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

A dual band monopole resonator antenna is proposed in this paper. The antenna works at two different bands with central frequencies of 2.4 GHz and 5 GHz. To cover the two bands of WLAN (i.e., lower band of 2.4 GHz and upper bands of 5 GHz), two monopoles are used: one working for the lower band and the other working for the higher band. However, there is a limit in most of these antennas to obtain the wideband characteristic especially at the 5-GHz band for WLAN applications, when operating simultaneously at 2.4 GHz. The proposed antenna achieves a good bandwidth at the upper frequency, the data rate has been increased with the help of MIMO configuration. The simulated results are giving a very good return loss of -22.14 dB for 2.4 GHz band and -35.43 dB for 5.0 GHz for the single antenna. © 2020 IEEE.

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IEMTRONICS 2020 - International IOT, Electronics and Mechatronics Conference, Proceedings

Dual band monopole antenna for WLAN MIMO applications at 2.4 and 5 GHz

Active control of noise for multi-channel applications is affected by the existence of nonlinear primary and secondary paths. There is a degradation in the performance of linear multi-channel active noise control (LMANC) systems based on minimization of sum of squared errors obtained from multiple sensors in presence of nonlinear primary path (NPP) and nonlinear secondary path (NSP) conditions. The NPP and NSP problems are more prominent and challenging for multi-point noise control applications owing to different locations of silent zones and acoustic coupling between secondary sources and error sensors. In order to surmount this problem, an incremental strategy based nonlinear distributed ANC (NDANC) system is developed in this article. The adaptive exponential functional link network (AE-FLN) is employed as an adaptive control unit at the acoustic sensor nodes (ASNs) for the design of NDANC system. The incremental co-operation scheme is utilized to provide uniform noise cancellation in presence of NPP and NSP conditions. Simulation study is conducted extensively to demonstrate the efficiency of the proposed system for different practical NPP and NSP scenarios. The detailed computational load analysis and subjective evaluation of reduction in perceptual noise levels are performed for different real noise conditions. Copyright © 2020 IEEE.

IEEE Open Journal of Signal Processing

Incremental learning based adaptive filter for nonlinear distributed active noise control system

In this article, we propose a new on-device photoplethysmography (PPG) signal quality assessment (SQA) system based on the first-order (FO) predictor coefficient (PC) of differenced sensor (DS) signal that is capable of significantly reducing false alarms and timely notifying sensor disconnection and saturation in unsupervised health monitoring. The proposed system consists of the DS signal computation, random noise addition, PC estimation, and hierarchical decision rules. The proposed system is evaluated by using varieties of sensor signals taken from standard databases and the PPG signals recorded using three PPG sensing modules available at our Biomedical System Laboratory. Results show that the proposed method achieves correct detection rates of 98.22\%, 80.09\%, and 99.79\% for noise-free PPG segments, motion artifacts corrupted segments, and pulse-free segments, respectively, and also outperforms other SQA methods. The proposed method had a false alarm reduction rate of 90.71\% and a missed acceptable quality rate of 1.78\%. Real-time implementation on the Arduino Due computing platform with a 32-bit Cortex-M3 processor, 512-kB flash memory, and 96-kB data memory demonstrates that the proposed on-device SQA system consumes 0.141 mJ with an overall accuracy of 93.21\%, whereas the kurtosis and Shannon entropy (KSE) and the fiducial and template (FT)-based methods consume 109.08 and 6.71 mJ with overall accuracies of 39.24\% and 74.13\%, respectively. The proposed system has great potential for developing energy-efficient accurate and reliable Internet of Things (IoT) and smartphone-based health monitoring systems.

IEEE Transactions on Instrumentation and Measurement

On-device integrated ppg quality assessment and sensor disconnection/saturation detection system for IoT health monitoring

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 pre-specified 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.

IET ENERGY SYSTEMS INTEGRATION

Islanding detection using total variation-based signal decomposition techniqueInspec keywordsOther keywords

In this paper, a new model-based fault detection and localization algorithm is proposed for cascaded H-bridge (CHB) multilevel converter to localize the open-circuit faults without the use of any additional sensors. Using DC bus voltages, switching states and grid voltage, grid current is estimated and compared with the measured grid current. Any significant deviations in the estimated and actual grid current of the CHB trigger an open circuit (OC) fault. Upon open circuit fault detection, the modulation scheme is altered from phase-shifted unipolar SPWM to phase-shifted bipolar SPWM for fault localization. At selected time instants, the change in measured grid current for a period of 5Ts (Ts being the step time of controller) is calculated and compared with the estimated change in grid current from the system model. The above-mentioned comparisons are used to localize the open-circuit faults in the CHB. The proposed method is verified on a scale-down CHB prototype and experimental results are presented to demonstrate the effectiveness of the proposed method. © 2020 IEEE.

