Thesis (Ph. D.)--University of Hong Kong, 1998. / Includes bibliographical references.

Improved actuator point-to-point positioning performance, as measured by settling time, has been demonstrated in the context of manufacturing automation applications such as circuit board assembly and other product-transfer operations. The control objective is to move a single mass in a single axis from a starting position to a target position following the fastest possible motion trajectory while meeting final-position accuracy requirements. The actuator's achievable force that is available for acceleration is the fundamental variable that determines optimal settling time. The actuator technology employed is the linear variable reluctance motor. Mathematical motor models and simulation programs have been developed to perform several tasks necessary for demonstrating improved actuator performance: (i) optimal commutation under force ripple constraints has been computed to determine ripple-specified force limits and to provide excitation waveforms necessary for force production, (ii) motion profiles for several positioning task scenarios have been generated based on computed ripple-specified force limits, (iii) state space integral position control simulations have been performed to evaluate the degree of success of the proposed relaxation of force ripple constraints in improving settling time and (iv) the computed settling times for positioning tasks have been examined in relation to the copper losses associated with them in order to assess the trade-off. It has been shown that higher force capability is achieved when force-ripple constraints, which have been customarily emphasized in positioning applications, are relaxed. The higher capability is exploited by adopting faster motion trajectories, which are then imposed under feedback control to achieve faster settling time. Improved force capability with relaxed ripple constraints is demonstrated by generating average force versus speed capability curves under ripple constraints ranging from minimal ripple to unconstrained ripple. Improved positioning performance, with relaxed ripple constraints and without violating the final-position accuracy specification, is demonstrated by computing and comparing settling time for multiple positioning tasks with trajectories based on both extremes of force capability, lowest (no-ripple) and highest (unconstrained-ripple) force limits. The results have been demonstrated for two LVR motor configurations: one motor configuration represents typical (switched) linear and rotary variable reluctance motors while the other exhibits features of both switched and synchronous varieties of variable reluctance motors.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 58-59). Also available via the Internet.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

No description available.

Bibliography: p. 321-333. / xii, 336 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Specifically addresses the problem of the robustness and reliability of the SR motor drive operation with sensorless position estimation. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1998

Thesis (Ph.D.) -- University of Western Sydney, 2007. / A thesis presented to the University of Western Sydney, College of Health and Science, School of Engineering, in fulfilment of the requirements for the degree of Doctor of Philosophy. Title from title screen. Includes bibliographical references. Thesis minus Appendix B (video clips and photos) also available online at: http://handle.uws.edu.au:8081/1959.7/26494.

Thesis MTech(Electrical Engineering))--Cape Peninsula University of Technology, 2006 / Reluctance Synchronous Machines (RSM) have, due to their rotor geometry, an inherently high torque ripple. This torque ripple is defined as the deviation of the minimum and maximum torque from the average value. It is unwanted as it indicates uneven pull on the rotor causing deformation of it and hence different air-gaps along the rotor circumference as well as acoustic noise. In applications such as power steering, robotics and radar positioning systems where high precision movement is vital, oscillating torque will lead to the malfunction of these devices and therefore suppressed the use and development of RSMs. Unlike the Induction machine (IM), the RSM has no copper losses in the rotor, which reduces the operating temperature significantly. With the development of electronic drives the quality of the output torque could be improved by means of accurate current- and flux space phasor control methods with much success and made the RSM a possible replacement for the IM. However, reducing torque ripple by means of purely geometrical changes is still a challenge to the machine designer. This thesis will focus on the reduction of torque ripple while leaving the average torque relatively unchanged by changing the rotor geometry. The rotor changes will take place by means of flux barriers and cut-outs while the stator has either semi-closed slots or magnetic wedges. In this work rotor structures with equal harmonic magnitudes but their angles 1800 apart. will be combined to form one machine and identify how torque harmonics respond. The change in average torque and power factor will be evaluated with all geometrical changes made to these machines throughout this work.

In recent years, the product life cycle has decreased and demands for new products have emerged due to competition, modern industrial needs and rapidly changing technology. This has necessitated changes in design, development and manufacturing processes to improve the quality and efficiency and to reduce the cost. Computer Aided Design (CAD) helps to meet this challenge both in the design evaluation and product design stages. This thesis contains the development of an interactive software for the optimal design of a motor intended for variable speed applications. The use of finite element analysis methods is proposed as an indispensable part of the CAD system for electrical machine design. An illustration of the method is presented for the design of a switched reluctance motor. / Master of Science

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This thesis deals with the design and optimisation of medium power traction switched reluctance machines with tapered and straight stator poles. Only the prototype of the tapered stator pole machine is constructed and evaluated in this study. A non-commercial finite element package is used in the design and optimisation of the machines. The finite element method is applied directly in the optimisation procedure to optimise the design of the machines in multi-dimensions. The lumped circuit analysis method is used only for the purpose of verifying some of the finite element calculated. It is not used in the optimisation procedure. The performance characteristics of the tapered and straight stator pole machines are compared and discussed and the tapered stator pole machine is found to have better torque performance. Also the calculated and measured static torque versus rotor position characteristics of the tapered stator pole machine are compared and discussed. / AFRIKAANSE OPSOMMING: Die tesis beskryf die ontwerp en optimering van medium drywing trekkrag geskakelde reluktansie masjiene met tapse en reguit stator pole. Slegs 'n prototipe van die tapse stator pool masjien is gebou en geëvalueer. Die masjiene is ontwerp en geoptimeer met behulp van 'n nie-kommersiële eindige element metode pakket. Die eindige element metode is direk in die optimerings algoritme gebruik vir die optimering van die masjiene in multi-dimensies. Die gekonsentreede parameter stroombaananalise is slegs gebruik om sommige van die eindige element berekenings te verifeer. Die vermoës van die tapse en reguit stator pool masjiene is vergelyk en bespreek. Die resultate toon dat die tapse stator pool masjien se draaimoment vermoë beter is as die van die reguit stator pool masjien. Die berekende en gemete statiese draaimoment teenoor rotorposisie van die tapse stator pool masjien is ook vergelyk en bespreek.