Dissertations / Theses: 'VARIABLE-SPEED MOTOR'

1

Stefani, Andrea <1976&gt. "Induction Motor Diagnosis in Variable Speed Drives." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2311/.

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Several diagnostic techniques are presented for the detection of electrical fault in induction motor variable speed drives. These techinques are developed taking into account the impact of the control system on machine variables and non stationary operating conditions.

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Maggs, John David. "Electromagnetic interference from variable speed motor drives." Thesis, Aston University, 1996. http://publications.aston.ac.uk/15347/.

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A methodology is presented which can be used to produce the level of electromagnetic interference, in the form of conducted and radiated emissions, from variable speed drives, the drive that was modelled being a Eurotherm 583 drive. The conducted emissions are predicted using an accurate circuit model of the drive and its associated equipment. The circuit model was constructed from a number of different areas, these being: the power electronics of the drive, the line impedance stabilising network used during the experimental work to measure the conducted emissions, a model of an induction motor assuming near zero load, an accurate model of the shielded cable which connected the drive to the motor, and finally the parasitic capacitances that were present in the drive modelled. The conducted emissions were predicted with an error of +/-6dB over the frequency range 150kHz to 16MHz, which compares well with the limits set in the standards which specify a frequency range of 150kHz to 30MHz. The conducted emissions model was also used to predict the current and voltage sources which were used to predict the radiated emissions from the drive. Two methods for the prediction of the radiated emissions from the drive were investigated, the first being two-dimensional finite element analysis and the second three-dimensional transmission line matrix modelling. The finite element model took account of the features of the drive that were considered to produce the majority of the radiation, these features being the switching of the IGBT's in the inverter, the shielded cable which connected the drive to the motor as well as some of the cables that were present in the drive.

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3

Zhu, Chaoying. "Induction motor speed sensing and control." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358985.

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Salmon, John C. "A variable speed unipolar induction motor inverter drive." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46449.

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5

Lewin, Paul Leonard. "Microprocessor control of a switched reluctance motor." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262359.

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Allaith, Noori A. "Intelligent power module for variable speed AC motor drives." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361134.

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Wheeler, Patrick W. "A matrix converter for variable speed AC motor drives." Thesis, University of Bristol, 1993. http://hdl.handle.net/1983/1eec4275-808a-4125-813b-4f6e00881f44.

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Saad, S. "Efficiency of mining electrical variable speed drive systems." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381103.

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Wheeler, Jeremy Nicholas. "Back-to-back converters for variable speed motor drive applications." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294550.

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10

Chikwanda, Herbert Simbarashe. "The naturally commutated, converter-fed, variable speed induction machine drive." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47805.

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11

Zhang, Yong. "A DSP based variable-speed induction motor drive for a revolving stage." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/273.

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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.

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Dinu, Andrei. "FPGA neural controller for three-phase sensorless induction motor drive systems." Thesis, De Montfort University, 2000. http://hdl.handle.net/2086/4132.

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Lee, Shiyoung. "Effects of Input Power Factor Correction on Variable Speed Drive Systems." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/26493.

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The use of variable speed drive (VSD) systems in the appliance industry is growing due to emerging high volume of fractional horsepower VSD applications. Almost all of the appliance VSDs have no input power factor correction (PFC) circuits. This results in harmonic pollution of the utility supply which could be avoided. The impact of the PFC circuit in the overall drive system efficiency, harmonic content, magnitude of the system input current and input power factor is particularly addressed in this dissertation along with the development of analytical methods applicable to the steady-state analysis of input power factor corrected VSD systems. Three different types of motors - the switched reluctance motor (SRM), permanent magnet brushless dc motor (PMBDC) and dc motor (DCM) are employed in this study. The C-dump converter topology, a single switch per phase converter, is adopted for the prototype SRM- and PMBDC-based VSD systems. The conventional full-bridge converter is used for DCM-based VSD systems. Four-quadrant controllers, utilizing PI speed and current control loops for the PMBDC- and DCM-based VSD system, are developed and their design results are verified with experiment and simulation. A single-quadrant controller with a PI speed feedback loop is employed for the SRM-based VSD system. The analysis of each type of VSD system includes development of loss models and establishment of proper operational modes. The magnitude of the input current harmonic spectra is measured and compared with and without a front-end PFC converter. One electromagnetic compatibility (EMC) standard, IEC 1000-3-2 which describes the limitation on harmonic current emission is modified for 120V ac system. This modified standard is utilized as the reference to evaluate the measured input current harmonics. The magnitude of input current harmonics for a VSD system are greatly reduced with PFC preregulators. While the input PFC circuit draws a near sinusoidal current from an ac source, it lowers the overall VSD system efficiency and increases cost of the overall system.
Ph. D.

