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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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    A particle swarm optimization approach for model independent tuning of PID control loops
    (IEEE, 2007-09) Nelendran Pillay; Poobalan Govender
    The 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.
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    PWM-VSI inverter-assisted stand-alone dual stator winding induction generator
    (Institute of Electrical and Electronics Engineers (IEEE), 2000-11) Ojo, Olorunfemi; Davidson, Innocent Ewean
    This 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.
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    Evaluation and effective management of non-technical losses in power networks
    (2002-10) Davidson, Innocent Ewean
    Market-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.
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    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%.
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    Logistics CIM modeling and simulation
    (2003) Li, Qingxue; Bright, G.
    This study presents a development of a method for Logistic Computer Integrated Manufacturing (LCIM) modelling. Based on this new model, a small LCIM cell simulation system was developed