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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The Four-Quadrant Transducer System : for Hybrid Electric Vehicles

Nordlund, Erik January 2005 (has links)
In this thesis a hybrid electrical powertrain called the Four Quadrant Transducer (4QT) has been evaluated through different driving simulations, which later resulted in the manufacture of a prototype. The simulation of a 12 metric ton distribution truck showed that the 4QT system can reduce the fuel consumption by approximately 30 % during the FTP75 drive cycle. The reduction in fuel consumption is due to a more optimal control of the combustion engine and regenerative braking of the vehicle. The prototype 4QT has been down scaled from the distribution truck size used in the simulations to a size suitable for a medium sized passenger car. This was done to fit the test rig in the electric machine laboratory. The prototype was tested in the test bench to analyse performances such as efficiency, losses and thermal behaviour. These factors were investigated using both analytical models and the finite element method and later by measurements. The measured results were according to expectations. / I denna doktorsavhandling presenteras ett nytt elhybridsystem för vägfordon benämnt fyrkvadrant omvandlare, "Four Quadrant Transducer (4QT)". Detta system har simulerats under körcykler som t ex FTP75 för att kunna bilda sig en uppfattning om bränsleförbrukningen för hybridsystemet och för att kunna dimensionera elmaskinerna till systemet. En elmaskinprototyp för hybridsystemet har konstruerats och provats i momentvåg. Enligt utförda simuleringar blir besparingen i bränsleförbrukning ca 30% för en tolv tons distributionslastbil utrustad med en 100kW dieselmotor under körcykeln FTP75. Denna minskning av bränsleförbrukning kommer främst från en mera optimal kontroll av förbränningsmotorn samt regenerativ bromsning av fordonet. Den konstruerade prototypen är avsedd för en medelstor bil. Anledningen till att prototypen inte byggdes i en storlek passande för distributionslastbilen var att prototypen skulle passa i testutrustningen i elmaskinlaboratoriet. Prototypen provades i momentvåg för att undersöka verkningsgrad, förluster och termiska prestanda. Resultaten är enligt förväntningarna. / QC 20101014
12

High-speed high-power permanent magnet machine parameters, qualities, and considerations

Bergstrom, John Paul 18 December 2013 (has links)
Permanent magnet machines have become an attractive topology for several applications due to their high power density and brushless qualities as compared to conventional wound field machines or squirrel cage machines. The presences of permanent magnets provide distinct advantages, but at the same time unique behaviors that must be accounted for. Recent work has developed permanent magnet machines for high-power and high-speed applications such as may be found in the petro-chemical industry, naval ships, and energy storage systems. / text
13

Calculation of unbalanced magnetic pull in cage induction machines

Dorrell, David George January 1993 (has links)
If the rotor of an induction motor is not concentric with the stator then an electromagnetic force is generated in a direction that will increase the eccentricity. This is called unbalanced magnetic pull (UMP). The first part of the work presented in this dissertation develops theoretical models which allow the calculation of the UMP in cage induction motors due to static rotor eccentricity. These account for any winding configuration including parallel stator winding connection. The second part of the work verifies the models experimentally using two different cage induction motors. The agreement between predicted and measured values of UMP and line current is found to be good. The investigation leads to several new aspects of the damping effects of parallel stator windings and the cage rotor being highlighted.
14

A Study of Flat Linear Induction Machines

Nolan, Paul 27 July 2016 (has links)
<p> Of greatest interest in the field of linear motion electrical machines are, the flat linear induction motor and liquid metal pump. The former has feasibility in high speed transportation while the latter is becoming of increasing importance in metallurgical processes. </p> <p> This thesis examines and extends the traditional representation for the usual sheet secondary classification and then presents a common theory which also allows composite secondary machines to be analysed. An idealized model is developed consisting of a number of regions representing air gaps, iron segments, and secondary conductors. A general solution for the field quantities is obtained. The concept of wave impedance and a transfer matrix approach allow a wide variety of configurations to be analysed. Unlike previous work the approach developed here allows for simultaneous investigation of lateral variation and skin effect. In the limiting cases where in tum skin effect and lateral variation are neglected the solutions are in agreement with known results. </p> / Thesis / Master of Engineering (MEngr)
15

Técnicas de otimização baseadas no paradigma de enxames de partículas e sua aplicação ao projeto de equipamentos eletromagnéticos. / Optimization techniques based on particle swarm paradigm and its application to the design of eletromagnetic devices.