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Alolah, A. I. "Microprocessor controlled three-phase inverter for variable-speed induction motor drive." Thesis, University of Bradford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371466.

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15

Blödt, Martin Faucher Jean Regnier Jérémi. "Condition monitoring of mechanical faults in variable speed induction motor drives." Toulouse : INP Toulouse, 2006. http://ethesis.inp-toulouse.fr/archive/00000313.

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Torrey, David Allan. "Optimal-efficiency constant-speed control of nonlinear variable reluctance motor drives." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14713.

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17

Lovelace, Edward Carl Francis. "A mechanical-state observer for high-speed variable-reluctance motor drives." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40232.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.
Includes bibliographical references (p. 191-192).
by Edward Carl Francis Lovelace.
M.S.

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18

Khumalo, Siboniso T. "Induction motor variable speed drive performance and impact on energy savings." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/8751.

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Bibliography: p. 132-134.
ESKOM, together with Municipalities distribute power at a line-to-line voltage of 400+/-10%. Hence in theory, the user ends up with a voltage of 340 to 440. In urban areas 2% voltage unbalance is considered acceptable, while 3% voltage unbalance is considered acceptable for rural areas. The combined effects of under or overvoltages coupled with "acceptable maximum" voltage unbalance is not understood or documented. This project is a comprehensive study of the effects of voltage unbalance in combination with under or overvoltages on induction machines (1M) variable speed drives. In addition the performance with PWM inverters connected to 1M via long cables is also studied. The project starts by an evaluation of previous work on the subject and related topics. Relevant conclusions are made based on the literature review in Chapter One. The second step of the project was to develop two test beds in the UCT Machine's Laboratory. The test beds are for performance testing of low (up to 15kW) and medium (up to 75kW) power 1M and their VSDs. The test bed losses are determined at 4 different operating points and documented. Several tests such as the blocked rotor and no load tests were undertaken to determine the machine parameters. A PSpice simulation model was developed and tested for the low voltage test bed. The test results compared well to simulation predictions. Furthermore, tests under unbalanced and overvoltage conditions were performed and the results verified with simulations. This proves that the developed PSpice model can reliably simulate the actual test bed for both balanced and unbalanced conditions. Moreover, it can be easily applied to model different size machines and drives. The information required includes: the motor parameters, drive dc-link parameters, modulation ratio (ma) and the switching frequency. The impact of voltage unbalance in drives with long cables between the inverter and motor is examined. A 36m long, 4-core, PVC insulated cable is used on the low voltage test bed for a case study. The model used for the cable is a lumped parameter model. The 1M model is also taken from the literature to include a high frequency branch, to model the reflected voltage wave phenomenon. A basic analysis of energy savings in pumps and fans load associated with the application of variable speed drives is also done. Boiler feed-pumps from Tutuka power station are used as a case study that may be replicated for other applications in utilities or industry. The developed Excel Spreadsheet program to project the value of savings and determine the payback period is compared to an ABB program. The two results agree within an acceptable range. Therefore, the knowledge of the pumping system specifications and the cost of energy in kWh with the Energy Savings Program would enable one to project energy savings.

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19

Lee, Jae Ryong. "Microprocessor-based soft variable structure control for D.C. motor speed regulation." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/50045.

