Electric vehicles are a key technology in the reduction of our carbon footprint and this has motivated significant research interest. The electrical traction motor is one of the main areas of research in attempts to further improve electric vehicle performance. The permanent magnet motor is the predominant device in this application because of its high specific torque. However, it has suffered from market speculation in the raw magnet materials which has generated efforts to develop electrical machines which have a high specific torque and do not contain rare earth materials. In the past the induction motor used to be the preferred motor for electric vehicles due to its low costs, low maintenance requirements, mature technology and robustness. The induction motor requires a higher specific torque to make it an alternative to permanent magnet machines. For this reason, this research had the primary aim of improving the specific torque of induction machines by undertaking a detailed review of the motor design because this process has conventionally focussed on the requirements for industrial applications. The first stage of the work presented in this thesis consisted of identifying the designs already in use for this purpose and the potential technologies applicable to the induction motor that could be transferred from other electric traction machines. A full review of the design process was also conducted in order to identify the key areas of the process with special reference to the electromagnetic design which used finite element techniques as the main modelling tool. New induction motor designs were developed which showed potential for improving the specific torque; two of these were selected for further refinement, prototyping and testing. Although these designs were modified to facilitate construction, some major difficulties were still encountered during the prototype rotor manufacture. The test results were used to validate the design process and to identify further improvements in the designs. The issues encountered with the rotor manufacture prototype however lead to some overheating during the experimental testing. Comments about the design experience gained during this research are summarized including suggestions for further research.

This dissertation focuses mainly on the airgap-less electric machine. An extensive literature review has been presented along with a systematic study that included analytical modeling, simulation with both steady-state and trasient analysis, prototype building, and experimental validation. In this type of device, the rotor is allowed to touch the stator at a contact point, which maximizes the internal flux and therefore the electromagnetic torque. A higher torque density motor is proposed in this dissertation due to a reduced reluctance caused by zero airgap situation. A comparison with other high torque density electric ma-chines demonstrates the advantages of the proposed machine. Switched reluctance motor for hybrid vehicle, integrated magnetic gear, induction machines, are some examples of the machines with lower torque density than the airgap-less electric machine. This machine will maximize the generated torque allowing these type of machines to be competitive in applications where hydraulic motors are prevalent, i.e., low-speed and high-torque requirements. Hydraulic motor systems face two major problems with their braking system and with low efficiency due to a large number of energy conversion stages (i.e., motor-pump, hydraulic connections and the hydraulic motor itself). The proposed electric motor, unlike hydraulic motors, converts electrical energy directly to mechanical energy with no extra braking system necessary and with higher efficiency. The evolution of the airgap-less electric machine from three poles to 9 bi-poles is discussed in this dissertation. The modeling of this machine with a minimum number of poles is discussed before a generalization is presented. The simulation and analysis of the airgap-less electric motor has been done using Euler integration method as well as Runge Kutta 4th order integration method due to its higher precision. A proof-of-concept electric machine with nine magnetic bipoles is built to validate the theoretical assumptions.

