Tesis sobre el tema "High inductions"
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KHAN, MAHMOOD. "Experimental and Theoretical Analysis of Soft Magnetic Materials for Power applications". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2669467.
Texto completoKwong, Kam-Yuen. "Quantum induction and Higgs mass". Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289767.
Texto completoHua, Xia. "Induction heating for high temperature catalysis". Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695372.
Texto completoJohnson, Andrew P. (Andrew Peter). "High speed linear induction motor efficiency optimization". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/10945/11052.
Texto completoCIVINS
One of the reasons linear motors, a technology nearly a century old, have not been adopted for a large number of linear motion applications is that they have historically had poor efficiencies. This has restricted the progress of linear motor development. The concept of a linear motor as a rotary motor cut and laid out flat with a conventional rotary motor control scheme as a design basis may not be the best way to design and control a high-speed linear motor. End effects and other geometry subtleties of a linear motor make it unique, and a means of optimizing efficiency with both the motor geometry and the motor control scheme will be analyzed to create a High-Speed Linear Induction Motor (LIM) with a higher efficiency than what is possible with conventional motors and controls. This thesis pursues the modeling of a short secondary type Double-Sided Linear Induction Motor (DSLIM) that is proposed for use as an Electromagnetic Aircraft Launch System (EMALS) aboard the CVN-2 1. Mathematical models for the prediction of effects that are peculiar to DSLIM are formulated, and their overall effects on the performance of the proposed machine are analyzed.;3 |a(cont.) These effects are used to generate a transient motor model, which is then driven by a motor controller that is specifically designed to the characteristics of the proposed DSLIM. Due to this DSLIM's role as a linear accelerator, the overall efficiency of the DSLIM will be judged by the kinetic energy of the launched projectile versus the total electric energy that the machine consumes. This thesis is meant to propose a maximum possible efficiency for a DSLIM in this type of role.
Telford, Dwayne. "Techniques for high performance induction machine control". Thesis, Heriot-Watt University, 2002. http://hdl.handle.net/10399/445.
Texto completoCeron, Guerrero Jose Hermilo. "Design of a high specific torque induction motor". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/design-of-a-high-specific-torque-induction-motor(723d535b-d9f0-400d-b0ba-84e77af0e8c0).html.
Texto completoVazquez, Kalty. "Synthesis of Carbon Nanotubes Using High Voltage and High Frequency Induction Field". FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1031.
Texto completoDe, Jesus Cristina Gililland. "Principal induction and training within conversion charter schools". Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1930906681&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Texto completoBlasco, Giménez Ramón. "High performance sensorless vector control of induction motor drives". Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/13038/.
Texto completoEnglebretson, Steven Carl. "Excitation and control of a high-speed induction generator". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34369.
Texto completoIncludes bibliographical references (leaves 97-99).
This project investigates the use of a high speed, squirrel cage induction generator and power converter for producing DC electrical power onboard ships and submarines. Potential advantages of high speed induction generators include smaller size and weight, increased durability, and decreased cost and maintenance. Unfortunately, induction generators require a "supply of reactive power" to run and suffer from variation in output voltage and frequency with any changes to the input reactive power excitation, mechanical drive speed, and load. A power converter can resolve some of these issues by circulating the changing reactive power demanded by the generator while simultaneously controlling the stator frequency to adjust the machine slip and manage the real output power. This combination of real and reactive power control will ensure a constant voltage DC bus over the full load range. Tests were performed on a three horsepower motor to help validate models and simulations at both the two kilowatt and 5 megawatt level. After determining the equivalent circuit of the demonstration motor, it was tested as a generator under grid connected and capacitor excited conditions. A stand-alone five megawatt, 12,000 RPM generator designed specifically to operate at high efficiency and power factor over the full load rang was used to design converter parameters. A variety of reactive power excitation strategies were briefly examined before the flow of reactive currents through a converter was explained using a six step inverter with two different switching schemes.
(cont.) Steady state and transient simulations matched the measured machine performance and illustrated the performance of the control strategy as the load changes. Keywords: induction generator, self-excitation, reactive power, power converter, rectifier.
by Steven Carl Englebretson.
S.M.