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The theory of soft variable structure control, which produces robustness to parameter variation and fast transient response, is discussed in this thesis. The digital implementation techniques are presented in the aspects of sample rate, prefilter design, hardware selection, and microprocessor arithmetic operation. Simulation and experimental results showed good performance in negative speed range, but this controller created unwanted high armature current fluctuation in positive speed range. The reasons turned out to be the limitation of sample rate, noise from the tachometer, and high gain at positive speed.
Master of Science
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20

Patel, Sagarkumar. "Speed Control of Three-Phase Induction Motor Using Variable Frequency Drive." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10690223.

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There are various methods for speed control of induction motors. This paper specifically describes one of the methods: speed control using variable frequency. The proposed system is a MATLAB simulink model, which is a closed loop model designed to achieve desired speed control of a three-phase induction motor by varying its frequency. The simulink model has four main blocks, namely the inverter, synchronous machine, proportional integral control and current hysteresis control. For accuracy of output results and simplicity, we have used dq to abc transformation block and sin function block. The inverter is comprised of six integrated gate bipolar transistors (IGBTs), which are fired by gate pulses generated by current hysteresis control block. The inverter generates variable frequency and variable voltage output, which is given to motor terminals. The project presents the working principle of variable frequency drive (VFD), its performance, and the use of Pulse Width Modulation (PWM) in a three-phase inverter to control the frequency and thus the speed. The proposed method conformed to performance predictions and delivered the desired outputs.

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21

Faiz, J. "Computational methods for the design of multi-tooth-per-pole switched reluctance motors." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383963.

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22

Sagar, Pidaparthi. "A knowledge-based control system model for variable speed a.c. drives." Thesis, Open University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253731.

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23

Shehada, Ahmed. "Novel Multilevel Converter for Variable-Speed Medium Voltage Switched Reluctance Motor Drives." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/85111.

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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.

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Kim, Jaehyuck. "Variable-Speed Switched Reluctance Motor Drives for Low-Cost, High-Volume Applications." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77320.

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Demand for energy-saving variable speed drives in low-cost, high-volume appliances has increased due to energy and environmental concerns and hence the need to comply with new regulations. Switched reluctance motor (SRMs) have been considered by many as attractive alternatives for brush commutated motors or permanent magnet brushless dc motors (PMBDCMs) in such cost-sensitive applications. The SRMs' unique features such as simple and fault-tolerant structure and unidirectional flow of their phase currents endow them with the possibility of various configurations on both machine and converter topologies for different applications. In the present study, three different variable-speed motor drive systems are proposed, studied, and implemented for their deployment in low-cost, high-volume applications with the power rating of 1.5kW or less. Two different two-phase SRMs and three different power converters are employed to realize three different low-cost drive systems. The first drive system is realized using a novel converter requiring only a single-controllable switch and an asymmetric two-phase 8/4 SRM capable of self-starting and four-quadrant operation. The second drive system is realized using another novel converter requiring two controllable switches, that way to achieve better control and utilization of the asymmetric 8/4 motor. The target applications for both drive systems are low power, low performance drives such as fans, hand tools, small appliances, etc. The third system is realized using a high-speed two-phase 4/2 SRM and a split ac source converter, which is designed for high-speed applications such as vacuum cleaners, ultracentrifuges, etc. The control and design aspects for each drive system are studied. Selection of optimal firing angles and optimal number of winding turns are also investigated. All of the drive systems are first demonstrated on the position sensor-based speed-control scheme. To make the drive system even more cost-competitive, operation without the position sensor using the novel parameter insensitive sensorless control scheme is proposed and implemented. Concept, analysis, simulation, and experimental verification of the proposed sensorless scheme are discussed in detail.
Ph. D.

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Neuroth, Matthias. "Design, implementation and performance of conventional and intelligent control schemes and speed estimators for variable speed induction motor drives." Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU177656.

