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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

Controlling a Brushless DC Motor in a Shift-by-Wire System / Styrning av en borstlös DC-motor i ett Shift-by-Wire-system

Wiberg, Johan January 2003 (has links)
<p>Shift-by-Wire is about replacing the mechanical link between the automatic transmission and the shift lever with an electromechanical system. This will make new safety functions possible and assist the driver in other ways. </p><p>To do this, an actuator with a brushless DC motor is built into the transmission. It controls the position of the shift valve, which decides the driving position. </p><p>This thesis concerns the controlling of the brushless DC motor. This is done by programming a shift control unit with a Motorola HC12 microcontroller. The performance of the motor is then tested and evaluated.</p>
22

Controlling a Brushless DC Motor in a Shift-by-Wire System / Styrning av en borstlös DC-motor i ett Shift-by-Wire-system

Wiberg, Johan January 2003 (has links)
Shift-by-Wire is about replacing the mechanical link between the automatic transmission and the shift lever with an electromechanical system. This will make new safety functions possible and assist the driver in other ways. To do this, an actuator with a brushless DC motor is built into the transmission. It controls the position of the shift valve, which decides the driving position. This thesis concerns the controlling of the brushless DC motor. This is done by programming a shift control unit with a Motorola HC12 microcontroller. The performance of the motor is then tested and evaluated.
23

Robust Speed Control of Brushless DC Motor Drive Using Quantized Current Regulator

Chan, Wei-Chun 24 August 2009 (has links)
Based on sliding-mode control theory, this thesis proposes an integrated design of robust speed controller and quantized current regulator to achieve the control of inverter for BLDC motor. Moreover, using Digital Signal Processor (DSP) as well as the proposed inverter technology as the control kernel, a fully digital drive module of Brushless DC motor (BLDC) is robustly designed to achieve the high-performance speed control. Under the influence of system disturbances, the designed drive module can obtain a good tracking response for speed and current control. According to the simulation and experimental studies, the proposed hybrid control strategy can simultaneously achieve the objective for the speed and current control of BLDC motor. Compared with traditional pulse-width modulation (PWM) based PID control, the better speed control performance can be conducted by the provided approach.
24

IMPROVEMENTS IN INVERTER MODELING AND CONTROL

Liu, Xiao 01 January 2017 (has links)
In this dissertation, the generalized averaging method models for inverters, reactive power control methods for photovoltaic inverters, and a noise immunity improvement for hybrid position observers for brushless dc motor drives are studied. Models of inverters and other converters based on averaging have been widely used in numerous simulation applications. Generalized averaging can be applied to model both average and switching behavior of converters while retaining the faster run times associated with average-value models. Herein, generalized average models for single- and three-phase pulse width modulation inverters are proposed. The modulation signal for the proposed model could be either a sinusoidal waveform without high order harmonics or a sinusoidal waveform with third-harmonic injection. And this generalized average models also can apply for modeling three-phase pulse width modulation inverters with varying modulation signal frequency in the reference frame. These models are based on a quasi-Fourier series representation of the switching functions that includes fundamental and switching frequency components as well as sideband components of the switching frequency. The proposed models are demonstrated both in simulation and experimentally and are found to accurately portray both the fundamental and the switching behavior of the inverter. In particular, the use of sideband components allows accurate representation of the variation in switching ripple magnitude that occurs in the steady state. The generalized average models are found to have simulation run times that are significantly faster than those associated with detailed models. Therefore, the proposed generalized average models are suitable for simulation applications in which both accuracy (including the switching behavior) and fast run times are required (e.g., long simulation times, systems with multiple converters, and repeated simulations). Variations in the output power of intermittent renewable sources can cause significant fluctuations of distribution system voltage magnitudes. Reactive power control methods that employ the reactive power capability of photovoltaic three-phase inverters to mitigate these fluctuations are proposed. These control methods cause the three-phase inverters to substitute reactive output power for real output power when fluctuations in the solar power are experienced, allowing the fluctuations to be controlled. Performance metrics for assessing the ability of these controllers to perform this mitigation are defined. The controllers are examined using the IEEE 123-bus feeder distribution system, and it is found that the controllers can effectively mitigate voltage magnitude fluctuations and that the appropriate choice of controller depends on the performance metrics of interest. Finally, a noise immunity improvement for hybrid position observers for brushless dc motor drives is proposed. A finite state machine is used to detect Hall-effect sensor transitions to determine if these transitions are true transitions or the result of momentary glitches. This filter causes a delay in the detection of the Hall-effect sensors that is compensated in the proposed observer. The proposed observer is compared in simulations with the original hybrid position observer under both non-noisy and noisy conditions for both constant and variable speed operation, and it has good performance even under high noise and variable speed conditions.
25

LabView-baserat produktionstest för borstlösa trefasiga likströmsmotorer / LabView-based production test for brushless three phase direct current motors