Spits, Warnars Harco Leslie Hendric. "Attribute Oriented Induction High Level Emerging Pattern (AOI-HEP)". Thesis, Manchester Metropolitan University, 2013. http://e-space.mmu.ac.uk/315710/.
Texto completoPapini, Luca. "Performance calculation of high speed solid rotor induction machine". Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52180/.
Texto completoPiercy, Garth Eugene Klass Patricia Harrington. "Illinois secondary school teachers' perceptions of 1988-89 induction year activities". Normal, Ill. Illinois State University, 1990. http://wwwlib.umi.com/cr/ilstu/fullcit?p9105740.
Texto completoTitle from title page screen, viewed November 21, 2005. Dissertation Committee: Patricia H. Klass (chair), Joseph H. Braun, Ronald L. Laymon, Mary Ann Lynn, Patricia O'Connell, Sally B. Pancrazio. Includes bibliographical references (leaves 122-128) and abstract. Also available in print.
Pforr, Johannes. "Single-ended resonant pre-converters for high-frequency induction heaters". Thesis, Teesside University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489035.
Texto completoSaleh, Kamel Subhi. "Sensorless Control of High Power Induction Motors Using Multilevel Converters". Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523161.
Texto completoBrown, Christopher P. (Christopher Perry). "Design for manufacturability of a high-performance induction motor rotor". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38170.
Texto completoRajamani, Haile-Selassie. "High speed, three-phase induction motor drives for domestic appliances". Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627054.
Texto completoKhan, Irshad. "Analysis and design of a high frequency induction-heating system". Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/17437.
Texto completoAdvances in power electronic semiconductor technology are making high frequency converters for induction heating more feasible at power levels up to 50kW. This research presents the development and analysis of a solid-state induction-heating system, operating directly off single-phase mains frequency, which enables optimum and efficient operation over a frequency range of 80kHz to 200kHz. The system essentially comprises a DC-DC converter configured as a controlled current source, which feeds a load resonant DC-AC inverter, driving a parallel resonant load circuit. The load circuit comprises an induction-heating coil and a reactive power compensating capacitor. The systems active switching elements comprise power MOSFET's but can be extended to almost any other controlled power devices such as IGBT's, BJT's, SCR's, GTO's or SIT's. An automatic frequency control system ensures that the DC-AC inverter drives the load at its resonant frequency, thereby achieving zero voltage switching of the power semiconductors. This operating mode always ensures maximum power transfer to the load as well as maximum operating efficiency of the DC-AC inverter. Driving the load at resonance presents an essentially resistive load to the DC-DC converter, thereby reducing the losses associated with a reactive load. A compact circuit layout combined with this optimum mode of operation eliminates the need for any snubber circuit components in both the DC-DC and DC-AC converters at this power level. An overview into various applications and technologies of induction-heating is presented in this research. A detailed analysis of the induction-heating coil and work- piece are presented in order to aid the design of the load circuit. The induction-heating technology overview presents various induction-heating power sources, discussing the configurations of various topologies. A brief mathematical analysis is used to describe the operation of power electronic converters employed in the induction-heating system developed for this research. The parallel resonant induction-heating load circuit is characterised mathematically, allowing for the determination of the optimum operating conditions. This is followed by a simulation analysis, which is used to gain insight into the problem of frequency control. The frequency control system is modelled and the steady-state error response evaluated under different input conditions. Experimental results on the system implemented, based on operating waveforms and efficiency measurements of the solid-state induction-heating system are presented along with recommendations for future work. The implemented power source was tested at a maximum power of 2.3kW at 151kHz. A system efficiency of 86% at 1.3kW was measured when operating at 138kHz. This design however, provides for scaling to power levels up to 50kW. The induction-heating system's frequency tracking capability is evaluated by heating a steel work-piece through its Curie transition temperature. The induction-heating system is used to heat a 26mm x 35mm stainless-steel billet (work-piece) to 1200°C in 130 seconds using the calculated power of 1.35kW .
DOERGER, DANIEL W. "FINDING FORESTT HIGH SCHOOL: FORMAL AND INFORMATION INDUCTION AND THE ENCULTURATION OF NEW TEACHERS". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1027006640.
Texto completoAmrhein, Andrew Aloysius. "Induction Heating of Aluminum Cookware". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/77400.