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This thesis discusses the implementation and performance of various conventional and artificial-intelligence-based control and estimation techniques for variable speed induction motor drives. The drive types considered are scalar drives, and high-performance vector and direct torque controlled drives. In the first part, various conventional control design techniques are developed and applied to conventionally controlled drives. The performance of these drives is compared to that of fuzzy logic controlled drives, for which a specific design method is developed using universal fuzzy logic controllers. The developed methods are studied using simulations and experimental results. Implementation issues are presented in detail. In the second part, the design and implementation of conventional and artificial-intelligence-based speed estimators for use in scalar, vector and direct torque controlled drives are discussed. The conventional estimators considered comprise both a mathematical-model-based speed estimator and a model-reference-adaptive-system-based speed estimator. The artificial-intelligence-based estimators considered use artificial neural networks which are trained on data collected in simulations. The performance of both types of estimator, in the entire operating range of the drive, is discussed extensively.

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26

Jasim, Omar. "An extended induction motor model for investigation of faulted machines and fault tolerant variable speed drives." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11285/.

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High performance variable speed induction motor drives have been commercially available for industrial applications for many years. More recently they have been proposed for applications such as hybrid automotive drives, and some pump applications on more electric aircraft. These applications will require the drive to operate in the presence of faults i.e. they must be “Fault Tolerant” and be capable of “Fault Ride Through”. The aim of this project was therefore to investigate fault ride through control strategies for induction motor drives, particularly with respect to open circuit winding or power converter faults. Three objectives were identified and addressed to meet this aim. a) A new simulation model for an induction motor was created which reflects both saturation and space harmonics effects within the drive under both symmetric (healthy) and asymmetric (faulted) conditions. The model has a relatively low computational requirement to allow it to be used in conjunction with the simulation of high performance control algorithms and power electronic equipment. For operation in both healthy and faulty conditions, comparisons show that the simulated saturation and space harmonic effects match those obtained from an experiment system. Therefore this model is a very useful tool for the development and optimisation of new control strategies for fault tolerant drive systems. b) A novel on-line fault detection and diagnosis algorithm based on the measurement of the third harmonic component in the motor line currents has been proposed. The location of the open circuit fault is detected based on detecting a magnitude reduction for the third harmonic component of the current flowing to the motor terminals, and can be implemented in real time to give a fast response with little additional computational overhead. c) A new open circuit fault tolerant control strategy has been designed for a delta connected induction machine suddenly affected by an open circuit winding fault. The fault ride through is achieved without any modification to either the power converter or the motor circuit. A novel feedforward compensation algorithm is introduced which considerably reduces the current and the torque ripple in the faulted drive motor. Two methods for controlling the neutral point voltage are also presented so that the available voltage capacity of the inverter is maximised in both normal and fault mode. For high speed operation, two different methods for field weakening control are presented, so that the available voltage capacity is maximized in both normal and fault mode. This thesis describes the theoretical derivation of the new models and algorithms, and presents experimental results from a 4kW laboratory prototype to validate the proposals. The full fault tolerant system is experimentally demonstrated on a delta connected machine which suffers an open circuit winding fault. The improved motor performance under fault conditions is clearly seen.

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27

Yun, Hayong. "The design and control strategies for automotive air conditioning systems using motor driven, variable speed centrifugal compressors." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11099.

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28

Buddemeyer, Jenna Leigh. "Variable speed limit decision support system for the Elk Mountain corridor phase 1." Laramie, Wyo. : University of Wyoming, 2009. http://proquest.umi.com/pqdweb?did=2065749141&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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29

Pina, Ortega Alejandro Jose. "Design and Comparison of Induction Motor and Synchronous Reluctance Motor for Variable Speed Applications: Design Aided by Differential Evolution and Finite Element Analysis." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365429279.

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30

Chandramouli, G. "Design of a PC based Data Acquistion System for a Switched Reluctance Motor." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/44777.

