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1
Ng, Kong. "Electromagnetic losses in brushless permanent magnet machines." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.579745.
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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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Evans, David. "Novel partitioned stator permanent magnet brushless machines." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8605/.
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Wiriyakitja, Wisaruda. "Winding current reconstruction of brushless permanent magnet motor." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09ENS/09ensw798.pdf.
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Bibliography: leaves 101-102. The main objective of this thesis is to reconstruct the winding currents accurately by using the information of DC link current and the switching signals. Describes the advantages and disadvantages of the BLPM motor and presents a comparative study. Reports the current measurement techniques and related devices and then discusses the requirement of current sensors and their locations in detail. Explains the simulation program of the BLPM motor drive. Describes the experimental setup that is used to validate the simulation results. Provides the details of all possible switching states of the inverter that is obtained by analysing the switching patterns and the directions of the currents and the details of the LabVIEW-based simulation block diagrams.
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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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Atallah, Kais. "Iron losses in brushless permanent magnet DC machines." Thesis, University of Sheffield, 1993. http://etheses.whiterose.ac.uk/14941/.
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A closed-loop computer-controlled single-sheet test system has been developed to characterise lamination materials and to measure, the iron loss density under any specified flux density waveform. The system has been 'used to validate predictions from a recently developed theoretical model, for the calculation of the excess loss component associated with domaiQ wall movement, under flux density waveforms typical of those encountered in the stator core of brushless permanent magnet dc motors. In addition, an improved expression for the calculation of the iron loss density component, from measured 71 and 7!vectors, due to rotatio~ in non-purely rotating flux conditions, has been derived. A simple analytical model from which the airgap flux density and spread of magnet working points can be determined and which accounts for the effects of curvature for radial-field permanent magnet machines has been developed and validated. The model has been coupled to an analytical technique for the prediction of the open-circuit flux density waveforms in different regions of the stator core, and has subsequently been employed for the prediction of the open-circuit iron loss. In order to predict the iron loss under any specified load condition, a technique which couples a brushless dc drive system simulation to a series of magnetostatic finite element analyses corresponding to discrete instants in a commutation cycle has been developed. It enables the prediction of the local flux density waveforms throughout the stator core under any operating condition, and has been employed to predict the local iron loss density distribution 'and the total iron loss and their variation with both the load and the commutation strategy, Finally, the theoretical findings have been validated against measurements on a representative low power brushless drive system.
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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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Al-Hadithi, Khalid Salih Mohammad. "Mathematical modelling of permanent-magnet brushless DC motor drives." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/7302.
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Brushless dc motor drives have become increasingly popular, following recent developments in rare-earth permanent-magnet materials and the semiconductor devices used to control the stator input power and to sense the rotor position. They are now frequently used in applications such as flight control systems and robot actuators, and for drives which require high reliability, long life, little maintenance and a high torque-to-weight ratio. In many motor drives the presence of torque and speed ripples, especially at low speed, is extremely undesirable. The mathematical model developed in this thesis was used to investigate their occurrence in a typical brushless dc drive system, with the objective of establishing factors which effect their magnitude and ways by which they may be reduced. The model is based on the numerical solution of the differential equations for the system, with those for the motor being formulated in the phase reference frame. Tensor methods are used to account for both the varying topology and the discontinuous operation of the motor arising from changes in the conduction pattern of the inverter supply switches. The thesis describes the design, construction and testing of an experimental voltage source PWM inverter, using MOSFET switching devices, to drive a 1.3 kW 3-phase brushless dc motor. A practical circuit is described which implements current profiling to minimize torque ripple, and the optimum phase current waveforms are established. The effect of changes in the firing angle of the inverter switches on the torque ripple are also examined. Throughout the thesis, theoretical predictions are verified by comparison with experimental results.
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Shen, Yang. "Novel permanent magnet brushless machines having segmented Halbach array." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/3376/.
