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 paper proposes a new forty nine level stacked inverter topology using low voltage devices for drives applications. The forty nine level inverter is developed by stacking three seventeen level inverters. The seventeen level inverter is developed by cascading a flying capacitor inverter and three H-Bridges. The inverter can operate with lower number of voltage levels if any of the H-Bridges fail. The capacitor voltage balancing in the inverter can be done irrespective of modulation index and load power factor. The topology is further modified to reduce the capacitor and switch count. Also, the inverter does not use any pulse width modulation between the different voltage levels. Therefore switching losses are reduced. In addition, since the switches need to block only lower voltages, MOSFETs can be used which will further improve the efficiency. An induction motor driven by this inverter using V/f control is simulated in MATLAB simulink and both steady state and transient results are presented. © 2016 IEEE.

World University root node

IECON Proceedings (Industrial Electronics Conference)

A novel forty nine level stacked inverter topology using low voltage devices for drives

This work presents micro-electromechanical system (MEMS) based switches and phase shifters for transmit/receive module applications. All designs are implemented using coplanar waveguide (CPW) transmission line and fabricated on 635-μm alumina substrate using surface micromachining process. Different switching networks like series/shunt configuration, single-pole-double-throw (SPDT), single-pole-four-throw (SP4T), SP8T, SP9T and SP12T are presented for application in multi-bit digital phase shifters. One configuration of the 5-bit phase shifter demonstrates an average insertion loss of 2.65 dB in the 16.75 - 17.25 GHz band with a return loss better than 22 dB and average phase error less than 0.680 at 17 GHz. Total area of the fabricated 5-bit phase shifter is 13 mm2. © 2016 EuMA.

European Microwave Week 2016: "Microwaves Everywhere", EuMW 2016 - Conference Proceedings; 46th European Microwave Conference, EuMC 2016

Micromachined switches and phase shifters for transmit/receive module applications

A state-dependent jump linear system (SDJLS) is a particular type of stochastic switching system, where the transition rates or probabilities of the underlying random jump process depend on the state variable. In this paper, a continuous-time SDJLS subject to external disturbances with finite energy is considered. Regarding the underlying random jump process, the transition rates are assumed to have different values across different sets where the state of the system evolves. By evaluating the infinitesimal generator for the stochastic Lyapunov function of SDJLS, a state-feedback H∞ controller is synthesized that guarantees disturbance rejection while ensuring stochastic stability via solving a set of sufficient linear matrix inequalities. The overall approach is illustrated with a numerical example. © 2016 IEEE.

Conference on Control and Fault-Tolerant Systems, SysTol

State-feedback H∞ stabilization of state-dependent jump linear systems

Band structure Lab uses the sp3s*d5 tight binding method to compute E(k) for bulk, planar, and nanowire semiconductors. Using this tool, you can quickly compute and visualize the band structures of bulk semiconductors, thin films, and nanowires for various materials, growth orientations, and strain conditions. Physical parameters such as the bandgap and effective mass can also be obtained from the computed E(k). The bandedges and effective masses of the bulk materials and the nanostructures structures can be analyzed as a function of various strain conditions.

Band Structure Lab

This paper demonstrates light-load instability in a 100-kW open-loop induction motor drive on account of inverter deadtime. An improved small-signal model of an inverter-fed induction motor is proposed. This improved model is derived by linearizing the nonlinear dynamic equations of the motor, which include the inverter deadtime effect. Stability analysis is carried out on the 100-kW 415-V three-phase induction motor considering no load. The analysis brings out the region of instability of this motor drive on the voltage versus frequency (V-f) plane. This region of light-load instability is found to expand with increase in inverter deadtime. Subharmonic oscillations of significant amplitude are observed in the steady-state simulated and measured current waveforms, at numerous operating points in the unstable region predicted, confirming the validity of the stability analysis. Furthermore, simulation and experimental results demonstrate that the proposed model is more accurate than an existing small-signal model in predicting the region of instability.

IEEE Transactions on Industry Applications

Small-Signal Stability Analysis of an Open-Loop Induction Motor Drive Including the Effect of Inverter Deadtime

This paper proposes a deterministic estimator for the estimation of the attitude of a rigid body. A deterministic estimator uses a minimal set of information and does not try to minimize a cost function or fit the measurements into a stochastic process. The proposed estimator obtains the attitude estimation utilizing only the properties of the rotational group SO(3). The information set required by the proposed estimator is a single vector information and rate gyro readings. For systems in which one of the rotational freedom is constrained, the proposed estimator provides an accurate estimate of the reduced attitude. The performance of the algorithm is verified on different experimental testbeds. © 1996-2012 IEEE.

