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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.
21

Electric Propulsion for a High Altitude Unmanned Aerial Vehicle

Hjort Friderichsen, Jacob, Jönsson, David January 2022 (has links)
The catalogue of observational platforms for space and atmospheric research can be expanded by utilising drones equipped with specialised instrumentation and capable of flying at high altitudes. In this project the requirements for an electric propulsion system applicable to the KTH Royal Institute of Technology ALPHA project are evaluated. A selection of electric motors, propellers and electronic speed controllers are tested to analyse their applicability using two different test setups. The tests include evaluation of propeller characteristics such as thrust and torque generation along with operational angular velocity ranges and the efficiency of brushless DC motors. The results are analysed and extrapolated to approximate the performance in the dynamic environment that the ALPHA aerial vehicle will encounter. From the tested hardware a propeller with a diameter of ten inches and a pitch of seven inches is found to fulfil the requirements. Out of the tested motors, six of them achieve the necessary performance and these are presented with suggestionsfor further analysis. / Mängden observationsplatformar inom rymd och atmosfärisk forskning kan utvidgas genom att använda drönare utrustade med specialicerade instrument som är kapabla att flyga på hög höjd. I detta projekt evalueras kraven på ett elektriskt drivsystem tillämpningsbart p ̊a KTH Royal Institute of Technologys ALPHA projekt. Ett urval av elektriska motorer, propellrar och elektroniska hastighetsregulatorer testas för att analysera deras tillämplighet genom använding av två olika testuppställningar. Testerna inkluderar evaluering av propellrars dragkraft, vridmoment samt operativ spann av vinkelhastighet, men även börstlösa DC motorers effektivitet och prestanda. Resultaten analyseras och extrapoleras för att approximera prestanda i den dynamiska miljön som ALPHA drönaren kommer att möta. Av den testade hårdvaran uppfyller en propeller med en diameter på tio tum och en stigning på sju tum kraven. Av de testade motorerna uppnår sex av dem den prestanda som krävs och dessa presenteras med förslag på vidare analys / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm
22

Zařízení pro testování malých elektrických motorů a lineárních aktuátorů / Testing equipment for small electrical motors and linear actuators

Červínek, David January 2018 (has links)
Aktuální postup testování je příliš zdlouhavý a nepřesný, zároveň není měření některých vlastností motoru vůbec možné. Hlavním úkolem zařízení je zrychlení a zjednodušení procesu testování spolu s možností otestovat všechny vlastnosti motorů. Realizace zařízení začala definováním požadavků zákazníka, dalším krokem byla analýza daných požadavků a návrh zařízení. Následovala výroba a programovaní firmwaru spolu se softwarem. Výsledkem práce je funkční přístroj schopný automatického testování sedmi základních typů motorů, měření všech požadovaných funkcí spolu s novou možností měření počtu tiků enkodéru, periody FG signálu z řídící elektroniky BLDC motorů a napěťové úrovně těchto signálů. Dalšími rozšířeními jsou možnost uložení výsledků z uskutečněných testů pro možné budoucí využití a možnost vizualizace proudu motorem. Uživatel je tedy schopný otestovat velké množství motorů v kratším časovém úseku a zároveň se o testovaných motorech dozvědět mnohem více informací než doposud.
23

Pokročilé řízení stejnosměrného třífázového motoru / Advanced driving system of the three-phase DC motor

Hanuš, Radek January 2020 (has links)
The main aim of this thesis is to design and develop a control unit for a three-phase direct current motor that will be able to maximize its efficiency. To accomplish this request a field oriented control combined with modified phase driving signals is used. The emphasis is put on the creation of a simple and unique solution as well as the ability to use this device in the single wheel wehicle, which previous bachelor thesis was focused on. The first part of this thesis lists some of commercially available and do-it-yourself solutions together with their attributes. The next part describes target motors and different options of how to control them. The third part focuses on the field oriented control, its individual parts and features, as well as the final solution. And finally the realization of the electrical part, firmware, PC application and necessary settings are described at the very end of the thesis.
24

