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

Radio frequency micro electromechanical system (RF MEMS) based switches are widely used in microwave and millimeter wave communication systems for their low loss, excellent linearity, low power consumption and compact size compared to other contemporary solid state devices [1]. Surface micromachining technology is typically used to develop different types of single pole multi-throw (SPMT) switches like SPST, SPDT and SP4T. MEMS series and shunt switches are extensively used in SPMT RF switches for multiband selectors, filter banks, reconfigurable antennas and phase shifter applications in transmit/receive modules. © 2014, Springer India.

World University root node

Springer Tracts in Mechanical Engineering

RF MEMS single-pole-multi-throw switching circuits

A radio frequency micro-electro-mechanical system (RF-MEMS) phase shifter based on switchable delay line concept with maximum desirable phase shift and good reliability is presented in this paper. The phase shifter is based on the switchable reference and delay line configurations with inline metal contact series switches that employs MEMS systems based on electrostatic actuation and implemented using coplanar waveguide (CPW) configuration. Electromechanical behaviour of the MEMS switch has been extensively investigated using commercially available simulation tools and validated using system level simulation. A detailed design and performance analysis of the phase shifter has been carried out as a function of various structural parameters with reference to the gold-based surface micromachining process on alumina substrate. The mechanical, electrical, transient, intermodulation distortion (IMD) and loss performance of an MEMS switch have been experimentally investigated. The individual primary phase-bits (11.25°/22.5°/45°/90°/180°) that are fundamental building blocks of a complete 5-bit phase shifter have been designed, fabricated and experimentally characterized. Furthermore, two different 5-bit switched-line phase shifters, that lead to 25% size reduction and result in marked improvement in the reliability of the complete 5-bit phase shifter with 30 V actuation voltage, have been developed. The performance comparison between two different CPW-based switched-line phase shifters have been extensively investigated and validated. The complete 5-bit phase shifter demonstrates an average insertion loss of 5.4 dB with a return loss of better than 14 dB at 17.25 GHz. The maximum phase error of 1.3° has been obtained at 17.25 GHz from these 5-bit phase shifters. © 2014 IOP Publishing Ltd.

Journal of Micromechanics and Microengineering

Design and development of a CPW-based 5-bit switched-line phase shifter using inline metal contact MEMS series switches for 17.25 GHz transmit/receive module application

This Letter presents a fairly straightforward and robust QRS detector for wearable cardiac monitoring applications. The first stage of the QRS detector contains a powerful l1-sparsity filter with overcomplete hybrid dictionaries for emphasising the QRS complexes and suppressing the baseline drifts, powerline interference and large P/T waves. The second stage is a simple peak-finding logic based on the Gaussian derivative filter for automatically finding locations of R-peaks in the ECG signal. Experiments on the standard MIT-BIH arrythmia database show that the method achieves an average sensitivity of 99.91% and positive predictivity of 99.92%. Unlike existing methods, the proposed method improves detection performance under small-QRS, wide-QRS complexes and noisy conditions without using the searchback algorithms. © The Institution of Engineering and Technology 2014.

Healthcare Technology Letters

Straightforward and robust QRS detection algorithm for wearable cardiac monitor

Dead-time is introduced between the gating signals to the top and bottom switches in a voltage source inverter (VSI) leg, to prevent shoot through fault due to the finite turn-off times of IGBTs. The dead-time results in a delay when the incoming device is an IGBT, resulting in error voltage pulses in the inverter output voltage. This paper presents the design, fabrication and testing of an advanced gate driver, which eliminates dead-time and consequent output distortion. Here, the gating pulses are generated such that the incoming IGBT transition is not delayed and shoot-through is also prevented. The various logic units of the driver card and fault tolerance of the driver are verified through extensive tests on different topologies such as chopper, half-bridge and full-bridge inverter, and also at different conditions of load. Experimental results demonstrate the improvement in the load current waveform quality with the proposed circuit, on account of elimination of dead-time. © 2014 IEEE.

2014 IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2014

An advanced gate driver for insulated gate bipolar transistors to eliminate dead-time induced distortions in inverter output

This paper proposes an intelligent relaying scheme for transmission lines compensated by Unified Power Flow Controller (UPFC). The algorithm uses a new relaying signal termed as imaginary part of integrated impedance (IPII). The synchronized phasor measurement units at both ends of the transmission line are used to extract voltage and current phasors from instantaneous volatage and current signals. The volatage and current phasors are utilised to derive IPII of each phase. Further, IPII of each phase are used as input to a data-mining model termed as decision tree (DT) which provides the final relaying decision. The proposed algorithm is validated on real time digital simulator (RTDS) platform and the results obtained indicate that the proposed scheme is reliable in protecting transmission system compensated by UPFC. © 2014 ACPE.

