Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this thesis is to perform modeling from different perspectives for an airgapless motor. The airgapless motor is a proposed type of electric machine whose purpose is to replace hydraulic machines in low speed high torque applications. Because of the nature of the movement for this device, modeling of this device is atypical to the modeling done with other electric machines. This thesis will present the operating principle of the airgapless motor and take an analytical approach to modeling the torque and total energy in the device. In addition, this thesis will present the power electronics necessary to drive this device and offer recommendations to maximize the torque and minimize the torque ripple. MATLAB simulations are used to verify that the conclusion of this thesis are consistent with observations made by previous publications and prototypes.

<p>As a cost-effective, healthy, and environmentally friendly personal mode of transportation, electric bicycles (E-bikes) are gaining an increasing market share from conventional bicycles and automobiles. Considering the legal rules in Ontario, Canada, a 500W motor makes the E-bike more attractive for travelling use. At the same time, the simple structure, high torque and power density, as well as the low cost of the switched reluctance machine (SRM) makes it a strong candidate for E-bikes.</p> <p>In this thesis, a 3-phase, external-rotor SRM with 6 stator poles and 10 rotor poles is designed for E-bike. The design of an external rotor arrangement of the 6-10 SRM topology has not previously been reported, hence it offers a new contribution to the published works. The machine design is initiated by the output power equation and is followed by a comprehensive finite element analysis (FEA). The external-rotor arrangement is chosen to facilitate ease of integration into the wheel hub structure of a typical pedal bicycle. The increasing rotor poles yield improved torque ripple reduction than more conventional (i.e. 6-4, 12-8 etc.) SRM design, which is an essential feature for low speed rider comfort.</p> <p>A new torque ripple reduction control scheme is investigated. Although the comparison shows that the torque sharing function has more positive result than angular position control with regards to torque ripple, this is at the expense of higher losses. Detailed thermal analysis ensures this machine is suitable to require no additional cooling system. The final machine design is experimentally tested via a full system prototype. Results highlight some limitation of the 2-D FEA in terms of the winding inductance calculation. Here, the end winding introduce more influence on short thickness machine, which will reduce its output power. However, its power-speed curve shows that this prototype machine has very strong overload ability.</p> / Master of Applied Science (MASc)

Doubly-Salient Reluctance Machines (DSRMs) sidestep many of the issues with permanent magnet and induction machines and embody the lowest cost and simplest manufacturing of the motor technologies. Major drawbacks to RMs have been (1) the need for failure-prone electrolytic capacitors, (2) large torque ripple, and (3) acoustic noise. Conventionally, these drawbacks have been addressed independently either through (1) excitation control or (2) machine design, but not as a holistic system or solution. This disseratation presents a design for high-efficiency low-cost RM while producing smooth output torque and avoiding pulsating inverter input current and the associated electrolytic capacitor. We propose a method for shaping the machine reluctance profile to reduce machine torque ripple to a desired level (here, <5%) without compromising on machine efficiency or power density, a Shaped Reluctance Machine (ShRM). Furthermore, a comprehensive approach which combines both phase excitation control and machine design to cooperatively address the excursions of input and output powers from their average values which results in less than 5% ripple for both electrical and mechanical net power — essentially a DC Reluctance Machine (DCRM). Compared to conventional practice in DSRMs, electrical power ripple is reduced by 85 times and torque ripple is reduced by almost 20 times, while overall efficiency, torque density, and power density are maintained. / Ph. D.

The permanent magnet switched reluctance motor (PMSRM) is hybrid dc motor which has the potential to be more effect than the switched reluctance (SRM) and permanent magnet (PM) motors. The PMSRM has a both a salient rotor and stator with permanent magnets placed directly onto the face of common pole stators. The PMSRM is wound like the SRM and can be controlled by the same family of converters. The addition of permanent magnets creates nonlinearities in both the governing electrical and mechanical equations which differentiate the PMSRM from all other classes of electric motors. The primary goal of this thesis is to develop a cohesive and comprehensive control strategy for the PMSRM so as to demonstrate its operation and highlight its efficiency. The control of the PMSRM starts with understanding its region of operation and the underlying torque production of the motor. The selection of operating region is followed by a both linear and nonlinear electrical modeling of the motor and the design of current controllers for the PMSRM. The electromechanical model of the motor is dynamically simulated with the addition of a closed loop speed controller. The speed controller is extended to add an efficiency searching algorithm which finds the operating condition with the highest efficiency online. / Master of Science