Texto completoMaster of Science
Elkhomri, Othman. "DSP IMPLEMENTATION OF DC VOLTAGE REGULATION USING ADAPTIVE CONTROL FOR 200 KW 62000 RPM INDUCTION GENERAT". Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2926.
Texto completoM.S.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering
Doering, Sagui Araceli. "The Induction Mentor Voice| A Phenomenological Study of Effective Practices for High Quality K-12 Teacher Induction Mentoring". Thesis, Pepperdine University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10743861.
Texto completoIn education, mentoring is pivotal in the early development and long-term success and self-directed efficacy of new teachers. With increasing acknowledgment of the importance of mentoring as the preferred means of induction support for new teachers, mentors can serve to positively impact the overall quality of teaching and learning. Yet, like the induction protocols in other professional occupations, the nature of induction programs in education has taken a variety of forms in more recent years. For mentors, these experiences create added obligations and time away from their own professional responsibilities. Although previous research points to the importance of mentoring and its effectiveness in supporting novices, giving voice to the induction mentor as related to the most effective practices for high quality induction mentoring merits further investigation and an obligation to those who lead them.
The purpose of this study was therefore to contribute to the body of knowledge and literature pertaining to high quality mentoring experiences, specifically as related to the lived experiences and perceptions of effective practices for preparing, developing, and retaining K-12 teacher induction mentors. The participants in this study consisted of K-12 teacher induction mentors at a teacher induction program in Southern California. This study was made possible through the utilization of a phenomenological method, namely through a qualitative phone interview approach.
The findings led to the following five conclusions: (1) prior life and professional experience are pivotal to the manner in which situational learning is acquired and internalized, strongly influencing the way mentors engage in future action; (2) induction mentor preparation and support are crucial to the success of the mentor in their service to new teachers and in their own professional development as educators; (3) time is pivotal to the formulation of and reaping of quality induction experiences; (4) the value of required induction projects is key to the significance of the induction work; and (5) meaningful reflective practices are fundamental to the internal motivation and transformation of the mentor as a professional learner. Implications for policy and recommendations for additional research are discussed at the end of the study.
Teske, Nikolas. "Sensorless position control of induction machines using high frequency signal injection". Thesis, University of Nottingham, 2001. http://eprints.nottingham.ac.uk/13117/.
Texto completoAl-Obaidi, Amar Baker Salim. "Induction Assisted Single Point Incremental Forming of Advanced High Strength Steels". Universitätsverlag der Technischen Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A31527.
Texto completoDie induktionsgestützte, inkrementelle Blechumformung (englisch: Induction Assisted Single-Point Incremental Forming IASPIF) ist Warmumformprozess, bei dem keine komplexen Werkzeuge wie beim Tiefziehen und Biegen benötigt werden. Inhalt dieser Arbeit ist die inkrementelle Umformung eines Bleches mit gleichzeitig ablaufender induktiver Erwärmung. Das Forschungsziel bestand in der Verbesserung der Umformbarkeit von hochfesten Stahlwerkstoffen wie DP600, DP980 und 22MnB5 durch eine gezielte partielle Erwärmung. Der prinzipielle Aufbau des Versuchsstandes besteht aus einem Spuleninduktor, der unterhalb des umzuformenden Blechs platziert ist, und der synchron mit dem Werkzeug – einem Drückdorn – während des Umformvorganges verfährt. Ein wesentlicher Untersuchungsschwerpunkt bestand in der Ermittlung der Einflussgrößen auf den untersuchten IASPIF-Prozess. Für die Bewertung der Umformbarkeit wurden hierbei der maximal erreichbare Teilwandwinkel und die Profiltiefe, die in einem Umformdurchgang herstellbar waren, ermittelt und ausgewertet. Darüber hinaus konnten im Rahmen der Arbeit die Induktionsleistung des Generators, der Werkzeugdurchmesser und die Werkzeugvorschubgeschwindigkeit als relevante Prozessparameter identifiziert werden. Im