2014 Australasian Universities Power Engineering Conference, AUPEC 2014 - Proceedings

Synchrophasor measurement based smart relays for UPFC compensated transmission system

This paper presents a differential relaying scheme for a tapped transmission line in presence of Unified Power Flow Controller (UPFC) and wind-farm together. The process starts at retrieving the fault current signal at the respective busses connecting the lines involving fault and pre-processing it using multi-resolution based Wavelet transform to derive third level approximate coefficients (CA3). Further the Discrete Fourier Transform (DFT) is used to compute the RMS value of the signal from the reconstructed signals expressed in terms of Wavelet approximate coefficients. Once the RMS value of the signal is estimated the operating (tripping) and restraining signals are computed for fault detection and classification in transmission lines including UPFC and wind-farm. The proposed scheme has been extensively tested on faulted conditions with wide variations in operating parameters and the test results indicate that it can reliably detect and classify faults including the ability to discriminate internal faults from external faults in transmission lines with a response time of less than two cycles from fault inception. © 2014 Elsevier Ltd. All rights reserved.

International Journal of Electrical Power and Energy Systems

Differential relaying scheme for tapped transmission line connecting UPFC and wind farm

In this paper the authors suggest a novel protection scheme for a tapped transmission line connected to wind-farm in presence of UPFC. The powerful analyzing and decomposing features of Wavelet Transform(WT) along with the accurate phasor extraction feature of Discrete Fourier Transform(DFT) has been combined to develop this useful and effective protection scheme. The whole idea of the proposed scheme is to extract third level decomposed current signals at each substation using Wavelet Transform. Then third level approximate coefficients(CA3) are reconstructed for each line current at every substation to derive operating and restraining quantities after extracting the respective fundamental phasors by using DFT. The proposed scheme has been tested on a 500 kV, teed-transmission line in the presence of UPFC and Wind Farm (as one of the substation) under various fault and operating conditions on MATLAB environment. The results given in section-V shows the feasibility of the proposed relaying scheme. To compare effectiveness of the proposed differential relaying scheme along with the conventional relaying scheme, different types of faults have been simulated at different location of the transmission line by considering three statistical metrics (i.e Dependability, Security and Yield) and result has been compared and shown in table-1 © 2014 IEEE.

IEEE TechSym 2014 - 2014 IEEE Students' Technology Symposium

A differential protection scheme for tapped transmission line containing UPFC and wind farm

An asymmetrical pulse width modulated (APWM) full-bridge DC-DC converter for interfacing photovoltaic (PV) system with electric vehicle (EV) battery system is presented in this paper. The active switches in the front end converter are turned on at zero voltage with the proposed APWM technique. The operation of the converter with this technique is explained with detailed analysis. The theoretical waveforms and equations governing the operating intervals of the converter are also discussed. Simulation results of the proposed APWM soft switched full-bridge DC-DC converter are used to verify the theoretical analysis. A 100kHz, 1kW full-bridge converter prototype is developed and hardware results for zero voltage transition are presented. © 2014 IEEE.

2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014

An APWM soft switched DC-DC converter for PV and EV

Thermal properties are of great interest in modern electronic devices and nanostructures. Calculating these properties is straightforward when the device is made from a pure material, but problems arise when alloys are used. Specifically, only approximate band structures can be computed for random alloys and most often the virtual crystal approximation (VCA) is used. Unfolding methods [Boykin, Kharche, Klimeck, and Korkusinski, J. Phys.: Condens. Matter 19, 036203 (2007)10.1088/0953-8984/19/3/036203] have proven very useful for tight-binding calculations of alloy electronic structure without the problems in the VCA, and the mathematical analogy between tight-binding and valence-force-field approaches to the phonon problem suggests they be employed here as well. However, there are some differences in the physics of the two problems requiring modifications to the electronic-structure approach. We therefore derive a phonon alloy band-structure (vibrational-mode) approach based on our tight-binding electronic-structure method, modifying the band-determination method to accommodate the different physical situation. Using the method, we study In(x)Ga(1-x)As alloys and find very good agreement with available experiments. © 2014 American Physical Society.

Fulltext

Physical Review B - Condensed Matter and Materials Physics

Brillouin zone unfolding method for effective phonon spectra

Narrowband active noise control (ANC) systems are used to mitigate periodic or nearly periodic noises produced by large scale cutting machines, engines, turbines, compressors etc. These systems employ a non acoustic sensor such as accelerometer for identifying the frequencies present in the input noise signal. These frequency values are used by the cosine wave generator to synthesize the input waveform. However, when the frequencies sensed by the tachometer are different from the actual frequencies it results in the problem of frequency mismatch (FM). In this paper through simulations degradation in the performance of conventional narrowband ANC system is observed even in the presence of FM of about 1 %. Hence, a new method using functional link artificial neural network (FLANN) is proposed which outperforms the conventional method in the presence of less to high FM. Simulation results demonstrate the efficacy of the proposed ANC system. © 2014 IEEE.