Dissertations / Theses: 'Permanent magnet motors'

1

Devgan, S. K. "Permanent magnet synchronous motors." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235056.

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Varghese, Sajan. "Electromagnetic Noise from Permanent Magnet Motors." Thesis, KTH, Farkost och flyg, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143492.

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With today’s increase in rail traffic the impact of noise on the people near railway lines is increasing. To control this problem European Union regulations, including TSI (Technical Specifications for Interoperability) Noise, has come into force by implementing many strict norms on new railway vehicles put on the market. One TSI regulation is limiting the acceleration noise, which in turn calls for low noise solutions for drive systems which typically governs the vehicle noise at low speeds, up to around 80 Km/hr. This regulation on railway noise has become a major challenge for many train manufacturers. This calls for electromagnetic-Vibration-Acoustics multi physics analysis of the motor. The thesis mainly focuses on numerical modelling of the electromagnetic-vibro-acoustics system. Ideally such models can compute the audible magnetic sound power radiated from the motor as a function of its speed, PWM strategy applied and geometry. Here a pulse modulated permanent magnet traction motor was modelled with finite elements (FE), using a commercial software. Thereafter, the dynamic characteristics of the motor was analysed by FE modal analysis (eigen-frequencies and eigen-modes) as well as by point force frequency response analysis. The FE model was validated by comparing the Eigen-modes, Eigen-frequencies and point accelerance with the experimental modal analysis results. Thereafter, frequency response analysis was performed to calculate the vibration velocities on the surface of the stator frame using realistic electromagnetic forces. These forces were calculated with a dedicated motor analysis tool (FLUX). Moreover, the vibration velocities calculated were used in boundary element model to calculate the radiated sound power and the directivity. Finally the calculated vibration and sound power levels were compared with measurement results.

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Patni, Chandra Kumar. "Digital control of permanent magnet motors." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47613.

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4

Bottomley, Jack S. "Self-sensing permanent magnet servo motors." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14179/.

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The use of Permanent Magnet Synchronous Machines (PMSMs) has become widespread across numerous applications and industries. Their high power density, efficiency and accuracy of control make them excellent choices, leading them to become the industrial standard. Two issues concerning PMSMs use in recent years have been associated with the elevated cost of rare earth materials required for the Permanent Magnet (PM) rotor poles and the reliance on a direct rotor position sensor such as an encoder. PMSMs require an accurate rotor position feedback within the control scheme, traditionally provided by an encoder or resolver. These devices are excellent at providing the realtime rotor position accurately but have a negative impact on the machine as a whole. Their use increases the size, weight and cost of the electrical machine, while reducing reliability and often limiting use in extreme environments. This has created motivation for sensorless control of PMSMs, which removes the need for a position sensor. Sensorless control can be categorized into two distinctive aspects. The first is the control scheme and focuses on how position dependent properties can be used to estimate rotor position. The second, which has had less focus, is the machine design. This is focused on the ability of a machine to act as a position sensor with clear position dependent properties. Self-sensing machine design is the common term applied to this field since in essence the machine acts as its own position sensor. This thesis is concerned with self-sensing oriented design. The work presented is focused on PMSMs with inset rotor topologies. A methodology was developed to assess the position tracking capability of a machine and incorporated within a traditional machine design optimization routine. The conceptual design of the machine emphasized a generic geometrical topology, accounting for practical material selections and construction techniques. This ensured the design outcome had widespread implications, as opposed to a novel machine design with limited commercial relevance.

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Parsa, Leila. "Performance improvement of permanent magnet ac motors." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2419.

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Multi-phase motors have several advantages over the traditional three-phase motors. In this study, the additional degrees of freedom available in five-phase permanent magnet motors have been used for three purposes: 1) enhancing the torque producing capability of the motor, 2) improving the reliability of the system, and 3) better adjusting of the torque and flux linkages of the five-phase direct torque controlled system. 1) Due to the fact that space and time harmonics of the same orders will contribute positively to output torque, a five-phase permanent magnet motor with quasi-rectangular back-EMF waveform is supplied with combined fundamental and third harmonic of currents. For modeling and analysis of the motor a 0 3 3 1 1 q d q d frame of reference is defined where 1 1q d rotates at the synchronous speed and 3 3q d rotates at the three times synchronous speed. Based on the mathematical model in the 0 3 3 1 1 q d q d frame of reference, it is shown that this system while having a higher torque density with respect to a conventional permanent magnet synchronous machine, is also compatible with vector control algorithm. 2) A resilient current control of the five-phase permanent motor with both sinusoidal and trapezoidal back-EMF waveforms under asymmetrical fault condition is proposed. In this scheme, the stator MMF is kept unchanged during healthy and faulty condition. Therefore, the five-phase permanent magnet motor operates continuously and steadily without additional hardware and just by modifying the control algorithm in case of loss of up to two phases. The feature is of major importance in some specific applications where high reliability is required. 3) High torque and flux ripple are the major drawbacks of a three-phase direct torque controlled system. The number of space voltage vectors directly influences the performance of DTC system. A five-phase drive, while benefiting from other advantages of high order phase drives, has inherently 32 space voltage vectors which permits better flexibility in selecting the switching states and finer adjustment of flux and torque. A sensorless direct torque control of five-phase permanent magnet motor is implemented. Speed information is obtained based on the position of stator flux linkages and load angle. Experiments have been conducted on a 5kW five-phase surface mount permanent magnet motor and a 3kW five-phase interior permanent magnet motor by using TMS320C32 DSP. The results obtained are consistent with theoretical studies and simulation analysis, which further demonstrate the feasibility and practical significance of the five-phase permanent magnet motor drives.

