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.

&nbsp;

IIT Palakkad

Most of the recently occurred cascaded outages are resulted due to zone-3 mal-operations of distance relays. This paper introduces some new sensitivity factors to identify and monitor vulnerable relays functioning in the power transmission network. This information will help in enhancing the back-up protection operation of the power transmission system. To accomplish this task, indices such as line-outage-induced relay margin shift factor and generation-outage-induced relay margin shift factor are defined. An offline analysis of the power system is made to calculate the above two factors. This information helps in ranking the relays of the power system in terms of their vulnerability. Once the vulnerable relays are identified, their zone-3 operation is supervised by a new wide area information-based event detection logic. IEEE 9-bus and IEEE 39-bus test systems are used to validate the proposed scheme. The test results indicate that the proposed scheme can enhance the back-up protection operation of transmission network, which is very much essential to mitigate blackouts. © 2019 IEEE.

World University root node

IEEE Systems Journal

Event-Triggered Vulnerable Relay Identification and Supervision to Prevent Zone-3 Mal-Operations

The electrocardiogram (ECG) signals represent the electrical activities of the heart. Noise and artifacts are inherent contaminating components of the ECG signal and denoising of these signals is quite an important issue, since the noise can hinder accurate diagnosis and detection of cardiac diseases. Also, automated noise detection and classification and selective removal of noises can play a vital role in the development of robust unsupervised ECG analysis systems. This paper mainly deals with the comparison of two different approaches for noise detection and classification of ECG signals. A unified framework is followed for noise detection and classification which consists of a signal decomposition method, short term temporal feature extraction and decision rules for detecting the noises. The two approaches for noise detection and classification only differ at the decomposition step, one uses the complete ensemble empirical mode decomposition and the other uses the wavelet packet decomposition. The decomposed signals are then analysed using certain short term temporal features for automatic detection, localization and classification of single and combined ECG noises. This framework is evaluated on MIT-BIH arrhythmia database and results for both the cases are compared. Results show that, the performance of wavelet based decomposition is comparable to CEEMD. This enables the proposed wavelet decomposition based approach to be an ideal candidate for real-time continuous monitoring systems such as ECG Holter monitors. © 2019 IEEE.

IEEE Region 10 Annual International Conference, Proceedings/TENCON

Automated Noise Detection and Classification for Unsupervised ECG Analysis Systems Using CEEMD and Wavelet Packet Decomposition

An event-based state estimation problem for a discrete-Time system when the measurements are corrupted with multiplicative noise is considered in this letter. A general event-based sampling is employed to obtain the measurements, where the event-based strategy is implicitly utilized to obtain state estimate and covariance. To deal with multiplicative noise, maximum a posteriori (MAP) estimator is used in conjunction with the Newton-Raphson iterative method. The proposed results are depicted using a numerical example. © 2017 IEEE.

IEEE Control Systems Letters

Event-based state estimation under the presence of multiplicative measurement noise

Photovoltaic (PV) system inverters have been frequently utilized for reactive power support in the literature. Although the benefits of PV reactive power for the grid have been quantified, the costs incurred by the PV owner have largely been ignored. This paper combines the findings from power electronics research and power system economics to formulate the cost of reactive power from PV inverters, considering the inverter degradation due to the reactive power provision. One-year simulations with real weather and load data for the case of Singapore for different levels of PV penetration have been conducted. Subsequently, the benefits of local reactive power provision to the system and its effect on the lifetime of PV inverters were analyzed. It was found that the cost of inverter lifetime reduction is a significant part of the reactive power cost (more than 50% at lower PV penetration), but decreases at higher PV penetration when the reactive power support is distributed over more PV systems. Through comprehensive analysis, the feasible range for monetary incentives for PV reactive power support has been identified. The results from this paper can, therefore, be used as a foundation for future research, formulating regulations, and for market analysis. © 2018 IEEE.

IEEE Transactions on Sustainable Energy

Reactive Power Cost From PV Inverters Considering Inverter Lifetime Assessment

Circulating current control is one of the critical issues in modular multilevel converters (MMCs). When a frequency-droop-regulated MMC is used to integrate an offshore wind farm into an high-voltage dc transmission system, the variation in its operating ac line frequency induces a change in circulating current harmonic frequencies. Hence, the conventional circulating current controllers, such as proportional-resonant or repetitive controller, which are tuned to a specific frequency, fail to alleviate the circulating current harmonics. In this paper, a new control architecture comprising of a spatial comb filter (SCF) and a spatial repetitive controller (SRC) is proposed to effectively attenuate the even-order harmonics in the circulating current independent of the operating ac line frequency of the MMC. The proposed controller incorporates the phase sampling technique to achieve the dynamic change in the sampling frequency, which is the key to strong periodic disturbance rejection capability of the SCF and SRC even under variable frequency operation. A system level simulation model has been developed on PLECS simulation software to demonstrate the performance of the proposed control architecture. In addition, a scaled-down laboratory prototype of a 1-kW, 400-V, five-level single-phase MMC is developed and the experimental results are presented to substantiate the performance of the proposed control scheme. © 1986-2012 IEEE.