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Permanent magnet brushless machines having Halbach array exhibit a number of attractive features. Therefore, they have been increasingly applied to different market sectors, including aerospace, industrial, domestic, renewable, and healthcare, etc. The need of fast global optimization, cost-effective design, and physical understanding of the relationship between parameters and performance requires a powerful analytical model. This thesis develops a general analytical model which is capable of predicting the electromagnetic performance of slotted/slotless permanent magnet brushless machines with both even- and odd-segment Halbach array, having different magnet remanence, magnetization angle and arc for each single magnet segment. The validity of proposed analytical model is examined by finite-element analyses. The price of Neodymium Iron Baron magnet has been raised rapidly over the last few years, which has increased the awareness of cost-effective design and leads the magnet usage efficiency, viz. the ratio of average output torque over permanent magnet volume, to be an important design concern for industry applications. Meanwhile, the needs of high electromagnetic performance including lower torque ripple and sinusoidal air-gap flux density are also critically required. In order to meet such demands, the magnet poles having unequal-magnet height, modular high cost and low cost magnets, together with Halbach magnetization are proposed in this thesis. Based on the developed analytical models, extensive investigation has been performed. Furthermore, in order to fast optimize design parameters, e.g. optimal magnet arc ratio for 2-segment Halbach array and split ratio for external rotor PM machine, two analytical models are developed and validated by finite-element analysis and measurements. With the aid of developed analytical models and finite element analyses, the findings provide useful guidelines for design and analysis of permanent magnet brushless machine having conventional and proposed Halbach arrays.
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Al-Ani, Mahir. "Switched flux permanent magnet brushless machines for electric vehicles." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8159/.
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This thesis investigates different topologies of switched flux permanent magnet (SFPM) machines and variable flux (VF) methods for high speed applications. Although several novel topologies of SFPM machines have been proposed and investigated recently, their torque-speed capability has not been studied systematically. Therefore, the torque-speed capability as well as the open circuit and electromagnetic performance of conventional SFPM machines with three different stator/rotor pole combinations, i.e. 12/10, 12/13 and 12/14, and three novel SFPM machine topologies, i.e. multi-tooth, E-core and C-core are analysed and investigated by the finite element (FE) method and experiments. Moreover, in order to improve the flux-weakening capability of these machines a variable flux method using flux adjusters (FAs) is employed and the corresponding electromagnetic performance of the machines are investigated, analysed and compared. Both FE and measured results show when the FAs are used the torque-speed capability of the three conventional machines can be improved significantly, while no improvement is shown in the three novel topologies primarily due to the large winding inductances. The technique of using flux adjusters has been improved by reducing the number of FAs. Thus, a new mechanical variable-flux machine topology, which uses only half of FAs outside the stator at alternative stator poles, is proposed, developed and analysed. Open circuit results, electromagnetic performance and torque- and power-speed curves of the 12/10, 12/13 and 12/14 stator/rotor pole SFPM machines with alternative FAs are predicted and compared by 2D and 3D-FE, and experimentally validated. Furthermore, a novel SFPM machine topology with radial and circumferential PMs is proposed, investigated and optimized. This topology reduces the stator flux leakage and offers high magnetic utilization. Moreover, this topology can also be developed as a mechanical variable flux machine. Finally, three SFPM machines with variable flux techniques, i.e. mechanically movable flux adjusters (MMFA), mechanically rotatable permanent magnet set (MRMS) and hybrid excitation with backside DC coils (HEBC) are analysed. Their open circuit results and electromagnetic performance with emphasis on torque-speed characteristic are investigated and compared. Additionally, the required power to switch between flux weakening and strengthening states, flux weakening capability and permanent magnet demagnetization withstand capability are predicted, analysed and compared. The influence of end-effect on the torque-speed capability in the conventional, multi-tooth, E-core and C-core SFPM machines is investigated. Measurements and 3D-FE are performed to obtain the torque-speed curve in order to validate the findings of the research. The 3D-FE predicted results match well with the measured results, while the 2D-FE predicted results are lower due to the high end-effect in the SFPM machines.
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da, Silva Helder Sá Alves. "Design for manufacture of brushless permanent magnet synchronous servomotors." Thesis, University of East London, 2014. http://roar.uel.ac.uk/4620/.