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Arvidsson, Amanda. "Generic Control of Permanent Magnet Synchronous Motors." Thesis, Linköpings universitet, Fysik och elektroteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-110898.

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7

Mantala, Chawanakorn. "Sensorless control of brushless permanent magnet motors." Thesis, University of Bolton, 2013. http://ubir.bolton.ac.uk/625/.

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In this thesis, a sensorless control method of permanent magnet synchronous machines (PMSMs), whose machine neutral points are accessible, for all speeds and at standstill is proposed, researched and developed. The sensorless method is called Direct Flux Control (DFC). The different voltages between a machine neutral point and an artificial neutral point are required for the DFC method. These voltages are used to extract flux linkage signals as voltage signals, which are necessary to approximate electrical rotor positions by manipulating the flux linkage signals. The DFC method is a continuous exciting method and based on an asymmetry characteristic and machine saliencies. The DFC method is validated by implementing on both software and hardware implementation. A cooperative simulation with Simplorer for the driving circuit and programming the DFC and Maxwell for doing finite element analysis with the machine design is selected as the software simulation environment. The machine model and the DFC method are validated and implemented. Moreover, the influences of different machine structures are also investigated in order to improve the quality of the measured voltages. The hardware implementation has been employed on two test benches, i.e. for small machines and for big machines. Both test benches use a TriCore PXROS microcontroller platform to implement the DFC method. There are several PMSMs, both salient poles and non-salient poles, which are used to validate the DFC method. The flux linkage signals are also analyzed. The approximation of the flux linkage signal is derived and proposed. A technique to remove the uncertainty of the calculated electrical rotor position based on the inductance characteristics has been found and implemented. The electrical rotor position estimation method has been developed based on the found flux linkage signal approximation function and analyzed by comparing with other calculation techniques. Moreover, the calculated electrical rotor position is taken into account to either assure or show the relation with the exact rotor position by testing on the hardware environment. The closed loop speed sensorless control of PMSMs with DFC is presented and executed by using the assured calculated electrical rotor position to perform the DFC capability. This thesis has been done in the Electric Machines, Drives and Power Electronics Laboratory, South Westphalia University of Applied Sciences, Soest, Germany.

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Ede, Jason David. "High-speed permanent magnet brushless DC motors." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.719807.

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Martin, Benjamin C. "Geometric Design Optimization of Brushless Permanent Magnet Motors." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/MartinBC2009.pdf.

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Elvestad, Eirik. "Implementation of Permanent Magnet Motors in Electric Vehicles." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9743.

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This thesis has studied permanent magnet motors in electric vehicles (EVs) under the assumption that they are tractable due to a low weight and high compactness. The implementation has been investigated through a case study, which resulted in an EV simulation model. The model contains a maximal torque per ampere and a closed-loop field weakening controller. Abstract Faults are a special concern in permanent magnet motors. Fault sources and faulted behavior are addressed separately. The EV model was used to simulate faulted behavior. Abstract Two passive fault measures are suggested as the most attractive for propulsion purpose motors; these are shutting down the inverter and imposing a balanced short to the machine terminals. The balanced three phase short circuit showed a considerable transient behavior not seen during inverter shutdown. This results in an increased requirement to the inverter rating using the balanced short. Also, demagnetization risk of rotor magnets is higher under the balanced short. Abstract The maximal braking torque during inverter shutdown was high for the simulation model, and exceeded the braking torque of any fault. This concern led to a mathematical examination of the inverter shutdown, resulting in two equations that may be of use during design. The resulting equations are based on simplifications done in the literature, and show the relationship of the balanced short to the inverter shutdown.

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11

Sooriyakumar, Gunaratnam. "Efficient design methodology for permanent magnet synchronous motors." Thesis, University of East London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532988.

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12

Alhassan, Muhtar Hanif. "Permanent magnet synchronous motors in position control systems." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333398.

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13

Milanfar, Peyman. "Failure monitoring in small permanent-magnet synchronous motors." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/17270.

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14

Peralta, Sanchez Edgar. "Analysis of canned line-start permanent magnet motors." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709828.

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15

Li, Zhou, of Western Sydney Nepean University, and of Mechatronic Computer and Electrical Engineering School. "Numerical computation of core losses in permanent magnet machines." THESIS_XXXX_MCEE_Li_Z.xml, 2000. http://handle.uws.edu.au:8081/1959.7/284.