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The Switched Reluctance Motors(SRM) have gained considerable attention in the variable speed drive market mainly due to the simple construction of the motor and the possibility of developing low cost converters and controllers. As these machines are under development, a considerable amount of research effort is directed to the experimental performance evaluation of the SRM drives. System efficiency, electromagnetic torque, torque ripple, output and losses are some of the required measurements.
Master of Science

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31

Wai, Lo-kau. "Microprocessor-based field-oriented control of a synchronous motor drive using a three-phase solid-state sinusoidal current source /." Hong Kong : University of Hong Kong, 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12434425.

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韋盧溝 and Lo-kau Wai. "Microprocessor-based field-oriented control of a synchronous motor drive using a three-phase solid-state sinusoidal current source." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31208940.

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33

Blödt, Martin. "Condition Monitoring of Mechanical Faults in Variable Speed Induction Motor Drives - Application of Stator Current Time-FrequencyAnalysis and Parameter Estimation." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2006. http://tel.archives-ouvertes.fr/tel-00105482.

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Ce travail de thèse traite de la détection et du diagnostic de défaillances mécaniques par analyse du courant statorique dans les entraînements électriques à base de machine asynchrone. Deux effets d'un défaut mécanique, des oscillations de couple et une excentricité d'entrefer, sont supposés. La modélisation par approche des ondes de forces magnétomotrices et de perméance conduit à deux modèles analytiques du signal courant. La conséquence des défauts est soit une modulation de phase, soit une modulation d'amplitude du signal courant statorique. Ces phénomènes sont détectés par une analyse spectrale en régime permanent, ou des méthodes temps fréquence en régime transitoire. Les méthodes étudiées sont la fréquence instantanée, le spectrogramme et la représentation de Wigner-Ville. L'estimation paramétrique d'indices de modulation a également été traitée. Des résultats de simulation et expérimentaux permettent de valider les signatures et d'extraire de façon automatique des indicateurs de défaut. De plus, une méthode permettant la distinction des oscillations de couple d'une excentricité dynamique est proposée. L'étude est complétée par une implémentation sur DSP des méthodes temps-fréquence afin de démontrer la faisabilité d'une surveillance en ligne.

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Lee, Cheewoo. "Analysis and Design of a Novel E-Core Common-Pole Switched Reluctance Machine." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77319.

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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.

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35

Lange, Martin T. "INFLUENCE OF VOLTAGE SOURCE PULSE WIDTH MODULATED SWITCHING AND INDUCTION MOTOR CIRCUIT ON HARMONIC CURRENT CONTENT." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1230942161.

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36

Halilovic, Amer. "Experimental Transient Behaviour Characterisation of Induction Motor fed by Variable Frequency Drives for Pump Applications." Thesis, KTH, Elektrisk energiomvandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157319.

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The use of variable frequency drives in centrifugal pump applications has raised the question of how to select a drive. Clogging obstacles in waste water applications create unknown transient loads for the pump system. A sudden load increase occurrence can clog the pump if the drive cannot supply enough current to reach the motor’s torque demand. In order to select a suitable drive, an empirical approach has been implemented, investigating three different drives. Results have shown that selecting a drive with the highest possible overload capabilities, even if for a short time is most suitable. Operation in vector speed control gives the most reliable operation if an automatic parameter tuning is performed by the drive.
Användningen av frekvensomriktare i centrifugalpumpar har väckt fr ågan om hur en omriktare skall väljas. Igensättande objekt i avloppsvatten kan ge upphov till transienta laster i pumpsystemen. En oförutsedd lastökning kan sätta igen pumpen om frekvensomriktaren inte kan förse motorn tillräckligt med ström för att möta momentbehovet. För att välja en lämplig omriktare har ett empiriskt tillvägag ångssätt valts i en undersökning av tre olika omriktare. Resultat har visat att det är lämpligast att välja en omriktare med högst överbelastningskapacitet, även om under en kort tid. Vektor hastighetskontroll är metoden som ger stabil körning om omriktaren f ått automatiskt ställa in motorparametrarna.

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37

Blödt, Martin. "Condition Monitoring of Mechanical Faults in Variable Speed Induction Motor Drives. Application of Stator Current Time-Frequency Analysis and Parameter Estimation." Phd thesis, Toulouse, INPT, 2006. http://oatao.univ-toulouse.fr/7468/1/blodt.pdf.