A novel multilevel converter that is especially suited for high speed multi-megawatt switched reluctance motor drives operating at the medium voltage level is presented. The drive is capable of variable speed, four-quadrant operation. Each phase leg of the converter contains an arbitrary number of cascaded cells connected in series with the phase winding. Each cell contains a half-bridge chopper connected to a capacitor. The converter is named the cascaded chopper cell converter. The modular nature of the converter with the ability to add redundant cells makes it very reliable, which is a key requirement for medium voltage drive applications. A comprehensive control algorithm that overcomes the challenges of balancing and controlling cell capacitor voltages is also proposed. A suitable startup algorithm to limit startup current and switching losses, as well as ensure that cell capacitor voltages remain controlled at startup, is suggested. Details of the drive design such as component sizing and control parameter selection are also discussed. A detailed simulation model is developed and explained, and simulation results are provided for primary validation. Operation with standard current and speed control is first simulated. Then a scheme that gives way to a controller that operates the drive in single-pulse mode is developed and presented. This single-pulse control scheme controls the turn-on and turn-off angles, as well as the energization voltage level, in order to obtain high efficiency. Practical considerations related to the drive such as reliability, efficiency, and cost considerations are also discussed. Finally, a detailed comparison of the proposed converter to another competing converter is performed. Besides its scalability to high voltages and powers, the reliability and efficiency of the proposed converter makes it also a candidate for sub-megawatt applications requiring minimum downtime, or any application where high efficiency or improved performance is required. A small part of this work is also dedicated to brushless dc machines. Control methods for a new converter for brushless dc machines are proposed and verified via simulation. The main advantage of this converter with the proposed control is that it allows exact control of torque or speed up to twice the rated speed, without resorting to current phase advancing or other flux-weakening techniques. / Ph. D. / Electric motors are used in a very wide range of applications. They are found in power tools, in household appliances like washers and dryers, in compressors for HVAC, in fans, blowers and pumps in industry, and in electric vehicles and electric transit systems, only to name a few. An electric motor that is combined with an electronic circuit that allows precise control of the motor speed and torque is referred to as an electric drive. Very large electric drives – reaching multi-megawatt powers – are used in several applications such as in ship propulsion, in large pumps for moving water and sewage, and others. Very few electric motor drive options currently exist at that power level, and so multi-megawatt electric motor drives present an interesting research opportunity. This work proposes a novel drive system that is best suited for high speed multi-megawatt electric drives employing the switched reluctance motor. The switched reluctance motor was chosen due to its robustness, high efficiency, and high speed capability. A novel electronic converter that is scalable to high power and voltage levels is proposed. It features high reliability which is essential in multi-megawatt applications that typically require very high uptime. It has a modular structure, thereby allowing for simple construction. A comprehensive control algorithm for the drive system consisting of the converter and motor is proposed. Also a suitable algorithm that keeps the electrical and thermal variables within the allowed limits during the startup stage is proposed. A detailed simulation model is developed and explained, and simulation results are provided for primary validation. Next, a control scheme that results in high efficiency through appropriate control of the drive’s various parameters is proposed. Practical considerations related to the drive such as reliability, efficiency, and cost considerations are also discussed. Finally, a detailed comparison of the proposed converter with another competing converter is performed. Besides its scalability to high voltages and powers, the reliability and efficiency of the proposed converter makes it also a candidate for sub-megawatt applications requiring minimum downtime, or any application where high efficiency or improved performance is required. A small part of this work is also dedicated to drives using another type of machine called the brushless dc motor. Control methods for a new converter for brushless dc machines are proposed and verified via simulation. The main advantage of this converter with the proposed control is that it allows exact control of torque or speed up to twice the rated speed, which makes it useful in traction applications.

