Modelling and Analysis of Multi-Three-Phase Drives for Radial Force Control

In the field of electrical machines for radial force control, several solutions have been proposed, all of which are able to simultaneously generate a magnetic flux distribution at the airgap required to produce torque and radial force. It is possible to divide the solutions into two main categories based on the arrangement of the windings. The first makes use of two separate sets of windings: one to generate the torque and the other to produce the radial force. The second is based on a combined winding, typically multiphase, that contributes simultaneously to the production of torque and radial force. The study presented in this thesis focuses on multiphase solutions. Multiphase electrical machines have a better fault-tolerance capability and the utilization of the entire winding for both torque and force production is considered potentially more efficient, due to the higher exploitation of the copper in the slots. The radial force control is proposed in order to reduce bearing stress since bearings are one of the most critical parts of an electric machine in terms of the probability of failure. Therefore, improving the fault-tolerance capability through radial force control is a promising research topic in the field of multiphase electrical machines. The purpose of the thesis activity is to obtain a mechanical model of the electric motor and incorporate it with the electromagnetic model of a multiphase electric machine, simulate the behavior of the motor through a numerical model (in Matlab/Simulink environment) and evaluate a control algorithm that allows improving the motor's performance by active compensation of rotor vibration. The multiphysics model of the multiphase drive and the control are based on a prototype and available in the laboratory of the PEMC (Power Electronics, Machines and Control) group at the University of Nottingham, UK. Preliminary experimental tests have been carried out to validate the models

Comparison of interior permanent magnet synchronous machines for a high-speed application

Permanent Magnet machines have been increasingly used in high-speed applications due to the advantages they offer such as higher efficiency, output torque and, output power. This dissertation discusses the electrical and magnetic design of permanent magnet machines and the design and analysis of two 10 kW, 30000 rpm Interior Permanent Magnet (IPM) machines. This dissertation consists of two parts: the first part discusses high-speed machine topologies, and in particular the permanent magnet machine. Trends, advantages, disadvantages, recent developments, etc. are discussed and conclusions are made. The second part presents the design, analysis and testing of interior permanent magnet machines for a high-speed application. The machines are designed from first principles and are simulated using Ansys Maxwell software to understand the finite element analysis. In order to obtain a fair comparison between the machines, the required output criteria was used as the judging criteria (10kW, 30000 rpm). As a result, the rotor diameter, stator diameter, airgap length, and stack length were kept the same for both machines. The winding configuration was set as distributed windings, however the number of turns and other details were kept flexible in order to be able to obtain the best design for each machine. Similarly, the magnet volume was kept flexible as this could be used as a comparison criteria relating to the cost of the machines. The two IPM topologies are compared with respect to their torque, magnetic field, airgap flux, core loss, efficiency, and cost. The radial IPM produces a smoother torque output, with lower torque ripple, and has lower losses compared to the circumferential IPM which produces a higher torque and power output. Furthermore, the circumferential IPM also experiences much higher torque ripple and core losses, both of which are highly undesirable characteristics for high-speed machines. In addition, the circumferential IPM has a much more complex manufacturing process compared to the radial IPM which would significantly increase the cost of prototyping the machine, thus the radial IPM was selected for prototyping and brief experimental analysis. The radial IPM has been experimentally tested under no-load conditions. These results were successfully compared to the simulated and analytical results to show correlation between the design and experimental process. Potential areas of further work may include conducting detailed loss analysis to understand the effects that changing various design parameters has on the core loss and overall performance. Detailed thermal and mechanical analysis of the machines may also result in interesting conclusions that would alter the design of the machine to make it more efficient

Magnetically levitated hysteresis motor driven linear stage for in-vacuum transportation tasks