Ergebnis der durchgeführten Untersuchungen zeigten die Werkzeugvorschubgeschwindigkeit und die Induktionsleistung einen wesentlichen Einfluss auf die erreichbare Profiltiefe. Aufbauend auf den erzielten Ergebnissen konnte eine prozessangepasste Umformstrategie entwickelt werden, bei der eine konstante Erwärmungstemperatur durch das Koppeln der momentanen Profiltiefe mit einer sukzessiv steigenden Werkzeugvorschubgeschwindigkeit erreicht wird. Weiterhin ließen sich die Kräfte bei der Umformung eines Stahlbleches aus DP980 von 7 kN (bei Raumtemperatur) auf 2,5 kN (bei erhöhter Temperatur) reduzieren. Aufgrund des mit einem Streckziehvorgang vergleichbaren Spannungszustandes während des Umformprozesses war eine starke Verringerung der resultierenden Wanddicke zu beobachten. Als neue Erkenntnis in dieser Untersuchung konnte die umgekehrte Beziehung zwischen der Zustelltiefe und dem Dickenreduktionsprozentsatz abgleitet werden. Aus der Finite - Elemente - Simulation des vorgestellten Umformprozesses wurde erkennbar, dass die Erhöhung der Erwärmungstemperatur einen direkten Einfluss auf die plastische Dehnung von 0,2 (bei Raumtemperatur) auf 1,02 (bei 800 °C) hat. Mittels der numerischen Simulation und der nachfolgenden experimentellen Validierung erfolgte darüber hinaus die Bestimmung der maximalen wahren Dehnung, die in der resultierenden Wanddicke erreicht wurde. Bei den Versuchen mit der größten Zustellung ließ sich durch die Bestimmung der Teileformgenauigkeit die höchste Abweichung von der Sollgeometrie CAD Modell feststellen. Abschließend wurde nachgewiesen, dass der IASPIF Prozess auch zur Einstellung maßgeschneiderter Bauteileigenschaften wie der resultierenden mechanischen Eigenschaften des Blechmaterials aus 22MnB5 einsetzbar ist. Zu diesem Zweck wurden die Bleche während des Umformprozesses lokal induktiv erwärmt und anschließend zur Einstellung des gewünschten Gefüges bei unterschiedlichen Abkühlgeschwindigkeiten abgeschreckt.
Low, Zhen Ning. "High efficiency loosely coupled wireless power transfer system via magnetic induction". [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024707.
Texto completoYohn, Jason Lee. "The perceptions of Alabama high school principals on the key components of teacher induction programs". Auburn, Ala., 2007. http://repo.lib.auburn.edu/07M%20Dissertations/YOHN_JASON_24.pdf.
Texto completoAllen, Benjamin William. "Creep and Elevated Temperature Mechanical Properties of 5083 and 6061 Aluminum". Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/52630.
Texto completoMaster of Science
Jenson, Lacey Jo. "Induction and Inhibition of a Neuronal Phenotype in Spodoptera Frugiperda (Sf21) Insect Cells". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/40929.
Texto completoMaster of Science
Peabody, Frank Gerald. "An investigation of high speed, thin steel rotor, annular, double sided, linear induction motors". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29056.
Texto completoApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Hayford, Frank. "CLEANLINESS ASSESSMENT OF STEEL BARS PRODUCED FROM A HIGH FREQUENCY INDUCTION FURNACE". Thesis, KTH, Tillämpad processmetallurgi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-125018.
Texto completoSewell, Henry Isaac. "The design and analysis of a high power factor induction heating system". Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632417.
Texto completoYu, Xing. "Control aspects of a high performance induction machine drive with parameter identification". Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/1229.
Texto completoCartwright, Anthony. "Computer simulation of high performance, reed valve induction, two-stroke cycle engines". Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318929.
Texto completoYan, Pei. "High frequency induction welding & post-welding heat treatment of steel pipes". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609702.
Texto completoNorman, Rosemary Anne. "High-performance current regulation for voltage-source-inverter-fed induction motor drives". Thesis, University of Bradford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514187.
Texto completoLiu, Zidong. "High Frequency Inverter Power Stage Design Considerations for Non-Magnetic Materials Induction Cooking". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/40674.
Texto completoMaster of Science
Razzak, M. A., Y. Suzuki, S. Takamura y Y. Uesugi. "High Pressure Radio Frequency Induction Thermal Plasma Generation Using T-LCL Immittance Circuit". IEEE, 2004. http://hdl.handle.net/2237/7108.