Dans le domaine du véhicule électrique, la chaîne de traction allant de la batterie de stockage aux roues en passant par le moteur constitue le cœur du système. Elle bénéficie régulièrement d’innovations technologiques rendant ce véhicule de plus en plus attractif. Actuellement, les motorisations proposées par les constructeurs sont classiques, de type synchrone à rotor bobiné, à aimant permanent ou asynchrone. De conception éprouvée et dotées de lois de commande complexes et parfaitement maîtrisées, elles offrent de bonnes performances.Cependant, les industriels explorent de nouvelles motorisations moins conventionnelles permettant de réduire leur coût de fabrication, tout en maintenant les performances. Une des solutions possibles est la machine à réluctance variable à double saillance (MRVDS). En effet, elle est de conception simple et constituée de matériaux peu couteux. Son rotor complètement passif lui confère une très bonne robustesse et une vitesse de rotation élevée, nécessaire à une certaine compacité.Néanmoins, son pilotage est beaucoup plus complexe que pour les autres machines, elle est relativement bruyante et son couple présente des ondulations non négligeables.Nos travaux ont pour but de contribuer à l’amélioration des performances de la MRVDS du point de vue contrôle, caractéristiques de couple et efficacité énergétique sur une plage de vitesse importante. Ils ont alors été conduits selon deux axes : un axe commande et un axe conception.Afin de satisfaire un contrôle du couple le plus parfait possible, de nouveaux régulateurs de courant à la fois performants et relativement simples à implémenter sur cible logicielle ont été présenté dans un premier temps. Ensuite, nous avons proposé une implémentation partitionnée de la commande de la MRVDS sur cibles logicielle et matérielle. L’objectif est ici de conserver les performances de la commande dans le cas de l’utilisation d’un processeur économique, dont la période d’échantillonnage serait relativement importante, et tout particulièrement à haute vitesse. Une carte FPGA (Fied Programmable Gate Array) a alors été mise en œuvre.Pour améliorer les caractéristiques de couple en fonction de la vitesse ainsi que le rendement de l’ensemble moteur-convertisseur, une nouvelle structure de MRVDS non conventionnelle a été proposée. Elle est munie d’un bobinage auxiliaire créant une excitation magnétique dans chaque phase.Une étude a d’abord été menée à l’aide de simulations basées sur un nouveau modèle. Elle a permis de mettre en évidence les avantages d’une excitation par rapport à une MRVDS classique. Afin de valider les résultats, un prototype a ensuite été conçu, réalisé et expérimenté.Une part importante de ces travaux a ainsi été consacrée à la mise en œuvre de plateformes expérimentales et à la réalisation de nombreux essais permettant de valider les développements théoriques, tant du point de vue commande sur une MRVDS 8/6 que conception sur une MRVDS 6/4. / For electric vehicles, traction from storage battery to the wheels through the engine is the heart of the system. It regularly enjoys technological innovations making this vehicle more attractive. Currently, machines offered by manufacturers are classic, synchronous and induction machines. With complex laws, they offer good performance.However, manufacturers are exploring new unconventional machines to reduce their manufacturing cost while maintaining performance. One possible solution is the switched reluctance machine (SRM). Indeed, its design is simple and made of inexpensive materials. Its rotor completely passive gives it a very good robustness and high rotational speed required for certain compactness. However, its operation is much more complex than for other machines, it is relatively noisy and has significant torque ripple.Our work contributes to the improvement of SRM’s performance in terms of control torque characteristics and global efficiency over a large range speed. They were driven on two axes: one control axis and one design axis.To satisfy a torque control as perfect as possible, new currents controller both efficient and relatively simple to implement on software target were first presented. Then we proposed a SRM's control implementation on hardware and software targets. The objective is to maintain the performances in the case of an important sampling period, especially at high speeds. So an FPGA circuit (Fied Programmable Gate Array) was used.To improve torque characteristics depending on the speed, and global efficiency, a new SRM structure has been proposed. It is provided with an auxiliary coil creating a magnetic excitation in each phase. A study was initially conducted using simulations based on a new model. It helped to highlight the benefits of excitement compared to a conventional SRM. To validate the results, a prototype was then designed, built and tested.An important part of this work has been devoted to the implementation of experimental platforms and implementation of numerous tests to validate the theoretical developments, both in terms of control on a 8/6 SRM and design on a 6/4 SRM.

A finalidade inicial deste estudo foi desenvolver um modelo computacional multifísico de um acionamento eletrônico, composto por um motor de relutância 4/2 bifásico, um conversor eletrônico de potência, um controlador, os componentes mecânicos estruturais do motor e os acoplamentos entre os diferentes domínios físicos. Para a implementação do modelo proposto, foram utilizados recursos de simulações numéricas e acopladas do MEF (Método dos Elementos Finitos) em uma plataforma de simulação multifísica, de modo a realizar acoplamento entre três áreas do conhecimento: circuitos elétricos, campos eletromagnéticos e componentes mecânicos estruturais e de vibração. Uma vez desenvolvido o modelo multifísico, este foi associado a um procedimento de otimização dos ângulos de disparo que utiliza um modelo de algoritmos genéticos e, como um conjunto, estes foram aplicados na redução da vibração e da ondulação de torque do motor de relutância chaveado, resultando em uma nova metodologia para a abordagem desses problemas. De modo a comprovar os resultados obtidos nas simulações, foram realizados diversos ensaios experimentais para a validação de cada etapa do desenvolvimento, tais como levantamento das formas de onda de tensão e correntes, ensaios de vibração, etc. Os modelos desenvolvidos foram testados em função de modificações realizadas tanto nos parâmetros de controle do acionamento, como também em função de modificações mecânicas estruturais na geometria do rotor. / The initial purpose of this study was developing a multi-physical computational model of a power electronic motor drive, composed to a 2-Phase Switched Reluctance Motor (SRM) 4/2, a power electronic converter, a controller, motor mechanical and structural components and the coupling among different physical domains. For implementing of the proposed model, it was used FEM (Finite Element Method) coupled and numerical simulations resources in a multi-physic simulation platform, in order to accomplish the coupling among the three areas of knowledge: electrical circuits, electromagnetic fields and structural and mechanics components and vibration. Once finished the multi-physical model, it was associated with a optimization procedure of firing angles which uses genetic algorithm model and, as a whole, it was applied on the SRM vibration and torque ripple reduction, resulting in a new methodology to approaching these problems. In order to prove obtained simulation results, it was carried out several experimental tests to validate each development stage, such as the voltage and currents wave forms mapping, vibration tests, etc. The developed models were tested as much function of drive control parameters as the rotor geometry mechanical and structural modifications.

