Faculty Publications

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Now showing 1 - 9 of 9
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    Techniques of communication
    (Indian Society for Education and Environment indjst@gmail.com, 2007) Jayachandran, M.; Manikandan
    Communication is vital in teaching- learning process. The appropriate selection and mixing of its component can help for the effective transmission of curricular material from mentor to pupils. Body language and graphics language often communicate more than verbalism. Various types of graphics and colours make communication more meaningful. ICT-driven digital communication can be an effective tool which can overtake the conventional verbal communication and black-board and chalk techniques. © Indian Society for Education and Environment.
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    Active vibration control of a smart cantilever beam on general purpose operating system
    (Defense Scientific Information and Documentation Centre, 2013) Parameswaran, A.P.; Pai, A.B.; Tripathi, P.K.; Gangadharan, K.V.
    All mechanical systems suffer from undesirable vibrations during their operations. Their occurrence is uncontrollable as it depends on various factors. However, for efficient operation of the system, these vibrations have to be controlled within the specified limits. Light weight, rapid and multi-mode control of the vibrating structure is possible by the use of piezoelectric sensors and actuators and feedback control algorithms. In this paper, direct output feedback based active vibration control has been implemented on a cantilever beam using Lead Zirconate-Titanate (PZT) sensors and actuators. Three PZT patches were used, one as the sensor, one as the exciter providing the forced vibrations and the third acting as the actuator that provides an equal but opposite phase vibration/force signal to that of sensed so as to damp out the vibrations. The designed algorithm is implemented on Lab VIEW 2010 on Windows 7 Platform. © 2013, DESIDOC.
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    Feedback active noise control based on transform-domain forward-backward LMS predictor
    (Springer London, 2014) Pavithra, S.; Narasimhan, S.V.
    In this paper, a new feedback active noise control (FBANC) system based on the transform-domain forward-backward LMS (TFBLMS) predictor has been proposed. The new ANC system employs the TFBLMS predictor for its main-path (MP) predictor as well as for the noise canceller. To overcome the ill effect of the primary noise field, which acts as an observation noise for the secondary-path (SP) identification, the noise canceller is used. As the main-path predictor is based on the TFBLMS, its convergence rate improves due to its input orthogonalization. Further, its FBLMS nature reduces misadjustment. The use of TFBLMS predictor for noise canceller also gives a good prediction of primary noise at a faster rate, enabling improved SP identification. This improved SP identification indirectly aids the MP predictor to achieve an improved performance. A new filtered-x LMS structure has been proposed to realize the new MP predictor to accommodate the TFBLMS algorithm. The TFBLMS algorithm is applied directly to the noise canceller for SP identification. The proposed new ANC system has been found to have a significantly better noise reduction (by 14.6 dB) over the FBANC system based on tapped delay line time-domain FBLMS algorithm. © 2012 Springer-Verlag London Limited.
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    Design and performance analysis of quantitative feedback theory based automated robust controller: An application to uncertain autonomous wind power system
    (AIMS Press, 2018) Gudimindla, G.; Manjunatha, S.K.
    Use of a robust controller for handling the operational uncertainties has become imperative in real time. This paper presents a modified fitness function based automated robust controller with the aid of quantitative feedback theory (QFT) using Genetic algorithm (GA). A controller exhibiting the desired decreasing modular plot and descending phase response is devised. The addition of arctangent function as one of the fitness function term is the proposed modification that facilitates in capturing the ideal controller characteristics. The proposed controller is applied to extract maximum power from a permanent magnet synchronous generator based autonomous wind power system. The step by step design guidelines for the automated QFT robust controller is deliberated in detail. The performance evaluation is carried out for step change and stochastically varying wind speed. Finally, benchmarking of the proposed controller against those available in the literature is accomplished through extensive simulations and it will be shown that the maximum power extraction along with least electromagnetic torque oscillations are achieved with the proposed fitness function based automated QFT controller. © 2018 the Author(s).
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    FPGA based direct torque control with speed loop Pseudo derivative controller for PMSM drive
    (Springer, 2019) Karthikeyan, A.; Koothu Kesavan, K.; Nagamani, C.
    This paper presents a comprehensive evaluation of proposed speed loop pseudo derivative feedback (PDF) controller based DTC with speed loop PI based direct torque controller (DTC) for permanent magnet synchronous motor (PMSM) drive. The proposed PDF-DTC system significantly improves dynamic response i.e. completely eliminates overshoot in speed, reduces 50% overshoot in electromagnetic torque and has two times faster settling time compared to PI-DTC system during step changes in speed with load disturbance. The proposed controller is verified for different cases viz., speed variation at constant load and variation in the load torque at constant speed. The proposed controller is implemented for 1.5 kW laboratory prototype PMSM drive using FPGA ALTERA cyclone II. Experimental results demonstrates the efficacy of the proposed controller. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
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    Time Constant Enhancement Technique for Low-Frequency Filters
    (Birkhauser, 2020) Rao, G.H.; Rekha, S.
