Flux switching machine design for high-speed geared drives

Electrical machines capable of high-speed operation are key technology used in many modern applications, such as gas turbine electrical systems, high-speed fly-wheels, turbochargers, and computer numerical control (CNC) machines. The use of geared high-speed machines to replace low-speed high torque drives has not been adequately researched to-date. The rationale of this thesis is to investigate a candidate high speed machine, namely flux switching machines to be used together with new types of core material with mechanical gearing to deliver high-torque and low speeds. Modern developments in advanced material technology have produced new magnetic materials capable of dealing with high resulting in very low losses in high speed machines. However, such metals typically have low mechanical strength, and they are found to be brittle. In order to manufacture electromechanical device with such new materials, it has to be reinforced with a mechanically strong structure. The use of multiple types of magnetic materials referred as a MMLC has been proposed in this thesis for high-speed machine design. In this research, a generic method using magnetic equivalent circuit to model flux switching machines (FSMs) is investigated. Moreover modeling, based on machine dimensions for multiphase FSMs having any pole and slot number has been introduced. The air-gap permeance modeling to simplify the magnetic circuit calculation of FSMs was also investigated in this thesis. It is shown that the permeability of magnetic material can be adjusted with the use of MMLC material. Using this feature, the FSM mathematical model is used to show the impact on electromagnetic performance using MMLCs and is shown to be beneficial. In order the evaluate the weight benefits of using geared high speed FSMs, the planetary gear systems are studies and their design constraints have been identified. An abstract form of weight estimation for given torque and speed requirements has been developed and validated using commercially available planetary gear specifications. FSMs together with gear boxes have been considered and it is shown that significant weight savings can be achieved at higher diameter and at high speeds

Magnetically Geared Electrical Machines

Considerable research efforts are being carried out worldwide to develop technologies which meet the increasing demand for the efficient utilisation of energy resources. Modern applications, such as renewable energy and electrical vehicles, place a premium on electro-mechanical energy conversion in a power dense and high efficiency manner. Magnetic gears (MG) and magnetically geared machines, offer an attractive alternative to existing systems which may favour the combination of a high speed electrical machine with a mechanical gearbox. This has led to the opportunity to use Pseudo Direct Drives (PDDs) and MGs to be developed for use on an industrial scale. Therefore, in this thesis techniques for facilitating the manufacture and robustness of PDDs are presented, for both radial and axial field topologies. This includes use of alternative windings and soft magnetic composites. PDDs and MGs has so far mainly been developed in the radial topology and little attention has been given to axial topologies. The pole piece (PP) rotor required for MG operation, represents the main difference between PDD/MG and a conventional electrical machine. As such the PP shape and supporting structures have been investigated both in terms of electromagnetic and mechanical performance. Furthermore, detailed electromagnetic and thermal design and analysis of an axial field PDD (AFPDD) with improved robustness was undertaken, and a prototype was manufactured to demonstrate the operation of the AFPDD and validate the predictions

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

Modeling And Analysis Of Multi–Phase Permanent Magnet Synchronous Machines: Direct–Drive Electric Vehicle Application

In commercially existing electric vehicles (EVs), power is transferred from the motor to the wheels through a fixed gear mechanical transmission system. However, such a transmission system contributes to a power loss between 2% to 20% of output power of the motor depending on the operating speed and torque of the motor. Therefore, by removing the transmission, a direct–drive EV configuration is obtained with lower component count, improved motor to wheel efficiency and frequency dependent losses. However, challenges in developing a single on–board permanent magnet synchronous machine (PMSM) for such a configuration include high torque density, low torque ripple and high torque per permanent magnet (PM) volume. Therefore, this dissertation proposes a novel PMSM addressing the aforementioned challenges for a direct–drive application. Initially, the design targets, stator and rotor configuration and phase numbers of the PMSM are chosen to satisfy the requirements of a direct drive application. A novel torque and torque ripple model based on multiple reference frames is proposed, in which the torque ripple from spatial harmonics of flux, inductances and the time harmonics of stator currents are included. Using the analytical model, optimal slot–pole combination of the machine is selected based on adaptive gradient descent algorithm. A new consequent pole rotor topology is proposed to improve the torque density and torque per PM volume thereby reducing the usage of expensive rare earth magnets. The proposed PMSM with novel rotor is further improved in terms of torque density, losses and cost by performing an intensive structural optimization based on novel hybrid analytical model, finite element analysis and supervised learning. The optimized PMSM is then analyzed for various drive cycles and performance in terms of torque, speed and efficiency are discussed. A scaled–down prototype of the proposed PMSM is developed and comprehensive experimental analysis in terms of torque ripple, torque–speed characteristics and efficiency are performed under different speeds and load conditions and are compared with the results obtained from proposed analytical model

