Sanjeevikumar Padmanaban

Bio: Sanjeevikumar Padmanaban is an academic researcher from Aarhus University. The author has contributed to research in topics: Photovoltaic system & Boost converter. The author has an hindex of 34, co-authored 367 publications receiving 5244 citations. Previous affiliations of Sanjeevikumar Padmanaban include Sathyabama University & National Institute of Technology, Puducherry.

Electric field analysis of extra high voltage (EHV) underground cables using finite element method

Abstract: Transmission and Distribution of electric power through underground cables is a viable alternative to overhead lines, particularly in residential or highly populated areas. The electrical stresses are consequences of regular voltages and over voltages and the thermal stresses are related to heat produced inside the conductor due to flow of high rated current which is the main factors that affect its reliability. The performance of these underground power cables is important for proper operation of the power system. Long-term problems with them are related to the degradation of polymer materials used for the insulator due electrical, thermal or environmental stress. Most of these problems are related to the electric field stress on the insulation of the underground cables. The objective of the electric field analysis by using different numerical techniques is to find electric field stress and other parameters, which are an inevitable tool in various electricity concerned technologies; in particular for analyzing discharge phenomenon and designing Extra High Voltage (EHV) underground cables. In this paper Finite Element Method (FEM) numerical method has been discussed and used to find 2-D electric field stress and other parameters of EHV underground cables with given boundary conditions using 2-D electric field analysis software package (IES-ELECTRO module) which is based on the finite element method (FEM).

Simulation Analysis of Selective Harmonics Elimination scheme for a Symmetric CHB-Multilevel inverter

Abstract: A selective harmonics elimination (SHE) method for Cascaded H-Bridge (CHB) multilevel inverter (MLI) is proposed in this paper. The proposed modulation scheme is a low switching frequency modulation scheme and it is derived from the nearest level modulation scheme. The proposed modulation scheme reduces the total harmonic distortion (THD) at the ac output of the inverter. The SHE follows an algorithm presented in the paper in order to arrive at a set of switching angles for MLI which offers reduced THD. The Simulation is carried out using MATLAB / Simulink 2015b software and the results are presented which validates the simulation results. Results show that the lower order harmonics are eliminated in the THD content with the use of proposed modulation scheme. As a result of the improved THD content, improvement in the other inverter parameters such as rms voltage, rms current and output power is also observed.

Systematic Implementation of Multi-Phase Power Supply (Three to Six) Conversion System

Abstract: Multiphase (more than three) power system has gained popularity due to their inherent advantages when compared to three-phase counterpart. Multiphase power supply is extensively used in AC/DC multi-pulse converters, especially supply with multiple of three-phases. AC/DC converter with multi-pulse input is a popular solution to reduce the ripple in the DC output. Single-phase and three-phase transformers and phase transformation from single to multiphase are employed in variable speed drives application to feed the multi-cell H-Bridge converters and multi-pulse AC-DC converters. Six-phase system is extensively discussed in the literature for numerous applications ranging from variable speed drives to multiphase wind energy generation system. This paper shows the systematic phase transformation technique from three-phase to six-phase (both symmetrical and asymmetrical) for both understanding and teaching purposes. Such an approach could help students understand a promising advanced concept in their undergraduate courses. When phase difference between the two consecutive phases of six phases has a phase difference of 60°, it is called a symmetrical six-phase system; while an asymmetrical or quasi, six-phase has two set of three-phase with a phase shift of 30° between the two sets. Simulation and experimental results are also presented.

Isolated/non-isolated quad-inverter configuration for multilevel symmetrical/asymmetrical dual six-phase star-winding converter

Abstract: This article presents the developments of a novel isolated/non-isolated quad inverter configuration for multilevel dual six-phase (twelve-phase) star-winding converter. The modular circuit consists of four standard voltage source inverters (VSIs). Each VSI is incorporated with one bi-directional switch (MOSFET/IGBT) per phase and links with the neutral line through two capacitors which allows symmetrical and asymmetrical operations. A modified single carrier five-level modulation (MSCFM) algorithm is developed and modulates each 2-level VSI as a 5-level output multilevel inverter. The entire AC converter is numerically modeled using Matlab/PLECS simulation software and the predicted behavior of the system is analyzed and presented. Good agreement is obtained between these results and the theoretical analysis. Suitable applications for the converter include (low-voltage/high-current) medium power systems, electrical vehicles, AC tractions, and ‘More-Electric Aircraft’ propulsion systems.

Neural network-based model reference adaptive system for torque ripple reduction in sensorless poly phase induction motor drive

Abstract: This paper proposes the modified, extended Kalman filter, neural network-based model reference adaptive system and the modified observer technique to estimate the speed of a five-phase induction motor for sensorless drive. The proposed method is generated to achieve reduced speed deviation and reduced torque ripple efficiently. In inclusion, the result of speed performance and torque ripple under parameter variations were analysed and compared with the conventional direct synthesis method. The speed estimation of a five-phase motor in the four methods is analysed using MATLAB Simulink platform, and the optimum method is recognized using time domain analysis. It is observed that speed error is minimized by 60% and torque ripple is reduced by 75% in the proposed method. The hardware setup is carried out for the optimized method identified.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Exoelectrogenic bacteria that power microbial fuel cells

Abstract: The use of microbial fuel cells to generate electrical current is increasingly being seen as a viable source of renewable energy production In this Progress article, Bruce Logan highlights recent advances in our understanding of the mechanisms used by exoelectrogenic bacteria to generate electrical current and the important factors to consider in microbial fuel cell design There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities Enriched anodic biofilms have generated power densities as high as 69 W per m2 (projected anode area), and therefore are approaching theoretical limits To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell–cell communication