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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.
31

Návrh synchronního stroje s permanentními magnety / Design of permanent magnet synchronous motors

Bureš, Petr January 2018 (has links)
Given today’s trend with environment being very important, there has been an ongoing attempt in the rotating machine industry to create machines with highest efficiency possible. And so, permanent magnet synchronous machines represent types of machine with very high efficiency and are gradually replacing other machines in many applications. This work deals with familiarization of the properties of permanent magnet synchronous motor as well as typical design choices. The main focus of this work is the design of permanent magnet EC motor and following comparison of results obtained from analytical design and analysis in the RMxprt program. Finally, the results of design methods are compared.
32

Regulátor otáček pro střídavé motory / Controler for brushless motors

Zdařil, Tomáš January 2012 (has links)
The goal of the thesis was to design and create one-way speed controler for brushless DC motors, that is used in air modeling. The circuit is controlled by the Atmel AVR. As power unit for motor is used Li–pol accumulator. The controller is equipped with BEC to power the receiver and allows monitoring of current consumption and voltage on the accumulator. Measured data can be upload to a PC where they can be displayed by RegulatorPC in graphical form.
33

Bezsensorové řízení BLDC motoru / Sensorless control of BLDC motor

Križan, Jakub January 2012 (has links)
This thesis is focused on problematics of control of brushless DC motor in the sensor and also in the sensorless mode. Also it interprets possibilities of BLDC motor control with one faulty sensor and derivation and simulation of mathematical model. First part mentions options of rotor position sensing as well as existing methods of sensorless BLDC motor control. Second part describes control algorithms of sensor and sensorless motor control realised on device dSPACE and also realisation of faulty sensor control algorithm. Third part deals with derivation of mathematical model, its realisation using Matlab Simulink software and identification of its parameters. Last part concludes results and compares control methods used on the real system.
34

Automatic Torque Control for Bicycle Driven Brushless DC (BLDC) Generator

Müller, Luke, Sjöström, Kasper January 2021 (has links)
This work was carried out on behalf of Science Safari. Science Safari wants to create a product that facilitates the understanding of how much physical work is required to create electrical energy. This is done by cranking the pedals of a bicycle. The purpose of this work is to create a control unit that keeps the torque required to crank the pedals close to constant. The torque can be kept constant by creating a variable load for the generator, in this case, a pulse modulated JFET is used. The output of the current sensor and the Hall-effect sensor are used to calculate the required resistance of the JFET to keep constant torque. All this is controlled via a Raspberry Pi 3 Model B (RPi) which also shows real-time values on a display. The functionality of the sensors and JFET has largely been completed, but the assembly of all components is lacking in this work. / Detta arbete är utfört i uppdrag av Science Safari. Science Safari vill skapa en produkt som underlättar förståelsen av hur mycket fysiskt arbete som krävs för att skapa elektrisk energi. Detta genom att användaren vevar på en cykels pedaler för hand. Syftet med detta arbete är att skapa en styrenhet som ungefär håller ett konstantvridmomentet på en cykels pedaler. Vridmomentet kan hållas konstant genom att skapa en variabel last till generatorn, med hjälp av en pulsmodulerad JFET. För att beräkna vilken resistans JFETen ska ha för att hålla konstant vridmoment används en strömsensor och en Hall-effect sensor. Allt detta styrs via en Raspberry Pi 3 ModelB som även visar värden i realtid på en display. Funktionaliteten av sensorerna och JFET har till stor del färdigställts men sammansättning av alla komponenter saknas i detta arbete.
35

Electric Self Propelled Shoe : A shoe mountable last mile personal transportation vehicle / Elektriskt motordriven sko