Thulin, Marlene January 2019 (has links)
Testning är en viktig del i tillverkningskedjan för att säkerställa kvalitet och funktion hos elektronikprodukter, och utförs ofta på flera nivåer innan den färdiga produkten lämnar fabriken. Produktionstester är rutinmässiga tester som tillämpas under masstillverkning och vid utformning av dessa måste tidseffektivitet prioriteras för att minimera negativ inverkan på produktionstakten. I detta projekt överfördes ett produktionstest för färdigmonterade borstlösa DC-motorer med drivelektronik till en ny testutrustning hos företaget Allied Motion. Testet skulle moderniseras och införas i företagets mjukvaruplattform uppbyggd i programspråket LabView. Testsekvensen kunde effektiviseras främst genom att kombinera dess delmoment och låta körningar av motorn användas för att testa flera egenskaper istället för att upprepas. Resultatet blev ett test som täckte in samma mätningar som i det äldre systemet med undantag för enstaka moment, samt mätte hastighet och momentkarakteristik med högre precision. Det omarbetade testet bestod av fyra deltester jämfört med tidigare tolv steg, och implementerades i fyra LabView-baserade testfall som kunde användas för att skapa en komplett testsekvens i plattformen. Uppgiften visade sig dock kräva mer tid och arbete än vad som uppskattats inledningsvis, och därför återstod flera av de arbetsuppgifter som planerats inom projektet att slutföra innan det nya testet skulle kunna tas i bruk i produktionen. / Testing is an important part of the manufacturing process to ensure the functional quality of electronics products, and is often performed in multiple stages during product assembly before the final product leaves the factory. Production tests are applied as a routine on all units in a production line, therefore time efficiency must be prioritized in the design of such tests in order to minimize the negative effect imposed on production rate. In this project an existing production test for fully assembled brushless DC motors was re-implemented for a new test equipment at Allied Motion. The purpose was to modernize the test and implement it in the company’s own LabView-based software platform. The test sequence was streamlined by combining and thereby reducing the number of steps, using the same motor runs to test multiple functions rather than repeating run sessions to collect data for similar test steps. The project resulted in a new test that, with a minor exception, covered the same measurements as in the old system and measured speed and torque performance with higher precision. The new test consisted of four partial tests instead of the earlier version’s twelve test steps, which were implemented in LabView-code as four separate test cases that could be used in creating complete test sequences in the software platform. The project task though turned out to require more time and effort than was initially estimated, and several parts that had been planned to be completed within the project time still remained before the test could be taken into use in the production line.
26

Novel Multilevel Converter for Variable-Speed Medium Voltage Switched Reluctance Motor Drives

Shehada, Ahmed 31 March 2017 (has links)
A novel multilevel converter that is especially suited for high speed multi-megawatt switched reluctance motor drives operating at the medium voltage level is presented. The drive is capable of variable speed, four-quadrant operation. Each phase leg of the converter contains an arbitrary number of cascaded cells connected in series with the phase winding. Each cell contains a half-bridge chopper connected to a capacitor. The converter is named the cascaded chopper cell converter. The modular nature of the converter with the ability to add redundant cells makes it very reliable, which is a key requirement for medium voltage drive applications. A comprehensive control algorithm that overcomes the challenges of balancing and controlling cell capacitor voltages is also proposed. A suitable startup algorithm to limit startup current and switching losses, as well as ensure that cell capacitor voltages remain controlled at startup, is suggested. Details of the drive design such as component sizing and control parameter selection are also discussed. A detailed simulation model is developed and explained, and simulation results are provided for primary validation. Operation with standard current and speed control is first simulated. Then a scheme that gives way to a controller that operates the drive in single-pulse mode is developed and presented. This single-pulse control scheme controls the turn-on and turn-off angles, as well as the energization voltage level, in order to obtain high efficiency. Practical considerations related to the drive such as reliability, efficiency, and cost considerations are also discussed. Finally, a detailed comparison of the proposed converter to another competing converter is performed. Besides its scalability to high voltages and powers, the reliability and efficiency of the proposed converter makes it also a candidate for sub-megawatt applications requiring minimum downtime, or any application where high efficiency or improved performance is required. A small part of this work is also dedicated to brushless dc machines. Control methods for a new converter for brushless dc machines are proposed and verified via simulation. The main advantage of this converter with the proposed control is that it allows exact control of torque or speed up to twice the rated speed, without resorting to current phase advancing or other flux-weakening techniques. / Ph. D. / Electric motors are used in a very wide range of applications. They are found in power tools, in household appliances like washers and dryers, in compressors for HVAC, in fans, blowers and pumps in industry, and in electric vehicles and electric transit systems, only to name a few. An electric motor that is combined with an electronic circuit that allows precise control of the motor speed and torque is referred to as an electric drive. Very large electric drives – reaching multi-megawatt powers – are used in several applications such as in ship propulsion, in large pumps for moving water and sewage, and others. Very few electric motor drive options currently exist at that power level, and so multi-megawatt electric motor drives present an interesting research opportunity. This work proposes a novel drive system that is best suited for high speed multi-megawatt electric drives employing the switched reluctance motor. The switched reluctance motor was chosen due to its robustness, high efficiency, and high speed capability. A novel electronic converter that is scalable to high power and voltage levels is proposed. It features high reliability which is essential in multi-megawatt applications that typically require very high uptime. It has a modular structure, thereby allowing for simple construction. A comprehensive control algorithm for the drive system consisting of the converter and motor is proposed. Also a suitable algorithm that keeps the electrical and thermal variables within the allowed limits during the startup stage is proposed. A detailed simulation model is developed and explained, and simulation results are provided for primary validation. Next, a control scheme that results in high efficiency through appropriate control of the drive’s various parameters is proposed. Practical considerations related to the drive such as reliability, efficiency, and cost considerations are also discussed. Finally, a detailed comparison of the proposed converter with another competing converter is performed. Besides its scalability to high voltages and powers, the reliability and efficiency of the proposed converter makes it also a candidate for sub-megawatt applications requiring minimum downtime, or any application where high efficiency or improved performance is required. A small part of this work is also dedicated to drives using another type of machine called the brushless dc motor. Control methods for a new converter for brushless dc machines are proposed and verified via simulation. The main advantage of this converter with the proposed control is that it allows exact control of torque or speed up to twice the rated speed, which makes it useful in traction applications.
27

