Improved 3-D Analytical Model for Axial-Flux Eddy-Current Couplings with Curvature Effects

International audienceAn improved three-dimensional analytical model for axial-flux permanent-magnet eddy-current couplings is presented in this paper. As the problem is solved in a 3-D cylindrical coordinate system, the proposed model directly takes into account the radial edge effects and the curvature effects on the torque prediction without the need of any correction factor. It is shown that the new analytical model is very accurate, even for the geometries where the curvature effects are very pronounced. Another advantage of the proposed model is the great reduction of computation time compared to 3-D finite elements simulations and an easier adaptation for parametric studies and optimization

Design of the Annular Suspension and Pointing System (ASPS) (including design addendum)

The Annular Suspension and Pointing System is an experiment pointing mount designed for extremely precise 3 axis orientation of shuttle experiments. It utilizes actively controlled magnetic bearing to provide noncontacting vernier pointing and translational isolation of the experiment. The design of the system is presented and analyzed

Optimal Design of Special High Torque Density Electric Machines based on Electromagnetic FEA

Electric machines with high torque density are essential for many low-speed direct-drive systems, such as wind turbines, electric vehicles, and industrial automation. Permanent magnet (PM) machines that incorporate a magnetic gearing effect are particularly useful for these applications due to their potential for achieving extremely high torque density. However, when the number of rotor polarities is increased, there is a corresponding need to increase the number of stator slots and coils proportionally. This can result in manufacturing challenges. A new topology of an axial-flux vernier-type machine of MAGNUS type has been presented to address the mentioned limitation. These machines can attain high electrical frequency using only a few stator coils and teeth, which can simplify construction and manufacturing under certain conditions. Additionally, the inclusion of auxiliary small teeth within the stator main teeth can generate a noteworthy increase in output torque, making it a unique characteristic of this motor. By analyzing the operating principle of the proposed VTFM PM machine, possible pole-slot combinations have been derived. The process of designing an electric machine is complicated and involves several variables and factors that must be balanced by the designer, such as efficiency, cost, and performance requirements. To achieve a successful design, it is crucial to employ multi-objective optimization. Using a 3D FEA model can consider the impact of magnetic saturation, leakage flux, and end effects, which are not accounted for in 2D. Optimization using a 3D parametric model can offer a more precise analysis. Validating the machine\u27s performance requires prototyping a model and testing it under different operating conditions, such as speed and load, which is a crucial step. This approach provides valuable insights into the machine\u27s behavior, allowing the identification of any areas for improvement or weaknesses. A large-scale multi-objective optimization study has been conducted for an axial-flux vernier-type PM machine with a 3-dimensional (3D) finite element analysis (FEA) to minimize the material cost and maximize the electromagnetic efficiency. A detailed study for torque contribution has indicated that auxiliary teeth on each stator main teeth amplify net torque production. A prototype of optimal design has been built and tested

Contribution à la modélisation analytique des actionneurs électromécaniques

Ce mémoire de synthèse dresse un bilan de mes activités de recherche réalisées au GREEN pendant ces dix dernières années. Le point d’ancrage de mes recherches concerne la modélisation analytique des actionneurs électromécaniques. L’objectif est de développer des outils rapides et efficaces pour l’analyse et le dimensionnement des actionneurs conventionnels ou supraconducteurs. Une part importante de mon travail concerne la validation expérimentale des modèles proposés.Dans le premier chapitre, je présente un résumé détaillé de mes activités pédagogiques, administratives et de recherche. Le deuxième chapitre porte sur la modélisation analytique des machines synchrones à réluctance variable prenant en compte les effets de la saturation magnétique et des harmoniques d’espace pour l’étude des régimes dynamiques et la commande. Le troisième chapitre concerne le développement de modèles analytiques en 2D et 3D des convertisseurs électromagnétiques basés sur la résolution formelle des équations de Maxwell par la méthode de séparation des variables. L’originalité des modèles concerne la prise en compte directe des effets de saillance magnétique et des effets 3D sur la distribution du champ dans l’entrefer des machines électriques. Dans le chapitre 4, je présente mes travaux sur l’étude et la conception de structures innovantes de machines et d’actionneurs mettant en œuvre des matériaux supraconducteurs. Le chapitre 5 dresse un bilan de mes activités de recherche et présente des perspectives à moyen et long terme