Advanced design methodology for permanent magnet synchronous machines in power applications

Most of the world electrical energy is consumed by electric motors, and then, the improvement in their performance leads to essential savings in the global energy consumption, required to reduce the CO2 emissions. Actually, the policies of governments and institutions are becoming more demanding and the manufacturers are forced to offer more and more optimized products. Moreover, many applications are increasingly demanding high performance in terms of power density, reliability or dynamic response, as in the case of electric vehicle, wind power generation or railway traction. The high energetic content of neodymium magnets causes that the permanent magnet machines (PMSM) are the more attractive option with respect to power density. In addition, thanks to the almost complete elimination of the rotor losses they are the most energetically efficient machines. The PMSM design requires of a multiphysical approach since it comprises electric, magnetic and thermal aspects. In this work, a comprehensive review of the technical literature regarding these machines has been done, and some areas for improvement have been found. Firstly, it is common that the procedure starts from a quite defined machine and just an optimization of a specific part is realized. Moreover, excessive dependence on designer’s experience and knowhow is observed, without giving clear instructions for taking design decisions. Finally, excessive dependence on time consuming FEM models is found. Hence, the main objective of this thesis is to develop and propose an advanced design methodology for PMSM design, characterized by being clear and complete, considering whole the design process and giving criteria and tools for taking decisions which lead to an optimum choice of the final solution. A PMSM design methodology has been proposed that enables the evaluation of large amounts of configurations in an automatic manner, easing to the designer the process of taking the final design decision. To implement this methodology, several tools have been developed and explained in detail: electromagnetic models coupled to thermal models and lumped parameter electromagnetic models. Some important modifications were done in the thermal models taken as a reference in order to consider different cooling conditions. In addition, a basis permeance network model was adapted to the selected machine topology and it was used to demonstrate its suitability to be used in combination with Frozen Permeability technique. Following the proposed design methodology, a 75 kW PMSM prototype was designed and validated at the IK4‐IKERLAN medium voltage laboratory. The obtained results have validated both the proposed design methodology and the developed and employed tools.La mayor parte de la energía eléctrica mundial es consumida en motores eléctricos, por lo que la mejora de sus prestaciones conduce a ahorros en el consumo energético esenciales si se quieren reducir las emisiones de CO2. De hecho, las políticas de gobiernos y asociaciones cada vez son más exigentes, y los diseñadores se ven forzados a lanzar productos cada vez más optimizados. Además, cada vez hay más aplicaciones que son muy exigentes en términos de densidad de potencia, fiabilidad o prestaciones dinámicas, como son el vehículo eléctrico, la generación eólica o la tracción ferroviaria. El altísimo contenido energético de los imanes de neodimio provoca que las máquinas imanes permanentes (PMSM) sean las más atractivas en términos de densidad de potencia. Además, debido a la casi total eliminación de pérdidas en el rotor se convierten en las máquinas más eficientes energéticamente. El diseño de una PMSM requiere de un enfoque multidisciplinar, ya que engloba aspectos eléctricos, magnéticos y térmicos. En este trabajo, se ha realizado una revisión exhaustiva de la literatura técnica publicada hasta la fecha en relación con el diseño de estas máquinas, y se han encontrado ciertos puntos de mejora. En primer lugar, muchas veces se parte de un diseño bastante definido y se optimiza una parte concreta del mismo. Además, se aprecia excesiva dependencia de la experiencia y knowhow del diseñador, sin establecer pautas