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This thesis presents a study on core loss calculations in rotating electrical machines. The basic concepts concerning magnetic moments, ferromagnetism, magnetic domains and magnetic hysteresis are introduced. The three-term models for alternating and rotational core losses in electrical steel sheets are presented. Several core loss measurement techniques are reviewed and an experiment is carried out to measure the total core losses in an electrical sheet steel sample under alternating and rotational magnetic fields of various frequencies and amplitudes. The coefficients in the loss models for alternating and rotational core losses are obtained through curve fitting process. The theory of electromagnetic fields is presented through the Maxwell equations and field scalar equations. A detailed review on core loss models for rotating electrical machines is presented. A rotational core loss model is adopted to calculate the core losses in a PM motor. The total core loss in the PM motor is obtained by summing the element losses using a MATLAB program. An experiment is conducted to measure the total core loss in the PM motor. The calculated total core loss in the PM motor is compared with the experimental results. The calculated total core losses are about 19% lower than the tested results. Various possible causes for this discrepancy are discussed
Master of Engineering (Hons)

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16

Judge, Andy. "Air Gap Elimination in Permanent Magnet Machines." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/123.

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In traditional Permanent Magnet Machines, such as electric motors and generators, power is transmitted by magnetic flux passing through an air gap, which has a very low magnetic permeability, limiting performance. However, reducing the air gap through traditional means carries risks in manufacturing, with tight tolerances and associated costs, and reliability, with thermal and dynamic effects requiring adequate clearance. Using a magnetically permeable, high dielectric strength material has the potential to improve magnetic performance, while at the same time offering performance advantages in heat transfer. Ferrofluids were studied as a method for improved permeability in the rotor / stator gap with a combined experimental and computational approach. Results show promise for the ferrofluid technique. An off-the-shelf motor system showed improved performance with ferrofluids vs. fluids of equivalent viscosity, and improved performance vs. an air gap at low RPM. New generator designs showed design dependent performance gains, although some potential for negative performance effects. A proof of concept generator was built and tested, with increased voltage vs. RPM predicted through virtual prototyping, and validated through experimentation, showing ~10% improvement on voltage vs. RPM at the <600 RPM range. More repeatable engineering tests demonstrated a ~30% increase in the voltage / RPM relationship for designs with an isolated stator chamber and a large stator - rotor gap. However, the effects were negative for a similar system with a small stator-rotor gap due to leakage flux effects. New contributions to the body of knowledge in this area include: Ã¢â‚¬Â¢ Application of the ferrofluid technique to axial flux designs. Ã¢â‚¬Â¢ Development of a virtual prototype, including variations in the fluid viscosity due to ferrohydrodynamic effects. Ã¢â‚¬Â¢ Consideration of negative effects of ferrofluid immersion, such as shear losses and increases in leakage flux. Ã¢â‚¬Â¢ Optimization of the design to eliminate increased viscous losses. The improved design has been designed, built, and tested, featuring isolation of the ferrofluid from the rotating region. This offers all of the performance gain of improved magnetic permeability, while minimizing the offsetting losses from increased shear effects.

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17

Karacan, Cuneyt. "Comparison Of Performance Of Switched Reluctance Motors, Induction Motors And Permanent Magnet Dc Motors." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604925/index.pdf.

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Since most of the electrical energy is consumed by the electrical motors, it is necessary to use the electrical energy as efficient as possible. Throughout this study four different types of motors (induction motor, permanent magnet radial flux DC motor, permanent magnet axial flux DC motor, switched reluctance motor) are considered and compared based on their torque per unit volume and speed performance comparison. Torque per unit volume equations are obtained for each of the motor, related to quantities such as magnetic flux density and electric loading and the speed performances are compared by using a washing machine application, which has a wide speed range. As a result of this study torque per unit volume and speed performance of each of these four types of motors are obtained and motors of different types are evaluated due to their torque per motor volume, torque per ampere, efficiency and etc. over a wide speed range to have an idea about the applications of these motors.

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18

Mi, Chunting. "Modelling of iron losses of permanent magnet synchronous motors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58959.pdf.

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19

Modeer, Tomas. "Modeling and testing of line start permanent magnet motors." Licentiate thesis, Stockholm : Elektrotekniska system, Electrical Engineering, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4488.

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20

Bentouati, Syham. "Permanent magnet brushless DC motors for low cost applications." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487427.

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21

Bai, Kun. "Direct field-feedback control for permanent magnet spherical motors." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50141.

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There are emerging requirements for high accuracy multi-DOF actuators in numerous applications. As one of the novel motors capable of multi-DOF manipulation, permanent magnet spherical motors (PMSMs) that can provide continuous and dexterous motion in one joint have been widely studied for their advantages in structure and energy efficiency. The demands to bring forward the performance of PMSMs for precision applications have motivated this thesis to develop a closed-loop orientation control system with high accuracy and bandwidth. Unlike traditional control methods for PMSMs, which rely on explicit orientation feedback, a new control method (referred to here as direct field-feedback control or in short DFC) directly utilizing the magnetic fields for feedback have been developed in this thesis. Because magnetic field measurements are almost instantaneous and the need for real-time orientation estimation is eliminated in DFC, the system sampling time is greatly reduced. Meanwhile, several field-based methods have been developed for the major components in the DFC system and each component can be processed independently and concurrently with the magnetic field measurements. The parallel computation further improves the system bandwidth and also reduces accumulated error. The DFC system has been experimentally implemented and evaluated. The results show excellent control performances in terms of accuracy and bandwidth. To facilitate the design and analysis of the DFC system, several new algorithms have been developed, which include the modeling and computing of magnetic fields as well as forces and torques, an analysis of bijective relationship between orientation and magnetic fields, and a method for calibration and reconstruction of the rotor magnetic field in 3 dimensional space. These algorithms not only enable the implementation of the DFC system for a PMSM, but also benefit the PMSM studies in design, modeling and field-based sensing. While the immediate outcome of this research is a control system for PMSMs, this new control method can be applied to a broad spectrum of electromagnetic motion systems.

