Faculty of Engineering and Built Environment
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Item A particle swarm optimization approach for model independent tuning of PID control loops(IEEE, 2007-09) Nelendran Pillay; Poobalan GovenderThe paper proposes a model independent tuning technique that yields optimal proportional-integral-derivative parameters for a range of typical process control loops. The proposed tuning technique utilizes the particle swarm optimization algorithm to generate optimal tuning parameters. The PSO tuning method is applied to typical process models. Comparisons are made between the proposed PSO technique and other conventional methods. ©2007 IEEE.Item PWM-VSI inverter-assisted stand-alone dual stator winding induction generator(Institute of Electrical and Electronics Engineers (IEEE), 2000-11) Ojo, Olorunfemi; Davidson, Innocent EweanThis paper presents a novel usage of a dual stator winding three-phase induction machine as a stand-alone generator with both controlled output load voltage magnitude and frequency. This generator, with both three-phase power and control windings housed in the stator structure, has the load connected to the power winding and a three-phase pulsewidth modulation (PWM) voltage-source inverter sourcing the control winding. The input to the PWM inverter is either a battery source or a charged dc capacitor. The operational characteristics of these generator schemes with either of the two inverter sources are investigated and shown to have desirable performance. How the load voltage magnitude depends on the various control and design parameters such as rotor speed, compensating capacitance, and load impedance is determined using a detailed mathematical model of the system.Item Evaluation and effective management of non-technical losses in power networks(2002-10) Davidson, Innocent EweanMarket-driven economies and deregulated electricity industry environment have stimulated the minimization of technical and non-technical losses (NTL) even though they do not constitute major operational or quality of supply problems. Their impact is economic and utilities often passed down the costs to consumers. NTL need to be addressed to determine the overall performance of power networks, as these losses are expected to be more dominant at the sub-transmission (132kV-33kV) and reticulation (22kV and 11kV) levels of the electricity supply industry value chain. In some national grid operations, NTL are estimated to account for up to 30% in revenue losses to electric utilities, and overhead expenditure in added maintenance costs. This paper discusses a method for NTL evaluation and an effective management approach to loss minimization and revenue collection. Copyright © 2002 IEEE.Item Performance analysis of a shaded-pole linear induction motor using symmetrical components, field analysis, and finite element method(Institute of Electrical and Electronics Engineers (IEEE), 2000-03) Davidson, Innocent Ewaen; Gieras, Jacek F.The application of symmetrical components of two-phase asymmetric systems, field theory, and finite element method (FEM) to the performance calculation of the shaded-pole linear induction motor (LIM) is presented. The results compared with measurements are satisfactory though the performance of the shaded-pole single-phase LIM is poor when compared to three-phase LIMs. LIMs generally have low efficiencies due to their open airgap. The maximum efficiency of rotary shaded-pole induction motors with cage-rotors rated at 100 W usually does not exceed 20%.Item Methodologies for the optimal design of fibre-reinforced composite structures(2003) Smith, Ryan Elliot; Walker, MarkComposites have become important engineering materials, especially in the fields of automotive, aerospace and marine engineering. This is due to the high specific strength and stiffness properties they offer. At present, fibre-reinforced plastic (FRP) laminates are some of the most common types of composite used. They are produced in various forms with different structural properties. As with all engineering materials, there is the existence of both advantages and disadvantages. One of the main disadvantages is the expense involved in producing both the material and the finished product. The design time is also costly as the material has to be designed concurrently with the structure.Item Laboratory optimisation of the carbonatation process with regard to colour removal at the Malelane Refinery(2001) Moodley, Manogran; Lionnet, G. R. E.The purpose of this investigation was to identify and then optimise the factors that affect the decolourisation during the carbonatation process. Batch carbonatation tests, carried out in a pilot plant in the laboratory, were performed to establish the effect of selected factors on the decolourisation of melt.Item The development and evaluation of an on-line sugar purity meter for use in a low grade continuous centrifugal(2001) Moodley, Manogran; Pillay, Visvanathan LingamurtiThere are two process operations in the sugar factory that directly affect the recovery of sugar from evaporated syrup, namely crystallisation (boiling) and centrifugal operation. Successful automation of the vacuum pans (boiling) has been implemented using brix (total dissolved solids) control, but to date on-line measurement of continuous centrifugal performance has not been successfully accomplished in South Africa. The purpose of this investigation was to continue the preliminary work performed by Tongaat Hulett Sugar in developing a purity meter for the measurement of sugar purity (sucrose content) in a continuous centrifugal. This instrument would provide the centrifugal operator with a reliable tool to perform on-line measurement of sugar purity and would also facilitate the automation of the centrifugalItem An investigation into the factors affecting precoat performance in woven-fibre microfiltration(2002) Vallabh, Shadana; Pillay, LingamCrossflow microfiltration (CFMF) using a fabric support has been successfully used to treat a range of problematic waters. Experimental evidence indicates that the formation of a dynamic membrane or precoat on a woven-fibre microfilter can significantly increase the performance of the filter, that is, the production rate and rejection. The use of precoats in filtration applications is based on the precoat's unique microstructure that is able to trap sub-micron particles while maintaining a permeable filter cake. However, to date the precoating step has been more of an art than a science. Very little knowledge exists on the best type of precoat to use, or the the optimal velocity, pressure and concentration to form a stable precoat. Further, although various models have been proposed for CFMF, their still exists a lack of knowledge of the mechanisms by which precoats improve performance.Item The integration of a high voltage cable fault location instrument with modern information technology(2002) Kelly, Roger James; Bajic, Vladimir B.Modern society as a whole seems destined to have an ever-increasing demand for power for both industrial and domestic use, as continued population growth means that cities, suburbs and industrial areas become larger and denser. At the same time the trend toward increased productivity in all segments of industry is influencing the development and techniques employed at locating faults in power cables and networks to ensure only limited downtime and reduced direct and indirect costs associated with the location of faultsItem A study of the chemical quality of ambient air at selected intersections in the Durban Metropolis(2003) Singh, Shalini; Moodley, K. G.Motor vehicles are considered a major source of air pollution in urban environments. Nitrogen dioxide (N02) and nitric oxide (NO) which are collectively referred to as oxides of nitrogen (NOx) are formed at high temperatures during combustion processes in the engines of motor vehicles and are emitted via the exhaust into the atmosphere. Nitrogen dioxide is regarded as an irritant of the respiratory system.