Kårefjärd, Viktor, Stridfeldt, David January 2021 (has links)
The purpose of this work was to investigate how a last mile-transport vehicle can be constructed around a shoe. The prototype, which is controlled without a handheld controller, was designed to propel an adult forward with the use of an electric driveline. The user can easily stop driving, and instead walk short distances without removing the prototype. Research questions have been answered regarding how the battery and motor can be configured to reach a top speedof 15 km/h and a range of 3 km. In addition, answers were given as to how a user should control the vehicle’s speed in a safe and simple way, without the use of a handheld remote controller. The results show that the prototype reaches the specified top speed, and that the specified range is reached and exceeded. The user controls the motor power by moving their weight from the left to the right foot. The applied weight is measured by load cells under the heel, and after calibration, this user input method can be seen as satisfactory. The electric driveline, which is mounted under the shoe, allows the user to walk short distances without removing the prototype. Future work may add safety equipment such as lamps and a bell to make the product legal for use in public areas. In addition, a left shoe needs to be developed further, due to how the concept is dependent on it to function optimally. / Det här arbetet hade till avsikt att undersöka hur ett sistasträckan-fordon kan konstrueras kring en sko. Prototypen, vilken styrs utan en handkontroller, utformades för att förflytta en vuxen person med hjälp av en elektrisk drivlina. Användaren kan enkelt sluta åka, och istället gå kortare sträckor utan att ta av sig prototypen. Forskningsfrågor har besvarats angående hur batteri och motor kan konfigureras för att uppnå topphastigheten 15km/h och färdsträckan 3 km. Dessutom besvarades hur en användare ska kontrollera fordonets hastighet på ett säkert och enkelt sätt, utan användning av en handkontroll. Resultaten visar att prototypen uppnår topphastigheten, och att den angivna räckvidden uppnås och överskrids. Användaren styr motoreffekten genom att förflytta sin vikt från vänster till höger fot. Den applicerade vikten mäts av lastceller under hälen, och efter kalibrering kan denna användar-inmatningsmetod ses som tillfredsställande. Den elektriska drivlinan, som monteras under skon, tillåter att användaren går kortare sträckor utan att ta av sig prototypen. Framtida arbete kan tillägga säkerhetsutrustning, som lampor och ringklocka för att göra produkten laglig för användning på allmän plats. Dessutom behöver en vänstersko utvecklas mer, på grund av hur konceptet är beroende av denna för att fungera optimalt.
36

Transformação dq não senoidal para máquinas síncronas com imã permanente no rotor / Non-sinusoidal dq transformation for rotor permanent magnet synchronous machines

Monteiro, José Roberto Boffino de Almeida 19 December 2002 (has links)
O presente trabalho apresenta uma transformação dq não senoidal e sua aplicação em máquinas síncronas com ímã permanente na superfície do rotor (MSIP) e forma de onda de FEM não senoidal. O modelo resultante da aplicação dessa transformação permite o controle direto do torque eletromagnético, permitindo reduzir as ondulações do torque produzido nesse tipo de máquina. A redução dessas ondulações em MSIPs não senoidais possibilita que esse tipo de máquina seja empregado em aplicações onde somente MSIPs senoidais, que possuem custo mais elevado, poderiam ser usadas. Simulações e resultados práticos, obtidos pela implementação do sistema de controle vetorial não senoidal desenvolvido, são apresentados no trabalho. Pelos resultados obtidos, pode-se verificar que o método proposto é eficaz na redução das ondulações do torque eletromagnético em MSIPs não senoidais. / This work presents a non-sinusoidal dq transformation and its application in permanent- magnet synchronous machines (PMSM) with a non-sinusoidal back-EMF waveform. The resulting model of the application of such transformation permits direct control of machine electromagnetic torque, which achieves the reduction of torque ripple. The reduction of torque ripple in non-sinusoidal PMSMs makes possible the use of this kind of PMSM instead of sinusoidal PMSMs, which are more expensive. Simulation and practical results, obtained by the implementation of such non-sinusoidal vectorial control system, are shown in this work. Those results show that the method presented is efficacious in the torque ripple reduction in non-sinusoidal PM synchronous machines.
37

Estratégias de acionamento e controle em máquinas CA de ímã permanente com fluxo não senoidal / Control strategies for permanent magnet AC machines with non-sinusoidal flux

Monteiro, José Roberto Boffino de Almeida 29 August 1997 (has links)
O objetivo desse trabalho é o estudo e a análise do desempenho de máquinas brushless com ímã permanente no rotor, com fluxo de entreferro não senoidal. São consideradas máquinas brushless com ímã permanente na superfície do rotor. Três modelos matemáticos são considerados: o modelo por fase de estator, o modelo vetorial e o modelo velocidade-tensão de segunda ordem. Máquinas com diferentes tipos de enrolamento de estator são comparadas, incluindo as máquinas síncronas com ímã permanente no rotor (com a densidade dos enrolamentos distribuída de forma senoidal no estator). Os resultados para o torque eletromagnético das máquinas foram obtidos considerando-se dois tipos de acionamentos em malha aberta: um acionamento de seis pulsos e um acionamento senoidal. Por fim, um método de controle é apresentado para máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais, utilizando controle vetorial, são comparados aos das máquinas senoidais. / The aim of this work is to analyse the torque performance of brushless machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brushless machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines.
38

Direct torque control of permanent magnet synchronous motors with non-sinusoidal back-EMF