Ce manuscrit de thèse, intitulé " Dimensionnement d’un actionneur pour organe de pilotage à entraînement direct avec redondance passive magnétique ", s’inscrit dans un projet ANR du nom de TEMOP pour, TEchnologie Mécatronique pour Organe de Pilotage, en lien avec la société UTC Aerospace de Figeac. L’objectif de cette thèse est de développer une solution de machine électrique permettant de générer le retour d’effort actif d’un mini-manche latéral d’aéronef, dans le but d’améliorer les sensations haptiques des pilotes. Cette machine doit être assez performantes pour générer des efforts massiques importants, tout en tenant dans un encombrement réduit et en limitant l’échauffement. Un cahier des charges précis rédigé par l’industriel donne les contraintes à respecter et impose une redondance triplex sur chaque axe de tangage et de roulis. Nous avons opté pour une solution comportant un duplex actif associé à un simplex passif. Sur chaque axe, deux machines électriques actives seront montées en parallèle et une solution à retour d’effort passif magnétique a été développée. Pour ce faire, nous avons divisé notre thèse en deux parties distinctes. La première partie du manuscrit traite du dimensionnement de la machine active appelée DARM pour Double Airgap Rotative Machine. Il s’agit d’une machine synchrone à aimants permanents en configuration Halbach, comportant deux entrefers et à débattement limité. La stratégie de dimensionnement est basée sur une optimisation locale et analytique sous contraintes non-linéaires. La première partie développe les contraintes sous forme analytiques. Puis, un modèle magnétique est créé de manière à connaître le couple que la structure développe en fonction des différentes variables d’optimisation. Ce modèle a été validé par éléments finis grâce aux logiciels ANSYS et JMAG. Une optimisation permet d’aboutir aux dimensions de l’actionneur satisfaisant au cahier des charges. Puis, dans le but de vérifier les températures atteintes dans chaque zones, un modèle thermique global, utilisant des résistances thermiques équivalentes a été établi et validé par simulations. Ainsi, on vérifie que la structure optimisée n’atteint pas des températures critiques. Enfin, nous validerons nos calculs par des mesures expérimentales. Un chapitre du manuscrit est dédié au dimensionnement de la partie passive. Nous avons imaginé un système innovant qui couple une fonction de ressort et d’amortisseur. La fonction de ressort s’appuie sur le phénomène de répulsion entre deux aimants permanents, alors que la fonction d’amortisseur est créée par un système de freinage passif par courants de Foucault. La stratégie de dimensionnement est divisée en deux partie. Les dimensions du système de ressort sont préalablement choisies grâce à une optimisation paramétrique locale couplant le logiciel MATLAB au logiciel de simulations par éléments finis FEMM. Lorsque ces dimensions sont fixées, le système d’amortisseur est dimensionné par une optimisation locale analytique où la fonction objectif a pour vocation de maximiser le couple de freinage. Nous nous sommes donc entachés à développer un modèle qui permet de calculer ce couple. Sur cette base, un prototype a été élaboré, sur lequel des mesures expérimentales ont permis de valider le concept. / This thesis manuscript titles "Dimensionnement d’un actionneur pour organe de pilotage à entraînement direct avec redondance passive magnétique ", which means " Design of an active flight control direct drive actuator with a passive magnetic redundancy ", is seen against an ANR project named TEMOP for, " TEchnologie Mécatronique pour Organe de Pilotage ", and is in connection with the UTC Aerospace industry in Figeac in France. The objective of this thesis is to develop a solution of electrical machine, which permits to create an active force feed-back for an aircraft side-stick, in order to improve the haptic sensations of the pilot. This machine have to be enough powerful to create high forces per unit of mass. We also need to respect the overall dimensions and to decrease the heating as much as possible. A precise set of specifications, redacted by UTC Aerospace, gives the constraints and impose to have a triple redundancy on each axis of pitch and roll. We chose to develop a duplex active redundancy with an added simplex passive actuator. Our full system have 6 machines : 4 are actives and 2 are passives. Our thesis is divided in two main parts. The first part of the manuscript deals with the design of the active machine called DARM for " Double Airgap Rotative Machine ". It is a synchronous permanent magnet machine, with a Halbach pattern, with two airgaps and a non-entire arc. The design method is based on an analytical optimization process under a set of non-linear constraints. Each of them are traduced mathematically and an electromagnetic 2D model is developed, in order to give the theoretical torque reached, in function of the variables of the problem. This model has been validated with FEM simulations with the ANSYS and JMAG softwares. An optimization is realized to give the dimensions of the DARM. Then, in order to verify the temperatures, we developed a global thermal model, based on an equivalent electric circuit. It permits to verify that the temperatures reached in the structure, are under the limits given by the set of specifications. This model is verified by FEM simulations using ANSYS. Finally, we will validate our models with experimental measures. However, a chapter is dedicated to the design of the passive actuator. We imagined an innovative system, which have two different utilities. The first one is a function of spring, the second is a function of shock absorber. The spring is based on the repulsion phenomenon between two magnets. The shock absorber is created with a system of Eddy currents breaker. The design method is divided in two. In the first time, we design the spring with a parametric optimization using the FEMM software coupled to the MATLAB software. When the dimensions of the spring are known, we design the shock absorber with an analytical optimization process which use an electromagnetic torque model developed in this part. A prototype has been built in order to verify the models.

With the rapid growth of air travel, concerns about the emissions of greenhouse gas emissions resulting from the air transportation sector are growing. Although the current battery technologies might not be adequate for all-electric regional aircraft, the energy density of the current battery technologies could be adequate to electrify light-sport aircraft used for training and recreation. Due to the nature of the propeller load and noise isolation of the cabin, switched reluctance motors can be an excellent candidate for the propulsion system of electrified light-sport aircraft. The proposed SRM is designed to replace a 70 kW permanent magnet synchronous motor used in the aerospace industry with similar volume constraints and operational requirements. In order to meet the high-power density requirements of this application, a design framework is proposed which includes several layers of the design process. The design objectifies are the average torque, torque ripple, and radial forces by integrating the control and geometry design into the proposed framework. A comprehensive design process is carried out with the proposed framework, and a detailed coil design process is performed. The rotor cut-outs are designed to reduce the weight of the motor. The thermal performance of the motor has been analyzed for the calculated motor losses and the cooling system constraints. / Thesis / Master of Applied Science (MASc)