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Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices. In this study, a three phase induction motor drive using Insulated Gate Bipolar Transistors (IGBT) at the inverter power stage is introduced to implement speed and position control for the revolving stage in the Frederic Wood Theatre This thesis presents a solution to control a 3-phase induction motor using the Texas Instruments (TI) Digital Signal Processor (DSP) TMS320F2407A. The use of this DSP yields enhanced operations, fewer system components, lower system cost and increased efficiency. The control algorithm is based on the constant volts-per-hertz principle because the exact speed control is not needed. Reflective object sensors which are mounted on concrete frame are used to detect accurate edge position of revolving stage. The sinusoidal voltage waveforms are generated by the DSP using the space vector modulation technique. In order to satisfy some operating conditions for safe and agreeable operation, a look-up table, which is used to give command voltage and speed signals in software, is applied to limit the maximum speed and acceleration of the revolving stage. Meanwhile, a boost voltage signal is added at the low frequency areas to make the motor produce maximum output torque when starting. A test prototype is then built to validate the performance. Several tests are implemented into the IGBT drive to explore the reason for unacceptable oscillations in IGBT’s gate control signals. Improvement methods in hardware layout are suggested for the final design.

Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices. In this study, a three phase induction motor drive using Insulated Gate Bipolar Transistors (IGBT) at the inverter power stage is introduced to implement speed and position control for the revolving stage in the Frederic Wood Theatre This thesis presents a solution to control a 3-phase induction motor using the Texas Instruments (TI) Digital Signal Processor (DSP) TMS320F2407A. The use of this DSP yields enhanced operations, fewer system components, lower system cost and increased efficiency. The control algorithm is based on the constant volts-per-hertz principle because the exact speed control is not needed. Reflective object sensors which are mounted on concrete frame are used to detect accurate edge position of revolving stage. The sinusoidal voltage waveforms are generated by the DSP using the space vector modulation technique. In order to satisfy some operating conditions for safe and agreeable operation, a look-up table, which is used to give command voltage and speed signals in software, is applied to limit the maximum speed and acceleration of the revolving stage. Meanwhile, a boost voltage signal is added at the low frequency areas to make the motor produce maximum output torque when starting. A test prototype is then built to validate the performance. Several tests are implemented into the IGBT drive to explore the reason for unacceptable oscillations in IGBT’s gate control signals. Improvement methods in hardware layout are suggested for the final design.

Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices. In this study, a three phase induction motor drive using Insulated Gate Bipolar Transistors (IGBT) at the inverter power stage is introduced to implement speed and position control for the revolving stage in the Frederic Wood Theatre This thesis presents a solution to control a 3-phase induction motor using the Texas Instruments (TI) Digital Signal Processor (DSP) TMS320F2407A. The use of this DSP yields enhanced operations, fewer system components, lower system cost and increased efficiency. The control algorithm is based on the constant volts-per-hertz principle because the exact speed control is not needed. Reflective object sensors which are mounted on concrete frame are used to detect accurate edge position of revolving stage. The sinusoidal voltage waveforms are generated by the DSP using the space vector modulation technique. In order to satisfy some operating conditions for safe and agreeable operation, a look-up table, which is used to give command voltage and speed signals in software, is applied to limit the maximum speed and acceleration of the revolving stage. Meanwhile, a boost voltage signal is added at the low frequency areas to make the motor produce maximum output torque when starting. A test prototype is then built to validate the performance. Several tests are implemented into the IGBT drive to explore the reason for unacceptable oscillations in IGBT’s gate control signals. Improvement methods in hardware layout are suggested for the final design. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In this dissertation, a novel two-phase switched reluctance machine (SRM) with a stator comprised of E-core structure having minimum stator core iron is presented for low-cost high-performance applications. In addition, three new magnetic structures for the E-core SRM comprising two segmented stator cores or a monolithic stator core are proposed for good manufacturability, mechanically robustness, ease of assembly, and electromagnetic performance improvement. Each E-core stator in the segmented structure has three poles with two small poles at the ends having windings and a large center pole containing no copper windings. The common stator pole at the centers in the segmented E-core is shared by both phases during operation. Other benefits of the common poles contributing to performance enhancement are short flux paths, mostly flux-reversal-free-stator, constant minimum reluctance around air gap, and wide pole arc equal to one rotor pole pitch. Therefore, two additional common poles in the monolithic E-core configuration are able to significantly improve efficiency due to more positive torque and less core loss by the unique design. Using a full MEC analysis, the effect of the common-pole structure on torque enhancement is analytically verified. Efficiency estimated from the dynamic simulation is higher by 7% and 12% at 2000 rpm and by 3% and 7 % at 3000 rpm for the segmented and single-body SRMs, respectively, compared to a conventional SRM with four stator poles and two rotor poles. The new E-core SRMs are suitable for low-cost high-performance applications which are strongly cost competitive since all the new E-core SRMs have 20% cost savings on copper and the segmented E-core SRMs have 20% steel savings as well. Strong correlation between simulated and experimentally measured results validates the feasibility of the E-core common-pole structure and its performance. A simple step-by-step analytical design procedure suited for iterative optimization with small computational effort is developed with the information of the monolithic E-core SRM, and the proposed design approach can be applied for other SRM configurations as well. For investigating thermal characteristics in the two-phase single-body E-core SRM, the machine is modeled by a simplified lumped-parameter thermal network in which there are nine major parts of the motor assembly. / Ph. D.

