Impulse magnetized magnetic screws

This paper is an investigation in the performance of two types of magnetic screws (MSs). The first is the magnet to magnet and consists of permanent magnet (PM) nut and PM screw and the second is a magnet to reluctance and consists of PM nut and a double-start reluctance screw. It is argued that for cost sensitive and long stoke applications, a magnet-to-reluctance MS may be the preferred option. It is also shown that capacitor discharge magnetization techniques can be employed for imprinting helical magnetization distributions on cylindrical PMs, significantly reducing the complexity and facilitating the practical realization of MS systems

Trans-Rotary Magnetic Gear for Wave Energy Application

This dissertation looks into a type of magnetic gear, referred to as the Trans-Rotary Magnetic Gear (TROMAG), for reciprocating Wave Energy Converters (WECs). A TROMAG consists of two main parts: a translator that is coupled, mechanically or magnetically, to a buoy and a rotor that is coupled to a rotary generator. The device accomplishes two tasks: it converts linear motion to rotation (and vice versa) through magnetic fields, and at the same time it does a gearing action. This means that it can convert the high-force, low-speed linear motion of a buoy to a low-torque, high-speed rotation, which enables using a compact, high-speed rotary generator. As a magnetic gear, the TROMAG offers contact-free force transmission and its consequent advantages such as reduced wear and tear, reduced need for lubrication and maintenance, high reliability, and inherent overload protection capability. In this dissertation, first, the motivation behind developing the TROMAG is presented. Then, the structure of the device and its principles of operation are laid out. Moreover, aspects of magnetic design are studied by using either an analytical model, three-dimensional (3D) finite element analysis (FEA) or two-dimensional (2D) FEA. It is shown that, for a high-force, low-speed load characteristic, a system comprising a TROMAG and a rotary machine would far surpass a direct drive linear machine (DDLM) designed for the same force and speed, in terms of weight, cost, and volume of the required active material. In addition, a nonlinear analytical model is proposed to describe the dynamic behavior of the TROAMG. The model is then linearized and combined with the linearized model of a buoy in order to study the dynamics of the entire wave energy conversion system. Furthermore, a demonstrative prototype of the TROMAG is constructed and tested to verify the theoretical concepts and employed analyses

Projeto e desenvolvimento de um fuso magnético de relutância variável

Esta dissertação aborda o desenvolvimento de um fuso magnético de relutância variável com topologia de caráter inovador. Este dispositivo magnético é composto de um translator, que se desloca linearmente ao longo de um eixo, e um rotor que gira em torno do mesmo eixo. Ele é capaz de converter, sem contato mecânico entre suas partes móveis, movimentos de alta densidade de força e baixa velocidade linear em baixa densidade de conjugado e alta velocidade angular, atrativo para inúmeras aplicações industriais. Por possuir ímãs permanentes somente na menor de suas partes móveis, a topologia proposta torna-se economicamente viável em aplicações de longos cursos. O fuso magnético é projetado em software de elementos finitos e um estudo de sensibilidade paramétrica é realizado com o objetivo de maximizar a força produzida por unidade de volume dos ímãs permanentes. Após a definição dos parâmetros de projeto, um protótipo é construído e experimentalmente ensaiado. Os resultados obtidos das simulações são confrontados com os experimentalmente adquiridos apresentando boa concordância.This master thesis presents the design and realization of a novel reluctance-based magnetic lead screw (RBMLS) topology. This magnetic device is composed of two moving-parts: a translator moving linearly back and forth along the z-axis and a rotor rotating about the same axis. The device is capable of convert low-speed, high-force linear motion to high-speed, low-torque rotary motion, without mechanical contact between the two moving parts, which makes it attractive for many industrial applications. The RBMLS has permanent magnets (PMs) in only the shortest of its moving parts, making it economically suitable for long-stroke-applications. The proposed RBMLS is designed in a finite element analysis software, in which a parametric study is conducted in order to maximize the stall force produced per PM volumetric unit. Once the parameters were chosen, a prototype was fabricated and experimentally analyzed. The experimental results are then compared to those supplied by the FEA analysis, showing good agreement

High-Speed Applications for Electromagnetic Propulsion Technology

In this thesis, different types of the magnetic lead screw systems are considered, and the effects of the key design parameters, such as magnet thickness, air-gap length, pole-pitch, number of pole-pairs, dimension etc. on the force/torque transmission are investigated. Moreover, research into the realisation of helical magnetisation distribution employing a novel impulse magnetisation process is undertaken, in order to reduce the complexity and cost of manufacture. This avoids the complex and/or time-consuming methods, which may require the assembly of a large number of small magnets to approximate helical magnetisation distribution. A prototype reluctance type magnetic screw system is realised, it consists of a double start mechanical screw and a permanent magnet nut equipped with impulse magnetised cylindrical permanent magnets, using purpose designed double-sided impulse magnetising fixture. Furthermore, a test-rig to measure the transmitted force is developed and used to compare the predicted and measured results