Barbosa, Leandro Zavarez 11 October 2012 (has links)
O presente trabalho propõe a utilização do método de otimização baseado no paradigma de enxame de partículas no projeto de um dispositivo eletromagnético, modelado analiticamente. A otimização baseada em enxames de partículas pertence à classe dos algoritmos evolutivos e é baseada no algoritmo de simulação do movimento de pássaros na busca por comida. O trabalho será focado na resolução de problemas de otimização multiobjetivo e apenas alguns casos de otimização mono-objetivo serão resolvidos para demonstrar a funcionalidade do método de otimização. Dois métodos de otimização multiobjetivo são propostos: um é baseado num algoritmo de otimização multiobjetivo que utiliza o paradigma de enxames em conjunto com soluções adotadas pelo algoritmo genético multiobjetivo denominado Nondominated Sorting Genetic Algorithm-II (NSGA-II) e o outro é baseado também no paradigma de enxames utilizando elementos do algoritmo de otimização multiobjetivo intitulado Strength Pareto Evolutionary Algorithm (SPEA). Ambos algoritmos são validados em um problema de otimização baseado no projeto de um motor de corrente contínua sem escovas, um benchmark de otimização. / This work proposes the use of the optimization method based on the particle swarm paradigm in the design of electromagnetic device, analytically modeled. Particle swarm optimization belongs to the class of evolutionary algorithms and is based on the movement simulation of birds searching for food. This work will be focused on solving multi-criteria optimization problems and some cases of single-objective optimization problems will be solved only to demonstrate the functionality of optimization method. Two multi-criteria optimization methods are proposed: one based on an optimization algorithm that uses the multiobjective particle swarm paradigm and some concepts extracted from the multiobjective genetic algorithm called Nondominated Sorting Genetic Algorithm-II (NSGA-II) and the other is based on the particle swarm paradigm by using some elements of another multiobjective optimization algorithm entitled Strength Pareto Evolutionary Algorithm (SPEA). Both methods are applied to an optimization problem related to the design of a brushless direct current motor.
16

Análise do curto-circuito trifásico em geradores de indução duplamente alimentados. / Three-phase short-circuit analysis on double fed induction generators.

La Macchia, Hermes Francisco de Barros Santos 25 July 2013 (has links)
Este trabalho propõe a análise de curtos-circuitos trifásicos em geradores de indução duplamente alimentados (DFIG Doubly Fed Induction Generator). Os DFIGs voltam à pauta de hidrogeração devido aos recentes investimentos em usinas hidrelétricas reversíveis com velocidade variáveis empregando DFIGs. Esta configuração de geração, que permite velocidade do eixo diferente da frequência da rede, também é uma opção para usinas hidrelétricas convencionais, trazendo benefícios em termos de eficiência energética, estabilidade e otimização do sistema de potência. As pesquisas envolvendo este tipo de gerador tem se concentrado em aplicações para energia eólica. Os estudos são focados em aspectos de controle e otimização da geração não havendo muitos trabalhos voltados ao estudo de curto-circuito do ponto de vista da máquina principalmente relativos à solução analítica. Os trabalhos voltados a transitórios tratam em geral de afundamentos de tensão na linha de transmissão e metodologias para manter o gerador conectado ao sistema durante estes transitórios. Na área de hidrogeração, na maioria dos casos, os estudos tratam de aspectos de controle, de otimização da operação e de ganhos para o sistema de potência quando do uso do DFIG. Assim, faz-se necessário aumentar a gama de estudos do comportamento desses geradores frente a transientes elétricos, mais especificamente a curtos-circuitos. Para o estudo de transientes do curto-circuito trifásico foi desenvolvida a solução analítica e um modelo baseado no proposto por Krause (KRAUSE, 2002) para simulação em Simulink do Matlab para comparação de resultados. / This work proposes the analysis of three-phase short circuit on doubly fed induction generator, DFIG. This generator is again a subject of study for hydrogeneration as per recent investments on variable-speed Pumped Storage Power Plants. This configuration, which allows asynchronous shaft speed, is also an alternative for conventional hydro power plants, providing improvements on energy efficiency and stability and optimization of power system. Current studies on this subject are focused on wind power applications, covering mostly control and generation optimization aspects while there aren\'t so many studies on short-circuit especially with analytical solution. Electrical transient studies are usually covering voltage dips or sags on transmission line and associated methods to maintain power unit connected to power system during such. The researches on hydro power are also about control, operational optimization and power system improvements when DFIGs are installed. Thus, it is necessary to contribute to research regarding behavior of such generators under electrical transient conditions, more specifically under short circuits. The analytical equation for three-phase short circuit was developed as well the electric model based on the one proposed by Krause (KRAUSE, 2002) for simulations on Simulink of Matlab.
17

Análise do curto-circuito trifásico em geradores de indução duplamente alimentados. / Three-phase short-circuit analysis on double fed induction generators.