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22

Staton, David Alan. "C.A.D. of permanent magnet D.C. motors for industrial drives." Thesis, University of Sheffield, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319912.

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23

Greamo, Christopher Anthony. "Active torque ripple reduction in permanent-magnet AC motors." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36575.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
Includes bibliographical references (leaves 101-104).
by Christopher Anthony Greamo.
M.S.

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24

Knight, Andrew Michael. "Analysis of line-start single-phase permanent magnet motors." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624867.

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25

Li, Jiangui, and 李建贵. "Design, analysis and control of permanent-magnet vernier machines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49617655.

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Electric machines are indispensable part in modern industry and they are widely used in many applications such as power generation, vehicles, elevator, robot, and so on. Owing to the diversity of the application occasions, different requirements have been proposed. In the applications, such as wind power generation, low-speed, high-torque and high-efficiency electric machines are required to match with the low-speed load. Currently, this problem is handled by either adopting a speed-boost mechanical gear, or using low-speed machine design. The former one causes mechanical wear and tear, audible noise and low efficiency, whereas the latter one increases the generator size and weight as well as raw material cost. In recent years, another option, namely integrating a coaxial magnetic gear into a permanent-magnet (PM) machine has been proposed. This option allows for directly mounting the outer, low-speed shaft with the load while enables the electric machine coupled with the high-speed inner gear to operate at high speeds. However, this magnetic-geared electric machine desires a complex structure, involving two rotating bodies and three air-gaps, which increases manufacture difficulty and cost. The research work of this thesis attempts to solve the speed-matching problem by developing a new electric machine. The incorporation of vernier concept with PM machine gives birth to the permanent-magnet verier (PMV) machine. Different from traditional synchronous machine, the rotor of the PMV machine rotates at a definite fraction of the synchronous speed, as if it were geared down from the high rotating field set up by the stator. The PMV machine, therefore, can be regarded as a combination of a gear with fixed gear ratio and an electric machine. This kind of machine is attractive in applications which require low speed and high torque, and mechanical gearing is undesirable. The main objective of this thesis is to present the design, analysis and control of the proposed PMV machine. After the introduction on mechanical gears, magnetic gears, and low-speed machines, the design details of the proposed outer-rotor PMV machine are provided. Moreover, the working principle, stable torque generation mechanism and structural features are presented. Due to the introduced vernier effect, it is important to perform the finite element analysis (FEA) for the proposed PMV machine. The electric circuit equation and the motion equation are coupled with the Maxwell’s equation to calculate the key parameters of the proposed machine. The analysis results of the magnetic field distributions, air-gap flux density distributions, flux linkages, winding inductances, back electromotive forces (EMFs), cogging torque and static torque are presented in detail. The performances of PMV machine are compared with other machines to show its advantages and disadvantages. The control strategy of the PMV machine as a brushless DC machine is also presented. The conventional 120-degree conducting, dual-closed-loop control strategy is used for speed and torque control and the experimental setup are given. The results are obtained and compared with the simulation results, thus verify the validity of the design. Finally, the potential applications for the proposed PMV machine are suggested.
published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy

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26

Al-Aubidy, Kasim Mousa A. "Rotor position sensing and microprocessor control of a permanent magnet machine." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257508.

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27

Liu, Chunhua. "Design, analysis, control and application of permanent-magnet hybrid brushless machines." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841665.

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Niu, Shuangxia. "Design, control and application of double-stator permanent magnet brushless machines." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841677.

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29

Li, Zhou. "Numerical computation of core losses in permanent magnet machines." Thesis, View thesis, 2000. http://handle.uws.edu.au:8081/1959.7/284.

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This thesis presents a study on core loss calculations in rotating electrical machines. The basic concepts concerning magnetic moments, ferromagnetism, magnetic domains and magnetic hysteresis are introduced. The three-term models for alternating and rotational core losses in electrical steel sheets are presented. Several core loss measurement techniques are reviewed and an experiment is carried out to measure the total core losses in an electrical sheet steel sample under alternating and rotational magnetic fields of various frequencies and amplitudes. The coefficients in the loss models for alternating and rotational core losses are obtained through curve fitting process. The theory of electromagnetic fields is presented through the Maxwell equations and field scalar equations. A detailed review on core loss models for rotating electrical machines is presented. A rotational core loss model is adopted to calculate the core losses in a PM motor. The total core loss in the PM motor is obtained by summing the element losses using a MATLAB program. An experiment is conducted to measure the total core loss in the PM motor. The calculated total core loss in the PM motor is compared with the experimental results. The calculated total core losses are about 19% lower than the tested results. Various possible causes for this discrepancy are discussed

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30

Cheng, Ming. "Design, analysis and control of doubly salient permanent magnet motor drives." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23340174.

