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 24-pulse rectifier has been designed for high voltage, low current applications. Four 3-phase systems are obtained from a single 3-phase source using novel interconnection of conventional single-and 3-phase transformers. From two 30º displaced 3-phase systems feeding two 6-pulse rectifiers that are series connected, a 12-pulse rectifier topology is obtained. Thus, from the four 3-phase systems that are displaced by 15º two 12-pulse rectifiers are obtained that are cascaded to realize a 24-pulse rectifier. Phase shifts of 15º and 30º are made using phasor addition of relevant line voltages with a combination of single-phase and three-phase transformers respectively. PSCAD based simulation and experimental results that confirm the design efficacy are presented.

World University root node

16th NATIONAL POWER SYSTEMS CONFERENCE,

Novel 24-Pulse Rectifier Topology based on Single 3-Phase to Four 3-Phase Transformation using Conventional Transformers for Phase Shifting

Computing the electronic energy levels of a finite system or nanostructure is more difficult than computing those of an infinite system or bulk material. In the literature, a technique for simplifying this computation has been proposed, wherein energy levels of a finite system are derived from those of the corresponding infinite system. So far, this method has been validated only for finite length one-dimensional systems and for higher-dimensional systems at k = 0. We establish that this technique, hereafter referred to as the confined Bloch wave (CBW) method, is valid for higher-dimensional symmorphic systems over the entire Brillouin zone, provided some symmetry requirements are satisfied. For this purpose we use a lateral surface superlattice as a model for the infinite system and a stripe or ribbon patterned in this superlattice as a model for the nanostructure. Finally, we compute the subbands of zigzag ribbons of one type patterned in artificial graphene and show that the CBW method predicts all the important subbands in these ribbons, and provides additional insight into the nature of their wavefunctions. © 2010 IOP Publishing Ltd.

Journal of Physics Condensed Matter

On a simple scheme for computing the electronic energy levels of a finite system from those of the corresponding infinite system

Fast and accurate spectrum sensing is one of the key functionalities in a cognitive radio (CR), targeted to exploit the unoccupied part of the licensed electromagnetic spectrum. The discrete Fourier transform filter bank (DFTFBs) employed in energy detection based spectrum sensing provides only fixed sensing resolution as it splits the wideband input signal into uniform bandwidth channels (frequency bands). In this paper, a modified DFTFB is presented which can be reconfigured with minimal overhead to extract channels of different bandwidths and thus enables variable resolution spectrum sensing. The proposed DFTFB consists of a prototype filter realized using the coefficient decimation technique for obtaining different passband widths. From the analysis of the architecture, it is clear that the reconfiguration over-head to obtain different sensing resolution in the proposed filter bank is only a few adders whereas reconfiguration of a conventional DFTFB involves reconfiguration of the prototype filter and DFT which is an expensive task. © 2010 IEEE.

12th IEEE International Conference on Communication Systems 2010, ICCS 2010

Reconfigurable discrete Fourier transform filter banks for variable resolution spectrum sensing

In a wireless communication receiver, channelization is the process of extracting individual narrowband radio channels from the digitized wideband input signal and providing these channels at baseband for further processing. Discrete Fourier transform filter banks (DFTFBs) are widely employed for the channelization purpose. This is because they efficiently utilize the polyphase decomposition of the prototype filter so that the prototype filter can be operated at a significantly reduced sampling rate. However DFTFBs suffer from the drawback that they can be employed only for the extraction of channels of uniform bandwidths. In this paper, a new DFTFB is presented which can be reconfigured with minimal overhead to extract channels of different bandwidths. The proposed DFTFB consists of a prototype filter which employs the concept of coefficient decimation for obtaining different passband widths. From the analysis of the architecture, it is clear that the overhead in the proposed filter bank is only few extra adders when compared to the conventional uniform DFTFB. Implementations results show that the proposed filter bank offers area and power reductions of 54% and 42% and speed improvement of 30.5% over conventional DFTFB respectively. © 2010 IEEE.