claras para la toma de decisiones de diseño. Finalmente, dependen excesivamente del temporalmente costoso FEM. Por lo tanto, el objetivo principal de esta tesis es desarrollar una metodología avanzada de diseño de PMSMs que sea clara y completa, abarcando todo el proceso de diseño y aportando criterios y herramientas para la toma de decisiones que conduzcan a una elección óptima de la solución final. Se ha propuesto una metodología de diseño que permite la evaluación de gran cantidad de configuraciones de PMSM de forma automática, facilitando la decisión de diseño final por parte del diseñador. Para la implementación de esta metodología, diversas herramientas han tenido que ser desarrolladas y son explicadas en detalle: modelos analíticos electromagnéticos acoplados con modelos térmicos, y modelos electromagnéticos de parámetros concentrados. Importantes modificaciones fueron realizadas sobre los modelos térmicos adoptados para considerar diferentes refrigeraciones. Además, el circuito electromagnético de parámetros concentrados fue adaptado a la topología seleccionada y demostró su validez para ser utilizado en combinación con la técnica de Frozen Permeability. Siguiendo la metodología propuesta, se ha diseñado y fabricado un prototipo de 75 kW y se ha realizado la validación experimental en el laboratorio de media tensión de IK4‐IKERLAN. Los resultados obtenidos han servido para validar tanto la metodología de diseño como las herramientas empleadas en la misma.Munduko energia elektrikoaren zatirik handiena motor elektrikoetan kontsumitzen da, eta, ondorioz, prestazioak hobetzeak lagundu egiten du kontsumo energetikoan funtsezko aurrezpenak egiten, CO2 igorpenak murriztu nahi badira. Berez, gobernuen eta elkarteen eskakizunak gero eta zorrotzagoak dira, eta diseinatzaileak produktu gero eta optimizatuak atera beharrean daude. Gainera, gero eta aplikazio gehiago daude zorroztasun handia eskatzen dutenak potentzi dentsitateari, fidagarritasunari edo prestazio dinamikoei dagokienez, esaterako, ibilgailu elektrikoan, sorkuntza eolikoan edo tren trakzioan. Neodimiozko imanen eduki energetiko itzelaren ondorioz, iman makina iraunkorrak (PMSM) dira erakargarrienak potentzi dentsitateari dagokionez. Gainera, errotorearen galerak ia guztiz deuseztatzen direnez, energetikoki makinarik eraginkorrenak dira. PMSM bat diseinatzeko diziplina askoko ikuspegia behar da, alderdi elektrikoak, magnetikoak eta termikoak hartzen baititu bere baitan. Lan honetan orain arte honelako makinen diseinuari buruz argitaratutako literatura teknikoaren azterketa zehatza egin da, eta hobetzeko hainbat puntu aurkitu dira. Lehenik eta behin, askotan, abiapuntua nahiko definituta dagoen diseinu bat izaten da, eta egiten dena da horren zati jakin bat optimizatu. Gainera, gehiegizko mendekotasuna egoten da diseinatzailearen esperientzia eta knowhow‐arekiko, diseinuaren inguruko erabakiak hartzeko jarraibide argiak ezarri gabe. Azkenik, mendekotasun handia dago FEMek behin‐behinean duen kostu handiarekiko. Horrenbestez, tesiaren helburu nagusia da PMSMak diseinatzeko metodologia aurreratu bat garatzea, argia eta osatua, diseinuaren prozesu osoa hartuko duena, eta erabakiak hartzeko irizpideak eta tresnak eskainiko dituena, amaierako soluziorik onena aukeratu ahal izateko. Diseinurako proposatu den metodologiarekin PMSMko konfigurazio kopuru handi bat ebaluatu daiteke automatikoki, diseinatzaileari amaierako diseinua erabakitzen laguntzeko. Metodologia inplementatzeko, hainbat tresna garatu behar izan dira, eta horiek zehatz esplikatzen dira: eredu analitiko elektromagnetikoak, eredu termikoekin uztartuta, eta parametro kontzentratuen bidezko eredu elektromagnetikoak. Hautatutako eredu termikoetan aldaketa garrantzitsuak egin behar izan ziren, hozkuntza desberdinak lantzeko. Horrez gain, parametro kontzentratuen zirkuitu elektromagnetikoa hautatutako topologiara egokitu zen, eta bere balioa frogatu zuen, Frozen Permeability teknikarekin konbinatuta erabiltzeko. Proposatutako metodologiari jarraituz, 75 kW‐eko prototipo bat diseinatu eta fabrikatu da, eta balioztapen esperimentala egin da IK4‐IKERLANeko tentsio ertaineko laborategian. Lortutako emaitzek diseinuaren metodologia zein bertan erabilitako tresnak balioztatzeko balio izan dute