IEEE/ASME Transactions on Mechatronics

A Deterministic Attitude Estimation Using a Single Vector Information and Rate Gyros

Observations during the Dynamics of the Madden-Julian Oscillation (DYNAMO) experiment focused on sensing atmospheric parameters, including vertical moisture profiles, cloud structure, precipitation processes, and planetary boundary layer properties, all of which are important for understanding and modeling the Madden-Julian Oscillation (MJO). These observations were performed using a variety of in-situ and remote sensors, including the S-band polarimetric and Ka-band (S-PolKa) radar, deployed by the National Center for Atmospheric Research (NCAR), and a colocated University of Miami microwave radiometer (UM-radiometer) operating at 23.8 and 30.0 GHz. These instruments sampled approximately the same volumes of the atmosphere at a variety of azimuth and elevation angles. The principal goal of this study is to develop a new retrieval strategy to estimate slant water vapor path (SWP) and slant liquid water (SLW) using UM-radiometer measurements from zenith to low elevation angles at a variety of azimuth angles. Retrievals of SWP along the radar signal path help to determine the error in radar reflectivity due to water vapor absorption. The retrieval algorithm has been developed using the vapor-liquid water ratio (VLWR) as well as both modeled and measured brightness temperatures for zenith to low elevation angles. Observation system simulation experiment (OSSE) results and measured radiosonde data have been used to determine that the retrieval uncertainty is less than 5% for integrated water vapor (IWV) and less than 12% for integrated liquid water (ILW). OSSE results for SWP show that the retrieval uncertainty is less than 8% at 5° elevation angle and less than 5% at 7° and 9°, while the mean difference between SWP retrieved from radiometer measurements and those retrieved from the S-PolKa radar during the DYNAMO campaign is less than 10% at 5° elevation angle and less than 7.5% at 7° and 9°. OSSE results for SLW show that the mean error is less than 24% for 5° elevation angle and less than 18% for 7° and 9°. Such retrievals of SWP and SLW help to characterize the distribution of water vapor and liquid water in the lower troposphere, which in turn may contribute to improvements in forecasting of convective initiation and precipitation. © 2015 IEEE.

Fulltext

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

Retrieval of Slant Water Vapor Path and Slant Liquid Water from Microwave Radiometer Measurements during the DYNAMO Experiment

This paper presents a new differential relaying scheme for a parallel transmission line in presence of Unified Power Flow Controller (UPFC). In this work, a new algorithm is proposed to detect and classify the fault along with to identify the faulty section with respect to UPFC location. The UPFC is placed at midpoint of the one of the transmission line. The scheme starts by retrieving the three phase currents signals at both ends of the transmission line synchronously and processing it though Fast Discrete S- transform to derive the spectral energy of the current signals. The differential spectral energy of current signals (i.e spectral energy of current measured at sending end minus spectral energy of current measured at receiving end) of respective phases of transmission lines is used to register the fault pattern. The proposed algorithm is very simple and accurate for fault detection and classification in double-circuit transmission lines including UPFC in one of the line. The scheme has been extensively tested on different faulted conditions with wide variations in operating parameters of the UPFC as well as transmission line and the test results indicate the effectiveness of this scheme. © 2015 IEEE.

International Conference on Electrical, Electronics, Signals, Communication and Optimization, EESCO 2015

Notice of Removal: Fast discrete S-transform based differential relaying scheme for UPFC compensated parallel line

Summary The paper presents integrated impedance-based intelligent relaying for thyristor-controlled series capacitor-compensated transmission lines on Real Time Digital Simulator platform. Integrated impedance is defined as the ratio of sum of the voltage phasors across two ends of the transmission line to the sum of the current phasors through two ends of the same transmission line. The imaginary part of integrated impedance of the transmission line is used as input to a data-mining model known as decision tree that determines whether the fault is within the protected zone or not. Critical issues such as power swing and fault during power swing are also included during validation of the relay on Real time digital simulator platform. The test results obtained indicate that the proposed integrated impedance-based intelligent relaying is highly dependable and secure for protection of extra high voltage transmission lines including thyristor-controlled series capacitor. © 2014 John Wiley & Sons, Ltd.

International Transactions on Electrical Energy Systems

Real time digital simulator implementation of data-mining-based integrated impedance relay for compensated lines

The paper suggests integrated impedance based intelligent relaying for thyristor controlled series capacitor (TCSC) compensated transmission lines. The scheme uses a new relaying signal termed as imaginary part of integrated impedance (IPII). Integrated impedance is defined as the ratio of sum of the voltage phasors across two ends of the transmission line to the sum of the current phasors through two ends of the same transmission line. IPII of each phase of the transmission line is used as input to a data mining model known as decision tree (DT) which selects the faulted phase(s) involved in the fault process. The scheme is validated on Real time digital simulator (RTDS) platform. The test results obtained indicate that the proposed IPII based intelligent relaying is reliable in protecting of extra high voltage (EHV) transmission lines including TCSC. © 2014 IEEE.