Ozturk, Salih Baris 15 May 2009 (has links)
This work presents the direct torque control (DTC) techniques, implemented in four- and six-switch inverter, for brushless dc (BLDC) motors with non-sinusoidal back- EMF using two and three-phase conduction modes. First of all, the classical direct torque control of permanent magnet synchronous motor (PMSM) with sinusoidal back-EMF is discussed in detail. Secondly, the proposed two-phase conduction mode for DTC of BLDC motors is introduced in the constant torque region. In this control scheme, only two phases conduct at any instant of time using a six-switch inverter. By properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table the desired quasi-square wave current is obtained. Therefore, it is possible to achieve DTC of a BLDC motor drive with faster torque response while the stator flux linkage amplitude is deliberately kept almost constant by ignoring the flux control in the constant torque region. Third, the avarege current controlled boost power factor correction (PFC) method is applied to the previously discussed proposed DTC of BLDC motor drive in the constant torque region. The test results verify that the proposed PFC for DTC of BLDC motor drive improves the power factor from 0.77 to about 0.9997 irrespective of the load. Fourth, the DTC technique for BLDC motor using four-switch inverter in the constant torque region is studied. For effective torque control in two phase conduction mode, a novel switching pattern incorporating the voltage vector look-up table is designed and implemented for four-switch inverter to produce the desired torque characteristics. As a result, it is possible to achieve two-phase conduction DTC of a BLDC motor drive using four-switch inverter with faster torque response due to the fact that the voltage space vectors are directly controlled.. Finally, the position sensorless direct torque and indirect flux control (DTIFC) of BLDC motor with non-sinusoidal back-EMF has been extensively investigated using three-phase conduction scheme with six-switch inverter. In this work, a novel and simple approach to achieve a low-frequency torque ripple-free direct torque control with maximum efficiency based on dq reference frame similar to permanent magnet synchronous motor (PMSM) drives is presented.
39

Transformação dq não senoidal para máquinas síncronas com imã permanente no rotor / Non-sinusoidal dq transformation for rotor permanent magnet synchronous machines

José Roberto Boffino de Almeida Monteiro 19 December 2002 (has links)
O presente trabalho apresenta uma transformação dq não senoidal e sua aplicação em máquinas síncronas com ímã permanente na superfície do rotor (MSIP) e forma de onda de FEM não senoidal. O modelo resultante da aplicação dessa transformação permite o controle direto do torque eletromagnético, permitindo reduzir as ondulações do torque produzido nesse tipo de máquina. A redução dessas ondulações em MSIPs não senoidais possibilita que esse tipo de máquina seja empregado em aplicações onde somente MSIPs senoidais, que possuem custo mais elevado, poderiam ser usadas. Simulações e resultados práticos, obtidos pela implementação do sistema de controle vetorial não senoidal desenvolvido, são apresentados no trabalho. Pelos resultados obtidos, pode-se verificar que o método proposto é eficaz na redução das ondulações do torque eletromagnético em MSIPs não senoidais. / This work presents a non-sinusoidal dq transformation and its application in permanent- magnet synchronous machines (PMSM) with a non-sinusoidal back-EMF waveform. The resulting model of the application of such transformation permits direct control of machine electromagnetic torque, which achieves the reduction of torque ripple. The reduction of torque ripple in non-sinusoidal PMSMs makes possible the use of this kind of PMSM instead of sinusoidal PMSMs, which are more expensive. Simulation and practical results, obtained by the implementation of such non-sinusoidal vectorial control system, are shown in this work. Those results show that the method presented is efficacious in the torque ripple reduction in non-sinusoidal PM synchronous machines.
40

Estratégias de acionamento e controle em máquinas CA de ímã permanente com fluxo não senoidal / Control strategies for permanent magnet AC machines with non-sinusoidal flux

José Roberto Boffino de Almeida Monteiro 29 August 1997 (has links)
O objetivo desse trabalho é o estudo e a análise do desempenho de máquinas brushless com ímã permanente no rotor, com fluxo de entreferro não senoidal. São consideradas máquinas brushless com ímã permanente na superfície do rotor. Três modelos matemáticos são considerados: o modelo por fase de estator, o modelo vetorial e o modelo velocidade-tensão de segunda ordem. Máquinas com diferentes tipos de enrolamento de estator são comparadas, incluindo as máquinas síncronas com ímã permanente no rotor (com a densidade dos enrolamentos distribuída de forma senoidal no estator). Os resultados para o torque eletromagnético das máquinas foram obtidos considerando-se dois tipos de acionamentos em malha aberta: um acionamento de seis pulsos e um acionamento senoidal. Por fim, um método de controle é apresentado para máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais. As ondulações no torque e o desempenho das máquinas não senoidais, utilizando controle vetorial, são comparados aos das máquinas senoidais. / The aim of this work is to analyse the torque performance of brushless machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brushless machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines.

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