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Urresty, Betancourt Julio César. "Electrical and magnetic faults diagnosis in permanent magnet synchronous motors." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/101505.

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Permanent magnet synchronous motors (PMSMs) are an alternative in critical applications where high-speed operation, compactness and high efficiency are required. In these applications it is highly desired to dispose of an on-line, reliable and cost-effective fault diagnosis method. Fault prediction and diagnosis allows increasing electric machines performance and raising their lifespan, thus reducing maintenance costs, while ensuring optimum reliability, safe operation and timely maintenance. Consequently this thesis is dedicated to the diagnosis of magnetic and electrical faults in PMSMs. As a first step, the behavior of a healthy machine is studied, and with this aim a new 2D finite element method (FEM) modelbased system for analyzing surface-mounted PSMSs with skewed rotor magnets is proposed. It is based on generating a geometric equivalent non-skewed permanent magnet distribution which accounts for the skewed distribution of the practical rotor, thus avoiding 3D geometries and greatly reducing the computational burden of the problem. To diagnose demagnetization faults, this thesis proposes an on-line methodology based on monitoring the zero-sequence voltage component (ZSVC). Attributes of the proposed method include simplicity, very low computational burden and high sensibility when compared with the well known stator currents analysis method. A simple expression of the ZSVC is deduced, which can be used as a fault indicator parameter. Furthermore, mechanical effects arising from demagnetization faults are studied. These effects are analyzed by means of FEM simulations and experimental tests based on direct measurements of the shaft trajectory through self-mixing interferometry. For that purpose two perpendicular laser diodes are used to measure displacements in both X and Y axes. Laser measurements proved that demagnetization faults may induce a quantifiable deviation of the rotor trajectory. In the case of electrical faults, this thesis studies the effects of resistive unbalance and stator winding inter-turn short-circuits in PMSMs and compares two methods for detecting and discriminating both faults. These methods are based on monitoring and analyzing the third harmonic component of the stator currents and the first harmonic of the ZSVC. Finally, the Vold-Kalman filtering order tracking algorithm is introduced and applied to extract selected harmonics related to magnetic and electrical faults when the machine operates under variable speed and different load levels. Furthermore, different fault indicators are proposed and their behavior is validated by means of experimental data. Both simulation and experimental results show the potential of the proposed methods to provide helpful and reliable data to carry out a simultaneous diagnosis of resistive unbalance and stator winding inter-turn faults.

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Salehi, Arashloo Ramin. "Fault tolerant vector control of five-phase permanent magnet motors." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/283138.

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Equipped with appropriate control strategies, permanent magnet (PM) machines are becoming one of the most flexible types of actuators for many industrial applications. Among different types of PM machines, five-phase BLDC machines are very interesting in fault tolerant applications of PM drives. Torque improvement in five-phase BLDC machines can be accomplished by optimizing their mechanical structure or by enhancing their controlling methods. New current controllers are proposed in this thesis to improve the quality of generated torque under normal operations of five-phase BLDC machines. Proposed current controllers are based on combination of predictive deadbeat controlling strategy and Extended Kalman Filter estimation. These controllers will be the basis for accurate faulty operation of the motor. Operation of five-phase BLDC machines under faulty conditions has also been considered in this study. To improve the generated torque under faulty conditions, both amplitude and phase angle of fundamental and third current harmonics are globally optimized for the remaining healthy phases. Under faulty conditions, appropriate reference currents of a five-phase BLDC machine have oscillating dynamics both in phase and rotating reference frames. As a result, the implemented current controllers under these conditions should be robust and fast. Predictive deadbeat controllers are also proposed for faulty conditions of five-phase BLDC machines. Fault tolerant five-phase BLDC machines are very interesting in automotive applications such as electrical vehicles and more electric aircraft. In addition, these devices are gaining more importance in other fields such as power generation in wind turbines. In all of these applications, the efficiency of PM machine is of most importance. The efficiency of a typical five-phase BLDC machine is evaluated in this thesis for normal and different faulty conditions. Experimental evaluations are always conducted to verify the theoretical developments. These developments include proposed controlling methods, optimized reference currents, and simulated efficiency of five-phase BLDC machine under different operational conditions.

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33

Al-Otaibi, Zaid Saad. "Single Phase Permanent Magnet Linear-Resonant Motors for Compressor Applications." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501053.

