Axial-field electrical machines abstract

Axial-field electrical machines offer an alternative to the conventional machines. In the axial-field machine, the air gap flux is axial in direction and the active current carrying conductors are radially positioned. This paper presents the design characteristics, special features, manufacturing aspects and potential applications for axial-field electrical machines. The experimental from several prototypes, including d.c. machines, synchronous machines and single-phase machines are given. The special features of the axial-field machine, such as its planar and adjustable air gap, flat shape, ease of diversification, etc., enable axial-fled machines to have distinct advantages over conventional machines in certain applications, especially in special purpose applications.

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AUTOMATIC SOLAR TRACKER .Electrical seminar topics

A new control scheme for a single – phase diode clamped rectifier is proposed to achieve a unity power factor, balanced neutral point voltage and constant DC-bus voltage. Four power switches are used in the rectifier to generate a three-level PWM wave form on the rectifier terminal voltage.The line current command is derived from a DC-link voltage regulator and an output power estimator. The hysteresis current Controller is used to track the line current command. To balance the neutral-point voltage, a capacitor voltage compensator is employed. The main advantages of using a three-level instead of a two-level PWM scheme are that the blocking voltage of each power switch is clamped to half the DC-bus voltage (if the off –state resistance of  power switches is equal),and the voltage  harmonic on the AC  side of rectifier is reduced.

AUTOMATED DISTRIBUTION SYSTEM With Full seminar Report

Distribution systems are usually composed of radial feeders. Each feeder is divided into load sections with sectionalizing switches and is usually connected to other feeders via normally open tie switches.

 When a fault occurs in the distribution system, it is firstly detected by protection relays, then a circuit breaker is opened and de-energizes the feeder where the fault exists. By operating sectionalizing switches, the faulted section is isolated and the un-faulted sections disconnected are re-energized after reclosing the circuit breaker.

As automation is introduced into the distribution systems, the above switching operations can become automated. Recent advances in digital technology have made possible the development of Distribution Automation System (DAS). The DAS offers many new opportunities for improved system operation. It provides an integrated system approach to monitoring, protection, and control.

 Distribution automation includes wide spread functions, among which feeder automation is an important aspect. By controlling line switches installed on the feeder, feeder automation functions can be accomplished by identifying and isolating permanent feeder faults and restoring service to the un-faulted feeder sections sequentially and automatically, and thus reduce significantly customer outage time. The distribution automation discussed in this paper is restricted to fault isolation, reconfiguration, and service restoration switching operations.
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Numerical modeling of active plasmonic nanoparticles

Enhanced scattering and light localization beyond the diffraction limit due to plasmon resonance in metallic nanoparticles is a well known phenomena and has been applied for a wide range of useful applications including nanoparticle waveguides, bio-sensors and several others. Based on the classical Mie theory it can be shown that by enclosing an active media in a nanoparticle, metallic losses can be overcome and a nanoparticle can be made to radiate by itself. This result can extend the use of plasmonic nanoparticles far beyond the current limitations and pave the way for lossless plasmonic waveguides, energy storage devices and nanolasers. This research aims to investigate, in theory and using numerical techniques, how these applications can be realized.

Ph.D. Seminar topic Analytical and Numerical Modeling of Subwavelength Plasmonic-waveguide Components for Nanophotonic Applications

Recently, in optics there has been a surge of interest in miniaturized metallic structures
that allow sub-wavelength control of electromagnetic energy in the infrared and visible
bands of the spectrum. This results an emerging field of science known as plasmonics,
which has plethora of applications such as nanoscale optical interconnects,
chemical/bio-sensors, high-resolution microscopy, etc.
This research aims to investigate various plasmonic waveguide-based optical
components in terms of equivalent transmission-line networks. This representation
allows one to use classical network analysis tools in microwave engineering to obtain
analytical expressions that describe the transmission response of useful devices in
nanophotonics. The derived formulae provide rapid design optimization paths unlike the
computationally expensive and time consuming numerical simulations.

Seminar on Photonic Band Gap Materials: Light Trapping Crystals

Photonic Band Gap (PBG) materials are artificial, periodic, dielectrics that enable engineering of the most fundamental properties of electromagnetic waves. These include the laws of refraction, diffraction, and spontaneous emission of light. Unlike traditional semiconductors that rely on the propagation of electrons through an atomic lattice, PBG materials execute their novel functions through selective trapping or localization of light. This is a fundamentally new and largely unexplored property of Maxwell's equations. This is also of practical importance for alloptical communications, information processing, efficient lighting, and solar energy trapping. Three dimensional (3D) PBG materials offer a unique opportunity to simultaneously (i) synthesize micron-scale 3D circuits of light that do not suffer from diffractive losses and (ii) engineer the electromagnetic vacuum density of states in this 3D optical micro-chip. This combined capability opens a new frontier in integrated optics as well as the basic science of radiation-matter interactions. I review recent approaches to micro-fabrication of photonic crystals with a large 3D PBG centered near 1.5 microns. These include direct laser-writing techniques, holographic lithography, and a newly invented optical phase mask lithography technique. I discuss consequences of PBG materials in classical and quantum electrodynamics.

Power transformers

Power transformers are the most significant pieces of equipment for electrical power delivery systems. One of the key parameters to be monitored in a power transformer is the internal temperature. High temperature accelerates the aging of winding paper insulation and increases the risk of bubbling under severe load conditions. Temperature is also an important parameter for transformer cooling system. The transformer winding hottest-spot temperature is one of a number of limiting factors for the loading capability of transformers. One way to increase the loading capability is to increase the efficiency of the cooling system by using fans and pumps. This research focuses on the investigation of the effect of the cooling system parameters, in particular the oil flow rate, on the thermal performance of power transformers.