整合電動馬達與齒輪減速機之設計

現有馬達與齒輪減速機是分別設計與製造後再選配，存在動力傳輸路 徑較長、機器組成元件較多、整體安裝空間較大等缺點。本研究提出一套 整合設計流程，用以有系統地將電動馬達之電磁場設計與齒輪減速機的運 動設計結合。依據電動馬達及齒輪減速機的構造特性與運動原理，歸納設 計需求與限制，藉由圖論表示法與創意性機構設計方法，提出整合設計構 想。建立一維及二維等效磁路法分析模型，解析整合裝置的電磁特性與輸 出性能，並配合有限元素分析進行驗證，其誤差值分別為3.21 %與3.06 %。 引入卡特係數建立槽開口與齒型之磁導模型，探討齒輪輪廓對馬達電磁場 之影響，結果顯示齒型不影響馬達之磁交鏈、磁通密度、及電磁轉矩。提 出齒輪系的設計方法，包含齒形、齒數、齒輪系構形、及齒輪強度分析。 最後，分別以現有直流有刷馬達整合行星齒輪減速機，及交流感應馬達整 合一般齒輪系為設計實例，有系統並完成整合裝置的設計。齒輪強度分析 結果顯示，透過矽鋼片堆疊之齒型，可承受之最大應力為312 MPa，齒輪 之動態負載，直流有刷馬達為7.94 MPa，交流感應馬達為98.32 MPa，足夠 承受傳輸需求。由性能分析結果得知，該整合裝置滿足現有設計的傳動能 力，大幅降低直流有刷馬達的頓轉扭矩92.02%及轉矩漣波50.14%，降低交 流感應馬達轉矩漣14.23%，且分別提高直流馬達與交流馬達之轉矩密度 16.66%與1.75%，改善整合裝置的電磁與輸出特性，其頓轉扭矩、轉矩漣 波，及軸向空間的使用，皆較現有設計有更佳的性能表現。[[abstract]]This work presents a novel design procedure for integrating electric motors with gear mechanisms. Based on the configurations of electric motors and the kinematic structure of gear trains, the design requirements and constraints are concluded. By applying the graph representations and creative mechanism design methodology, feasible design concepts are successfully generated systematically. The open-circuit magnetostatic field analysis of a DC commutator motor conducted by applying 1-D and 2-D equivalent magnetic circuit methods are obtained and verified using FEA. The differences in the air-gap flux density are 3.21% and 3.06% for 1-D and 2-D methods, respectively. The Carter’s coefficient is applied to model the permeance of the slot and gear-teeth space. The affection of the integrated gear-teeth on the flux linkage and the first derivative of the flux linkage can be ignored. The design methods for gear trains, gear profiles, number of gear teeth, and gear strength are also introduced. The maximum stress of the gear profile is 312 MPa, and the results show that the gear train can be used for transmission purposes. A DC commutator motor with a planetary gear mechanism and an AC induction motor with an ordinary gear train are applied as examples. A feasible integrated DC commutator motor device is presented that reduces the cogging torque and the torque ripple by 92.02% and 50.14%, respectively, while increasing the torque density by 16.66%. The torque of the AC induction motor is reduced by 8.96%, and the torque ripple is reduced by 14.23%. In addition, the torque density is increased by 1.75%. This indicates that the integrated devices provide more stable and efficiency output torque than the existing design.[[booktype]]電子版[[countrycodes]]TW