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This thesis presents research into the design of brushless permanent magnet (BPM) interior rotor synchronous servomotor for both performance and manufacturability. The investigation has been supported by experimental evidence gathered with the aid of two prototype servomotors, having the same frame sizes and stator stack lengths, designed by the author and manufactured by the sponsoring company, Control Techniques Dynamics (CTD) Ltd. One servomotor, upon which the research is focussed, has the relatively new segmented stator structure containing concentrated windings. The other servomotor has a conventional structure with a solid stator containing distributed windings and this has provided the means of assessing the degree of improvement attainable with the new structure. It has been established that the new structure enables more cost-effective manufacture than attainable with the conventional structure. A significant contribution of the research programme is the special notch for retention of the surface mounted permanent magnets in the rotor. This innovation enables a more uniform and smaller air gap, which greatly improves the dynamic and thermal performance for a given frame size and stator stack length, thereby advancing the state of the art. This, together with the greatly reduced stator winding overhang in the new structure, enables a physically smaller motor for a given application, thereby reducing active material usage. Also the design methodology has focused on reducing energy and eliminating waste in the manufacturing process. Regarding the thermal aspects, only natural cooling has been considered. Conduction, convection and radiation heat transfer in the servomotor has been investigated theoretically, by simulation and by experiments to identify where design improvements can be made. The most critical area identified is the paper wall insulation and comprehensive experiments have been carried out to identify the commercially available material with the highest thermal conductivity to maximise the removal of heat from the stator windings. An array of strategically located thermocouples was used to obtain temperature distributions. The performance indicators for comparison of the new and conventional servomotors are cogging torque, iron loss and dynamic torque. The cogging torque proved to iii increase with the permanent magnet retaining feature for the new servomotor and becomes unpredictable but this disadvantage was offset by material saving and its maximum torque being approximately 40% greater than that of the conventional servomotor. The iron losses have been measured at speeds ranging from 500 r/m to 6000 r/m and at surface housing reference temperatures approximately 810C. At maximum reference winding temperature ranging from 1000C and 1250C, the dynamic torque rating performances of the new and conventional servomotor prototypes have been compared, the torque/speed characteristics being generated from a near stall speed of 50 r/m to the rated 3000 r/m. The contributions of this research programme may be summarised as follows: 1. Above all this thesis provides valuable design steps for permanent magnet synchronous servomotors using three world leading software packages (OPERA_2D, SPEED and Motor-CAD) for machine design and will therefore be a useful reference for electrical machine designers, especially beginners. 2. Material saving and simplified BPM synchronous servomotor manufacturing process for segmented stator, concentrated winding configuration. 3. Novel permanent magnet retaining method permitting more uniform and smaller air gap giving performance enhancement. 4. Systematic finite element analysis (FEA) based optimisation is applied to implement a new design principle for BPM synchronous servomotors regarding the stator parameters. 5. A simplified frequency dependent equation for open-circuit iron loss calculation. 6. Experimental and theoretical investigation of thermal impact of stator wall paper insulation entailing comparison of several different materials. 7. Direct benefit to industry through adoption of the new servomotor design by the company who supported the research.
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Budden, Alan Stephen. "Sensorless zero-speed position detection for brushless permanent magnet machines." Thesis, University of Bristol, 2006. http://hdl.handle.net/1983/05c6fe86-20a7-4a40-b39d-4f62d0c774a7.
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Wing, Mitchell 1968. "Analysis of an energy efficient permanent magnet brushless universal motor." Doctoral thesis, University of Cape Town, 1996. http://hdl.handle.net/11427/9473.
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Bibliography: leaves 131-138.The vast improvements made in the development of rare earth magnets, power electronics and micro-electronics over the last two decades can claim to be the major driving forces behind the rapid growth of permanent magnet (PM) brushless motor drives. The state of the art in PM motor technology is the PM universal motor, i.e. a combination of a PM synchronous and a PM brushless direct current (DC) motor. The PM universal motor has the capability to operate as a variable speed DC shunt motor with high torque at low speeds, and also as a synchronous motor at constant speed with high efficiency. The literature on synchronous and PM brushless motors is very extensive, although no studies have dealt with the concept of a PM brushless universal motor in any detail. The objective of this thesis is to develop an energy efficient, high performance, reliable and inexpensive electrical motor to replace induction motors, in the 21st century. Initial research of different AC motors highlighted the importance of correctly designing electrical motors. The different PM synchronous motors used in this study revealed that a sound knowledge of the motor's performance characteristics, at the design stage, is crucial to the successful and optimal design of any PM motor.
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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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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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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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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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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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Yu, Chuang, and 余创. "Design, analysis and control of flux-mnemonic permanent magnet brushless machines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44769027.
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Braiwish, Nasser. "Design optimisation of brushless permanent magnet synchronous motor for electric vehicles." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/100265/.
