Evaluation of brake parameters in copper discs of various thicknesses and speeds using Neodymium – Iron – Boron Magnets

Neodymium – Iron – Boron (NdFeB) permanent magnets of 12.5 mm thickness and 50 mm diameter are chosen for analyses because of their higher remanence and coercivity. Experimental analyses were carried out with Copper discs of thickness 4 mm, 6 mm and 8 mm at 2000 rpm, 3000 rpm, 4000 rpm and 5000 rpm. Experiments were conducted with three different positions of magnets such as 2 coaxial magnets, single magnet and single magnet with sudden application conditions. The brake parameters recorded are % speed reduction, deceleration and time taken. In 2 coaxial magnets condition, brake parameters are better in 6 mm thick disc. In single magnet condition, the brake parameters in 6 mm thick disc are found to be more consistent than 4 mm and 8 mm thick discs. In single magnet with sudden application condition, in 4 mm thick disc, the brake parameters are found better. During analysis, very high repulsion was experienced by magnet with 8 mm thick Copper disc at all the above mentioned speeds in single magnet with sudden application condition. For high speed train applications, single magnet condition with 6mm thick disc may be suitable. For high speed automotive applications, single magnet with sudden application condition with 4 mm thick disc may be suitable

Modeling, Identification, Validation and Control of a Hybrid Maglev Ball System

In this thesis, the electrodynamics of a single axis hybrid electromagnetic suspension Maglev system was modeled and validated by applying it to a single axis hybrid maglev ball experiment. By exploring its linearized model, it was shown that the single axis hybrid Maglev ball has inherently unstable dynamics. Three control scenarios were explored based on the linearized model; (1) Proportional, Deferential (PD) control, (2) Proportional, Deferential, Integral (PID) and (3) PID controller with pre-filtering. This thesis has shown that a PID controller with a pre-filtering technique can stabilize such a system and provide a well-controlled response. A parametric system identification technique was applied to fit the theoretically derived model to a single axis hybrid maglev ball experiment. It is known that the identified model has different model parameters than the theoretically derived parameters. This thesis has examined and discussed the deviation from the theoretical model. Importantly, it was shown that such a system can be identified by estimating the values of two parameters instead of five to increase the accuracy. A Numerical nonlinear simulation was developed for the experiment based on the theoretically derived and experimentally identified model. This simulation was validated by real-time experiment outputs

Competitiveness of Hybrid Electric Aircraft on Short Range Scheduled Flights

Hybrid electric aircraft are expected to enter the small regional aircraft market within the next two decades. The aim of this study was to investigate if a hybrid electric passenger aircraft with 50 seats can be competitive against the established 100 seat aircraft on short range scheduled flights. The Embraer EMB 145 and EMB 190 regional jets were chosen as benchmarks for that market. A hypothetical hybrid version of the EMB 145 with increased fuel efficiency was tested on a cost per available seat mile (CASM) basis. The t tests confirmed significant (p \u3c 0.05) competitiveness of the hybrid version, while in contrast the conventional 50-seater was significantly more expensive compared to the 100seat aircraft. This indicates that hybrid aircraft could enter the short haul market with a competitive advantage, even against the established 100 seat regional jets

Assessment of Technologies for Noncryogenic Hybrid Electric Propulsion

The Subsonic Fixed Wing Project of NASA's Fundamental Aeronautics Program is researching aircraft propulsion technologies that will lower noise, emissions, and fuel burn. One promising technology is noncryogenic electric propulsion, which could be either hybrid electric propulsion or turboelectric propulsion. Reducing dependence on the turbine engine would certainly reduce emissions. However, the weight of the electricmotor- related components that would have to be added would adversely impact the benefits of the smaller turbine engine. Therefore, research needs to be done to improve component efficiencies and reduce component weights. This study projects technology improvements expected in the next 15 and 30 years, including motor-related technologies, power electronics, and energy-storage-related technologies. Motor efficiency and power density could be increased through the use of better conductors, insulators, magnets, bearings, structural materials, and thermal management. Energy storage could be accomplished through batteries, flywheels, or supercapacitors, all of which expect significant energy density growth over the next few decades. A first-order approximation of the cumulative effect of each technology improvement shows that motor power density could be improved from 3 hp/lb, the state of the art, to 8 hp/lb in 15 years and 16 hp/lb in 30 years