IEEE Transactions on Power Electronics

A new control architecture with spatial comb filter and spatial repetitive controller for circulating current harmonics elimination in a droop-regulated modular multilevel converter for wind farm application

This paper has presented an extensive review of the bidirectional phase-modular and semi-modular Solid-State-Transformer (SST) topologies, specific to the matrix-type variants with single-stage AC-DC conversion. This includes a qualitative and mathematical explanation of each topology and the corresponding modulation(s). A comparative analysis incorporating the criteria of power density, failure rate, cost and component count is also done among all these topologies along with the conventional Cascaded-Modular-SST (CMSST) topology with two-stage AC-DC conversion. The matrix-based topologies clearly prove to be better than the CMSST topology in terms of power density and reliability, with the entirely phase-modular topologies proving to be superior overall. The AC-DC DAB type submodule has been estimated to have the best characteristics in terms of all the comparison indices and thus it can be considered to be the best among the grid-connected matrix-based SST topologies for the application-type under consideration. © 2019 IEEE.

2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019

A Review on Bidirectional Matrix-Based AC-DC Conversion for Modular Solid-State-Transformers

In this paper, we consider a multi-input driftless bilinear system evolving on the n-dimensional sphere Sn. We first provide examples drawn from rigid body mechanics that provide the motivation for the control of bilinear systems on Sn. For the general framework, we establish the global controllability on Sn and propose two linear control laws on Sn that achieve asymptotic stabilization of an equilibrium point with an almost global domain-of-attraction. Further, the asymptotically stable closed-loop system trajectories are shown to be arcs on the geodesics of Sn for a particular choice of the equilibrium point. Next, we propose two linear time-varying control laws to achieve trajectory tracking on Sn and show the asymptotic stability of the tracking error. A distributed control is designed for the consensus of multiagent bilinear systems on Sn with an undirected tree as the communication graph. The consensus manifold is shown to have an almost global domain of attraction. © 2019 IEEE.

IEEE Transactions on Automatic Control

Control of a Driftless Bilinear Vector Field on n-Sphere

Journal of Guidance, Control, and Dynamics

Concurrent rendezvous control of underactuated space manipulators

Automatic removal of lung sounds from a phonocardiogram (PCG) signal is most essential for accurately detecting and recognizing the fundamental heart sounds such as the first heart sound (S1) and second heart sound (S2). In this paper, we propose an automated lung sound removal method using the empirical wavelet transform (EWT). The proposed method consists of three major stages: the EWT based signal decomposition; the frequency based mode selection; and the signal reconstruction. The proposed method is evaluated by synthetically adding the different lung sounds available in Littmann lung sound library with the real-time recorded PCG signals from 20 volunteers. The quality of the reconstructed signals is assessed by using both objective quality assessment metrics and subjective quality test such as mean opinion score (MOS). For the performance comparison, two lung sound removal methods have been implemented based on the ensemble empirical mode decomposition (EEMD) and frequency selective filtering techniques. The objective and subjective evaluation results and the heart sound segmentation results demonstrate that the EWT based lung sound removal method outperforms the other methods. The proposed method based heart sound segmentation scheme achieves an average sensitivity (Se) of 100%, positive predictivity (Pp) of 99.22%, and overall accuracy (OA) of 99.22%. © 2019 IEEE.

ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings

Empirical Wavelet Transform Based Lung Sound Removal from Phonocardiogram Signal for Heart Sound Segmentation

A computationally efficient diffusion cooperation scheme-based distributed active noise control (DANC) system is proposed in this paper. It is observed that the conventional centralized multi-channel ANC (MANC) systems employed for noise reduction in a wide region are computationally complex and lack scalability. Additionally, the noise reduction for practically encountered noises is a challenging task, especially for multi-point environments. To overcome these drawbacks, in this paper, a diffusion filtered x least mean square (DFxLMS) algorithm is developed for DANC systems. The proposed DFxLMS-DANC scheme is modified using proximal secondary path bounds to reduce computational overhead. Also, the practical application of air-conditioner noise control is addressed in the presence of real primary and secondary path scenarios. It is shown that the total computational improvement in proposed DFxLMS-DANC and modified DFxLMS-DANC systems is 23.13% and 49.87%, respectively, over multiple error FxLMS-based MANC system. It is also demonstrated that the proposed method helps to achieve ∼ 18 dB reduction in the air-conditioner noise levels in practical environments. © 2019, Springer-Verlag London Ltd., part of Springer Nature.