Texto completoMurgatroyd, Scott Richard. "'Parameters determining the induction and recovery of high intensity exercise intolerance in man". Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521468.
Texto completoRanft, Cornelius Jacobus Gerhardus. "Mechanical design and manufacturing of a high speed induction machine rotor / Cornelius Ranft". Thesis, North-West University, 2010. http://hdl.handle.net/10394/4940.
Texto completoThesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2011.
MOHAMED, MAHMOUD. "Model predictive control: an effective control approach for high performance induction machine drives". Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424942.
Texto completoGli azionamenti con machine ad induzione (macchine asincrone nelle loro varie configurazioni), stanno riacquistando molta attenzione in diverse applicazioni industriali. A causa di questo crescente interesse applicativo, è diventato di essenziale importanza lo sviluppo di efficaci tecniche di controllo per ottenere dagli azionamenti in questione elevate prestazioni dinamiche. Fino ad oggi, il controllo degli azionamenti con macchina a induzione alimentati da convertitori di potenza è basato sul “principio del valore medio” delle grandezze in commutazione, utilizzando la modulazione di larghezza di impulsi con controllori lineari in una struttura a cascata. Recenti ricerche hanno dimostrato che è possibile utilizzare il Controllo Predittivo per controllare gli azionamenti con macchina a induzione, con l'utilizzo di convertitori di potenza senza utilizzare modulatori e controllori lineari. Questo nuovo approccio avrà un forte impatto sul controllo dell'elettronica di potenza nei prossimi decenni. I vantaggi del Controllo Predittivo derivano dalla possibilità di perseguire problemi multi-obiettivo, di includere facile le non linearità all'interno del modello, di trattare in modo semplice i vincoli di sistema, nonché dalla facilità di implementazione digitale e dalla flessibilità di includere modifiche ed estensioni al controllo secondo le applicazioni richieste. Inlinea con tutto ciò, la ricerca presentata in questa tesi riguarda lo sviluppo di diverse topologie di controllo per varie configurazioni di azionamenti con macchine a induzione, basate sul principio di Controllo Predittivo a modello con insieme finito degli stati di controllo (Finite Control Set Model Predictive Control - FCS-MPC), che definisce direttamente l’assetto dell'inverter di tensione (VSI). Inoltre, per aumentare la robustezza degli azionamenti, vengono proposti e sperimentati diversi approcci senza sensori elettromeccanici (sensorless). La prima topologia studiata di azionamenti con macchina a induzione (IM) è l'azionamento con motore a gabbia. Il controllo diretto di coppia (DTC) è aggiornato in termini di controllo predittivo a modello (MP DTC) e usato per controllare la coppia e il flusso statorico attraverso l'utilizzo di una efficace funzione di costo attraverso la quale è anche possibile facilmente comprendere e confrontare le varianti di implementazione e studiare i problemi di convergenza e di stabilità. Viene analizzato l'effetto della velocità sulle diverse versioni di controllo e sulle prestazioni complessive del MP DTC proposto; ciò consente di comprendere appieno il principio del DTC, nonché perché e quando esso funzioni bene. Vengono utilizzate due diverse procedure di stima della posizione e della velocità del rotore nel MP DTC proposto; il primo utilizza uno stimatore adattivo con modello di riferimento (MRAS), mentre l'altro sfrutta la stessa fase di predizione del MP DTC proposto per ottenere le informazioni sulla velocità effettuando infine un'estrapolazione lineare dei valori di velocità a partire dagli ultimi due campioni stimati. Sono state eseguite numerose prove in simulazione e sperimentali per convalidare l'efficacia di entrambi gli approcci sensorless nell’ottenere un preciso inseguimento del comando di velocità per una vasta gamma di situazioni. Per migliorare la robustezza del MP DTC proposto rispetto alle variazioni parametriche, il controllo del flusso dello statore viene sostituito con quello della potenza reattiva assorbita dal motore ad induzione; di conseguenza la sensibilità del controllo alle variazioni dei parametri è limitata e ciò è confermato attraverso i risultati ottenuti sia dalla simulazione che dalle prove sperimentali. Inoltre, viene presentato un ulteriore efficace approccio alternativo per il MP DTC, basato sul principio del controllo predittivo a modello dei valori istantanei delle potenze attive e reattive dell'azionamento, invece di controllare la coppia e il flusso come nell’usuale MP DTC. Questa variante