Improving the torque density of C-GEN Direct Drive Axial Flux Air Cored Permanent Magnet Generator

In the energy sector, the fossil fuels available are being exhausted and to support the increase in energy demand and reduction of greenhouse gases, countries are looking towards renewable energy. Wind power offers many advantages, which explains why it's one of the fastest-growing energy source and it is expected to continue to flourish as countries seek to reduce their carbon footprint. The newer wind turbines are better at generating wind power, especially in variable wind speeds. They have bigger rotors, higher towers, and lighter blades which increases the capacity of the turbine, therefore, improving reliability and e ciency. Nevertheless, as wind turbines grow increasingly in size and weight, this can make it di cult to manufacture and to transport the generator as a whole. The C-GEN air-cored permanent magnet machine o ers many attractive advantages over existing generator technologies used for direct drive. It's modular concept makes it easy to assemble and disassemble for transportation, manufacture and repairs. The output power depends on the number of stages among other factors, which gives rise to the idea of stackability. This thesis lays out the concept and operating principles of Halbach arrays and applies it to a C-GEN Axial Flux Air-Cored Permanent Magnet Generator. The machine is analysed using analytical methods and 2D/3D FEA simulations. A conclusion of the undertaking is given with a brief discussion of possible design considerations in a bid to nd a highly torque-dense generator

Microprocessor-controlled brushless DC linear stepping motor

Presently, there is a rapidly growing research interest for an efficient, high thrust density and high thrust to input power electrical linear machine. However, only limited work has been carried out in terms of the development of brushless DC linear motors (BDCLM). Focusing on this research gap which presently exist in this field, this thesis makes the development of the BDCLM the research objective, in order to produce a large thrust to input power, compared to the already existing designs. The motor is designed in such way that the motor core accommodates twenty-four independent multi-layer coil sections wound with enamelled copper wire and each layer section has 470 turns without compromising the effective air-gap. Also, a design commutation algorithm to provide a smooth movement and a high thrust for the BDCLM is implemented. The design, analysis and optimization of the BDCLM in applications that requires a high thrust to input current ratio is described in this project. The investigation includes; the analysis, design, and control of the BDCLM through appropriate modelling, construction and experimental validation of the modelled results, employing both the static and dynamic approaches. The BDCLM design was analysed from electrical, mechanical and magnetic perspectives. A Finite Element Method (FEM) was used to predict the performance of the BDCLM and to optimise the motor parameters. Additional challenges such as force ripple and normal force are investigated and analysed. A Proportional Integral Derivative (PID) control system, based on an Arduino Mega board is used to control the motor speed and position. A graphical user interface (GUI) is built in LabVIEW environment to control the Arduino board. V The experimental results were within 8.9 %, 2 % and 3 % of the modelled results with respect to the motor thrust, speed and position. These results demonstrate a good agreement between the two approaches. This research work can be considered as an initial step to developing the BDCLM for commercial applications

Reducción de la fuerza de detención en motores síncronos lineales de imanes permanentes en disposición Halbach