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A novel new application of optimisation algorithm “Bess Algorithm” in the design of electric machine is presented in this thesis. The optimisation has the ability to perform global and local search and can be applied on constrained, unconstrained optimisation problem with multi-objective function, which all counted when consider optimisation algorithm for the design of electric machine. The searching procedure of the optimisation algorithm has been described in detailed. Furthermore, novel instructions and recommendation were implemented to tune the optimisation parameters, particularly for the purpose electric machine design, which in turn reduced the search space, increase efficiency and ability to find optimal solution with lower computation time. The optimisation was applied to search for optimal parameters of a benchmark electric machine with multi-objective to reduce the cost and increase the power density, power-volume ratio and efficiency. Throughout the thesis, a full detailed analytical model for the design of brushless permanent magnet synchronous motor that account for electromagnetic and thermal aspects was described. The optimisation was employed to search for optimal parameters of the analytical model that satisfy the design requirements. Then, the generated optimal parameters were evaluated and verified by Finite Element Analysis, FEA. The results from the FEA show good agreement with their corresponding values in the analytical model within acceptable range. At the same operational conditions and output specifications, the results show that the power density, volume to power ratio and cost of the new optimised motor IV were all increased by 19%, 39%, 24% respectively and the efficiency reduced only by -1%. The optimisation was also compared with one of the most usable optimisation algorithm used in the design of electric machine i.e. Genetic Algorithm. The results show that bees algorithm has more ability to cover the search space with less number of recruited bees and less number of iterations and higher computation efficiency.
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Gangla, Vineeta. "Analytical methods for electromechanical forces and torque computation in brushless permanent magnet machines." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12052009-020038/.
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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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Othman, Md Nazri Bin. "Design and evaluation of high power density brushless DC permanent magnet machines." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/14530/.
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Permanent Magnet brushless DC motors are now competing with many other types of motors in the world industries application. However, for low and medium power applications, brushless DC motors are often the main option due to its recognized advantage such as having no commutator, more efficient, need less maintenance, smaller in size and can operate at higher speeds than conventional motors. The overall objective of this project is to produce an improved prototype BLDC motor with concentrated winding concept for an aircraft actuator application. Specifically, the aim is to extract the maximum power density and torque per kilograms by utilizing high switching frequencies, high pole numbers and minimizing magnetic material content. In this work, the research has focused on developing a procedure to design the BLDC motor by selecting several parameters and analysing their effects on the overall performance. Therefore, this research involved software and hardware methods which are broken down into field and circuit modeling, calculation of basic dimensions, magnetic circuit calculations, stator slot design, winding design, performance and loss calculation and lastly prototyping. Magnet software for finite element method (FEM) analysis and analysis programs based on standard software are used to optimize the overall performances. The proposed methods are verified by actual experimental result on the developed prototype. The performance of the prototyped machine is evaluated by using a high speed 150kw, 20,000 rpm test rig and data capturing equipment.
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Mhango, Landson Manase Caron. "High power density, high speed, three phase brushless permanent magnet DC motor." Thesis, University of East London, 2010. http://roar.uel.ac.uk/2608/.
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This thesis describes a development of a high power density, high-speed 3-phase permanent magnet brushless dc motor developed specifically for use in aircraft and defence applications. The drive is essentially intended for low power, high-speed application and it incorporates an integral electronic controller. Special attention is paid to the geometry of the rotor assembly. The development of high power density permanent magnet machines has had several unsuccessful attempts by distinguished researchers. These past attempts made use of the concept of flux focusing technique which provides the airgap flux density that is higher than that in the magnets. The original contribution of the thesis is a novel rotor construction that achieves high power density through flux focusing, but in contrast to the approach of Prof K Binns, also achieves a cost effective design regarding manufacturability. The work in this thesis considers the use of 2D finite element techniques that is used to handle the electromagnetic part of the design process and provides the way in which its results identify benefits that arise from use of different forms of the rotor geometries. New design principles are described and methods of analyzing and predicting the motor performance from design data are presented and validated by comparisons of experimental and predicted results. A motor design programme is developed and its design format is presented. The essential technical features of a proposed integral power electronic controller are described. The methods of selecting an appropriate motor for an application, simulation and prediction of motor performance, thermal analysis and acceleration performance are all presented and validated by experimental measurement. The constructional features land the design techniques of the 3-phase permanent magnet brushless dc motor developed in this study have been applied to a number of commercial aerospace and defence applications and have proved to be extremely effective and competitive. Typical practical examples of applications are presented. The challenge of the study was to improve motor efficiency significantly and to design a motor that can withstand very high peripheral speeds while at the same time develop high power density without suffering from overheating. These special requirements are typical in modern aerospace and defence applications.
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夏偉 and Wei Xia. "A new phase decoupling permanent magnet brushless DC motor and its control." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31235426.
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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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Brown, D. "The analysis and simulation of permanent magnet machines for brushless drive applications." Thesis, University of Bath, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480528.
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Gong, Liming. "Carrier signal injection based sensorless control of permanent magnet brushless AC machines." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2113/.