Hermes Francisco de Barros Santos La Macchia 25 July 2013 (has links)
Este trabalho propõe a análise de curtos-circuitos trifásicos em geradores de indução duplamente alimentados (DFIG Doubly Fed Induction Generator). Os DFIGs voltam à pauta de hidrogeração devido aos recentes investimentos em usinas hidrelétricas reversíveis com velocidade variáveis empregando DFIGs. Esta configuração de geração, que permite velocidade do eixo diferente da frequência da rede, também é uma opção para usinas hidrelétricas convencionais, trazendo benefícios em termos de eficiência energética, estabilidade e otimização do sistema de potência. As pesquisas envolvendo este tipo de gerador tem se concentrado em aplicações para energia eólica. Os estudos são focados em aspectos de controle e otimização da geração não havendo muitos trabalhos voltados ao estudo de curto-circuito do ponto de vista da máquina principalmente relativos à solução analítica. Os trabalhos voltados a transitórios tratam em geral de afundamentos de tensão na linha de transmissão e metodologias para manter o gerador conectado ao sistema durante estes transitórios. Na área de hidrogeração, na maioria dos casos, os estudos tratam de aspectos de controle, de otimização da operação e de ganhos para o sistema de potência quando do uso do DFIG. Assim, faz-se necessário aumentar a gama de estudos do comportamento desses geradores frente a transientes elétricos, mais especificamente a curtos-circuitos. Para o estudo de transientes do curto-circuito trifásico foi desenvolvida a solução analítica e um modelo baseado no proposto por Krause (KRAUSE, 2002) para simulação em Simulink do Matlab para comparação de resultados. / This work proposes the analysis of three-phase short circuit on doubly fed induction generator, DFIG. This generator is again a subject of study for hydrogeneration as per recent investments on variable-speed Pumped Storage Power Plants. This configuration, which allows asynchronous shaft speed, is also an alternative for conventional hydro power plants, providing improvements on energy efficiency and stability and optimization of power system. Current studies on this subject are focused on wind power applications, covering mostly control and generation optimization aspects while there aren\'t so many studies on short-circuit especially with analytical solution. Electrical transient studies are usually covering voltage dips or sags on transmission line and associated methods to maintain power unit connected to power system during such. The researches on hydro power are also about control, operational optimization and power system improvements when DFIGs are installed. Thus, it is necessary to contribute to research regarding behavior of such generators under electrical transient conditions, more specifically under short circuits. The analytical equation for three-phase short circuit was developed as well the electric model based on the one proposed by Krause (KRAUSE, 2002) for simulations on Simulink of Matlab.
18

Técnicas de otimização baseadas no paradigma de enxames de partículas e sua aplicação ao projeto de equipamentos eletromagnéticos. / Optimization techniques based on particle swarm paradigm and its application to the design of eletromagnetic devices.