This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 241-246).This thesis presents a new in-vacuum reticle transportation mechanism for extreme ultraviolet (EUV) photolithography machines. In the photolithography process, the reticle is a quartz plate that contains a pattern of the integrated circuit, which needs to be transported between a storage position and the exposure stage. In next-generation EUV lithography machines, the reticle handling system must satisfy the following requirements: (1) transport the reticle through a distance of 2 meters, (2) the height of the mechanism needs to be within 100 mm, (3) operate in vacuum, and (4) satisfy ultra-tight contamination requirements. To fulfill these requirements, a conventional robotic reticle handler is inadequate. In this work, we designed, built, and tested a magnetically-levitated linear stage prototype, targeting at the reticle transportation application. Compared with robot manipulators, linear stages typically require less volume for long-distance transportation tasks.Magnetic suspension is used to eliminate mechanical contact and thereby avoid particle generation that can contaminate the reticle. The stage's linear motion is driven by linear hysteresis motors, which allows using solid-steel motor secondaries on the moving stage. This is desirable for in-vacuum operation, since permanent magnets can out-gas in high vacuum when not encapsulated. The magnetic suspension of the stage is achieved using a novel linear bearingless slice motor design, where the stage's magnetic suspension in three degrees of freedom, including vertical, pitch, and roll, are achieved passively. This compact design effectively reduces the number of sensors and actuators being used. The prototype system has successfully levitated the moving stage. The resonance frequency of the passively levitated degrees of freedom is approximately 10 Hz, and the suspension bandwidth of the actively-controlled degrees of freedom is about 60 Hz.The stage's maximum thrust force is 5.8 N under a 2.5 A current amplitude, which corresponds to a stage acceleration of 1200 M/s². This is able to satisfy the acceleration requirement for reticle transportation task. The stage was tested to track a reticle handling reference trajectory, where the maximum position tracking error of our linear stage is 50 [mu]m. The stage's lateral displacements during motion is below 50 [mu]m, which is well below making mechanical contact to the side walls. To our knowledge, this work represents the first study of linear hysteresis motors, and the first linear bearingless slice motor design. Hysteresis motors are a type of electric machine that operates using the magnetic hysteresis effect of the secondary material. Since the magnetization in the rotor lags behind the external field, a thrust force/torque can be generated.In prior usage, hysteresis motors have been operated in open-loop, which makes them unsuitable for applications where dynamic performance is critical. As a part of this thesis work, we also studied the modeling and closed-loop torque and position control for hysteresis motors. The proposed control method was tested with three rotary hysteresis motors, including two custom-made motors of different rotor materials and one off-the-shelf hysteresis motor. Experimental results show that position control for all three motors can reach a bandwidth of 130 Hz. To our best knowledge, this is the first work that enabled high-bandwidth torque and position control for hysteresis motors, which allows this motor to be used for servo applications.Sponsored by ASMLby Lei Zhou.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineerin

Design, construction, analysis and control of a 3D printed permanent magnet motor prototype

Este proyecto de tesis comienza resaltando la importancia de la reducción de la huella de carbono y la disminución del uso de combustibles fósiles, para ello se hace una revisión exhaustiva de los diferentes tipos de motores eléctricos que se utilizan actualmente en la industria, con especial énfasis en los motores utilizados en el campo de la movilidad eléctrica, se explican los diferentes tipos de materiales magnéticos utilizados en la construcción de los motores, los imanes permanentes, y el conjunto Halbach. Además, este barrido incluye una explicación de las nuevas técnicas de fabricación emergentes, las diferentes tecnologías de impresión 3D, y la relevancia que la construcción de un motor eléctrico puede tener para la industria y el mundo académico local, regional y nacional. Tras el barrido inicial, se explican los diferentes tipos de motores síncronos de imanes permanentes (PMSM), partiendo de su modelo matemático hasta explicar el flujo magnético esperado a partir de la implementación del conjunto Halbach. Una vez que se dispone de estos elementos iniciales, se propone el modelo 3D inicial del motor y se realizan las primeras pruebas de impresión. Una vez construido el rototipo, se realizan las primeras pruebas para identificar la función de transferencia, se implementa el control PI en el motor para el control de velocidad, y se realiza un análisis termográfico para evaluar el comportamiento de la temperatura del motor funcionando sin carga. Finalmente, se muestran las conclusiones y el trabajo futuro del proyecto.This thesis project begins by highlighting the importance of reducing the carbon footprint and reducing the use of fossil fuels, for this a thorough review of the different types of electric motors currently used in the industry, with particular emphasis on the motors used in the field of electric mobility, the different types of magnetic materials used in the construction of motors, permanent magnets, and the Halbach array are explained. Additionally, this sweep includes an explanation of the new emerging manufacturing techniques, the different 3D printing technologies, and the relevance that the construction of an electric motor can have for the local, regional and national industry and academia. After the initial sweep, the different types of permanent magnet synchronous motors (PMSM) are explained, starting from their mathematical model to explaining the expected magnetic flux from implementing the Halbach array. Once these initial elements are available, the initial 3D model of the motor is proposed, and the first printing tests are performed. Once the prototype is built, initial tests are performed to identify the transfer function, PI control is implemented on the motor for speed control, and a thermographic analysis is performed to evaluate the temperature behavior of the motor running without load. Finally, the conclusions and future work of the project are shown.MaestríaMagíster en Ingeniería EléctricaContents 1 Introduction 2 1.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Justification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.1 General objective . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.2 Specific objectives . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.4 State of the art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.5 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2 Permanent Magnet Synchronous Motor (PMSM) 13 2.1 Mathematical description of PMSM model . . . . . . . . . . . . . . . 13 2.1.1 Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.1.2 Simplified Electrical Equations . . . . . . . . . . . . . . . . . 17 2.2 Surface mounted PMSM . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2.1 Projecting type . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2.2 Inset type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.3 Interior PMSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.4 Inner rotor PMSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.5 Outer rotor PMSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.6 Radial Halbach array . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3 Design and Construction of the 3D Printed PMSM 25 3.1 Preliminary design of the PMSM prototype . . . . . . . . . . . . . . . 25 3.2 Optimization of 3D printing parameters . . . . . . . . . . . . . . . . 28 3.3 Stator winding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4 Selection of permanent magnets . . . . . . . . . . . . . . . . . . . . . 32 3.5 Rotor weight balancing . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.6 Halbach array check . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.7 PMSM initial prototype design variation . . . . . . . . . . . . . . . . 43 4 Analysis and Control of a 3D Printed PMSM 47 4.1 Closed-loop control system implementation . . . . . . . . . . . . . . . 47 4.2 Speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.3 Temperature Analysis at steady state . . . . . . . . . . . . . . . . . . 62 5 Conclusions and Final Remarks 6

