National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Computer science. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

An Implementation of Hybrid Control Strategy for Distributed Generation System Interface Using Xilinx System Generator

Abstract: This paper presents an analytical study and hardware-in-loop (HIL) cosimulation design of a grid-connected inverter system with a combinational robust observer-based modified repetitive current controller. In this study, main attention is paid to improve power quality and tracking performance of a distributed generation (DG) interfacing system under various perturbations. The inherent delay in convergence of conventional repetitive controller (RC) is reduced by introducing a low pass filter in delay line and this configuration is named as modified RC (MRC). By adding an observer with MRC, system states can be reconstructed, which improve the system dynamic response. Robust stability and convergence criterion are derived in terms of linear matrix inequality using combined Lyapunov function and singular value decomposition technique, which determine the suitable parameters of feedback control and state observer gains. By utilizing these gains, the switching signals are generated to operate the DG interfacing inverter effectively. The performance of proposed controller is compared with traditional proportional integral, proportional resonant, and MRC under both normal and fault conditions. Finally, HIL cosimulation is performed by realizing the power circuit in MATLAB/Simulink as a simulation model and a control structure using Xilinx system generator platform as burnt in hardware Virtex-6 field programmable gate array (FPGA) ML605 evaluation kit.

A New Heuristic for $N$ -Dimensional Nearest Neighbor Realization of a Quantum Circuit

Abstract: One of the main challenges in quantum computing is to ensure error-free operation of the basic quantum gates. There are various implementation technologies of quantum gates for which the distance between interacting qubits must be kept within a limit for reliable operation. This leads to the so-called requirement of neighborhood arrangements of the interacting qubits, often referred to as nearest neighbor (NN) constraint. This is typically achieved by inserting SWAP gates in the quantum circuits, where a SWAP gate between two qubits exchanges their states. Minimizing the number of SWAP gates to provide NN compliance is an important problem to solve. A number of approaches have been proposed in this regard, based on local and global ordering techniques. In this paper, a generalized approach for combined local and global ordering of qubits have been proposed that is based on an improved heuristic for cost estimation and is also scalable. The approach can be extended to ${N}$ -dimensional arrangement of qubits, for any arbitrary values of ${N}$ . Practical constraints, however, restrict the maximum value of ${N}$ to 3. Extensive experiments on benchmark functions have been carried out to evaluate the performance in terms of SWAP gate requirements. 3-D organization of qubits shows average reductions of 6.7% and 37.4%, respectively, in the number of SWAP gates over 2-D and 1-D organizations. Also compared to the best 2-D and 1-D results reported in the literature, on the average 8.7% and 8.4% reductions, respectively, are observed.

Detection and Mitigation of Cyber-Attacks on AGC Systems of Low Inertia Power Grid

Abstract: Automatic generation control (AGC) plays a salient role in modern power systems by maintaining grid frequency within acceptable limits. Since AGC is the only automatic feedback loop between cyber and physical infrastructures, it is greatly vulnerable to malicious attacks and hence, required urgent investigations. Attackers can falsify the sensor measurements employed for AGC operation causing service outage and infrastructural damage. In this article, a method is developed to detect and mitigate possible cyber-attack schemes such as false data injection and denial-of-service attacks targeting the AGC systems. The proposed method is termed as cyber-attack detection and mitigation platform (CDMP) and utilizes the forecasted data of area control error for identification and mitigation of attacks. The CDMP strategy involves three stages for optimal operation and identifies any arbitrary false data injected to the grid. For the investigation, three area system with multiple generations and distribution companies under bilateral trading is considered. The test model is also equipped with inertia emulation technique supported by battery management system. It is because the modern power system is advancing toward inverter-dominated system from synchronous-based system due to high penetration of renewables. The effectiveness of the proposed strategy is verified using rigorous simulation results.