Electromagnetic Interference (EMI) problems in switching power supplies have been traditionally treated with cut-and-try approaches. In recent years, advancement has been made to better understand the problems and minimize the cut-and-try portion of the design process. However, there are still phenomena difficult to explain in many practical design situations. Often, the problems may be solved by luck but many puzzles remain unsolved. If not fully understood, these puzzles are very likely to come back to haunt the designers. According to the conventional theory, there are two modes of noise: the Differential-Mode (DM) noise and the Common-Mode (CM) noise. Recently, a new noise-coupling mode called Non-Intrinsic Differential-Mode (NIDM) noise was uncovered accidentally in the process of explaining certain EMI filter action [1]. This phenomenon has never been thoroughly studied. The focus of the present thesis is to investigate the NIDM phenomenon and its implications to practical EMI filter design issues. The generation mechanism and basic characteristics of this phenomenon will be briefly reviewed, which is crucial to the understanding of the remaining parts of the research. Two essential diagnostic tools are introduced. One is the DM/CM noise separator and the other is the zero-span mode operation of a spectrum analyzer. The results of the investigation will be presented. The results will be presented using practical examples, which tie the phenomenon to filter design issues. In some examples, explanations are given to dispel the puzzles commonly encountered in the practice. A filter design procedure is suggested for off-line power supplies. This procedure incorporates the NIDM phenomenon into an existing design procedure. Only first-order and second-order filter topologies are included in the discussion. / Master of Science

<p> This research indicates that present methods of water supply and sewerage for high arctic communities are inadequate from the point of view of health, aesthetics and economics. This thesis examines these present methods and their problems.</p> <p> Field work was conducted in three communities of the Eastern Canadian Arctic. Data were collected with regard to, - the biological quality of the drinking water and raw water sources, the quantities of river water available, the soil conditions, the construction equipment and generating capacities of the small communities, water consumption, and the sizes and types of storage tanks within the communities.</p> <p> In order to improve existing conditions, an entirely new method of water supply is developed in which water is intermittently distributed through electrically traced pipes to storage tanks within all the buildings. Computer programs are presented which will optimize the design on the basis of net annual cost. The related problems of water quality, power supply and sewerage are also examined and social, health and aesthetic effects are considered.</p> <p> The results are novel in many respects: Distributed storage allows the use of very small diameter pipes and results in very low capital, construction and operating costs.</p> / Thesis / Master of Engineering (MEngr)

No description available.

The distortions of input voltage and current waveforms generated by switch mode power supply (SMPS) operation are a major cause of concern in the power quality performance of commercial office buildings. These distortions are usually evaluated by performing a site survey of the building. In this thesis, a power quality simulator is proposed as an alternative method to site surveys in evaluating the power quality characteristics of such nonlinear loads in a commercial environment. The power quality simulator is built around the assumption that the total load kVA on each phase of the three-phase four-wire distribution system can be approximated. The proposed simulator is tested on two commercial office buildings, namely the Owen Hall and Dearborn Hall buildings of Oregon State University. Experimental time-domain and frequency-domain waveforms are presented. These are compared with the simulation results to prove the viability of the power quality simulator in determining the power quality characteristics of the building. Finally, a passive filtering technique was simulated to reduce the harmonic distortions in voltages and currents to further demonstrate the potential uses of the power quality simulator. / Graduation date: 2000

Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: This thesis presents the design and implementation of a voltage controller for an Uninterruptible Power Supply (UPS) Inverter. The inverter is capable of producing a nearly sinusoidal output voltage waveform, thereby keeping the Total Harmonic Distortion (THD) to a minimum. Digital controllers introduce a time delay in the control law that causes system instability. Various control techniques, which includes Pade approximations and system augmentation, are investigated to eliminate the effect of the time delay. These controllers employ classical control as well as modem control techniques. The selection of the various control parameters is verified by mathematical equations. A load-disturbance compensation scheme, implementing feed-forward and gain scheduling, is also developed to improve voltage distortion when varying loads, such as non-linear loads, are connected to the system. It is shown that the constructed pulse-width modulated (PWM) control scheme can achieve fast dynamic response as well as a low THD. / AFRIKAANSE OPSOMMING: Hierdie verhandeling ondersoek die ontwerp en implementering van 'n spanningsbeheerder vir 'n ononderbroke kragtoevoer omsetter. Die stelsel produseer 'n uittree spannigsgolfvorm met 'n lae Totale Harmoniese Distorisie (THD). Digital beheerders veroorsaak 'n tydvertraging in die beheerwet wat stelsel onstabiliteit kan veroorsaak. Verskeie beheertegnieke wat gebaseer is op die Pade benaderings van die tydvertraging en stelsel aanpassings, is ondersoek. Hierdie beheerders maak gebruik van klassieke en moderne beheertegnieke. Die seleksie van die verskeie beheerderveranderlikes word gestaaf deur wiskundige vergelykings. Spannigsvervorming word tot 'n minimum beperk deur gebruik te maak van 'n lasveranderings-kompensasietegniek wat onderskeidelik vorentoe-voer en aanwins skedulering implementeer. Verder word daar bewys dat die pulswydte modulasie (PWM) beheerskema vinnige dinamiese gedrag asook 'n lae THD bewerkstellig.

This master thesis concerns the design of DC power suply, which will be used for technological processes in engineering. This thesis concludes design of components and control curcuits for switching power supply. Output parameters of the machine will be measured.

The aim of my master’s thesis is the design and implementation of laboratory power supply with output parameters 0-25V and 0-2A and options to manage this resource by elements of the front panel or via a computer control program. Content is the theoretical analysis of the possibility of subsequent theoretical sources suggesting that it verified on the prototype laboratory resources.

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980 / Includes bibliographical references. / by Akhil Gupta. / M.S. / M.S. Massachusetts Institute of Technology, Department of Mechanical Engineering

This project deals with a design of power and control circuits for a laboratory power supply source, consisting of a continuous conduction mode active rectifier and DC/DC converter. Detailed design of input rectifier with active power factor correction, DC/DC converter and control circuits with their implementation to digital signal processor are the project results.

Call number: LD2668 .T4 1984 D83 / Master of Science