Design and Multi-physical Fields Analysis of High Speed Permanent Magnet Machines

Due to the advantages of high power density, high efficiency and compact size, high speed permanent magnet machines (HSPMMs) have found wide application in industrial areas. Compared with a conventional speed permanent magnet machine, a HSPMM rotor can reach speeds of more than 10,000 rpm, which brings challenges with regard to electromagnetic, thermal and mechanical aspects of machine design. The higher power density also results in larger power loss per unit volume; due to the small machine size, machine thermal dissipation becomes difficult. Moreover, air frictional loss rises dramatically when the rotor is in high speed operation and this may also further increase rotor temperature. Therefore, research into HSPMM power losses and improving machine thermal dissipation capability is of significant interest. HSPMM mechanical issues also need to be considered to ensure safe and reliable machine operation. As rotor speeds rise, rotor strength becomes prominent and critical as the permanent magnets are vulnerable to the large centrifugal force. In addition, the machine rotor should also have enough rigidity and avoid operating at critical speeds. As such, this dissertation focuses on HSPMM design and research. Multi-physical fields analysis of a HSPMM is carried out to calculate machine power losses and temperature distribution, with factors influencing machine performance considered; HSPMM rotor mechanical research and analysis are also carried out and presented in this study. Firstly, the HSPMM design methodology and process are illustrated with machine rotor parameters, PM material, pole numbers and rotor sleeve considered for a 150 kW, 17000 rpm HSPMM. Then, HSPMM performance for different machine stator structures and PM pole arc pole pitches is investigated using the Finite Element Method (FEM) for the machine operating at both no load and full load conditions; HSPMM electromagnetic performance and how it is impacted by machine parameters is also studied. HSPMM power losses are comprehensively investigated in the following chapter. As machine core loss can be significantly increased with increasing machine frequency, it is critical to accurately estimate HSPMM iron loss. Based on the machine iron core magnetic field variation that is obtained by FEM analysis, machine steel iron core loss estimation for HSPMM is performed using an improved method with the influences of alternating and rotating magnetic fields, as well as harmonics effects, considered for high precision. Then the HSPMM air gap magnetic flux density distribution considering machine stator slotting effect is also analytically calculated with its effectiveness verified by FEM results. Then rotor eddy current loss is studied by time-stepping FEM, while the effects of rotor sleeve dimensions and properties, copper shielding composite rotor structure, air gap length, as well as slot opening width are further researched in depth. A PM bevelling method is also proposed and investigated to reduce HSPMM rotor eddy current loss while having little effect on machine output torque. Then a fluid field analysis is carried out to study HSPMM rotor air frictional loss when the rotor is in high speed operation. According to the characteristics of a machine axial forced air cooling system, the HSPMM temperature distribution is investigated by 3-D fluid–thermal coupling CFD modelling with the calculated power losses results. The machine thermal analysis theory and modelling method are also detailed and further explained. HSPMM thermal performance variation due to impacting factors of cooling air velocity, rotor eddy current loss and sleeve thermal conductivity are also comprehensively investigated and studied in this dissertation. The designed HSPMM is prototyped, and temperature experimental tests are also carried out to verify the effectiveness of the research and analysis for HSPMM. Then, thick-walled cylinder theory is introduced to study rotor mechanical strength analytically, while it also verifies the FEM calculation results. Then based on FEM analysis, HSPMM rotor stress distribution is investigated with sleeve material effects on rotor strength discussed. In order to alleviate the rotor sleeve stress, three pole filler materials are comparatively studied, while the temperature impacts on rotor mechanical stress is further considered; sleeve thickness and the interference between PM and sleeve are investigated in an integrated fashion for HSPMM rotor strength analysis, with some conclusions also drawn for HSPMM rotor mechanical design. HSPMM rotor critical speeds are also calculated by the established 3D rotor dynamic analysis FEM model to ensure the rotor is operating in a desirable condition