El avance en materia tecnológica de los sistemas y medios de transporte tiene una vital importancia en el desarrollo de una sociedad. Existe un interés constante en promover avances tecnológicos de aplicación al transporte público que proporcionen a los usuarios un medio de transporte seguro, eficiente, limpio, no ruidoso, económico y fiable. En la actualidad el desarrollo y adaptación de medios de transporte que empleen motores eléctricos es una de las principales líneas de investigación al respecto. Las características que definen este motor eléctrico ofrecen una serie de mejoras y ventajas frente a los propulsores montados en los autobuses públicos actuales. El mayor aprovechamiento de la energía, la capacidad de alcanzar velocidades superiores, un aumento en el confort de marcha, la reducción de la fricción y un compromiso con el medio ambiente son sus principales argumentos. El sistema de propulsión con motor eléctrico lineal solo precisa del vínculo electromagnético entre los dispositivos móviles y fijos, eliminándose así la necesidad de un sistema de transmisión para convertir el movimiento rotativo en lineal, con las ventajas que esto conlleva. Las ventajas principales que presentan los motores lineales respecto a los rotativos se basan en que la transmisión de la fuerza se realiza ahora directamente por el campo magnético. Todo ello proporciona una serie de ventajas en aplicaciones de transporte sobre los accionamientos tradicionales basados en transmisiones mecánicas: • Mayores valores de velocidad, pudiendo llegar hasta 300 m/min. • Mayores valores de aceleración, lo que en muchas aplicaciones es más importantes que el valor de la velocidad máxima. • Mayor ancho de banda del sistema de accionamiento, mejorando la rapidez y la calidad de respuesta del eje. • El sistema es más preciso cuando se desplaza a altas velocidades, por lo que la calidad de la interpolación así como la velocidad y precisión en aplicaciones de contorneado se incrementan notablemente • Reducción de los niveles de vibración y del ruido sin comprometer el grado de prestaciones • Mayor fiabilidad porque hay menos desgaste (la aceleración y el frenado no dependen de la fricción). • No dependen de la fricción para salvar pendientes, es decir, pueden aplicarse para cualquier pendiente, incluida la posición vertical. • En aplicaciones de transporte, eliminan la necesidad de tener una alimentación para la propulsión y control del vehículo, por lo que el vehículo puede ser pasivo. El incremento de la disponibilidad de materiales magnéticos que han permitido construir imanes permanentes con la suficiente fuerza coercitiva para no ser desmagnetizados por efecto de la reacción de inducido durante el arranque y aceleración y la utilización generalizada de convertidores estáticos, han proporcionado la oportunidad de desarrollar Motores Síncronos Lineales de Imanes Permanentes (MSLIP) aplicados al transporte; son motores de elevadas prestaciones en velocidad y rendimiento y con un reducido tamaño en comparación con un motores de inducción de igual potencia. Los MSLIPs con núcleo ranurado presentan en el entrehierro unas variaciones de energía debidas a la tendencia que tienen los imanes de alinearse en la posición de mínima reluctancia con respecto a los dientes de la armadura, la denominada fuerza de diente (cogging force en ingles). Además, la inducción magnética de la excitación en el entrehierro es no sinusoidal, por la geometría del deslizador de imanes. La combinación de los efectos mencionados produce una fuerza de retención o de retención (en inglés se le conoce como “detent force”), que se manifiesta en pequeños saltos u ondulaciones y afectan el empuje del MSLIP originando variaciones momentáneas de la velocidad en el motor que especialmente, dificultan el control del mismo, pudiendo producir inestabilidad mecánica y generar ruido. En la literatura existente se encuentran técnicas para reducir la fuerza de retención aplicadas a las diferentes topologías de MSLIPs; pero en general, son pocas o casi inexistentes las aplicaciones de las técnicas de mejoras mediante el proceso de inclinación de los imanes en configuración Halbach. En general, en la tesis se presenta el diseño de un motor eléctrico capaz de propulsar un vehículo a la velocidad adecuada sin necesidad de necesidad de sistemas de acumulación de energía. Se propone inicialmente un MSLIP en disposición Halbach (MSLIP-H) cuyos parámetros de diseño se deducen a partir de un motor síncrono rotativo comercial. Se realizan varias mejoras sobre este prototipo inicial, como son: • El uso de una adecuada relación entre la longitud del imán y el paso de ranura, relación que consigue reducir la fuerza de retención en los MSLIP-H. • Se comprueba el efecto de la inclinación de los imanes MSLIP-H sobre las fuerzas que intervienen en el movimiento del motor, obteniendo los valores de la fuerza de empuje, y de la fuerza normal del motor. También se realiza un análisis de vibraciones de dos modelos de MSLIPs de polos opuestos con diferente ranurado estatórico. Sobre el diseño propuesto se modifica la geometría de los imanes del deslizador, haciendo nuevas propuestas que hemos denominado MSLIP-H TIPO 7, L & Z); con ellas, se reduce considerablemente el “stress” de los propios imanes y se concentra la mayor parte de flujo magnético en el entrehierro produciendo una reducción del rizado de la fuerza propulsora del motor, disminuyendo la vibración