Electrical and Electronics Commons^™

The Application Of Multi Frequency Resonant Controllers In In A Dfig To Improve Performance By Reducing Unwanted Power And Torque Pulsations And Reducing Current Harmonics., Joseph Kearney, Michael Conlon, Eugene Coyle

Conference papers

The paper describes a method to control the rotor-side and grid side converters in a DFIG when subjected to the effects of network voltage unbalance conditions. Multi Frequency Resonant Controllers are incorporated into the grid side and rotor side converters to assist in the control functions. The Resonant Controllers are tuned to twice the network frequency to assist in the control of power and torque pulsations and to three times the network frequency to assist in the control of the generated third harmonic currents. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque …

Wavelet Based Islanding Detection Of Dc-Ac Inverter Interfaced Dg Systems, Mohamed Moin Hanif, Malabika Basu, Kevin Gaughan

Conference papers

The increased penetration of distributed generation (DG) often connected to grid through dc-ac interface has made islanding detection an important and challenging issue to power engineers. Several methods based on passive and active detection scheme have been proposed in the literature. While passive schemes have a large non detection zone (NDZ), concern has been raised on active method due to its degrading power quality effect. This paper proposes a wavelet based passive islanding detection scheme with almost zero NDZ for dc-ac inverter interfaced grid connected DGs. The key idea is to utilize the spectral changes in the higher frequency components …

Validated Real-Time Energy Models For Small-Scale Grid-Connected Pv-Systems, Lacour Ayompe, Aidan Duffy, Sarah Mccormack, Michael Conlon

Articles

This paper presents validated real-time energy models for small-scale grid-connected PV-systems suitable for domestic application. The models were used to predict real-time AC power output from a PV system in Dublin, Ireland using 30-min intervals of measured performance data between April 2009 and March 2010. Statistical analysis of the predicted results and measured data highlight possible sources of errors and the limitations and/or adequacy of existing models, to describe the temperature and efficiency of PV-cells and consequently, the accuracy of power prediction models. PV-system AC output power predictions using empirical models for PV-cell temperature and efficiency prediction showed lower percentage …

Intelligibility Of Electrolarynx Speech Using A Novel Actuator, Brian Madden, Mark Nolan, Ted Burke, James Condron, Eugene Coyle

Conference Papers

During voiced speech, the larynx provides quasi-periodic acoustic excitation of the vocal tract. Following a laryngectomy, some people speak using an electrolarynx which replaces the excitatory function of the absent larynx. Drawbacks of conventional electrolarynx designs include the buzzing monotonic sound emitted, the need for a free hand to operate the device, and difficulty experienced by many laryngectomees in adapting to its use. Despite these shortcomings, it remains the preferred method of speech rehabilitation for a substantial minority of laryngectomees. In most electrolarynxes, mechanical vibrations are produced by a linear electromechanical actuator, the armature of which percusses against a metal …

Meshscan: A Fast And Efficient Handoff Scheme For Ieee 802.11 Wireless Mesh Networks, Yin Chen

Masters

As a next generation network solution, Wireless Mesh Networks (WMN) provides fast Internet access to a large area, which is from university campus to city scale. In order to provide an uninterrupted Internet experience to a mobile client, a process called handoff is required to maintain the network connection from one Mesh Node (MN) to another MN. Ideally, handoff should be completely transparent to mobile users. A critical application like VoIP will require a handoff capability that transfers a call from one mesh node (MN) to another in less than 50 msec. However the current IEEE 802.11 standards do not …

Power Quality In Grid Connected Renewable Energy Systems: Role Of Custom Power Devices, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon

Conference papers

This paper deals with the technical review of power quality problems associated with the renewable based distributed generation systems and how the custom power devices like STATCOM, DVR and UPQC play important role in power quality improvement. IEEE and IEC standard for the grid connected renewable energy systems are one of the critical point of interest for the selection of custom power devices. Special attention has been given on the compensation of reactive power, harmonic current and voltage fluctuation during the interconnected as well as islanding mode of operation. As the solar and wind are the most abundant resources therefore …

The Control Of Rotor Side And Grid Side Converters In A Dfig During Network Voltage Unbalance Conditions Using Resonant Current Controllers., Joseph Kearney, Michael Conlon, Eugene Coyle

Conference papers

This paper implements control techniques to enable improved operation of DFIG’s when subjected to the effects of network voltage unbalance conditions. The control scheme involves the integration of a resonant regulator into the PI controllers of both the rotor side and grid side converters in a DFIG. The resonant controller is tuned to twice the network frequency (2ω_e) and designed to mitigate against the oscillations in a DFIG due to network voltage unbalance conditions. The grid side converter controller also incorporates a second resonant controller tuned to three times the grid frequency (3ω_e) to alleviate the …