Study of a reluctance magnetic gearbox for energy storage system application

This work proposes the use of a magnetic gearbox to be applied on an energy storage system based on flywheel to allow the use of a conventional electric machine external to the vacuum chamber as the primary machine, maintaining the possibility of using a rotating mass with high speeds. Parametric simulations were performed using finite element software to determine the behaviour of the various variables of the magnetic gear in terms of its performance and design constraints. Finally, a prototype was built to validate the simulations and the considerations made.Este trabalho propõe o uso de uma engrenagem magnética para aplicação em um sistema de armazenamento de energia baseado em volante de inércia permitindo o uso de uma máquina elétrica convencional externa à câmara de vácuo como máquina primária, mantendo a possibilidade de utilizar altas velocidades da massa girante. Simulações paramétricas foram realizadas utilizando um software para simulação por elementos finitos para determinar o comportamento das diversas variáveis da engrenagem magnética quanto ao seu desempenho e restrições de projeto. Por fim um protótipo foi construído para validar as simulações e as considerações feitas

INVESTIGATION OF PERMANENT MAGNET SYNCHRONOUS MACHINES FOR DIRECT-DRIVE AND INTEGRATED CHARGING APPLICATIONS IN ELECTRIC VEHICLES

Electrified vehicles have proven to be potential candidates in the future for disrupting the automotive industry which is dominated by conventional gasoline vehicles. Electric vehicle (EV) technology has evolved rapidly over the last decade with new designs of EV drivetrain systems and components but no specific design has been able to serve as a solution that is affordable, reliable and performance-wise similar to existing gasoline vehicle equivalent. Extended driving range and overall cost of the vehicle still remain major bottlenecks. Understanding the state-of-the-art technologies and challenges in existing electric vehicle powertrain and charging systems, with major focus on permanent magnet synchronous machines & drives, this dissertation presents the following

9th International Conference on Energy Efficiency in Motor Driven Systems

The 9th International Conference on Energy Efficiency in Motor Driven Systems (EEMODS'15) was be held in Helsinki (Finland) on 15-17 September, 2015. The EEMODS'15 conferences have been very successful in attracting distinguished and international presenters and attendees. The wide variety of stakeholders has included professionals involved in manufacturing, marketing, and promotion of energy efficient motors and motor driven systems and representatives from research labs, academia, and public policy. EEMODS’15 provided a forum to discuss and debate the latest developments in the impacts of electrical motor systems (advanced motors and drives, compressors, pumps, and fans) on energy and the environment, the policies and programmes adopted and planned, and the technical and commercial advances made in the dissemination and penetration of energy-efficient motor systems. In addition EEMODS covered also energy management in organizations, international harmonization of test method and financing of energy efficiency in motor systems. The Book of Proceedings contains the peer reviewed paper that have been presented at the conference.JRC.F.7-Renewables and Energy Efficienc

Reduced--cost Permanent Magnet mottor drives: a comprehensive design procedure and a universall approach to the magnettiic modell identification and conttol

This research deals with the design, identification and control of Permanent Magnet Synchronous motor drives. Throughout the project, motor and control designs have been straightly integrated in order to meet the challenging requirements, typically coming from the industrial world. Namely, the purposes leading this research activity are: cost-reduction and standardization of both design and control tasks into straightforward and universal procedures. As a deeper insight, this work proposes a comprehensive procedure for the design of reduced-cost Permanent Magnet based electrical machines and a universal control technique, requiring minimum calibration and a simplified preliminary commissioning stage. The recent price volatility of rare earth raw materials has been compelling designers and manufacturers of electric motors to find out or re-evaluate alternative machine topologies, using either a reduced amount of such rare-earth magnets or lower energy density magnetic materials, such as hard ferrites, still providing for high-performance technologies. This thesis is about facing this issue, while enhancing general approaches to the optimal design of Permanent Magnet Synchronous machines via fully-analytical models showing a twofold purpos