Flywheel energy storage workshop

Since the November 1993 Flywheel Workshop, there has been a major surge of interest in Flywheel Energy Storage. Numerous flywheel programs have been funded by the Advanced Research Projects Agency (ARPA), by the Department of Energy (DOE) through the Hybrid Vehicle Program, and by private investment. Several new prototype systems have been built and are being tested. The operational performance characteristics of flywheel energy storage are being recognized as attractive for a number of potential applications. Programs are underway to develop flywheels for cars, buses, boats, trains, satellites, and for electric utility applications such as power quality, uninterruptible power supplies, and load leveling. With the tremendous amount of flywheel activity during the last two years, this workshop should again provide an excellent opportunity for presentation of new information. This workshop is jointly sponsored by ARPA and DOE to provide a review of the status of current flywheel programs and to provide a forum for presentation of new flywheel technology. Technology areas of interest include flywheel applications, flywheel systems, design, materials, fabrication, assembly, safety & containment, ball bearings, magnetic bearings, motor/generators, power electronics, mounting systems, test procedures, and systems integration. Information from the workshop will help guide ARPA & DOE planning for future flywheel programs. This document is comprised of detailed viewgraphs

Super High-speed Miniaturized Permanent Magnet Synchronous Motor

This dissertation is concerned with the design of permanent magnet synchronous motors (PMSM) to operate at super-high speed with high efficiency. The designed and fabricated PMSM was successfully tested to run upto 210,000 rpm The designed PMSM has 2000 W shaft output power at 200,000 rpm and at the cryogenic temperature of 77 K. The test results showed the motor to have an efficiency reaching above 92%. This achieved efficiency indicated a significant improvement compared to commercial motors with similar ratings. This dissertation first discusses the basic concept of electrical machines. After that, the modeling of PMSM for dynamic simulation is provided. Particular design strategies have to be adopted for super-high speed applications since motor losses assume a key role in the motor drive performance limit. The considerations of the PMSM structure for cryogenic applications are also discussed. It is shown that slotless structure with multi-strand Litz-wire is favorable for super-high speeds and cryogenic applications. The design, simulation, and test of a single-sided axial flux pancake PMSM is presented. The advantages and disadvantages of this kind of structure are discussed, and further improvements are suggested and some have been verified by experiments. The methodologies of designing super high-speed motors are provided in details. Based on these methodologies, a super high-speed radial-flux PMSM was designed and fabricated. The designed PMSM meets our expectation and the tested results agree with the design specifications. 2-D and 3-D modeling of the complicated PMSM structure for the electromagnetic numerical simulations of motor performance and parameters such as phase inductors, core losses, rotor eddy current loss, torque, and induced electromotive force (back-EMF) are also presented in detail in this dissertation. Some mechanical issues such as thermal analysis, bearing pre-load, rotor stress analysis, and rotor dynamics analysis are also discussed. Different control schemes are presented and suitable control schemes for super high- speed PMSM are also discussed in detail

Next-generation equipment and procedures for combined resonant column and torsional shear testing