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34

Ruddy, Bryan P. (Bryan Paul) 1983. "High force density linear permanent magnet motors : "electromagnetic muscle actuators"." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78177.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 181-194).
Actuator performance represents a key constraint on the capability of many engineered devices. Performance of these devices is often exceeded by their muscle-powered natural counterparts, inspiring the development of new, "active material" actuators. This thesis reconsiders a traditional actuator, the linear permanent magnet motor, as a form of active material actuator, and presents new, unified scaling and magnetic field models for its performance. This active material motor model predicts that motors composed of large numbers of very small, actively-cooled repeat units, similar to the architecture of biological muscles, can provide greatly enhanced force density over extant designs. Our model is constructed by considering the motor winding as an active material, with its performance limited by the diffusion of waste heat. This allows a quantitative scaling model for the motor constant and force-to-mass ratio to be built for the case of a winding immersed in a homogeneous magnetic field. This model is then modified with a small set of dimensionless parameters to describe the performance penalties imposed by the use of practical sources of magnetic field, specifically periodic arrays of permanent magnets. We explain how to calculate these parameters for a variety of different types of magnet arrays using analytical magnetic field and heat transfer models, and present a new field model for tubular linear motors having improved numerical stability and accuracy. We illustrate the use of our modeling approach with two design case studies, a motor for flapping-wing flying and an actuator for high-performance controllable needle-free jet injection. We then validate our predictions by building and testing a novel water-cooled motor using a tubular double-sided Halbach array of magnets, with a mass of 185 g, a stroke of 16 mm, and a magnetic repeat length of 14.5 mm. This motor generates a continuous force density of 140 N/kg, and has a motor constant of nearly 6 N/[square root]W, both higher than any previously reported motor in this size class.
by Bryan Paul Ruddy.
Ph.D.

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35

Germishuizen, Johannes Jacobus. "Analysis of interior permanent magnet motors with non-overlapping windings." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1400.

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36

Mohammad, Mohammad T. N. "Testing and analysis of axial gap permanent magnet DC motors." Thesis, University of Southampton, 2004. https://eprints.soton.ac.uk/47955/.

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This thesis is concerned primarily with the testing and analysis of design variations of the Lynch motor, which is an axial gap permanent magnet dc machine. These variants include: a standard production motor, a motor with low iron volume, a motor with bigger area of magnets and a motor using powder iron instead of laminations. The powder iron motor was constructed by the author, while all the other motors were provided by the Lynch Motor Company. Tests were conducted to evaluate motor circuit parameters, losses and efficiency using a purpose built test rig which was built in the first stage of the project. Finite element analysis (FEA) was used to determine the levels of the magnetic saturation in the different motors and calculate torque, inductance and EMF. The FEA was also used as bases for comparison with analytical electromagnetic calculations. A dynamic circuit model, whose parametric were derived from FEA and analytical calculations validated by test, was also constructed to study the effect of brush thickness on circulating current and torque production. The results of the work revealed that the larger magnet motor has a high level of saturation resulting in a higher slope of the torque-speed curve. The lower iron volume motor and the powder iron cored motor produced less torque and have less flux density than the standard Lynch motor. The test results proved that the selected powder iron material is usable in the Lynch rotated armature but it still needs improvements to close the performance gap with laminations. The powder iron motor has back emf that is 10% lower than the standard motor, and consequently a lower efficiency. The results show that performance of the Lynch motor can be improved by optimising the size of the saturated parts of the motor, which are the stator discs and the armature teeth. In addition, careful selection of brush number, geometry and type can improve the motor performance. An alternative single gap motor was also studied. The test results show that it has more armature reaction than the dual gap motor and therefore it produced less torque with less efficiency.

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37

Britten, Mark David. "Torque Controlled Drive for Permanent Magnet Direct Current Brushless Motors." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/5252.

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This thesis describes the design and implementation of a simple variable speed drive (VSD) based on a brushless direct current (BLDC) machine and discrete logic circuits. A practical VSD was built, capable of operating a BLDC machine in two quadrants, motoring and regenerative braking. The intended applications are electric scooters and electric bicycles, where the recovered energy from braking extends the range of the vehicle. A conceptual four quadrant VSD, suitable for three and four wheelers requiring reverse operation, was designed and tested in simulation. Simplicity was emphasized in this design to help achieve a robust, easy to analyse system. The versatility of multi-function gate integrated circuits (ICs) made them ideal for implementing the commutation logic and keeping the system simple. The BLDC machine has sensors with a resolution of 60 ed to determine rotor position. An electronic commutator or phase switcher module interprets the position signals and produces a switching pattern. This effectively transforms the BLDC machine into a direct current (DC) brushed machine. A synchronous step down converter controls the BLDC machine current with a tolerance band scheme. This module treats the BLDC machine as if it was a DC machine. The leakage inductance of the electric machine is used as the inductive filter element. The unipolar switching scheme used ensures that current flows out of the battery only for motoring operation and into the battery only during regeneration. The current and torque are directly related in a DC brushed machine. The action of an electronic commutator or phase switcher creates that same relationship between torque and current in a BLDC machine. Torque control is achieved in the BLDC machine using a single channel current controller. The phase switcher current is monitored and used to control the duty ratio of the synchronous converter switches. Successful operation of the practical VSD was achieved in two quadrants: forwards motoring and forwards regenerating. The maximum tested power outputs were 236W in motoring mode and 158W in regenerating mode. The output torque could be smoothly controlled from a positive to a negative value. iv v Simulation of the conceptual four quadrant design was successful in all the motoring, generating and active braking zones. The required manipulation of logic signals to achieve this type of operation was done automatically while the machine was running. The resulting output torque is smoothly controlled in all of the operating zones. Commutation at certain speeds and torques are handled better by some topologies than others. Some current sensing strategies adversely affect instantaneous phase currents under certain conditions. The final design chose the method where phase currents experience no overshoot, minimizing component stress. The battery, or energy storage system, used in verifying the operation of the VSD in the practical electric bicycle was found to be the most limiting component. In regenerating mode, the low charge acceptance rate of the battery reduced the maximum retarding torque and energy recovery rate.