ha il vantaggio che tutte le variabili controllate sono divenute quantità misurate (potenze attive e reattive) e quindi i problemi di stima comunemente presenti nei classici schemi DTC sono efficacemente limitati. Per gli ultimi due approcci di controllo (controllo di coppia e di potenza reattiva e controllo di potenza attiva e reattiva) viene anche adottato la stima della velocità rotorica che sfrutta la funzione predittiva del controllo. I risultati ottenuti attraverso la simulazione e la sperimentazione confermano la fattibilità delle due procedure alternative di controllo per ottenere una risposta dinamica robusta dell’azionamento con IM. Per limitare il ripple che accompagna gli andamenti controllati della coppia e del flusso statorico del motore, è stata presentata una tecnica efficace di riduzione della sua ampiezza. La tecnica è basata sull’impiego di un valore ottimale per il fattore di ponderazione w_f utilizzato nella funzione di costo per sommare i due contributi che la definiscono. Viene introdotta una derivazione matematica dettagliata del valore ottimale di w_f attraverso l'analisi dei comportamenti dell’ondulazione di coppia e del flusso. La tecnica di riduzione del ripple proposta è stata verificata tramite la simulazione usando il software Matlab/Simulink e sperimentalmente utilizzando la scheda di rapida prototipazione del controllo dSpace 1104. Ancora, l'implementazione adotta l'approccio sensorless basato sulla fase di predizione. Le prestazioni dell’azionamento con IM utilizzando quest’ultimo approccio proposto sono confrontate con i risultati ottenuti con l'approccio MP DTC che utilizza invece un valore arbitrario di w_f. Il confronto conferma la validità della procedura di riduzione del ripple nelle variabili controllate mantenendo nel contempo gli oneri di calcolo entro i limiti consentiti per l'implementazione. Il principio FCS-MPC è anche utilizzato per controllare la corrente del motore di induzione come alternativa al controllo classico ad orientamento di campo (Field Oriented Control -FOC). L'approccio proposto di controllo di corrente di tipo predittivo (Model Predictive Current Control - MPCC) appartiene alla classe del controllo predittivo ad isteresi (per limitare il frequenza di commutazione) in quanto il MPCC viene attivato dal raggiungimento dell’errore di corrente di una determinata soglia. In questo caso, la caratteristica sensorless dell’azionamento è ottenuta includendo un efficace osservatore Luenberger (LO) per una precisa stima del vettore del flusso del rotore insieme alla coppia di carico e alla velocità. È stata adottata una efficace procedura di allocazione dei poli per la selezione dei guadagni dell'osservatore; la procedura si basa sul posizionamento dei poli dell'osservatore a sinistra di quelli del motore nel complesso (piano di s) con una ridotta parte immaginaria, in modo che la stabilità dell'osservatore sia migliorata in un'ampia gamma di velocità. La fattibilità dell'azionamento sensorless con MPCC è ancora confermata attraverso la simulazione e i risultati sperimentali. La seconda topologia degli azionamenti con macchina a induzione che è stata studiata è l'azionamento con motore ad anelli con rotore alimentato da invertitore e statore da rete (Doubly Fed Induction Motor DFIM). È stato sviluppato un efficace algoritmo predittivo a modello (MP DTC) per il controllo dinamico della coppia e del flusso di rotore dell'azionamento DFIM. Inoltre, viene presentato un approccio efficace di soluzione sensorless che valuta la velocità e la posizione del rotore in modo esplicito senza la necessità di coinvolgere la stima del flusso nel processo di predizione; di conseguenza l'effetto delle variazioni dei parametri sulle prestazioni complessive dell'osservatore di posizione e velocità è sensibilmente limitato. Questo è stato provato attraverso i risultati ottenuti con test eseguiti in un'ampia gamma di velocità, dal sub-sincronismo a velocità super-sincrona. Durante l'operazione, la resistenza dello statore e i valori di induttanza di magnetizzazione sono stati modificati rispetto ai valori reali per studiare l'effetto di variazioni parametriche sulle prestazioni dell'osservatore. Anche in questo caso, il software Matlab/Simulink e una scheda di controllo dSpace 1104 sono stati utilizzati per convalidare l'efficacia dell'approccio sensorless del MP DTC per l’azionamento. I risultati dimostrano la robustezza del controllo sensorless proposto e la sua capacità di ottenere una precisa stima della posizione e della velocità del rotore. La terza topologia di azionamenti con macchina a induzione che è stata studiata è quella del generatore ad induzione con rotore avvolto (DFIG) e invertitore sul rotore. Viene presentata una derivazione analitica dettagliata del controllo predittivo diretto di potenza (MP DPC) per DFIG, che trasferisce ed estende l’approccio di controllo del MP DTC citato prima per il motore a induzione a doppia alimentazione (DFIM). Una soluzione sensorless ancora basata sull'osservatore adattivo a modello di riferimento (MRAS) è adottato per stimare la velocità e la posizione del rotore. Sia le simulazioni usando il software Matlab/Simulink che i test sperimentali utilizzando la scheda dSpace 1104 hanno mostrato le elevate prestazioni dinamiche dell'azionamento. I risultati ottenuti confermano la fattibilità del metodo MP DPC proposto per ottenere un controllo disaccoppiato di potenze attive e reattive per DFIG. In sintesi, si può dire che l'utilizzo proposto del controllo predittivo a modello ha dimostrato la sua capacità di ottenere elevate prestazioni dinamiche per le diverse topologie degli azionamenti con macchina ad induzione considerati. Inoltre, le tecniche sensorless proposte hanno confermato la loro efficacia per una vasta gamma di velocità. Tutto questo è stato verificato e validato attraverso una vasta attività analisi simulativa e di sperimentazione in laboratorio.
Nounezi, Thomas. "Light Weight and High Strength Materials Made of Recycled Steel and Aluminum". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20523.
Texto completoUugwanga, Tulonga Tulimeutho. "An investigation of the coping mechanisms of novice teachers : a study of selected high schools in the Oshikoto Region of Namibia". Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2155_1318832634.
Texto completoAlthough there are several achievements made by the Namibian government after independence, there are still many constraints and challenges facing the education system, particularly with regard to novice teachers&rsquo
support and professional development. Most novice teachers are coming into the teaching profession and receive little or no assistance. Nevertheless, novice teachers are expected to perform the full teaching responsibilities despite their inexperience. Novice teachers are expected to formulate their own coping strategies and to grapple with the challenges they encounter during their first year of teaching on their own. This study aims at investigating the coping mechanisms used by novice teachers to achieve their teaching goals during their first year of teaching. The study recommends that the teacher training institutions, the Ministry of Education and schools have an important role to play in facilitating the use of effective coping mechanisms and in assisting novice teachers in alleviating these challenges. Teacher training should ensure that a balance is maintained between theory and practice. In addition the Ministry needs to provide favourable working conditions and put up support systems for novice teachers. Schools should also provide orientation to all novice teachers and most especially render support to all novice teachers until they are fully integrated into the school and teaching culture.
Lee, Seung-Ju. "Multiple simultaneous specifications (MSS) control design method of a high-speed AC induction motor". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0024/MQ50487.pdf.
Texto completoChen, Fang. "Sliding-mode control and observer design for high performance control of an induction machine". Thesis, Heriot-Watt University, 2002. http://hdl.handle.net/10399/397.
Texto completoWang, Chien-Lin y 王建霖. "A Novel High Performance Parallel Resonant High Frequency Induction Heater". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/55ycsx.
Texto completo國立虎尾科技大學
電機工程研究所
102
In this thesis, a novel high performance parallel resonant high frequency induction heater is proposed. The induction heater consists of three-phase AC/DC buck-boost converter, single-phase DC/AC inverter and RLC parallel resonant circuit. Compare to the traditional two-stage resonant induction heater, the proposed induction heater has several advantages such as one-stage structure, unity power factor, pure sinusoidal input current and simple control circuit etc.. The three-phase AC/DC buck-boost converter is operated at discontinuous current mode. In order to produce maximum power output, three inductor currents are converted to single phase high frequency current source to supply RLC parallel resonant circuit. Make the switches of converter and inverter synchronous switching with Altera MAXR II Micro Kit EPM2210F324C3 and Quartus II 9.0 software for controlling signal. Finally, some experimental results are presented to verify the feasibility of the proposed induction heater.