Magnetic gears numerical modelling and optimization

The main focus of this thesis is to provide efficient modelling and optimization strategies for a certain electro-magnetic device known as magnetic gear. In particular, magnetic, thermal and mechanical models are discussed and the non-linear material models are examined, including permanent magnets demagnetization algorithms and hysteresis models in laminated sheets. From the magnetic modelling point of view, an analytic approach for the initial simplified gear design is presented. A special focus is given to the computational burden of the method that is especially tailored for stochastic optimization procedures. For the detailed analysis of magnetic gears, an algorithm based on Finite Element / Boundary Element coupling is proposed, including ferromagnetic non-linearities, mechanical ordinary differential equations, eddy currents and circuit equations. Detailed models are introduced and discussed to analyze the effects of soft material hysteresis and permanent magnets magnetization, demagnetization and recoil. Loss mechanisms in magnetic gears are also investigated, and the transmission losses at varying rotational speeds and load angles are analyzed. A simplified mechanical model of the magnetic gear is presented and formulated as a set of inequality constraints, thus giving a direct link to optimization strategies. The mechanical constraints include the iron poles displacements and stresses and the limitations on the rotational speed due to excessive stresses, resonances and vibrations. A simplified analysis based on an equivalent thermal network is also presented, where the axial cooling flux is also considered. Stochastic optimization techniques are discussed for a multi-physic optimized machine design, and the analytic model is embedded in a Differential Evolution scheme. Finally, the optimized results are discussed and compared to commercial mechanical gearboxes. A solution based on the stiffness rods connection is also proposed and analyzed to provide a damping effect when the gear operation becomes asynchronous. During the PhD, there has been a constant effort aimed at building a prototype for the validation of the numerical models but, for different reasons, none of the manufacturers finalized the project. Thus, all the algorithms have been validated by comparing their output with commercial codes or, when possible, with data from experiments retrieved from literature. Because of this reasons and since the major objective of this thesis regards the numerical techniques for magnetic gears simulation, different magnetic transmissions have been adopted as numerical test cases for the validation of the algorithms

Fourth International Symposium on Magnetic Suspension Technology

In order to examine the state of technology of all areas of magnetic suspension and to review recent developments in sensors, controls, superconducting magnet technology, and design/implementation practices, the Fourth International Symposium on Magnetic Suspension Technology was held at The Nagaragawa Convention Center in Gifu, Japan, on October 30 - November 1, 1997. The symposium included 13 sessions in which a total of 35 papers were presented. The technical sessions covered the areas of maglev, controls, high critical temperature (T(sub c)) superconductivity, bearings, magnetic suspension and balance systems (MSBS), levitation, modeling, and applications. A list of attendees is included in the document

MUSME 2011 4 th International Symposium on Multibody Systems and Mechatronics

El libro de actas recoge las aportaciones de los autores a través de los correspondientes artículos a la Dinámica de Sistemas Multicuerpo y la Mecatrónica (Musme). Estas disciplinas se han convertido en una importante herramienta para diseñar máquinas, analizar prototipos virtuales y realizar análisis CAD sobre complejos sistemas mecánicos articulados multicuerpo. La dinámica de sistemas multicuerpo comprende un gran número de aspectos que incluyen la mecánica, dinámica estructural, matemáticas aplicadas, métodos de control, ciencia de los ordenadores y mecatrónica. Los artículos recogidos en el libro de actas están relacionados con alguno de los siguientes tópicos del congreso: Análisis y síntesis de mecanismos ; Diseño de algoritmos para sistemas mecatrónicos ; Procedimientos de simulación y resultados ; Prototipos y rendimiento ; Robots y micromáquinas ; Validaciones experimentales ; Teoría de simulación mecatrónica ; Sistemas mecatrónicos ; Control de sistemas mecatrónicosUniversitat Politècnica de València (2011). MUSME 2011 4 th International Symposium on Multibody Systems and Mechatronics. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/13224Archivo delegad

Nuclear Fusion Programme: Annual Report of the Association Karlsruhe Institute of Technology/EURATOM ; January 2011 - December 2011 (KIT Scientific Reports ; 7621)

The Karlsruhe Institute of Technology (KIT) is working in the framework of the European Fusion Programme on key technologies in the areas of superconducting magnets, microwave heating systems (Electron-Cyclotron-Resonance-Heating, ECRH), the deuterium-tritium fuel cycle, He-cooled breeding blankets, a He-cooled divertor and structural materials, as well as refractory metals for high heat flux applications including a major participation in the preparation of the international IFMIF project