    This paper presents a simple and novel technique to enhance the time constant of a source follower (SF)-based low-pass filter (LPF) for front-end processing of biomedical signals. The proposed technique reduces the capacitor value significantly, which in turn reduces the area of the circuit. Inherent negative feedback and lower number of transistors in this circuit result in good linearity and dynamic range even with low power supply of 0.8 V. A second-order LPF of cutoff frequency (f-3dB) of 100 Hz is designed by cascading the proposed NMOS and PMOS SF LPFs. Cutoff frequency can be tuned linearly from 10 Hz to 1 kHz by varying the bias current and, hence, can be fit into the desired frequency range of different bio-potentials. The filter, designed in UMC 65 nm process, occupies an area of 0.008mm2. It offers a dynamic range of 61.85 dB while consuming a power as low as 8 nW. Figure of merit of the filter is as low as 3.23?10-14J which is better than many other filter designs reported in the literature. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
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    An Efficient Pseudo-Derivative-Feedback-Based Voltage Controller for DVR Under Distorted Grid Conditions
    (Institute of Electrical and Electronics Engineers Inc., 2021) Krishna, D.G.A.; Karthikeyan, K.; Koothu Kesavan, K.K.; Kumar, S.
    Grid integration of distributed energy resources has become a technical challenge in the distribution network operation due to the intermittent nature of renewable energy sources and their impact on grid voltage stability. Thus, a dynamic voltage restorer (DVR) is installed in the distribution network system to reduce such grid voltage impact on sensitive loads. In this article, a pseudo-derivative-feedback (PDF)-based voltage controller is implemented for the effective operation of DVR under voltage disturbances. Response of DVR primarily depends upon its controller action. This article addresses the issues in conventional P and PI multiloop controller with and without feedforward path then proposes PDF control strategy for DVR. Using the proposed controller, dynamic performance of DVR is improved. The efficacy of the proposed controller is illustrated by a comparative study with conventional P and PI controller using time response and relative stability analysis. Finally, PSCAD simulation studies for a 10 kV medium voltage DVR and experimental results using a low voltage laboratory prototype DVR are presented to prove the robustness of proposed controller for DVR under symmetric and asymmetric voltage sags. © 2020 IEEE.
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    Active feedback supported CMOS LNA blended with coplanar waveguide-fed antenna for Wi-Fi networks
    (John Wiley and Sons Inc, 2021) Roy, G.M.; Dwari, S.; Kumar Kanaujia, B.K.; Kumar, S.; Song, H.
    This study presents integration of complementary CMOS active feedback low noise amplifier with coplanar waveguide fed patch antenna for Wi-Fi networks. The LNA design-I, involves a cascode amplifier followed by active feedback common source amplifier offering wideband impedance matching with lowered parasitic losses. The inductor-less feedback mechanism is used to nullify noise effect with extended bandwidth in the range of 2.2 to 5.8 GHz and a peak forward gain of 22.5 dB. It is implemented on agilent's advance design system using 45 nm CMOS process. The noise figure (NF) is approximately 2 dB while the stability factors µ and µ prime are well above 1 dB with IIP3 of about 15 dBm. The chip area is 0.57 x 0.57 mm2 under dc power supply of 1V while power consumption of 0.8 mW. A CPW fed antenna design-II, achieves a wide band response similar to the bandwidth of LNA. The size of the fabricated antenna is calculated as 40 x 40 mm2. The peak gain is approximately 4.1 dBi at 3.9 GHz. The codesign-III, proposes a receiver achieving a much wider band of 1.6 to 6 GHz with a gain of 16.5 dB and NF of 2.59 dB at 2.06 GHz. The codesign improves the system integration by reducing overall chip area and offers saving in the effective cost. © 2021 The Authors. IET Microwaves, Antennas & Propagation published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
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    Effect of temperature on the performance of active constrained layer damping of skew sandwich plate with CNT reinforced composite core
    (Taylor and Francis Ltd., 2022) Kallannavar, V.; Kattimani, S.
    In this paper, the first attempt has been made to investigate the performance of the active constrained layer damping system in the thermal environment. For such investigation, a skew laminated composite sandwich plate with carbon nanotube-reinforced composite core is considered. The nonlinear strain-displacement relations are employed to generate the initial-stress stiffness matrix and the mechanical stiffness matrices using linear strain-displacement relations. The negative velocity feedback control-law is used to control the first few modes of the vibrating sandwich plate. Comprehensive investigation has been carried out to understand influence of geometric and material parameters on the damping performance of the system. © 2021 Taylor & Francis Group, LLC.