AVERAGE-VALUE MODELING OF HYSTERESIS CURRENT CONTROL IN POWER ELECTRONICS

Chen, Hanling 01 January 2015 (has links)
Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control. In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless dc motor drives is proposed. It incorporates a slew-rate limitation on the inductor current that occurs naturally in the circuit during large system transients. This new method is compared with existing methods in terms of simulation run time and rms error. The performance is evaluated based on a variety of scenarios, and the simulation results are compared with the results of detailed models. The simulation results show that the proposed model represents the detailed model well and is faster and more accurate than existing methods. The slew-rate limitation model of hysteresis current control accurately captures the salient detail of converter performance while maintaining the computational efficiency of average-value models. Validations in hardware are also presented.
28

Propulsion Unit of a 3DOF Helicopter

Ling, Gustav, Persson, Jesper January 2015 (has links)
This Bachelor thesis is a part of a bachelor project which includes building, programming and controlling a 3DOF tandem helicopter. This particular report deals with the propulsion units, i.e. the motors and propellers of the helicopter. It covers the process of how to determine the most suitable propulsion units for the rig that eventually will enable it to run. To achieve this, different data have been processed. Torque and thrust are two important parameters that have been studied. The data have been acquired by different tests, e.g. thrust measurements from a thrust rig. Also more complex analysis such as Blade Element Theory and Actuator Disk Theory have been carried out in order to determine the behaviour of the propulsion units. Study data sheets and databases was also a part of the work. The result of this work was two equal propulsion units which were mounted in the helicopter. They proved to work satisfactory and provided wanted dynamics to the system. / Design & Implementation of a 3DOF Helicopter
29

Acionamento do motor de corrente contínua a ímãs permanentes sem escovas utilizando estratégia a quatro chaves / Four-Switch Brushless DC Motor Drives

Brasão, Leandro Cândido 06 August 2012 (has links)
Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Permanent magnet motors possess high efficiency and can be commercially competitive. The main purpose of this paper is to describe a low cost four-switch brushless dc motor drive with compensated direct current controlled our compensated hysteresis strategy. The description of the mathematical model is used in the computational simulation models to four-switch and six-switch. These results are here compared in an experimental model of drive, where the six-switch PWM drive and hysteresis drive is compared to the four-switch hysteresis compensated drive and not compensated drive. The four-switch drive has the potential to reduce costs by reducing the number of switches in commercial, industrial and residential applications. / Motores a ímãs permanentes possuem alta eficiência e podem ser competitivos comercialmente em aplicações de potência fracionária. O trabalho apresenta uma estratégia de acionamento a quatro chaves para o motor de corrente contínua a ímãs permanentes sem escovas, com uma estratégia a baixo custo por meio do controle direto de corrente, ou controle por histerese compensado. A descrição do modelo matemático é utilizada em modelos de simulação computacionais a quatro e a seis chaves. Estes resultados são aqui comparados em um modelo experimental de acionamento, onde o acionamento a seis chaves por PWM e histerese é comparado à estratégia a quatro chaves por histerese compensado e por histerese não compensado. O acionamento a quatro chaves tem potencial para redução de custos devido à redução do número de chaves e pode ser utilizado em aplicações comerciais, industriais e residenciais. / Mestre em Ciências
30

Regulátor otáček pro střídavé motory / Controler for brushless motors

Zdařil, Tomáš January 2011 (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 function is based on the without sensors control method and circuit is controlled by the Atmel AVR. Power unit for motor is used Li – pol accumulator. The controller is equipped with a BEC to power the receiver and allows monitoring current and voltage on the accumulator. The measured data can be uploaded to a PC.

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