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.

A Study on Toxicity of Chemically Synthesised Silver Nanoparticle on Eudrilus eugeniae

Abstract: To evaluate the toxicity of the silver nanoparticle against earthworms - Eudrilus eugeniae, a model for soil organism. Silver nanoparticles were synthesised by chemical reduction and further characterised by UV Visible Spectroscopy and FeSEM. Earthworms were allowed to interact with different concentrations of the synthesized silver nanoparticles. After exposure period, histology and inductively coupled plasma optical emission spectrometry (ICP-OES) were done to determine the accumulation and toxic effects exhibited by the nanoparticle on earthworms. The synthesized nanoparticle was found to be between the size of 180 and 200 nm. Histology studies revealed that silver nanoparticles to cause fibrosis, lipofuscin-like deposits and also gut disruption in earthworms. Silver nanoparticles were found to be toxic to Eudrilus eugeniae, which was evidenced by histology.

Transistor-Clamped Multilevel H-Bridge Inverter in Si and SiC Hybrid Configuration for High-Efficiency Photovoltaic Applications

Abstract: Using wide bandgap (WBG) devices has been a promising solution to improve the efficiency of power inverters for photovoltaic (PV) applications. However, for multilevel inverters, using WBG devices to improve the inverter efficiency can increase the system cost dramatically due to the high price of WBG devices in the present market as well as the large number of power devices typically required in multilevel inverter topologies. In this paper, a five-level transistor clamped H-bridge (TCHB) inverter will be further investigated. This inverter requires much lower number of semiconductor switches and fewer isolated dc sources than the conventional cascaded H-bridge inverter. To improve the inverter efficiency, semiconductor switches operating at carrier frequency will be configured by Silicon Carbide (SiC) devices to reduce the dominant switching losses, while the switches operating at fundamental output frequency (i.e., grid frequency) will be constituted by Silicon (Si) devices. As a result, both of the peak efficiency and California Energy Commission (CEC) efficiency of the TCHB inverter are significantly improved and dramatic system cost increase is avoided. In addition, due to the faster saturation characteristic of the IGBT devices, the large short-circuit current in SiC MOSFETs is constrained under the condition of load short-circuit faults. In other words, this proposed “SiC+Si” hybrid TCHB inverter can ride through a load short-circuit fault. Simulation and experimental results are presented to confirm the benefits of this proposed hybrid TCHB inverter.

Comparative analysis of common MPPT techniques for solar PV system with soft switched, interleaved isolated converter

Abstract: This paper presents the comparative analysis of most commonly used Maximum Power Point Tracking (MPPT) techniques viz Open Circuit Voltage (OCV), Perturb and Observe (PnO) and Incremental Conductance (INC) methods that are capable of extracting maximum power from the PV generation system with Soft Switched Interleaved Flyback(SSIFB) converter. The OCV technique is an indirect MPPT method that tracks the Maximum Power Point (MPP) using empirical data or mathematical expressions with numerical corrections and approximations. The direct methods such as PnO and INC techniques measure the actual instantaneous values of PV voltage and PV current to seek the MPP. The steady state performance of each of the MPPT algorithms on PV-SSIFB system under different solar irradiations is compared in terms of accuracy, MPPT efficiency and tracking speed. MATLAB/SIMULINK software is used to simulate and investigate the suitability and limitations of the PV — SSIFB system implemented with MPPT algorithm. The simulation results prove that the OCV MPPT method provides an effective MPP tracking at low irradiations and INC MPPT method offers the better steady state performance at medium and higher irradiations.

Automated Distribution Networks Reliability Optimization in the Presence of DG Units Considering Probability Customer Interruption: A Practical Case Study

Abstract: Automation in power distribution systems and supervisory control and data acquisition (SCADA), which perform network switching automatically and remotely, allows distribution companies to flexibly control distribution power grids. Cross-section switches also has a significant role in the automation in distribution systems, in that the operational optimization of these switches is able to enhance the supply power quality and reliability indicators, and can be a prosperous solution to increase the reliability, efficiency and overall service quality in services to customers. In this regard, in this work, the genetic optimization algorithm (GOA) approach which integrated the Steepest Descend Technique (SDT) is proposed and enhanced based on the features of the mentioned issue to sketch the optimal location and control of automatic and manual cross-section switches and protection relay systems in distribution power systems. The GOA is able to search globally that can prevent the result from locally convergence, also, GOA gives superior primary solutions for the SDT. Thus, the SDT can search locally with higher performance which increase the solutions’ accuracy. Therefore, an optimization formulation is proposed to improve the value-based reliability of the suggested layout considering the cost of customer downtime and the costs related to segmentation of switches and relay protection devices. Also, a distributed generation (DG) system in distribution networks is considered based on the islanded state of generation units. The effectiveness of the optimal suggested procedure is evaluated and represented via performing a practical test system in the distribution network of Ahvaz city in Iran. The results show that using proposed method and by optimally allocating switches maneuver, energy losses without switches are reduced from 310.17 (MWh) to 254.2 (MWh), and also by using DG, losses are reduced from 554.01 to 533.61 which confirms the ability and higher accuracy of the proposed method to improve reliability indices.

An improved sensorless sliding mode control/adaptive observer of a five-phase permanent magnet synchronous motor drive

Abstract: This paper presents a new sliding mode observer (SMO) for sensorless sliding mode control (SMC) of five-phase permanent magnet synchronous motor (PMSM) with online stator resistance estimation The proposed approach is shown to guarantee stability in the sense of Lyapunov context The sliding mode controller considers the nonlinearities of the system The sliding mode control strategy is developed using an integral switching surface A sliding mode observer is proposed for the rotor speed and stator resistance estimation under assumptions that only the stator currents and voltages are available for measurement The effectiveness of the proposed strategy has been successfully verified through simulation results

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