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This thesis is focused on the carrier signal injection based sensorless control of Permanent Magnet (PM) Brushless AC (BLAC) machines. Based on the machine saliency property, carrier signal injection based sensorless techniques have been well developed in the past decade. In order to provide the insight into machine saliency information, a simplified experimental procedure is presented to obtain the machine saliency distribution in the dq plane, including magnetic saturation and cross-saturation effects. Based on the measured machine saliency information, Sensorless Safety Operation Area (SSOA), which accounts for quantization errors in the Analog to Digital (AD) conversion, is proposed to investigate the effectiveness of sensorless operation for practical applications. The SSOA defines a working area in dq plane, in which the machine can work in sensorless mode with guaranteed steady state performance for either pulsating or rotating carrier signal injection based methods. The non-ideal characteristics of machines and drives introduce additional carrier current disturbances in carrier signal injection based sensorless control, which eventually results in the deterioration of the position estimation accuracy, the degradation of dynamic performance and even stability problems. This thesis investigates the influence of inverter nonlinearity effects on rotating carrier signal injection based methods. With the aid of theoretical analysis and experimental measurement, it is proven that the positive sequence carrier current distortion resulting from inverter nonlinearity effects can be used to compensate the influence of inverter nonlinearity on negative sequence carrier current. Hence, a new online post-compensation scheme is developed in this thesis by utilizing the measured distortion of positive sequence carrier current. In sensorless control, great efforts are required to compensate for nonlinear effects in order to improve the accuracy of the estimated position information. Alternatively, the optimal efficiency of machines, instead of accurate position estimation, can be taken as the sensorless operation objective. In this way, the sensorless operation performance is improved by the proposed online optimal efficiency tracking without any compensation for nonlinear effects. In addition, a robust magnetic polarity identification scheme is developed in this thesis based on d-axis magnetic saturation effect. The proposed scheme can be seamlessly integrated into conventional carrier signal injection based sensorless control algorithm.
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Wang, Kai. "Novel rotor shaping and stator winding of permanent magnet brushless AC machines." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/5092/.
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Yong, Wang. "A new polygonal-winding permanent magnet brushless DC motor drive for electric vehicles." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/HKUTO/record/B38628739.
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Wang, Yong, and 王勇. "A new polygonal-winding permanent magnet brushless DC motor drive for electric vehicles." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B38628739.
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Ahmed, Saeed Mohamed. "Investigations into the improvement of a single phase permanent magnet brushless DC motor." Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/10114.
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The work presented in this thesis is aimed at improving single phase permanent magnet brushless DC motors; including their operation, design, efficiency and smoothness. Three main areas were identified and researched for further improvement. As a precursor to this work, a detailed literature study related to each area is also presented. The first of these areas concentrates on the improvement of the open circuit torque for a single phase BLDC motor. The open circuit torque is not only due to the slot openings, but is also contributed by the uneven airgap which is conventionally used to solve starting problem. The aim is to enhance the starting torque at alignment positions and attenuate the torque ripple between null points where the back EMF is non-zero. The improvement of the open circuit torque was investigated in two stages. In the first stage the open circuit torque due to the slot openings was reduced, and in the second stage the focus was on enhancing the open circuit torque contributed from the uneven air gap topology with minimum ripple. The second area of investigation was to devise a new encoderless control method for a single phase BLDC motor. A detailed analysis on the derivation of the method is presented. The method has been validated both analytically and numerically. The third area of investigation was the creation of a new non-complex phase advance control method. The details of the analytical simulation and practical implementation are presented. The method has been validated experimentally and it was shown that the experimental results agree well with the analytical predictions.
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Goss, James. "The design of AC brushless permanent magnet motors for electric vehicle traction applications." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685970.
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Brushless permanent magnet machines are a preferred topology for electric vehicle traction due to their inherent high efficiencies and excellent power densities. Electric and hybrid vehicles are a rapidly growing sector in the global automotive industry due to concerns regarding man made climate change, pollution in urban areas and the rising and volatile cost of fossil fuels. This research thesis investigates the design of brushless permanent magnet motors for electric vehicle applications from a technical and commercial perspective. A set of computationally efficient techniques are presented that enable the performance of any sinusoidal BPM machine to be evaluated over the entire operational envelope. By applying these techniques torque/speed characteristics, efficiency maps, complex duty cycles and thermally constrained performance envelopes can be modelled within a few minutes of computation. The techniques are comprehensively validated using experimental results from a 36 slot 10 pole interior permanent magnet motor designed for a small electric vehicle traction application. A complete design methodology is presented that provides a simple and rigorous approach to the design of BPM electric motors for traction applications. A number of modern CAD tools are utilised and electromagnetic, thermal and mechanical performance aspects are taken into account. It is shown that the use of this methodology can result in a significantly improved design, compared to the use of a unstructured iterative design approach, when used by an inexperienced designer.