A finalidade inicial deste estudo foi desenvolver um modelo computacional multifísico de um acionamento eletrônico, composto por um motor de relutância 4/2 bifásico, um conversor eletrônico de potência, um controlador, os componentes mecânicos estruturais do motor e os acoplamentos entre os diferentes domínios físicos. Para a implementação do modelo proposto, foram utilizados recursos de simulações numéricas e acopladas do MEF (Método dos Elementos Finitos) em uma plataforma de simulação multifísica, de modo a realizar acoplamento entre três áreas do conhecimento: circuitos elétricos, campos eletromagnéticos e componentes mecânicos estruturais e de vibração. Uma vez desenvolvido o modelo multifísico, este foi associado a um procedimento de otimização dos ângulos de disparo que utiliza um modelo de algoritmos genéticos e, como um conjunto, estes foram aplicados na redução da vibração e da ondulação de torque do motor de relutância chaveado, resultando em uma nova metodologia para a abordagem desses problemas. De modo a comprovar os resultados obtidos nas simulações, foram realizados diversos ensaios experimentais para a validação de cada etapa do desenvolvimento, tais como levantamento das formas de onda de tensão e correntes, ensaios de vibração, etc. Os modelos desenvolvidos foram testados em função de modificações realizadas tanto nos parâmetros de controle do acionamento, como também em função de modificações mecânicas estruturais na geometria do rotor. / The initial purpose of this study was developing a multi-physical computational model of a power electronic motor drive, composed to a 2-Phase Switched Reluctance Motor (SRM) 4/2, a power electronic converter, a controller, motor mechanical and structural components and the coupling among different physical domains. For implementing of the proposed model, it was used FEM (Finite Element Method) coupled and numerical simulations resources in a multi-physic simulation platform, in order to accomplish the coupling among the three areas of knowledge: electrical circuits, electromagnetic fields and structural and mechanics components and vibration. Once finished the multi-physical model, it was associated with a optimization procedure of firing angles which uses genetic algorithm model and, as a whole, it was applied on the SRM vibration and torque ripple reduction, resulting in a new methodology to approaching these problems. In order to prove obtained simulation results, it was carried out several experimental tests to validate each development stage, such as the voltage and currents wave forms mapping, vibration tests, etc. The developed models were tested as much function of drive control parameters as the rotor geometry mechanical and structural modifications.

This thesis presents a new modular structure of the axial flux Switched Reluctance Motor (SRM). The design consists of four stator disks with each adjacent disk rotated 30 degrees apart and four rotor disks connected to a common shaft. The proposed design aims to reduce the unwanted radial force, mitigate the torque ripple, and improve the efficiency. The modular structure distributes the radial force and torque strokes along the axial length of the motor, potentially damping the torque pulsation. In addition, the modular structure would deliver the rating power at a lower current level, reducing the overall ohmic loss. Moreover, if a fault occurs on a motor disk or its control unit, the motor would still operate through other disks, increasing the reliability of the system. To verify the effectiveness of the proposed design, the magneto-static and transient performance of the motor are compared with the conventional single layer structure using 3-D Finite-Element (FE) software tool to see that the proposed motor performs better with lower torque ripple and lower radial force than a conventional single layer structure.

In this study, three different programs are developed for the analysis of the three-phase induction motor, single-phase capacitor type induction motor and switched reluctance motor. The programs are developed by using Pascal and C++ programming languages. In the performance calculations of motors, analytical methods are used and these methods are tested for accuracy. These programs have also capabilities to design an optimum motor, which meets a set of performance, material and manufacturing constraints while minimizing the weight or any other defined objective function. In addition, in this study, an optimization tool is used to obtain an appropriate optimization method for the design of different types of motors. The software is tested over different commercial motors. The results illustrates that the performance calculations and optimization approach of the programs lead to good results.