Měnič pro BLDC motor / BLDC motor controller

Němec, Petr January 2021 (has links)
The goal of this Master thesis is to design a power convertor for BLDC motor 48V/2kW. Emphasis is placed on the small dimensions of the final printed circuit board. Therefore, power SMD transistors STL135N8F7AG are used in small packages PowerFlat 5x6. To reduce area of the PCB, electrolytic capacitors are mounted on a separate board, which is located above the main PCB. Small high-capacity 22F/100V ceramic capacitors are used in the DC-LINK as well. They are located as close as possible to the power SMD tranzistors. Control logic will be provided by microprocesor STM32G474RE. High resolution timer HRTIM1 is used. The first part of this thesis is devoted to the brief description of BLDC motor construction and driving. Next parts are focused on the design itself.
25

Program pro výpočet EC motorů / Program for calculation of BLDC motor

Chloupek, Karel January 2009 (has links)
This thesis focuses on problematics of BLDC motors. Thesis consist of theoretical and practical part. In introduction is the reader acquaint with problematics, principals of development, advantages and disadvantades of BLDC motors. Then folows a description of different types, their realization and construction. Main part of this thesis deals with segment stator. For this type of magnetic circuit was developed computing software. This software will design and provide calculation of motor due to given parameters. In second step, the program generates source code for FEMM software, which provides a simulation. This is the most effective way, how can designer simply verify his calculations
26

Řídicí modul BLDC motoru / BLDC Motor Control Module

Morávek, Lukáš January 2016 (has links)
Diploma thesis describes design and realization of hardware and software for controlling and regulation of the high-speed drive with BLDC motor, which will serve as a spindle for CNC milling machine. The thesis described in detail the schematic design and the design of printed circuit board of the power part, control part and power supply part of the three-phase transistor inverter controlled by DSP processor. It is also described in detail program of DSP processor for controlling and regulation of the BLDC motors, which the function is verified by the final measurements. The result of Diploma thesis is functional high-speed drive with BLDC motor.
27

Návrh měniče pro BLDC motor / Design of a convertor for a BLDC motor

Stejskal, Martin January 2017 (has links)
This master thesis deals with the design and realization of a drive for a 500 W BLDC motor powered with a battery power supply. It also deals with the possibilities of realization of drives and other possibilities to control these motors. Describes the implementation of the inverter using Atmel's AVR microcontroller. The thesis also deals with the design of an auxiliary switching inverter. Communication with UART and CAN interface is also implemented.
28

Modeling and Test of the Efficiency of Electronic Speed Controllers for Brushless DC Motors

Green, Clayton R 01 September 2015 (has links) (PDF)
Small electric uninhabited aerial vehicles (UAV) represent a rapidly expanding market requiring optimization in both efficiency and weight; efficiency is critical during cruise or loiter where the vehicle operates at part power for up to 99% of the mission time. Of the four components (battery, motor, propeller, and electronic speed controller (ESC)) of the electric propulsion system used in small UAVs, the ESC has no accepted performance model and almost no published performance data. To collect performance data, instrumentation was developed to measure electrical power in and out of the ESC using the two wattmeter method and current sense resistors; data was collected with a differential simultaneous data acquisition system. Performance of the ESC was measured under different load, commanded throttle, bus voltage, and switching frequency, and it was found that ESC efficiency decreases with increasing torque and decreasing bus voltage and does not vary much with speed and switching frequency. The final instrumentation was limited to low-voltage systems and error propagation calculations indicate a great deal of error at low power measurements; despite these limitations, an understanding of ESC performance appropriate for conceptual design of these systems was obtained. MODELING AND TEST OF THE EFFICIENCY OF ELECTRONIC SPEED CONTROLLERS FOR BRUSHLESS DC MOTORS
29

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.
30

Řízení stejnosměrného bezkartáčového motoru za podmínek ztráty napájecího napětí / Brushless dc motor control under power loss condition

Šedivý, Jozef January 2014 (has links)
Táto diplomová práca sa zaoberá implementáciou bezpečnostnej funkcie pre elektrický aktuátor, ktorá spočíva v riadení BLDC motora, po výpadku napájacieho napätia, keď je aktuátor poháňaný vstavanou pružinou.. Celé riadenie motora je navrhnuté v prostredí Matlab-Simulink technikou nazývanou návrh systému z modelu. Následne pomocou automatického generovania kódu bol získaný zdrojový kód, ktorý bol použitý v reálnom aktuátore a odtestovaný v reálnych podmienkach. Cieľom týchto testov bolo overiť reálnu možnosť nasadenia vyvinutých algoritmov v reálnych, komerčne dostupných produktoch.

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