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Liu, Yong. "Direct torque control of permanent magnet brushless AC/DC drives with reduced torque ripple." Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.630444.
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Gan, Jinyun, and 干金云. "Design, analysis and control of multiphase flux regulated permanent magnet brushless DC motor drives." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31245304.
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Salgues, Christophe Xavier. "Torque Control of a Permanent Magnet Brushless DC Machine for a Hybrid Electric Vehicle." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1216920443.
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Abed, Wathiq. "Robust fault analysis for permanent magnet DC motor in safety critical applications." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3550.
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Robust fault analysis (FA) including the diagnosis of faults and predicting their level of severity is necessary to optimise maintenance and improve reliability of Aircraft. Early diagnosis of faults that might occur in the supervised process renders it possible to perform important preventative actions. The proposed diagnostic models were validated in two experimental tests. The first test concerned a single localised and generalised roller element bearing fault in a permanent magnet brushless DC (PMBLDC) motor. Rolling element bearing defect is one of the main reasons for breakdown in electrical machines. Vibration and current are analysed under stationary and non-stationary load and speed conditions, for a variety of bearing fault severities, and for both local and global bearing faults. The second test examined the case of an unbalance rotor due to blade faults in a thruster, motor based on a permanent magnet brushed DC (PMBDC) motor. A variety of blade fault conditions were investigated, over a wide range of rotation speeds. The test used both discrete wavelet transform (DWT) to extract the useful features, and then feature reduction techniques to avoid redundant features. This reduces computation requirements and the time taken for classification by the application of an orthogonal fuzzy neighbourhood discriminant analysis (OFNDA) approach. The real time monitoring of motor operating conditions is an advanced technique that presents the real performance of the motor, so that the dynamic recurrent neural network (DRNN) proposed predicts the conditions of components and classifies the different faults under different operating conditions. The results obtained from real time simulation demonstrate the effectiveness and reliability of the proposed methodology in accurately classifying faults and predicting levels of fault severity.
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Ray, Subhasis. "Multi-objective optimization of an interior permanent magnet motor." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116021.
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In recent years, due to growing environmental awareness regarding global warming, green cars, such as hybrid electric vehicles, have gained a lot of importance. With the decreasing cost of rare earth magnets, brushless permanent magnet motors, such as the Interior Permanent Magnet Motor, have found usage as part of the traction drive system in these types of vehicles. As a design issue, building a motor with a performance curve that suits both city and highway driving has been treated in this thesis as a multi-objective problem; matching specific points of the torque-speed curve to the desired performance output. Conventionally, this has been treated as separate problems or as a combination of several individual problems, but doing so gives little information about the trade-offs involved. As a means of identifying the compromising solutions, we have developed a stochastic optimizer for tackling electromagnetic device optimization and have also demonstrated a new innovative way of studying how different design parameters affect performance.
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Tseng, Chih-Tang, and 曾智堂. "Sensorless Control of Brushless Permanent-Magnet Motors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/17868412774469163006.
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碩士大葉大學
電機工程學系
98
In this paper, a brushless DC (BLDC) motor is studied. We propose the detecting phase back-EMF sensorless controller architecture. This architecture combines analog hybrid digital-control and a control technology without sensor on brushless DC motor. Design of BLDC motor control of sensorless IC, brushless DC motor control is implemented by using Microchip Company PIC16F877 single-chip. In this study, we integrate key technologies including sensorless control technology, motor control chip design and motor drive power modules. The stationary position of rotor is first detected, and then the motor is accelerated until the back electromotive force is large enough. After this accelerating, the position of motor is estimated correctly in sensorless mode. In this method, no position sensors are required. Therefore the cost is reduced. Experimental results verify the feasibility of the proposed methods.
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Zhang, Zhengxin. "High Temperature, Buried Permanent Magnet, Brushless DC Motor." 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8507.
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A high temperature magnetic bearing system using high temperature permanent magnets from Electron Energy Corporation (EEC) is under development. The system consists of two radial bearings, one thrust bearing, two radial catcher bearings and one motor. The purpose of this research is to develop one of the critical components of the system, namely, the High Temperature Permanent Magnet motor.