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38

Lennartsson, Alexander, and Martina Blomberg. "Fault Detection in Permanent Magnet Synchronous Motors using Machine Learning." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-84909.

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In the aviation industry, safety and robustness are the number one priorities, which is why they use well-tested systems such as hydraulic actuators. However, drawbacks such as high weight and maintenance have pushed the industry toward newer, electrical, actuators that are more efficient and lighter. Electrical actuators, on the other hand, have some reliability issues. In particular, short circuits in the stator windings of Permanent-Magnet SynchronousMotors (PMSMs), referred to as Inter-Turn Short Faults (ITSFs), are the dominating faults, and is the focus of this thesis. ITSFs are usually challenging to detect and often do not become noticeable until the fault has propagated, and the motor is on the verge of being destroyed. This thesis investigates the possibility of detecting ITSFs in a PMSM, at an early stage when only one turn is shorted. The method is limited to finding the faults using ML algorithms. Both an experiential PMSM and a simulated model of the experimental PMSM, with the ability to induce an ITSF, were used to collect the data. Several Machine Learning (ML) models were developed, and then trained and tested with the collected data. The results show that four of the tested ML models, being: Random Forest, Gaussian SVM, KNN, and the CNN, all achieve an accuracy exceeding 95%, and that the fault can be found at an early stage in a PMSM with three coils connected in parallel in each phase. The results also show that the ML models are able to identify the ITSF when the simulated data is downsampled to the same frequency as the experimental data. We conclude that the ML models, provided in this study, can be used to detect an ITSF in a simulated PMSM, at an early stage when only one turn is shorted, and that there is great potential for them to detect ITSFs in a physical motor as well.

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39

Mevey, James Robert. "Sensorless field oriented control of brushless permanent magnet synchronous motors." Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1507.

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40

Cignali, Giovanni <1981&gt. "Nonlinear Observers for Sensorless Control of Permanent Magnet Synchronous Motors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5585/1/cignali_giovanni_tesi.pdf.

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In this thesis, the industrial application of control a Permanent Magnet Synchronous Motor in a sensorless conﬁguration has been faced, and in particular the task of estimating the unknown “parameters” necessary for the application of standard motor control algorithms. In literature several techniques have been proposed to cope with this task, among them the technique based on model-based nonlinear observer has been followed. The hypothesis of neglecting the mechanical dynamics from the motor model has been applied due to practical and physical considerations, therefore only the electromagnetic dynamics has been used for the observers design. First observer proposed is based on stator currents and Stator Flux dynamics described in a generic rotating reference frame. Stator flux dynamics are known apart their initial conditions which are estimated, with speed that is also unknown, through the use of the Adaptive Theory. The second observer proposed is based on stator currents and Rotor Flux dynamics described in a self-aligning reference frame. Rotor flux dynamics are described in the stationary reference frame exploiting polar coordinates instead of classical Cartesian coordinates, by means the estimation of amplitude and speed of the rotor ﬂux. The stability proof is derived in a Singular Perturbation Framework, which allows for the use the current estimation errors as a measure of rotor flux estimation errors. The stability properties has been derived using a specific theory for systems with time scale separation, which guarantees a semi-global practical stability. For the two observer ideal simulations and real simulations have been performed to prove the effectiveness of the observers proposed, real simulations on which the effects of the Inverter nonlinearities have been introduced, showing the already known problems of the model-based observers for low speed applications.

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41

Cignali, Giovanni <1981&gt. "Nonlinear Observers for Sensorless Control of Permanent Magnet Synchronous Motors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5585/.

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In this thesis, the industrial application of control a Permanent Magnet Synchronous Motor in a sensorless conﬁguration has been faced, and in particular the task of estimating the unknown “parameters” necessary for the application of standard motor control algorithms. In literature several techniques have been proposed to cope with this task, among them the technique based on model-based nonlinear observer has been followed. The hypothesis of neglecting the mechanical dynamics from the motor model has been applied due to practical and physical considerations, therefore only the electromagnetic dynamics has been used for the observers design. First observer proposed is based on stator currents and Stator Flux dynamics described in a generic rotating reference frame. Stator flux dynamics are known apart their initial conditions which are estimated, with speed that is also unknown, through the use of the Adaptive Theory. The second observer proposed is based on stator currents and Rotor Flux dynamics described in a self-aligning reference frame. Rotor flux dynamics are described in the stationary reference frame exploiting polar coordinates instead of classical Cartesian coordinates, by means the estimation of amplitude and speed of the rotor ﬂux. The stability proof is derived in a Singular Perturbation Framework, which allows for the use the current estimation errors as a measure of rotor flux estimation errors. The stability properties has been derived using a specific theory for systems with time scale separation, which guarantees a semi-global practical stability. For the two observer ideal simulations and real simulations have been performed to prove the effectiveness of the observers proposed, real simulations on which the effects of the Inverter nonlinearities have been introduced, showing the already known problems of the model-based observers for low speed applications.