A Novel Design of Ceiling Fan System

There are many electrical appliances used in every house. One of them is the ceiling fan where it consumes between 70 to 90 Watts of electrical energy. This makes it the second highest appliance to consume electricity. The conventional ceiling fan is designed based on induction machine. However, the induction machine is not very efficient. Another weakness of the conventional ceiling fan is that it does not fully utilize the rotating part in it. This paper aims to use the rotating part in the ceiling fan to regenerate electricity to be used in other household appliances. This concept uses the basic design of the internal and external rotor which is to be used to build the system. Thus, this design could help to reduce energy consumption and making the ceiling fan more efficient compared to the conventional ceiling fan. The literature review in this paper is done to study the various types of machines which could be selected to be used in designing the new type of ceiling fan. Such machines are the induction machine, synchronous machine, the DC machine and the permanent magnet. The proposed design for the motor and generator are determined after the comparison had been done between all the designs. The proposed design is simulated and analyzed using the finite element software, ANSYS software, ANSOFT MAXWELL. The results obtained from the simulation are in term of the flux distribution and the air gap distribution. After analyzing the result, it is found that the design chosen proved to be working successfully

Magnetic Bearings

The term magnetic bearings refers to devices that provide stable suspension of a rotor. Because of the contact-less motion of the rotor, magnetic bearings offer many advantages for various applications. Commercial applications include compressors, centrifuges, high-speed turbines, energy-storage flywheels, high-precision machine tools, etc. Magnetic bearings are a typical mechatronic product. Thus, a great deal of knowledge is necessary for its design, construction and operation. This book is a collection of writings on magnetic bearings, presented in fragments and divided into six chapters. Hopefully, this book will provide not only an introduction but also a number of key aspects of magnetic bearings theory and applications. Last but not least, the presented content is free, which is of great importance, especially for young researcher and engineers in the field

Novel active magnetic bearings for direct drive C-Gen linear generator

This document presents a novel active magnetic levitation system. In the pursued of this endeavour different topics related with wave energy were explore. Climate change and energy security are the main motivation to pursued new options for non-fossil fuels energy generation. An overview of renewable energy and specifically of wave energy was presented. The potential for wave energy in The United Kingdom turn out to be 75 TWh/year from wave energy, 3 times more of what wind energy has produced in 2013. This means a massive impact on the energy market and emission reduction. In order to achieve this, improvements on wave energy devices have to be done. An overview of wave energy converters was covered selecting the C-Gen as the generator topology this document will base its studies. Linear generator bearings are desired to have long lifespan with long maintenance intervals. The objective is to come with an active magnetic levitation design that can replace traditional bearings augmenting the reliability of the system. Therefore magnetic bearings option have been reviewed and simulation experimentations has resulted in a novel active magnetic levitation system using an air-cored coils Halbach array acting over a levitation track. The configuration would generate bi directional repulsion forces with respect of the levitating body. Different software were used to analyse the magnetic field and forces generation. Additionally a prototype was built and tested to corroborate the results. As part of the modelling a mathematical model was explored and robust control implementation was also realised. Finally a scalability study of the device as well as a reliability analysis was done. Although the reliability studies shows an increase of ten times of the mean time to failure, the concept is not able to endure the loads acting on the generator unless the magnetic bearings became bigger than the generator and therefore economically unfeasible

Habilitation à Diriger les Recherches : Contribution à la modélisation analytique des systèmes électromagnétiques basse fréquence au sein de leur environnement en vue de leur conception

Ce document est présenté en deux parties qui peuvent être consultées indépendamment. La première est une notice bibliographique qui décrit succinctement mes activités de recherche, mes activités administratives et mes activités d’enseignement. La deuxième partie est une tentative de synthèse des différents travaux de recherche dans lesquels je me suis investi à partir de mon doctorat. Cette deuxième partie se termine par des perspectives de recherche dans le contexte particulier de l’IRENav . Le travail présenté ici, regroupe des travaux personnels mais aussi des travaux issus de co-encadrement ou de supervision

Habilitation à Diriger les Recherches : Contribution à la modélisation analytique des systèmes électromagnétiques basse fréquence au sein de leur environnement en vue de leur conception

Ce document est présenté en deux parties qui peuvent être consultées indépendamment. La première est une notice bibliographique qui décrit succinctement mes activités de recherche, mes activités administratives et mes activités d’enseignement. La deuxième partie est une tentative de synthèse des différents travaux de recherche dans lesquels je me suis investi à partir de mon doctorat. Cette deuxième partie se termine par des perspectives de recherche dans le contexte particulier de l’IRENav . Le travail présenté ici, regroupe des travaux personnels mais aussi des travaux issus de co-encadrement ou de supervision