A novel High Temperature Permanent Magnet (HTPM) Brushless DC(BLDC) motor capable of operating at 1000 degrees F (538 degrees C) is designed. HTPMs developed at Electron Energy Corporation are buried into the rotor. The high temperature motor is designed to produce 5.1kw of power at a top running speed of 20000 rpm. The numerical values of the motor voltage, power and torque output are predicted from calculations of the nonlinear finite element model of the motor. The motor stator is wound, potted, cured and high potential tested at 1000 degrees F.
A servo amplifier from Advanced Motion Control is used to drive the high temperature motor. High temperature displacement sensors are set up for sensing the rotor position to form a closed loop motion control. However, the noise problem of the high temperature sensors causes a failure of this approach. An open loop approach is then developed and this approach succeeds in spinning the rotor with the capability of self-starting.
The status of the full system assembling is introduced. Some other components of the system are briefly presented.
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Shih, Pink-Kun, and 施炳坤. "Implementation of a Brushless Permanent Magnet Motor Driver." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/89400703326571444453.
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碩士逢甲大學
電機工程所
93
Abstract In this thesis, a permanent magnet synchronous motor drive system is implemented. Magnetic resistors rather then Hall elements are used for rotor position detection. The control is performed using DSP-TMS320LF2407. The prototype motor has been constructed using a 6-KW, AC220-V, 4800-rpm, 6-pole IPM motor. The test of the permanent magnet synchronous motor drive system are evaluated through experiments.
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Chen, Chang-Yen, and 陳衍璋. "Torque Ripple Control of Permanent Magnet Brushless Motor." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/22602954814945591352.
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碩士國立臺北科技大學
電機與能源研究所
88
The objective of this thesis is to present the techniques for reducing the torque and speed ripples of a Permanent Magnet Synchronous Motor (PMSM) drive. The torque ripple of PMSM motor drive is reduced by using new switching tables which either invoking zero switching states or new switching states. Two new switching tables are presented in this thesis. The first one invokes zero switching states for inverter control and turns the conventional three-level control into five-level control in the torque control loop. The second approach divides the area of space vectors into twelve sectors rather than six sectors in comparison with conventional approach. Experimental results derived from a PC-based test system will be presented to show that the speed ripples of the implemented PMSM drive can be significantly reduced using the proposed new techniques.
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Xie, Yun-Xuan, and 謝允軒. "Development of a Inset Permanent Magnet Brushless Motor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/34687545965623253258.
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碩士國立高雄應用科技大學
機械與精密工程研究所
103
The purpose of this thesis is to develop an inset permanent magnet brushless motor using soft magnetic composite (SMC) material. The inset permanent magnet motor design can generate additional reluctance torque and further reduce the use of permanent magnets. This study develops motors made of two different magnetic materials, SMC materials and silicon steel. Because the SMC material with powder sintering technology, comparing to silicon steel, can reduce the manufacturing processes, it is especially suitable for small motors with complex structures. The inset permanent magnet brushless motor has a stator outer diameter of 15mm, rotor outer diameter of 7.5mm, air gap of 0.35mm. This study applies JMAG software to evaluate motor performance with different rotor structure and permanent magnet designs. Based on two properties, torque ripple and torque per permanent magnet volume ratio, a design with permanent magnet pole pitch of 1.6mm is selected. This study compares motors made of two different magnetic materials. Theoretical analysis and experimental test find the motor using silicon steel 35CS300 has slightly better performance than SMC material Somaloy 700. The motor torque constant KT is tested with 2.44mNm/A for silicon steel and 2.26mNm/A for SMC. The inset permanent magnet brushless motor can easily replaces small motors in vehicle applications such as air conditioning spoiler, steering wheel vibration, mirror adjustment, HVAC and vehicle headlight axis adjustment.
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Shiu, Meng-Yuan, and 許孟原. "Design and Performance of Brushless Permanent Magnet Motors." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/qxz24z.