y el nivel de ruido. El análisis electromagnético se ha realizado mediante el cálculo numérico; se ha simulado por el método de los elementos finitos (FEM) con software Flux™ V10.3, licencia comercial; para validar los resultados de la simulación se han comparado con otros resultados publicados por diferentes autores que trabajan en el diseño de motores síncronos lineales de imanes y que han sido contrastadas con resultados experimentales.The advancement in technology systems and means of transport has a vital importance in the development of a society. There is a constant interest in promoting technological advances applicable to public transport to provide users a means of safe, efficient, clean, not noisy, economical and reliable transportation. Currently the development and adaptation of transport that use electric motors is one research about of the main lines. The defining characteristics of the electric motor offers a number of improvements and advantages over propellers mounted on existing public buses. The largest use of energy, the ability to reach higher speeds, increased ride comfort, reduced friction and a commitment to the environment are the main arguments. The propulsion system with linear electric motor only requires the electromagnetic link between the mobile and fixed devices, thus eliminating the need for a transmission system to convert the rotary motion into linear, with the advantages this entails as reducing efforts adherence by the driving wheels or reducing maintenance requirements. The main applications of MSLIP, derived from its particular characteristics have been widely described in the literature, fixing his attention on all drives that require a combination of bound motors and to be maintained at the same rate strictly . Its application has been especially advantageous in the textile industry and in glass. The increased availability of magnetic materials to build permanent magnets have allowed enough coercive force to not be demagnetized due to the armature reaction during starting and acceleration and the widespread use of static converters, have provided the opportunity to develop MSLIP applied to transport; are engine speed, high performance and efficiency and reduced size when compared to an induction motor of the same power. The main advantages offered by the linear motor with respect to the rotating based on the transmission of force are now carried out directly by the magnetic field. This provides a number of advantages in transport applications over traditional drives based on mechanical drives: • High speeds, can reach up to 300 m / min. • Increased acceleration, which in many applications is more important than the value of the maximum speed. • Higher bandwidth of the drive system, improving the speed and quality of response axis. • The system is more accurate when moving at high speeds, so that the quality of the interpolation as well as speed and accuracy in contoured applications are notably increased • Reduced levels of vibration and noise without compromising the level of benefits • Higher reliability because there is less wear (acceleration and braking do not depend on friction). • Do not rely on friction to save remaining, i.e., they can be applied for any slope, including vertical. • In transportation applications, eliminating the need for a power for propulsion and control of the vehicle, so the vehicle can be passive. In slotted PMLSMs exists an interaction between the secondary permanent magnets and the teeth of the primary core. Generally, undesired effect contributes to increase the vibration and noise. The potential causes of the thrust ripple in PMLSMs are resulted from the slotting, the finite length of the armature and current harmonics. To reduce thrust ripple in PMLSM several methods have been reported by many researchers. These methods are achieved either by an adequate control of the driver or by special motor design. Most widely used methods at the design stage include: • Changing the ratio of magnet width to pole pitch. • Skewing and optimally disposing the magnets. Or rearranging the permanent magnet. Sometimes these methods can be a burden during the manufacturing stage increasing manufacturing cost. However, investigation for the thrust ripple reduction of linear Halbach topology with skewed magnets has not been enough reported. An optimized slider structure incorporating permanent magnets in Halbach array is proposed; we compare it with a standard Halbach array as well as with other optimized design motors using inclined magnets in the slider New topologies of the slider are presented (which we called MSLIP-H TYP 7 L & Z) adapted to the Halbach magnet configuration; This greatly reduces the "stress" of the magnets themselves and concentrates the majority of magnetic flux in the air gap leading to a reduction of force ripple caused by the driving force of the motor, reducing vibration and noise. The electromagnetic analyzes were performed using the numerical calculation; has been simulated by the finite element method (FEM) with Flux ™ V10.3 software License; the simulation results are compared with other results published by different authors working on the design of linear permanent magnet synchronous motors that have been tested with experimental results.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Jaime Rodríguez Arribas.- Secretario: Jesús Fraile Ardanuy.- Vocal: Ana María Llo