2010 International Conference on Signal Processing and Communications, SPCOM 2010

Reconfigurable discrete fourier transform filter banks for multi-standard channelizers

Reconfigurability and low complexity are the two key requirements of finite impulse response (FIR) filters employed in multistandard wireless communication systems. In this paper, two new reconfigurable architectures of low complexity FIR filters are proposed, namely constant shifts method and programmable shifts method. The proposed FIR filter architecture is capable of operating for different wordlength filter coefficients without any overhead in the hardware circuitry. We show that dynamically reconfigurable filters can be efficiently implemented by using common subexpression elimination algorithms. The proposed architectures have been implemented and tested on Virtex 2v3000ff11524 field-programmable gate array and synthesized on 0.18 μm complementary metal-oxide-semiconductor technology with a precision of 16 bits. Design examples show that the proposed architectures offer good area and power reductions and speed improvement compared to the best existing reconfigurable FIR filter implementations in the literature. © 2010 IEEE.

IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

New reconfigurable architectures for implementing FIR filters with low complexity

A novel and robust method for heart sound activity detection (HSAD) is presented. In this method, a new discriminative feature is developed based on the lag-1 autocorrelation coefficient and feature smoothing is introduced to identify the endpoints of low-level heart murmurs. Several experiments on a large scale phonocardiogram database show that the method significantly outperforms the other HSAD methods under varying levels of heart sounds and different types of noise. For a signal-to-noise ratio of 5 dB, the method achieves a sensitivity of 99.56% and a positive predictivity of 99.41% and has a smallest average time error value of 4.26 ms. © 2010 The Institution of Engineering and Technology.

Electronics letters

Robust heart sound activity detection in noisy environments

We present a new nonlinear control law to stabilise the ball and beam system at a desired operating point. The control law is based on the interconnection and damping assignment-passivity-based control (IDA-PBC) methodology developed in Ortega, Spong, Gomez-Estern, and Blankenstien (Ortega, R., Spong, M., Gomez-Estern, F., and Blankenstien, G. (2002), 'Stabilization of Underactuated Mechanical Systems via Interconnection and Damping Assignment', IEEE Transactions on Automatic Control, 47, 1218-1233) that guarantees stability in the sense of Lyapunov. We present a novel proof of the asymptotic stability of the desired operating point. The validity of the proposed control law is demonstrated through the experimental results. © 2010 Taylor & Francis.

International Journal of Control

Asymptotic stabilisation of the ball and beam system: Design of energy-based control law and experimental results

Circuit breaker transient recovery voltage analysis with shunt capacitor bank configurations

In a typical multi-standard wireless communication receiver, the channelizer extracts multiple radio channels of distinct bandwidths from a digitized wideband input signal. The complexity of the digital front end of the receiver is dominated by the complexity of the channelizer which operates at the highest sampling rate in the system. Computationally efficient architecture is essential for cost-effective implementation of the channelizer. Reconfigurability is another key requirement in the channelizer to support different communication standards. In this paper, we propose a low complexity reconfigurable filter bank (FB) channelizer based on coefficient decimation, interpolation and frequency masking techniques. Design example shows that the proposed FB offers complexity reduction of 54.8% over modulated perfect reconstruction FB and 10.5% over discrete Fourier transform FB. Furthermore, the proposed FB has an added advantage of dynamic reconfigurability over these FBs. © 2009 IEEE.

ICT 2010: 2010 17th International Conference on Telecommunications

A reconfigurable filter bank for uniform and non-uniform channelization in multi-standard wireless communication receivers

The need for efficient usage of the scarce electromagnetic spectrum has resulted in the growth of cognitive radios (CRs). The primary task in any CR network is to dynamically sense the radio spectrum so as to reliably determine portion(s) of the frequency band that may be used for communication link(s). Recently spectrum sensing for CRs based on filter banks have been suggested in literature. It was suggested that using filter banks for spectrum sensing will enable multi-carrier communications at no extra cost. This paper presents a study of the requirements and challenges of digital filter banks from a CR perspective in contrast to traditional filter banks for wireless communications. The current state-ofthe- art filter banks are discussed, with both advantageous and disadvantageous and how such filter banks can be altered to meet the essential requirements of CR systems.