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The work presented in this thesis is concerned with the development of an on-line technique for detecting and locating partial discharges in the stator winding of a high voltage electrical machine. This technique forms part of an on-line health monitoring strategy for the insulation of high voltage machines. Existing diagnostic techniques and partial discharge measurement systems are reviewed. The requirement for an on-line partial discharge location technique is discussed. An experimental investigation was carried out into the propagation characteristics of partial discharge pulses within a model stator winding. This allowed identification of the main propagation characteristics which were used as the basis for the development of a partial discharge location technique. In the development of a location technique, a means of on-line detection of discharge signals at the motor terminals is required. A study was therefore made on the use of the Rogowski coil for the non-invasive measurement of partial discharges. A partial discharge location system was developed based on the correlation of partial discharge pulses detected at the two ends of a motor phase winding. The performance of the location system was investigated by injecting artificially generated discharge pulses into the model stator winding. Further verification of the ability of the technique to locate the position of discharges was done by injecting high voltage discharges. The final part of the research work was to develop a theoretical model to predict the propagation behaviour of partial discharge pulses in the stator winding of an electrical machine . The effect of electromagnetic propagation through the endwinding region is incorporated in the model of two adjacent coils in a winding.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

In an increasingly urgent climate crisis, the use of electric powertrains in smaller, purpose-built vehicles can expedite the global adoption of electrification. This thesis discusses the detailed design of an axial-flux switched reluctance motor for application in a light electric vehicle, such as an E-motorcycle. A vehicle application is studied based on typical driving conditions in an urban environment. The requirements of the propulsion motor are extracted, and a baseline machine topology is analyzed for its performance and manufacturability, towards the goal of a functional prototype. The prototype design includes a self-supporting foil winding, designed to maximize the use of axial space and allow for good conductive heat transfer to the machine casing. The rotor structure is found to be a limiting factor, where maximum speed is limited by the mechanical stresses. The performance of the motor is analyzed in detail, beginning with a numerical iron loss model that is implemented to provide faster simulation time of the machine efficiency than FEA. The efficiency is found to peak at 90%, comparable with other traction motors of similar size on the market. The switching angles are studied, and the trade-offs between torque quality and efficiency are quantified over the drive cycle. It was determined that the vehicle could save 19.6 Wh/km by accepting poor torque quality and operating with the most efficient control parameters. Thermal analysis is performed to determine the realistic performance limitations. The machine was found to have power ratings of 7.12 kW instantaneous and 4.76 kW continuous. The final temperature of the winding during the drive cycle was predicted not to exceed the temperature ratings of the insulation system. Finally, the prototype is assembled, and a test plan is outlined for qualification of the motor. / Thesis / Master of Applied Science (MASc) / This thesis documents the design of a new type of electric motor that is intended to be used in a small electric vehicle. The electric motor is different from the majority of motors used in this application for two reasons: firstly, the motor is a switched reluctance motor, which means that it does not contain any permanent magnets, offering cost savings and additional robustness. Secondly, the machine takes the form of a disk, where the magnetic interface between rotating and stationary components is on the face perpendicular to the axis of rotation. Normally, electric motors have the magnetic interface on the cylindrical surface which is parallel to the axis of rotation. The disk form factor presents multiple design challenges, which when coupled with the switched reluctance motor type, are addressed. A series of mathematical models are built to predict the performance of the motor in the vehicular application. Finally, a prototype of the motor is constructed.

Tightening systems are used in several industries, including assembly in the auto- motive industry and installation of computer hardware. Both the company mak- ing the tools and the customers need to know the performance of the tightening system to ensure that the screw joints tighten as desired. This can be done using a test joint system. High demands on safety as well as fast assembly speeds, puts high demands on the test equipment. The problem with the existing test joints is that they are hard to do repeatable tests on. The most common test joints are constructed us- ing mechanic or hydraulic systems. The mechanical systems have problems with wear of screws, changes in lubrication etc., while the hydraulic systems some- times are too slow. This master’s thesis is a study of whether it would be possible to construct a test joint using an electric motor. The electric motor together with a controller should simulate a screw joint so that the tool would perceive it as a real one. All investigation has been performed by system modeling and simulations in MATLAB. Four different control structures have been evaluated: a PID controller, one combined controller which uses feedforward from reference as well as distur- bance, one which is based on the same structure as the second but with an added inner current loop and the last one is an LQ controller. The conclusion is that it is possible to make a test joint using an electric motor and that the LQ controller seems to be the best choice. To prove the result, a few more aspects could be investigated more closely. One is to add a dynamic model of the tool, now only the reference to the tool is used. Another is to implement it on hardware.