Design and Application of Electrical Machines

Electrical machines are one of the most important components of the industrial world. They are at the heart of the new industrial revolution, brought forth by the development of electromobility and renewable energy systems. Electric motors must meet the most stringent requirements of reliability, availability, and high efficiency in order, among other things, to match the useful lifetime of power electronics in complex system applications and compete in the market under ever-increasing pressure to deliver the highest performance criteria. Today, thanks to the application of highly efficient numerical algorithms running on high-performance computers, it is possible to design electric machines and very complex drive systems faster and at a lower cost. At the same time, progress in the field of material science and technology enables the development of increasingly complex motor designs and topologies. The purpose of this Special Issue is to contribute to this development of electric machines. The publication of this collection of scientific articles, dedicated to the topic of electric machine design and application, contributes to the dissemination of the above information among professionals dealing with electrical machines

Studies on the Time-Dependent Demagnetization of Sintered NdFeB Permanent Magnets

Increasing utilization of sintered NdFeB permanent magnets in large electrical machines has raised the question about the thermal stability and possible polarization losses occurring during the long-term operation of the machines. Knowledge of the evolution of the magnetic properties of NdFeB compounds over time at elevated temperatures has been limited. This causes difficulties in the optimization of the magnetic material selection. In this work the polarization losses occurring in commercial sintered NdFeB magnets during long-term thermal exposures are studied. The influence of different parameters such as temperature, permeance coefficient of the sample, coercivity and JH curve squareness of the material, are examined. Also the influence of a stabilization heat treatment is studied. The losses detected in open- and closed-circuit exposures are compared. The demagnetization process is analyzed with the help of finite element modeling. The detected polarization losses were found to follow the logarithmic decay law in the time scale from 1 hour to 10 000 hours. By assuming the behavior to continue also over the next decade of the logarithmic time scale, the losses can be extrapolated even to 30 years. For each material and each Pc it is possible to determine a temperature at which the total loss is expected to be less than 1 % even after 30 years of exposure. Above this critical temperature, the time-dependent losses start to increase. In open-circuit exposures also the initial loss after 1 hour exposure increases rapidly with increasing temperature or decreasing Pc. In open-circuit exposures, the total loss estimated to occur after 30 years was roughly twice the loss detected after 1 hour. However, in closed-circuit exposure this was not the case. The time-dependent demagnetization was found to be more severe in the close-circuit condition. This is likely to result from the acceleration of a chain reaction type demagnetization process. In open-circuit exposures the time-dependent demagnetization process is likely to be damped, since the demagnetizing self-field is reduced during the process. The results show that the best way to control the time-dependent demagnetization is to use materials with a square JH curve. For this type of a material, the critical temperatures are easy to determine. The stabilization heat treatment is found to stabilize the magnets, but for a limited period of time only. An FEM analysis shows that the partial demagnetization applied to the magnets during the stabilization heat treatment is not homogenously distributed. The treatment needs to be performed in closed-circuit conditions to get a homogeneous stabilization. The detected time-dependent demagnetizations are due to the material characteristics as well as to the magnetostatic field effects. It is difficult to distinguish the proportion of these two. The comparison between the open- and closed-circuit test results suggests that the open-circuit results can be used to estimate the long-term behavior of the material. However, more studies are needed to confirm this