Leandro Zavarez Barbosa 11 October 2012 (has links)
O presente trabalho propõe a utilização do método de otimização baseado no paradigma de enxame de partículas no projeto de um dispositivo eletromagnético, modelado analiticamente. A otimização baseada em enxames de partículas pertence à classe dos algoritmos evolutivos e é baseada no algoritmo de simulação do movimento de pássaros na busca por comida. O trabalho será focado na resolução de problemas de otimização multiobjetivo e apenas alguns casos de otimização mono-objetivo serão resolvidos para demonstrar a funcionalidade do método de otimização. Dois métodos de otimização multiobjetivo são propostos: um é baseado num algoritmo de otimização multiobjetivo que utiliza o paradigma de enxames em conjunto com soluções adotadas pelo algoritmo genético multiobjetivo denominado Nondominated Sorting Genetic Algorithm-II (NSGA-II) e o outro é baseado também no paradigma de enxames utilizando elementos do algoritmo de otimização multiobjetivo intitulado Strength Pareto Evolutionary Algorithm (SPEA). Ambos algoritmos são validados em um problema de otimização baseado no projeto de um motor de corrente contínua sem escovas, um benchmark de otimização. / This work proposes the use of the optimization method based on the particle swarm paradigm in the design of electromagnetic device, analytically modeled. Particle swarm optimization belongs to the class of evolutionary algorithms and is based on the movement simulation of birds searching for food. This work will be focused on solving multi-criteria optimization problems and some cases of single-objective optimization problems will be solved only to demonstrate the functionality of optimization method. Two multi-criteria optimization methods are proposed: one based on an optimization algorithm that uses the multiobjective particle swarm paradigm and some concepts extracted from the multiobjective genetic algorithm called Nondominated Sorting Genetic Algorithm-II (NSGA-II) and the other is based on the particle swarm paradigm by using some elements of another multiobjective optimization algorithm entitled Strength Pareto Evolutionary Algorithm (SPEA). Both methods are applied to an optimization problem related to the design of a brushless direct current motor.
19

Method for design and optimization of surface mount permanent magnet machines and induction machines

Duan, Yao 17 November 2010 (has links)
Advances in electrical machinery with high efficiencies could significantly reduce the cost of industrial and residential energy systems, thereby reducing fossil fuel needs and emissions. Electrical machine design is a comprehensive process based on several factors, including economic factors, material limitations, specifications and special application-dependent factors. At the same time, machine design is a multi-physics task comprising of electric design, magnetic design, insulation design, thermal design and mechanical design. However, the out-of-date conventional machine design can neither reflect the advances in the past 30 years, nor exploit the trade-offs between design factors from the multi-physics nature of the electrical machine. This work focus on the development a fast and efficient method for the design and optimization of Surface Mount Permanent Magnet (SMPM) machines and induction machines, as influenced by the energy source, mechanical loads, thermal effects, and the up-to-date developments in materials and manufacturing capabilities. A new analytical design method is developed for the electromagnetic design of SMPM machines. Both distributed and concentrated winding types of SMPM machines are considered and compared. Based on the proposed electromagnetic analytical design method and a generic thermo-mechanical machine design model [1], an innovative and computationally efficient electromagnetic-thermo-mechanical integrated design method is developed for SMPM machines. Particle Swarm Optimization (PSO) is applied in a novel way based on this integrated design method for the multi-objective design optimization of SMPM machines. With the proposed method, the thermal and mechanical design is no longer treated separately and heuristically as in the traditional design, but has been systemically integrated with the electromagnetic design; the effect of power source, cooling capability, thermal limits, and up-to-date material capabilities are also reflected in the design and optimization. Superior designs compared to traditional designs can be achieved with PSO based multi-objective optimization. The proposed integrated design approach also has the merit of good computational efficiency and provides a significant time reduction of the design cycle compared to finite element analysis. A novel electromagnetic analytical design method of induction machines has been developed, which needs only six prime design variables but is able to design induction machines in fine details. The advantage over the traditional and other existing design method is that this proposed method does not have the heuristic selection of the design variables and does not need manual design iterations. The computing time is almost negligible and the design cycle is significantly reduced compared to the tradition machine design.
20

Estimating the magnetic characteristics of a salient pole synchronous machine using ampere turns distribution method

Subramanian, Jayaram 13 August 2015 (has links)
Modeling of electrical machines play a very important role in a variety of applications such as performance analysis, characterization, fault diagnosis, condition monitoring and stress analysis of the machines. One of the important parameter while modeling the electrical machine is the magnetic characteristics of the core material. This plays a huge role in the performance characteristics and analysis of the electrical machines. Existing techniques available to determine the magnetic characteristics of a material are mainly Epstein and single sheet tester. These two tests are invasive and destructive method of testing the magnetic characteristics of the material. This research work takes up this problem and comes with a simple yet effective solution to determine the average magnetic characteristics of the material in the salient pole synchronous machine (SPSM). An FE model of the SPSM was developed to closely emulate the characteristics of the experimental machine. This FE model was first subjected to magnetostatic simulation under different field currents using a known magnetic material. Ampere turn distribution technique was used to determine the magnetic characteristics of the material. Following the determination of the new material, this material was used in the FE simulation of the SPSM running as a motor and a generator under varying load condition and field currents. Then these results were compared with the real machine to determine the effectiveness of the developed scheme. / Graduate

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