Novel Ac Side P&O Maximum Power Transfer Control For Grid Connected Photovoltaic Systems, Mohamed Moin Hanif, Malabika Basu, Kevin Gaughan

Conference papers

Grid connected Photovoltaic inverters can convert PV energy into electricity with very high efficiencies. Power from the PV panels fluctuates depending on various weather conditions. PV inverters usually include a maximum power point tracker (MPPT) to track this varying power, in order to transfer all the available power to the grid efficiently. Control of power transferred to the grid along with the MPPT plays a crucial role in determining the efficiency of a PV system. This paper discusses about the basic power transfer theory between sources (PV and Grid) and focuses on the need of a DC-DC boost circuit, along …

The Size Ellect On The Infrared Spectra Of Condensed Media Under Conditions Of Id, 2d And 3d Dielectric Confinement, Igor I. Shaganov, Tatiana S. Perova, Vasily A. Melnikov, Kevin Berwick

Articles

A general expression for the dielectric loss spectrum of an absorbing composite medium was obtained from a Maxwell-Garnett general equation. This expression was simplified for the cases of one, two and three dimensional dielectric confinement in both ordered and disordered thin layers, rods (wires) and spheres of absorbing medium which are considered as mesoparticles or mesoscopic molecules. This theoretical approach was verified experimentally using high purity organic liquids with strong absorption bands in the infrared range. Three organic liquids, namely benzene, chloroform and carbon disulphide, were measured in various dielectric confinement configurations using Fourier Transform Infrared (FTIR) spectroscopy with a …

Double Quantum Dot Photoluminescence Mediated By Incoherent Reversible Energy Transport, S. Yu Kruchinin, A. V. Federov, A. V. Baranov, T. S. Perova, Kevin Berwick

Articles

We present a theoretical study of the stationary photoluminescence of two, direct-gap, semiconductor nanocrystals, taking into account electronic excitation energy-transfer processes due to electrostatic interaction. The results obtained here allow for the incoherent reversible energy transport that occurs when the intraband relaxation rate in a quantum dot acceptor is comparable to, or less than, the energy-transfer rate. We investigate the secondary emission of two different electronic level schemes that can be realized experimentally, obtain analytical expressions for the luminescence differential cross section, and perform an analysis of its spectrum. It is shown that when excitation is not in resonance with …

The Effects Of Harmonics On Power Quality And Energy Efficiency, Alan Harrison

Other resources

By making our electricity supply more secure, reliable and versatile will mean that we reduce our reliance upon oil, gas and solid fuels, which mostly exist outside of Ireland and the European community. The majority of our fuel is imported and this makes our economy dependent on outside interests and out of our control. Even more importantly as the world’s fossil fuel reserves are running out and electricity demand is ever increasing.

If we make our electricity networks secure and designed to the highest standards we can import and export electrical energy more easily as our demands change, for example …

Interactive Music Archive Access System, Martin Gallagher, Mikel Gainza, Derry Fitzgerald, Dan Barry, Matt Cranitch, Eugene Coyle

Conference papers

The goal of the Interactive Music Archive Access System (IMAAS) project was to develop an interactive music archive access system which was capable of allowing an end-user to easily extract rhythmic, melodic and harmonic musical metadata
descriptors from audio, and allow the user to interact with the archive contents in a manner not typically allowed in archive access systems. To this end, the IMAAS system incorporates a range of real-time interaction tools which allow the user to modify the retrieved audio in a number of ways including the ability to isolate individual instruments in stereo mixes, pitch and timescale modification, …

Electron-Electron Scattering In A Double Quantum Dot: Effective Mass Approach, S. Yu. Kruchinin, A. V. Federov, A. V. Baranov, Tatiana Perova, Kevin Berwick

Articles

We present a theoretical description of the first-order scattering of interacting electrons and holes in a double quantum dot. Assuming infinitely high walls, strong confinement, and a two-band approximation, we derive general expressions for the two-particle matrix elements of the screened Coulomb potential. We also determine the selection rules for different scattering channels and consider special cases where the corresponding matrix elements can be represented by simple analytical expressions. Numerical calculations of the matrix elements and an analysis of their dependence on the geometrical and material parameters of the double quantum dot have also been performed.

Blind Single Channel Sound Source Separation, Mark Leddy

Masters

In recent years source separation has become an increasingly popular area of research in the signal processing community. The subject has found applications in a variety of fields such as medical imaging, sound and audio, econometrics and geophysics. This document will discuss the application of source separation techniques to the area of audio. Sound source separation is the process of observing a mixture signal made up of a number of sources, and from this mixture estimating the individual source signals. Audio source separation techniques may be crudely split into the following areas; techniques that utilise attributes of the sources, and …

Passive All-Fiber Wavelength Measurement Systems: Performance Determination Factors, Ginu Rajan, Yuliya Semenova, Agus Hatta, Gerald Farrell

Books/Book Chapters

No abstract provided.