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42

Uddin, Mohammad Nasir. "Intelligent control of an interior permanent magnet synchronous motor drive." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0021/NQ55128.pdf.

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43

Niu, Shuangxia, and 牛双霞. "Design, control and application of double-stator permanent magnet brushless machines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841677.

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44

Liu, Chunhua, and 劉春華. "Design, analysis, control and application of permanent-magnet hybrid brushless machines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841665.

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45

Xia, Wei. "A new phase decoupling permanent magnet brushless DC motor and its control /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19667747.

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46

Li, Zhou. "Numerical computation of core losses in permanent magnet machines /." View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030901.113715/index.html.

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Thesis (M.Sc (Hons)) -- University of Western Sydney, Nepean, 2000.
"Submitted for the degree of Master of Engineering (Hons), School of Mechatronic, Computer & Electrical Engineering, University of Western Sydney, Nepean" Includes bibliographical references (leaves 107-114).

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47

Li, Fuhua, and 李富华. "Design, analysis, control and application of permanent magnet brushless dual-memory machines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208621.

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Conventional PM machines have fixed PM excitation and can only perform flux-weakening by controlling the d-axis current. This current incurs the power dissipation and reduces the efficiency during flux-weakening operations. Memory machines change this situation by introducing the memory function, namely magnetizing or reversely magnetizing Al-Ni-Co PMs to change the air-gap flux density. This provides another new way to realizing flux-weakening. And the elimination of the flux-weakening d-axis current improves the overall efficiency. But the single-memory machines have lower power density due to the low-energy Al-Ni-Co PMs. By incorporating the memory concept and with the intention of improving the power density, the DC-excited PMBL dual-memory machines have been proposed and implemented, based on two kinds of PMs which are high-coercivity Nd-Fe-B PMs and low-coercivity Al-Ni-Co PMs. The Nd-Fe-B PMs provide a strong magnetic field to excite high air-gap flux density; while the Al-Ni-Co PMs can be forward magnetized to strengthen the magnetic field produced by Nd-Fe-B PMs or can be reversely magnetized to cancel that field. Consequently the air-gap flux density can be controlled within a wide range. A series of design principles on such kind of dual-memory machine are devised for guidance. The key design principles involve how to determine the number of salient poles on the stator and rotor, how to choose the surface areas and thicknesses of the two kind of PM pieces and how to size the rotor dimension. Generally, increase on the proportion of Nd-Fe-B PMs will raise the base field and the load capacity. On the other hand, increment on the proportion of Al-Ni-Co PMs will extend the controllable flux range. Analysis is also carried out on the equivalent magnetic circuit to formulate the magnetizing force exerted on Al-Ni-Co PMs. The machine model is analyzed by using time-stepping FEM (TS-FEM) and co-simulation of FEM software and Matlab Simulink. The dynamic reverse magnetizing processes are simulated and presented in details under different magnetizing current. In addition the effect of adding iron bridges between the two kinds PMs is also evaluated by simulations. Furthermore, the control methods are evaluate by simulations and experiments. The direct torque control (DTC) scheme is adapted to this doubly-salient dual-memory machine and a torque estimator is proposed to facilitate the DTC method. Both of the simulation results and the experimental results confirm the validity of the proposed design principles and the effectiveness of the control methods. Eventually, this dual-memory machine is proposed as a pole-changing wind power generator and a pole-changing EV machine. Simulation and experimental results have verified the validity of the pole-changing scheme and the pole-protection scheme.
published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy

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48

Takahashi, Akeshi. "Dynamic and steady state characteristics of line starting permanent magnet motors." Aachen Shaker, 2010. http://d-nb.info/1001663578/04.

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49

Colberg, Francis R. "Damage analysis of internal faults in flux concentrating permanent magnet motors." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/25798.

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It is the purpose of the proposed research to develop a digital computer simulation model to study the effects of an internal fault in a large permanent magnet ac synchronous motor. Permanent magnet motors are being considered as an alternative for ships with electric propulsion systems. In an electric propulsion system a large motor will be directly connected to a propulsion shaft. A windmilling shaft will continue to turn the rotor of the propulsion motor after the motor has been disconnected from its electrical power supply source. Following an internal electrical fault in a propulsion motor, it is expected that the motor will be disconnected from its electrical supply source. With the ship operating at or near rated speed following a casualty to the propulsion plant, the ship will coast down to a stop or until the crew takes action to stop the ship. A windmilling permanent magnet motor will generate a large enough internal voltage to continue to support large fault currents. This research will focus on the fault transient and the motor behavior during the time that the propulsion shaft is windmilling. Shorting the motor terminals will be considered as a means of reducing the power input into the fault.

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Colberg, Francis R. (Francis Rodolfo). "Damage analysis of internal faults in flux concentrating permanent magnet motors." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36498.

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Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.
Includes bibliographical references (leaves 67-68).
by Francis R. Colberg.
M.S.
Nav.E.

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