Övertoner orsakade av varvtalsstyrda motordrifter ger problem i industrisystem. Syftet med studien är att identifiera problemen och ge rekommendationer för att undvika dem. Studien utfördes som examensjobb på KTH för konsultföretaget Ramböll. En litteraturstudie i ämnet kombinerades med elkvalitémätningar på drifter hos Sandvik Mining. Elkvalitéproblem orsakade av varvtalsstyrda motordrifter kommer till stor del av att frekvensstyrningen ger olinjärt strömuttag som, om nätet inte är tillräckligt starkt, påverkar spänningskvalitén. Problemen kan vara driftstopp, störd utrustning och ökat slitage på utrustning för att nämna några. Denna studie visar att vid ändringar i system innehållande övertoner kan framtida övertonshalter approximeras för vissa fall. För att upprätta en modell över systemet där lasten ses som en övertonsgenerator utförs mätningar före ändringen. Med vissa antaganden om nätimpedansen kan sedan beräkningar av övertonshalten i systemet efter ändring utföras. I denna studie har en förenklad modell använts för att förutse övertonshalter efter ändringar. Syftet är att visa på ett resurseffektivt sätt att approximera så att information för att förebygga problem finns vid beslutsfattande om ändringar. Elkvalitéproblem skulle kunna förebyggas i högre grad och att inte göra det är onödigt slöseri med ekonomiska, ekologiska och sociala resurser. / Harmonics caused by variable speed drives create problems in industrial systems. The purpose of this study is to identify these problems and give recommendations to avoid them. The study was conducted as a bachelor thesis at the Royal Technical University in Stockholm, Sweden for the consultant company Ramboll Energy. A literature review was combined with electrical power quality measurements on variable speed motor operations conducted at Sandvik Mining in Sandviken, Sweden. Electrical quality problems caused by variable speed drives origin mainly from frequency inverter control that gives a non-linear current usage which, if the grid is not strong enough, affects voltage quality. Examples of problems are production downtime, disruption and malfunction of equipment and increased wear of equipment. This study shows that when making changes in systems containing harmonics, future harmonic levels can be approximated in some cases. Measurements before the change provide input data to model the system, describing the load as a harmonic current generator. With some assumptions on the grid impedance, calculating an approximation on harmonic after the change is possible. This study has used a simplified model for the prediction of harmonic levels after a change in the system. The purpose is to propose a cost effective way to approximate so that information on how to prevent problems …in the decision making. Electrical power quality problems could be prevented more often and not doing that is a waste of economical, environmental and social resources.

Выпускная квалификационная работы выполнена на тему «Разработка принципов построения малогабаритного снегоболотохода с дистанционным управлением». Расчетно-пояснительная записка содержит 198 листов, 90 рисунков, 16 таблиц, 11 источников, 42 приложения. Объектом разработки является малогабаритный снегоболотоход с дистанционным управлением, предназначенный для инженерно-изыскательских работ. Цель работы – разработка принципов построения малогабаритного снегоболотохода с дистанционным управлением, в том числе разработка новых узлов, выбор из ранее представленных, модернизация и реконструкция элементов, разработанных для других машин. В результате проведенной работы спроектированы 3 шнековых движителя, 4 подвески, 2 системы управления, также рассмотрены блоки задания скорости, кольцевые распределители импульсов и преобразователи «Код-напряжение». В проекте также рассмотрены вопросы безопасности труда, радиационная безопасность и природопользование и охрана окружающей среды. В разделе технико-экономических показателей приведены единовременные, текущие и приведенные затраты. / The goal of the research was to justify the selection of various structural elements and control systems on the basis of both design parameters and the analysis of assigned tasks. Thus, a number of existing designs of machines, propellers and suspensions were considered in the course of the study, all of which could be used for different purposes: for example, it is more rational to utilize motor-in-wheel propellers to glide over the water, since those are most lightweight and waterproof of all, and to choose a spring suspension – since it contains the minimal number of elements which could fail in the water medium. As to the systems of control, the selection of their control blocks is made on the criteria of reliability, since it is necessary to ensure no-failure operation of the system as a whole. As a result of the work, 3 screw propellers, 4 suspensions, 2 control systems were designed, and a few speed assignment blocks, circular distributors of impulses and number-to-voltage converters were considered. The project also analyses the problems of work safety, radiation safety, conservation and environment control. The section on project feasibility cites nonrecurring, current and reduced costs.