Showing 3 results for Krishnan
S. Thangaprakash, A. Krishnan,
Volume 6, Issue 2 (June 2010)
Abstract
New control circuits and algorithms are frequently proposed to control the
impedance (Z) source inverter in efficient way with added benefits. As a result, several
modified control techniques have been proposed in recent years. Although these techniques
are clearly superior to the simple boost control method which was initially proposed along
with the Z-source inverter (ZSI), little or conflicting data is available about their merits
relating to each other. In this paper, it is shown how the shoot-through periods are inserted
in the switching waveforms of the power switches and the performances of them are
analyzed based on the operation of ZSI. Simple boost control, maximum boost control,
constant boost control and space vector modulation based control methods given in the
literature has been illustrated with their control characteristics. A critical investigation on
ripples of the impedance source elements, output voltage controllability, output harmonic
profile, transient response of the voltage across the impedance source capacitor and voltage
stress ratio etc has been presented with the simulation results. The simulation results are
experimentally verified in the laboratory with digital signal processors (DSP). DSP coding
for the above all control techniques has been generated by interfacing Matlab/Simulink
with DSP C6000 tool box and signal processing block set.
S. Sivasakthi, R. K. Santhi, N. Murali Krishnan, S. Ganesan, S. Subramanian,
Volume 13, Issue 2 (June 2017)
Abstract
The increasing concern of global climate changes, the promotion of renewable energy sources, primarily wind generation, is a welcome move to reduce the pollutant emissions from conventional power plants. Integration of wind power generation with the existing power network is an emerging research field. This paper presents a meta-heuristic algorithm based approach to determine the feasible dispatch solution for wind integrated thermal power system. The Unit Commitment (UC) process aims to identify the best feasible generation scheme of the committed units such that the overall generation cost is reduced, when subjected to a variety of constraints at each time interval. As the UC formulation involves many variables and system and operational constraints, identifying the best solution is still a research task. Nowadays, it is inevitable to include power system reliability issues in operation strategy. The generator failure and malfunction are the prime influencing factor for reliability issues hence they have considered in UC formulation of wind integrated thermal power system. The modern evolutionary algorithm known as Grey Wolf Optimization (GWO) algorithm is applied to solve the intended UC problem. The potential of the GWO algorithm is validated by the standard test systems. Besides, the ramp rate limits are also incorporated in the UC formulation. The simulation results reveal that the GWO algorithm has the capability of obtaining economical resolutions with good solution quality.
Sowmya M, Sumi M, Harikrishnan A I,
Volume 22, Issue 2 (June 2026)
Abstract
This article presents the design and optimization of a Minkowski fractal slot-integrated antipodal Vivaldi antenna (MFS-AVA) for brain stroke detection. The antenna is proposed on a 65 × 65 × 1.6 mm³ FR-4 substrate and integrates a tapered slot radiator with a microstrip feed. Key parameters are optimized through parametric analysis. The exponential curve of the radiator arms and edge conductor is fine-tuned for improved bandwidth and impedance matching, while Minkowski fractal slots enhance the reflection coefficient, gain, and directivity. Simulated using CST Studio Suite 2016, the antenna attains an extensive bandwidth spanning from 1.23 GHz to 12 GHz, a maximum gain of 9 dBi, and a radiation efficiency of 87%. The radiation pattern exhibits a directional beam with minimal side lobes, making it suitable for focused microwave imaging. Compared to a conventional design, the MFS-AVA shows improved S11, VSWR, and surface current performance. Its effectiveness is validated using a four-layered tissue-mimicking cylindrical human head model, confirming adequate field penetration and compliance with safety standards. These results demonstrate the proposed antenna’s suitability for UWB microwave imaging in brain stroke detection.