Protection Of Upqc Against The Load Side Short Circuits, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan

Articles

This study presents a protection scheme for protecting the series inverter of a unified power quality conditioner (UPQC). The proposed scheme protects the series inverter from overcurrents and overvoltages, which appear during short-circuit faults on the load side of the UPQC. The main protection element is a crowbar connected across the secondary of the series transformer and consists of a pair of antiparallel connected thyristors, which is governed by a simple Zener diode-based control circuit. In the case of an overvoltage, the crowbar short circuits the secondary of the transformer, thus removing the overvoltage and diverting the fault current from …

Electromagnetic Scattering Solutions For Digital Signal Processing, Jonathan Blackledge

Other resources

Electromagnetic scattering theory is fundamental to understanding the interaction between electromagnetic waves and inhomogeneous dielectric materials. The theory unpins the engineering of electromagnetic imaging systems over a broad range of frequencies, from optics to radio and microwave imaging, for example. Developing accurate scattering models is particularly important in the field of image understanding and the interpretation of electromagnetic signals generated by scattering events. To this end there are a number of approaches that can be taken. For relatively simple geometric configurations, approximation methods are used to develop a transformation from the object plane (where scattering events take place) to the …

The Integrated Control Of The Rotor Side And Grid Side Converters In A Dfig To Reduce Both Power And Torque Pulsations During Network Voltage Unbalance Conditions., Joseph Kearney, Michael Conlon, Eugene Coyle

Conference papers

No abstract provided.

Optimisation Of Multicast Routing In Wireless Mesh Networks, Brian Keegan, Karol Kowalik, Mark Davis

Conference papers

In recent years Wireless Mesh Networks have been deployed and grown in popularity in many metropolitan areas. The deployment of such networks has allowed clients to gain access to publicly available broadband networks. The implementation of wireless mesh networks requires that backhaul services (traditionally carried by wired networks) be maintained via wireless mesh points. Because of their structure, wireless mesh networks provide an excellent means for targeting a large group of end users or simply to relay data. This may be achieved by means of broadcasting or more specifically multicasting. The lack of standards and support for multicasting over wireless …

Investigation Of Across-Layer Modification To The Dsr Routing Protocol In Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis

Conference papers

This work introduces a cross-layer modification to the DSR protocol that increases the global throughput in wireless mesh networks. In our modified DSR protocol we have introduced the Access Efficiency metric as an alternative to the hop-count metric in order to improve the route selection mechanism. The selected path in the route selection mechanism is identified by choosing the path with the highest minimum Access Efficiency value. We have employed the OPNET modeller as a simulator to examine two different patterns of traffic for a series of randomly generated network topologies. Each topology was simulated twice. One simulation used the …

An Investigation Of The Correlation Between Passive Monitoring And Activie Probing Techniques Used In Wlan Mesh Networks, Chenzhe Zhang, Mark Davis

Conference papers

In recent years, Wireless Mesh Networks (WMNs) have emerged as a promising solution to provide low cost networks that extend Internet access and other networking services. Mesh routers form the backbone connectivity through cooperative routing in an often unstable wireless medium. Therefore, the techniques used to monitor and manage the performance metrics to help optimize the link performance in WMNs. This paper presents an assessment of the correlation between passive monitoring and active probing techniques used for link performance measurement in WMNs. This paper presents an assessment of the correlation between passive monitoring and active probing techniques used for link …

Effects Of Lline Rate On Vvideo Qos Over Wireless Networks: An Experimental Approach, Stuart Wallace, Mark Davis

Conference papers

Video streaming over Wireless Local Area Networks (WLANS) is becoming an increasingly popular service. However, end user OoS is highly influenced by many factors. These include the video codec used, the packetization scheme, error concealment and correction techniques, the complexity of the video, propagation losses, and the line rate. In this paper the effect of the line rate on the capacity of the network when streaming multimedia content is analyzed experimentally. It is shown that as the line rate decreases the bandwidth load of the video stream dramatically increases leading to poor QoS at the client side. As automatic line …

Hand-Held Flyback Driven Coaxial Dielectric Barrier Discharge: Development And Characterization, Victor J. Law, Vladimir Milosavljevic, Neil O’Connor, James F. Lalor, Steven Daniels

Articles

The development of a handheld single and triple chamber atmospheric pressure coaxial dielectric barrier discharge driven by Flyback circuitry for helium and argon discharges is described. The Flyback uses external metal-oxide-semiconductor field-effect transistor power switching technology and the transformer operates in the continuous current mode to convert a continuous dc power of 10–33 W to generate a 1.2–1.6 kV 3.5 μs pulse. An argon discharge breakdown voltage of ∼768 V is measured. With a 50 kHz, pulse repetition rate and an argon flow rate of 0.5–10 argon slm (slm denotes standard liters per minute), the electrical power density deposited in …

Control Of Double Fed Induction Generator Wind Turbine During Network Voltage Unbalance Conditions, Joseph Kearney, Michael Conlon

Conference papers

The behaviour of Double-Fed Induction Generators to supply network voltage unbalance is investigated. The paper describes a method to control the rotor-side converter in a DFIG when subjected to the effects of network voltage unbalance conditions. A parallel control scheme is implemented to control the positive and negative sequence components independently. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque oscillations and a reduction in the high unbalanced currents generated as a result of the applied voltage unbalance.

