for reducing false alarm rates and selecting appropriate noise-specific denoising techniques in automated ECG analysis applications. © 2013 IEEE.

IEEE Journal of biomedical and health informatics

Automated ECG noise detection and classification system for unsupervised healthcare monitoring

PCG is one of the most widely used physiological signals for cardiac monitoring due to its simplicity. PCG segmentation involves identifying or classifying S1 and S2 sounds that correspond to systolic and diastolic periods respectively. There are many PCG segmentation algorithms that can identify the start and end time instants of S1 and S2 sounds. However, most of the algorithms distinguish S1 and S2 sounds based on the time duration threshold, which may fail for abnormal patients. In order to solve this ambiguity, multi-channel approaches are used. In this work, a hardware for simultaneous acquisition of PCG and PPG (from the fingertip of the subject) is developed. Then by using the proposed low complex PCG and PPG processing algorithms, the correlation of occurrence of S2 event of PCG with the systolic peak point and foot point of PPG is analyzed. The correlation parameters of PCG and PPG are reported and validated with the existing multi-channel approaches. The simulation results performed on real-time database demonstrates that the proposed S2 sound detection method achieved the sensitivity of 98.23%, positive predictivity of 99.64%, and the accuracy of 94.50%. The detection error rate of proposed S2 sound detection algorithm is 7.07%. © 2017 IEEE.

TENCON 2017-2017 IEEE Region 10 Conference

Real-time detection of S2 sound using simultaneous recording of PCG and PPG

A modular multilevel converter (MMC) with traditional cascaded PI control structure suffers from poor steady state and dynamic performance. This is due to the limited harmonic rejection capability of PI controller thus failing to alleviate even order harmonics in circulating current and due to the slower outer average voltage control loop resulting in significant deviation in submodule capacitor voltages during load transients. This paper presents a new control structure with a repetitive controller (RC) in conjunction with a Lyapunov function-based controller (LFC) in the inner circulating current loop and an additional load current feed forward loop in addition to the outer voltage loop to improve both steady-state and dynamic performance of MMC. RC has a good steady-state harmonic suppression capability therefore can effectively alleviate the circulating harmonic currents, where as LFC ensures a stable operation and superior dynamic performance of the converter against load disturbances. Analytical equations governing the design of both the controllers are presented. Model of a single phase, 5-level MMC is developed on a PLECS RT box real-Time simulator for hardware-in-The-loop (HIL) testing, it operates along with the external Texas Instruments DSP controller hosting the developed control scheme. Real-Time simulation results are presented to substantiate the improvement in steady state and dynamic performance of MMC with the proposed repetitive and Lyapunov function based circulating current controller. © 2017 IEEE.

Proceedings IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society

A repetitive and Lyapunov function-based control approach for improved steady state and dynamic performance of modular multilevel converters

In orthogonal frequency division multiplexing systems, reduced feedback schemes provide essential channel state information from the users to the base station (BS) without overwhelming the uplink. For the practically important best-M scheme, in which each user feeds back only its M strongest subchannels and their indices to the BS, we derive a novel, throughput-optimal scheduling and rate adaptation policy that enables the BS to schedule the best user and its data rate for all the subchannels. The policy exploits the structure of the information fed back by the best-M scheme and the correlation among subchannel gains. We present it in closed-form for the widely studied exponential correlation model. Using insights gleaned from the optimal policy, we propose a novel, low-complexity two subchannel reduction approach, which is seen empirically to be near-optimal and easily handles practically important general channel correlation models, quantized feedback, and co-channel interference in multi-cell scenarios. Compared with several ad hoc approaches, the proposed approaches improve the cell throughput without any additional feedback. A modified gradient-based opportunistic scheduler is also proposed to ensure user fairness. © 2017 IEEE.

IEEE Transactions on Communications

Throughput-Optimal Scheduling and Rate Adaptation for Reduced Feedback Best-$M$ Scheme in OFDM Systems

Low frequency switching of voltage source inverters generates low order harmonic voltages in the output causing torque and speed ripple. In this paper, a multilevel space vector diagram formed by nine-concentric octadecagons (polygons with 18 sides) using a single DC source is presented which eliminates lower order harmonics till seventeenth order from the phase voltage output over the entire modulation range including overmodulation. The topology consists of a flying capacitor (FC) inverter followed by a capacitor fed cascaded H-bridge (CHB) inverter. Single DC source permits easy four quadrant operation. The PWM scheme implemented results in quasi-square waveform operation of the FC inverter resulting in low switching losses. The CHB inverter switching removes the harmonics generated by FC inverter, but operates at a lower voltage. Hence the switching loss is low in the CHB inverter also. The power circuit topology, the formation of the space vector structure and the steady state and transient simulation results are presented in this paper. © 2016 IEEE.

IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2016

A multilevel nine-concentric octadecagonal space vector structure for induction motor drives using a single DC source

This paper proposes a novel six-phase stacked multilevel inverter drive with only one dc source for a six-phase IM with symmetrically placed windings (60° apart). Using one dc source allows direct ac-ac conversion and the inverter can feed the power back to the grid at any power factor. This paper presents a systematic approach to use one dc source for the six-phase stacked multilevel inverter fed symmetric IM drive. Here the individual dc supply is realized by series connected (split) capacitors with inherent balancing of the neutral point (dc link capacitor mid point) current within a switching cycle. This also helps in reducing the dc-link capacitor size. To verify the concept experimentally, a six-phase stacked nine-level inverter is developed in the laboratory for a symmetric six-phase IM and it is run with V/f control. Detailed experimental results are presented to validate the concept. © 2016 IEEE.

IEEE Transactions on Industrial Electronics

Novel Symmetric Six-Phase Induction Motor Drive Using Stacked Multilevel Inverters With a Single DC Link and Neutral Point Voltage Balancing

This paper presents a new wide-area backup protection scheme based on the phase angle of positive-sequence integrated impedance (PAPSII). The proposed scheme uses phasor measurement units (PMUs) that comply with standard C37.118.1-2011 for retrieving the phasor information. The PMUs provide the positive-sequence phasor information of the voltage and current signals at each and every bus of a system to a phasor data concentrator (PDC). The positive-sequence integrated impedance of each line of the system is extracted, and the PAPSII of each line is continuously monitored at the PDC. The values of the PAPSII help in identifying the faulted line of the power transmission system. The proposed scheme is extensively tested for different types of fault scenarios on a three-machine nine-bus power transmission network on a real-time digital simulator platform. Critical issues such as voltage inversion, current inversion, load encroachment, and the power swing are addressed in the proposed scheme. The test results indicate that the proposed scheme can overcome the limitations of existing backup protection schemes and can provide a reliable protection measure. © 2007-2012 IEEE.