A Escola Politécnica da Universidade de São Paulo (EPUSP) e o Instituto Dante Pazzanese de Cardiologia (IDPC) estão realizando um projeto conjunto visando o desenvolvimento de um implante Dispositivo de Assistência Ventricular (DAV). Esta dissertação é parte do desenvolvimento de um VAD implantável em que o rotor da bomba é suspenso por uma suspensão magnética com um grau de liberdade (1-DOF). A suspensão magnética aqui utilizada apresenta o controle ativo somente na direção axial do rotor. Este mancal magnético foi apresentado por Silva e Horikawa (2000) no qual o controle ativo é executado apenas na direção axial do rotor. Neste trabalho o mancal magnético será referenciado como MMA-EPUSP. O motor de corrente contínua sem escovas (BLDC) foi selecionado pelo mesmo motivo que o mancal magnético: o motor não pode ter nenhum contato com o rotor, minimizando os problemas de danos aos componentes do sangue. Entretanto, o acionamento do motor através de forças magnéticas pode interferir na suspensão magnética. Como a estabilidade da suspensão magnética é garantida pela rigidez axial, é razoável presumir que a interação magnética entre o mancal magnético e o motor elétrico pode interferir na suspensão magnética. Este estudo analisa experimentalmente o motor BLDC com rotor apoiado pelo MMA-EPUSP, para identificar o comportamento desse conjunto utilizando duas configurações distintas de motor com fluxo magnético: radial e axial. A análise inclui: (i) projeto, construção e teste de um motor BLDC axial e um radial; (ii) projeto, construção e teste do MMA- EPUSP e do rotor para ser acionado pelos motores BLDC; (iii) estimativa do comportamento dos motores BLDC utilizando análise MEF; e (iv) execução dos testes experimentais para identificar como cada opção de montagem do motor interage com o MMA-EPUSP. A análise MEF corrobora com a recomendação do motor BLDC de fluxo magnético radial como a melhor opção de motorização para o DAV com o MMA-EPUSP, já que este motor não induz nenhuma força magnética axial que precise ser compensada pela suspensão magnética. Entretanto, o projeto do DAV pode ser mais complexo devido à interferência mecânica entre a saída do sangue do DAV e o estator do motor. Já a força magnética axial induzida pelo motor BLDC de fluxo axial é suficientemente forte para desestabilizar o MMA-EPUSP, demandando uma alta corrente do controle de posição do rotor. Os dados indicam que o projeto do controlador atual não conseguirá garantir a estabilidade do mancal magnético com este tipo de motor a altas velocidades. Neste caso, estudos adicionais são recomendados para avaliar a estabilidade dinâmica do rotor com MMA-EPUSP com o rotor imerso em sangue, já que um ambiente líquido poderá absorver a energia das oscilações e minimizar as restrições associadas à instabilidade da suspensão magnética a velocidades inferiores a 5000 RPM. / The Escola Politécnica of São Paulo University (EPUSP) and the Institute Dante Pazzanese of Cardiology (IDPC) is conducting a joint project aiming the development of an implantable Ventricular Assist Device (VAD). This study is part of the development of an implantasuporte@poli.usp.brble VAD in which the pump rotor is suspended by single degree of freedom (1-DOF) magnetic suspension. The magnetic suspension here utilized presents active control only in the rotor axial direction. This magnetic bearing had been presented by Silva and Horikawa (2000) in which the active control is executed only in the axial direction of a rotor. In this work this Axial Magnetic Bearing is referred as AMB-EPUSP. The brushless direct current (BLDC) motor has been elected due to the same reason why a magnetic bearing: the motor should not contact the rotor, minimizing problems of damage to the blood components. However, the driving of the rotor by magnetic forces may interfere in the magnetic suspension. As the stability of this magnetic suspension has been established by the axial stiffness, it is reasonable to expect that the magnetic interaction between the magnetic bearing and the used electric motor may interfere in the magnetic suspension. This study analyzes experimentally the BLDC motor, which rotor is supported by the AMB- EPUSP, to identify the behavior of this set using two distinct magnetic flux motor configurations: axial and radial. The analysis includes: (i) design, construction and testing of the axial and the radial BLDC motors; (ii) design, construction and testing of AMB-EPUSP and the rotor to be driven be both BLDC motors; (iii) estimate the BLDC motors behavior using FEM analysis; and (iv) experimental tests execution to identify how each motor assemble option interact with the AMB- EPUSP. The FEM analysis corroborates on the recommendation of the radial magnetic flux BLDC motor option as the best choice to drive the VAD with AMB- EPUSP, since this motor does not generate any axial magnetic force to be compensated by the magnetic suspension. However, a more complex VAD design may be required due to the mechanical interference between the VAD outlet and the motors winding. The axial force generated by the axial magnetic flux BLDC motor option, induces a strong instability on the AMB-EPUSP, demanding high current to control the rotor position. The data indicates the current controller design will not be able to guarantee the magnetic bearing stability with this motor on higher velocities. On any case, additional study is recommend to evaluate the rotordynamic rotor dynamic instability of the AMB- EPUSP with the rotor surrounded by blood, since the liquid environment should absorb the oscillation energy and minimize the restriction due to the magnetic suspension instability on speed below 5000 RPM.