An Evaluation Of A Conservative Transmit Power Control Mechanism On An Indoor 802.11 Wireless Mesh Testbed, Karol Kowalik, Marek Bykowski, Brian Keegan, Mark Davis

Conference papers

Power control techniques for IEEE 802.11 wireless networks have already gained considerable attention. Such techniques are particularly attractive because they can improve various aspects of wireless network operation such as interference mitigation, spatial reuse in dense wireless deployments, topology control, and link quality enhancement. In this paper we propose a novel delivery ration based Conservative Transmit Power Control (ConTPC) mechanism. Our implementation is conservative when it comes to deciding if the transmit power should be reduced for a given link. This is because we do not want poor quality wireless links to further reduce their quality and be overwhelmed by …

Practical Issues Of Power Control In Ieee 802.11 Wireless Devices, Karol Kowalik, Marek Bykowski, Brian Keegan, Mark Davis

Conference papers

Power control techniques for IEEE 802.11 wireless networks have already gained much attention. Such techniques are particularly attractive because they can improve various aspects of wireless network operations such as interference mitigation, spatial reuse in dense wireless deployments, topology control, and link quality enhancement. However, until recently implementing such advanced power control using off-the-shelf wireless devices was not considered possible. For example, Abdesslem et al. [1] stated that “many novel power control solutions cannot be efficiently implemented over existing IEEE 802.11 cards”. However, in this paper we demonstrate that power control is now feasible and can be implemented in current …

Real-Time Plasma Controlled Chemistry In A Two-Frequency, Confined Plasma Etcher, Vladimir Milosavljevic, Albert R. Ellingboe, Cezar Gaman, John V. Ringwood

Articles

The physics issues of developing model-based control of plasma etching are presented. A novel methodology for incorporating real-time model-based control of plasma processing systems is developed. The methodology is developed for control of two dependent variables (ion flux and chemical densities) by two independent controls (27 MHz power and O2flow). A phenomenological physics model of the nonlinear coupling between the independent controls and the dependent variables of the plasma is presented. By using a design of experiment, the functional dependencies of the response surface are determined. In conjunction with the physical model, the dependencies are used to deconvolve the sensor …

Throughput Enhancement Through Combined Fragmentation And Rate Method In Ieee 802.11b Wlans, Marek Bykowski, Karol Kowalik, Brian Keegan, Mark Davis

Conference papers

IEEE 802.11 allows for fragmentation tuning and rate selection. Their combined usage is referred sometimes to link adaptation. However, the algorithms of link adaptation are beyond the 802.11 standards. In this paper we investigate the benefits arising from proper use of link adaptation. Particularly, we develop a mathematical model describing the fragmented transmission in 802.11b. We examine potential benefits of it over AWGN and fading channels. More significantly we combine fragmentation tuning with bit-rate selection to yield the highest achievable throughput performance for any given channel conditions. Finally, we propose an algorithm that performs the optimal link adaptation.

Drop Photometer Design., Kevin Tiernan

Doctoral

The tensiograph drop analyser, operating in the mode of ultraviolet-visual absorption photometer, was re-engineered to improve measurement accuracy. As well as instrumentation re-design, the other objective of the research was to analyse tensiograph signals to explore how their features are defined by drop properties. Using fibre optic technology, the tensiograph emits a light beam into a growing pendant drop whereupon it undergoes a number of internal reflections. A portion of the reflected light energy is coupled to a photodiode producing a proportional current that is electronically processed and transferred to a computer for analysis. The signal produced, known as the …

Antennas For Portable Communications In The Uwb And Gps Spectra., Giuseppe Ruvio

Doctoral

The thesis describes a study of antennas for solutions in emerging systems. An account of the fundamental principles of these antennas is given together with an outline of the basic electromagnetic theory on which the designs are based. While the main focus is on antennas for Ultra Wideband (UWB) systems, some additional work was carried out on enhancing performance of circularly polarised antennas for satellite navigation systems. The study focussed on the design of highly efficient broadband antennas with particular requirements for size compactness, gain stability, phase-linearity, and the use of low-cost materials. These requirements are particularly important for UWB …