In this dissertation, work aimed at developing next-generation equipment and procedures for combined resonant column and torsional shear (RCTS) testing are detailed. The work in this dissertation covers three key areas of RCTS testing that need improvement to reach the next level of RCTS testing. The first area involved improvement in measurement resolution with modern control and monitoring equipment. Concurrently, original software was written to enhance the efficiency, accuracy, and repeatability of the test. The second area involved advancing concepts for evaluating and modeling nonlinear behavior of soil, which was done in part by using raw RCTS test data collected and stored from 2013-2017. The third area involved evaluating and modifying the design of the existing RCTS device to accommodate higher levels of shearing strain and provide higher loading capacity. First, when testing at small shear strains (< 0.001%) within the linear-elastic range of soils, very small excitation voltages must be used and very small voltages are recorded from the RCTS sensors. Obtaining accurate measurements in the linear-elastic range is critically important when testing at low confining pressures (in the range of 0.1 to 1 atm). In traditional RCTS data acquisition systems, very small recorded voltages are lost due to limited resolution of the control and monitoring subsystems. Concurrently, the very small recorded voltages are generally heavily contaminated by environmental background noise that invalidates the automated process for reducing raw data into engineering results. Control and monitoring equipment and software were developed that can enhance the measurement and data reduction process when making low-strain measurements. Second, testing of soil in the nonlinear shear strain range (typically greater than 0.001%) is a complex process that departs from traditional dynamic models for single-degree-of-freedom (SDOF) systems. Traditionally, RCTS results from testing in the nonlinear shear strain range involve slight adaptation of traditional SDOF models to obtain nonlinear relationships. Nonlinear dynamics model concepts were taken from literature and adapted to better understand and model nonlinear behavior of soils in RCTS testing. Furthermore, development of nonlinear models at moderate strains help to bridge the spectrum of soil testing which tends to divide into evaluating soils at small to moderate strains (< 0.2%) or at large strains (≥ 0.2%). Third, when testing soils at large shearing strains (> 0.2%), traditional RCTS systems are physically or electronically limited. At higher confining pressures (> 2 atm) where soils become quite stiff, the traditional RCTS control equipment is electronically incapable of driving enough torque output to strain soils in shear above desired levels (> 0.1%). At low confining pressures ( 0.5%). An RCTS testing device was designed that has a torque-output capacity at least three times greater than a traditional RCTS device and an allowable degree of twist that can generate shearing strains above 1%.Civil, Architectural, and Environmental Engineerin

Conception d’un embrayage de dérivation du couple à courants de Foucault pour les transmissions manuelles automatisées sans interruption de couple dans les véhicules à motorisation électrique ou hybride

Les voitures électriques ont peu d’énergie embarquée pour se mouvoir comparativement aux véhicules thermiques. Il est donc important d’optimiser l’efficacité de la chaîne de traction pour maximiser la distance parcourue entre les recharges. Ces voitures utilisent un ratio simple pour coupler le moteur aux roues de la voiture. Le remplacement du ratio simple par une transmission à plusieurs vitesses dans une voiture électrique améliore l’efficacité du système de propulsion. Cependant, l’introduction d’une transmission à plusieurs ratios ne doit pas seulement améliorer l’efficacité énergétique pour recevoir l’acceptabilité du marché. Elle doit aussi offrir un confort de conduite similaire au ratio simple. L’ajout d’un embrayage de déviation du couple à la transmission manuelle permet de réduire ou d’éliminer les interruptions de celui-ci lors du passage des ratios. Cependant, les technologies d’embrayages à friction secs et humides ne sont pas bien adaptées à cette tâche de déviation du couple cependant. D’abord, l’embrayage est ouvert la majeure partie du temps ce qui fait en sorte qu’un embrayage humide aurait de grandes pertes visqueuses. Ensuite, les moteurs électriques tournent rapidement (11 000 révolutions par minute). Cela fait en sorte que l’embrayage dissipe de grandes quantités de chaleur pour ralentir le moteur avant l’engagement du prochain ratio. Un embrayage sec ne contient pas d’huile pour aider à l’extraction de la chaleur et ses bandes de friction s’usent rapidement sous ces conditions. Ce travail de maîtrise propose d’utiliser un embrayage électromagnétique plutôt qu’un embrayage à friction pour dévier le couple moteur. La démarche de conception d’un tel embrayage est présentée. Premièrement, un modèle analytique simple sert à déterminer les dimensions physiques de l’embrayage pour qu’il développe un certain couple électromagnétique. Ce requis provient des spécifications techniques d’une plateforme véhiculaire électrique disponible à l’Université de Sherbrooke (Projet Phoebus). Deuxièmement, des études par éléments finis des champs magnétiques de l’embrayage servent à valider que l’embrayage produit le niveau de couple désiré. L’embrayage est finalement testé dans une transmission manuelle automatisée installée sur un banc de test dynamométrique. Des changements de ratios sans interruption de couple démontrent la viabilité de l’embrayage à courants de Foucault en tant qu’embrayage de déviation du couple