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碩士逢甲大學
電機工程所
91
Abstract The first part of the thesis is to write a design program for brushless permanent magnet motors. Then the program is applied to design a surface mounted (SPM) and an interior permanent-magnet (IPM) synchronous motors with the same specifications. Finite element electromagnetic field analysis is conducted to predict the performance of the motors. Results show that SPM motors have larger values of air gap flux density, open-circuit voltage, cogging torque and average torque than IPM motors when they have the same magnet volume, and SPM motors have smaller average torque than IPM motors when they have the same values of air gap flux density. Due to the manufacturing imprecision and long time running, the rotational axis of the rotor is shifted from the center of the motor and results in vibration and noise. Therefore, the second part of the thesis is to use the finite element method to study the effect of rotor eccentricity. Results show that cogging torque increases for IPM motors but decreases for SPM motors when the rotor is not in real circular shape. It is also shown that air-gap flux design, cogging torque and average torque increase for both IPM and SPM motors, especially for IPM motors. Keyword：Surface-mounted permanent magnet synchronous motor, Interior permanent magnet synchronous motor, Finite element method, Rotor eccentricity
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Shieh, Hung-Cheng, and 謝鴻成. "Computer Aided Design of Brushless Permanent-Magnet Motor." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/31185175024690389277.
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碩士國立海洋大學
電機工程學系
85
Brushless permanent-magnet motors have been found in a wide range of applications. There are many CAD(Computer Aided Design) software packagesdesigned for induction and synchronous machines, but only few ones forbrushless permanent-magnet motors. The main purpose of this thesis is to develop a personal computer (PC)based interactive and object-oriented program for aiding the design and analysis of brushless permanent-magnet motors. This program , named Brushless Permanent-Magnet Motor Design (BPMMD), is implemented by usingthe programming language of Visual Basic 4.0. It is found that utilizaionfo the developed program package will improve the efficiency for the design of brushless permanent-magnet motors.
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Bhogineni, Satishbabu. "Sensorless control of permanent magnet brushless DC motors." Thesis, 2016. http://localhost:8080/xmlui/handle/12345678/7124.
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Chiu, Wen-Han, and 邱彣漢. "Defects Induced Vibration Reduction In Permanent Magnet Brushless Motor." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3u2m2u.
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碩士國立交通大學
電控工程研究所
101
In recent years, these is a growing emphasis on energy saving and carbon reduction, people start using electric motor for its power resources of vehicles and riding on those transport with a long time, the vehicle comfortableness is important, so this research study a important factor for these — Vibration. This research study on a three phase permanent magnet brushless motor apply to E-Bike, investigate the motor eccentricity and offset on hall sensors position induced vibration which are cause in production, the first one can improve by different motor design, the second one can be improve use control compensation. To understand the motor eccentricity induced vibration, using the finite element method simulate the phenomenon of vibration,find the cause and simulate the motors which in various pole pairs to analysis the effect of improvement strategy; In the study on hall signal offset, understand the cause and phenomenon of vibration, improve by control compensation. With the understanding of vibration, we can identify the source of vibration, so we took a motor with various pole pairs and hall signal offset, compare the vibration with original motor, Verification the improvement strategy and compensation effect.
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Shou-LongYu and 余守龍. "Design and Realization of Permanent Magnet Brushless Starter Alternators." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/57090645878641983554.
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碩士國立成功大學
系統及船舶機電工程學系碩博士班
98
In this study, the design concept of the permanent magnet brushless motor is based on the permanent starter alternators (PMSA) and uses direct drive to start Wankel engine. The rotor driven PMSA provides electrical power and is able to reduce the spaces, weights and the mechanical losses of the transitional DC brush motors and generators. The purposed PMSA uses high performance rare-earth magnet to increase the power density, reliability and efficiency and reduce the weights and the difficulty of the assembling. Since the degree of difficulty will increase when the PMSA becomes larger, this study combines the Post-Assembly Magnetization (PAM) to solve the assembling problem. The design conditions and the restrictions of the PAM are known after the load analysis. The basic shape and size of the PMSA are designed by the electrical theory and the equivalent circuit. After all parameters are set, the magnetic characteristics and the performance are simulated by the finite element analysis. It can also be used in PAM method to find out the relative rotor position and assembling current. From above, the design proposes a novel PAM approach in pole-slot ratio at 3. The relative position of the rotor and the magnetizing current requirement are satisfied through the simulation. This method needs no angle rotation, and can be used in a variety of connection methods, magnetizing machine can match the specifications for the adjustment, and results are verified through experiment and simulation. Then, a completely list is sorted by the order of PAM external connection mode and relative rotor position. In the experiments, one time magnetization compare with twice magnetization so that shows the different and further discussion in details. Also, the new design of PMSA drive the Wankel Engine smoothly and is proved under rating operation at 3000rpm and 6500rpm. Finally, the magnetizing method combined with a magnetized for an integrated analysis and comparison, measurement, and experimental results with the theoretical design, design and realization of permanent magnet starter alternators with Post-Assembly Magnetization design and research is achieved.