Chuang, Erh-Lung y 莊二龍. "Characteristic Analyses of High Efficiency Induction Machines". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/20080491282489446650.
Texto completo國立成功大學
電機工程學系碩博士班
91
The purpose of this thesis focuses on both efficiency improvement and characteristic analyses of conventional induction machines. The primary drawback of a conventional induction machine is its lower efficiency as compared to a synchronous machine of the same ratings and size. This thesis employs both equivalent-circuit method and finite-element method to analyze transient and steady-state performance of an induction machine in order to promote efficiency by modifying its size, the employed core material, and difference design scheme, etc. The performance of two three-phase, 220 V(Δ)/380 V(Y), 4 poles, 1 HP induction machines of conventional and high-efficiency are employed to investigate and compared. Three operating modes of an induction machine, i.e., induction motor, isolated self-excited induction generator and grid-connected induction generator, are respectively utilized. Both steady-state and transient characteristics as well as both experimental and simulated results of the two studied induction machines are performed and compared in order to validate the important features of the high-efficiency induction machines.
Fung, Justin. "Induction heat treated high strength suspension spring steels". 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=442093&T=F.
Texto completoHUANG, CHIH-YI y 黃志毅. "Implementation of High Performance Induction Motor Drive System". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/86571539347420328066.
Texto completo國立成功大學
電機工程學系
88
This dissertation proposes an induction motor drive with current and torque control. The current control based on the current error with the current controller yields the control signal of current controller. The torque control based on the torque error with the torque controller yields a control signal of torque controller. According to the output signal of current controller and torque controller, the appropriate voltage vector is selected by using a look-up table to control the induction motor drive to obtain a rapid speed response. The torque controller, current controller, and stationary reference frame transform are constructed by the hardware which reduce the running time of the microcomputer to obtain a high performance drive. Meanwhile, employing the advantages of the added zero voltage vector to reduce the inverter switching frequency greatly increasing the efficiency of the inverter. This dissertation also presents a control scheme for an induction motor drive which consists of a compensator, neural network identification (NNI) and neural network load torque estimator (NNLTE) based on the conventional proportional-integral (PI) controller. The NNI is a two-layer neural network which uses a projection algorithm to estimate the parameters of the induction motor and to regulate the gain of the compensator such that the response of the induction motor follows that of the nominal plant. The NNLTE is a two-layer neural network which uses the steepest descent algorithm to estimate the load disturbance and forward feed resulting in equivalent control such that the speed response of the induction motor is robust against the load disturbance. Computer simulations and experiment results demonstrate that the proposed method can obtain a high performance induction motor drive.
Maly, Douglas. "High-frequency time harmonic losses in induction motors". 1991. http://catalog.hathitrust.org/api/volumes/oclc/24895859.html.
Texto completoTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 197-201).
Lee, Ching-Lin y 李青霖. "Saturated Reluctance Identification of high voltage Induction Motor and Estimation of Induction Motor/Generator Effect". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/77840688616175114971.
Texto completo國立中山大學
電機工程學系研究所
91
Saturated reluctance identification of induction motor can be implemented by additional sensor, finite-element method, spectrum analysis, or step voltage test in the research accounts. But it is not easy to implement in the field evaluation when we need to build up the power system model, because of the factory parameter absent, expansive cost, extra sensor installation, or variable voltage and frequency. To be concerned with practicality, it is always inconvenient to build up simulation for the end user. The linear model of motor can’t provide the simulation answer accurately when models run into saturated during power system transient. Accordingly, this thesis discuss two paragraphs as following: First, This thesis introduces a simple and practical method base on the manufacturer instruction manual to estimate the saturated reluctance of high / medium voltage induction motor in modeling. And we can analyze the motor dynamic characteristic by using the induction motor d-q-0 model directly, in place of traditional mathematical power equations. Moreover, we can evaluate the motor-generation reaction because of the rotor inertia due to loss of voltage. To identify the discrepancy between numeral situations what the line capacitor existed or not. Besides, we can explain the existing voltage after power system break down by comparing the simulation result with recorder chart.