ECCE 2020 - IEEE Energy Conversion Congress and Exposition

A New Model-Based Fault Detection and Localization Scheme for Cascaded H-bridge Multilevel Converter

The work proposes an interleaved modulation method for two three-level converters connected in parallel for grid applications such as high-power active front end rectifiers, STATCOMs, and so on. The parallel converter system is controlled using a centralised predictive controller and 60° discontinuous pulse width modulation, with phase-shifted/interleaved carriers. The proposed PWM utilises the switching state redundancy of '0' state of the flying capacitor topology such that instantaneous pole voltage difference between the converters is zero. The proposed method eliminates the circulating current flow between the converters, and shifts the dominant grid current harmonics to twice the switching frequency. The method also ensures the balancing of flying capacitor voltages along with a reduction in common mode voltage. © 2020 IEEE.

9th IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2020

Interleaved PWM for parallel converters with single DC link for zero circulating current

Phased array antennas are being increasingly used in weather radars. However, these antennas have the inherent property that the horizontal and vertical waves are not orthogonal in all azimuth and elevation angles range. Thus, designing phased array antennas with very low cross-polarization is of significant interest to radar scientists and engineers. This work aims at implementing a dual linearly polarized aperture-coupled antenna design and layout so as to reduce this undesired cross-polarization while maintaining the required beamwidth, radiation pattern and scan range range. Here, an antenna element and the corresponding subarray of the antenna elements are implemented, which result in significantly low cross-polarization. This sub-array will be used for full array design. © 2020 IEEE.

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

Enhancement in Dual Polarization Phased Array Antenna Performance and Calibration Techniques for Weather Radar Applications

This paper presents a new design for a Circularly Polarized Square Slot Antenna (CPSSA). The proposed antenna is single layered with L-shaped stubs loaded on both the opposite corners of the antenna, which is capable of generating orthogonal modes for the excitation of Circular Polarization. Two asymmetric strips on the top and the left portions of the proposed antenna and various other asymmetric strips are also loaded. The proposed structure is having the dimensions of 40 x 40 x 1.6 mm3.The designed CPSSA operates in the range of 3.2-12.5 GHz with Axial Ratio (AR) bandwidth in the range of 4.5-8.5 GHz. In this paper the improvement of the performance parameters like AR and Return Loss (S11) on the addition of asymmetric stubs is explained in detail. © 2020 IEEE.

A CPW-Fed square slot circularly polarized antenna with asymetrie stubs for ultra wideband applications

A 77 GHz polarization-agile radio frequency microelectromechanical system (RF MEMS) patch antenna integrated with single-pole single throw switches is presented. The polarization of the proposed antenna can be switched among linear polarization, right-hand circular polarization, and left-hand circular polarization. The RF MEMS antenna is fabricated on 25 mil alumina with permittivity of 9.8. The reflection and radiation parameters of antenna including return loss, radiation patterns, gain, and axial ratio are measured and are found to be in correlation with simulated results. The proposed work is useful for automotive radar applications. © 2020 Wiley Periodicals, Inc.

Microwave and Optical Technology Letters

A 77-GHz polarization-agile microelectromechanical system antenna

Doppler ultrasound based methods are widely used in investigating the vascular hemodynamics and to quantize the blood flow dynamics. But conventional Doppler ultrasound techniques are limited to the investigation of axial flows as it is not sensitive to the transverse flow component. When it comes to non-invasive imaging of the human vasculature, as most of the blood vessels are parallel to the skin surface, the flow is transverse and hence conventional Doppler estimates are not reliable. To tackle this, various methods like cross beam Doppler, cross-correlation methods and multi-transmit multi-receive schemes have been developed in the recent past. Most of the strategies in this regard use plane waves which are electronically steered at different angles for insonification. In this work, the performance of a triangulation based algorithm with non-steered plane wave transmit is investigated for transverse flows. The algorithm makes a best fit out of the triangulation estimates with different receive angles so that the variability in vector estimation with the receive angles are reduced. The performance of the developed algorithm is evaluated with extensive simulations using Field II. The algorithm is tested with different flow profiles at different velocities and the estimates are shown to be promising and the accuracy is comparable with that of other vector flow imaging methods. © 2020 SPIE.