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This Ph.D. thesis deals with condition monitoring of mechanical failures in variable speed induction motor drives by stator current analysis. Two effects of a mechanical fault are considered: load torque oscillations and airgap eccentricity. The analytical modelling using the magnetomotive force and permeance wave approach leads to two stator current models. The fault provokes amplitude or phase modulation of the fundamental current component. Suitable detection methods are spectral analysis and parameter estimation in steady state whereas time-frequency analysis is required during transients. Instantaneous frequency estimation, the Wigner Distribution and the spectrogram are studied. Simulation and experimental results validate the theoretical approach. Automatic extraction of fault indicators is proposed for an unsupervised monitoring system. Moreover, load torque oscillations and dynamic eccentricity can be discriminated with the proposed methods. The feasibility of an on-line monitoring system is demonstrated by a DSP implementation of the time-frequency analysis including indicator extraction.

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Ali, Emad, Jürgen Weber, and Matthias Wahler. "A Machine Learning Approach for Tracking the Torque Losses in Internal Gear Pump - AC Motor Units." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199438.

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This paper deals with the application of speed variable pumps in industrial hydraulic systems. The benefit of the natural feedback of the load torque is investigated for the issue of condition monitoring as the development of losses can be taken as evidence of faults. A new approach is proposed to improve the fault detection capabilities by tracking the changes via machine learning techniques. The presented algorithm is an art of adaptive modeling of the torque balance over a range of steady operation in fault free behavior. The aim thereby is to form a numeric reference with acceptable accuracy of the unit used in particular, taking into consideration the manufacturing tolerances and other operation conditions differences. The learned model gives baseline for identification of major possible abnormalities and offers a fundament for fault isolation by continuously estimating and analyzing the deviations.

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Melendez, Teddy Arturo Flores. "Avaliação de sistemas fotovoltaicos de bombeamento." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-30062009-141639/.

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A presente dissertação aborda a avaliação de três sistemas fotovoltaicos de bombeamento, que compreendem duas configurações com equipamentos dedicados à tecnologia fotovoltaica e um com equipamentos alternativos com potências entre 0,75 CV e 1,0 CV. Os resultados mostram que a configuração alternativa apresenta menor eficiência diária do sistema motobomba. A avaliação econômica revela a competitividade da configuração alternativa frente aos sistemas importados dedicados à tecnologia fotovoltaica. Alia-se a isso a disponibilidade dos equipamentos de condicionamento de potência e a facilidade de reposição. Verificou-se também que a configuração alternativa, conversor de freqüência WEG CFW08 e motobomba SOMAR de 1,0 CV e 8 estágios, trabalha com eficiência diária próxima aos 30% na faixa de operação de 20 a 40 metros de coluna dágua. Portanto, com uma adequada escolha da motobomba para a configuração alternativa, podem-se obter desempenhos semelhantes aos obtidos com sistemas importados dedicados à tecnologia fotovoltaica. Para 30 metros, a configuração alternativa bombeou somente 1% a menos do que o sistema Grundfos. O custo do volume bombeado para 30m de altura manométrica total do sistema alternativo é 22% menor do que o sistema Grundfos e 51% mais econômico do que o sistema Solarjack (Sun Pumps).
The present dissertation shows the evaluation of three Photovoltaic Pumping Systems, which involves two configurations: the equipment dedicated to the photovoltaic technology and the alternative equipment with nominal powers between 0.75 CV and 1.0 CV. The results show that the alternative configuration attained minor daily efficiency of the motopump system. The economic evaluation reveals the competitiveness of the alternative configuration in comparison with imported photovoltaic technology dedicated systems. It also should be considered the availability of equipment for power conditioning and the facility of replacement. It was also verified that the alternative configuration, variable speed drive WEG CFW08 and 1.0 CV SOMAR motor pump with 8 stages, works with daily efficiency near 30% in the 20 to 40 meters operation range. Therefore, with an adequate choice of the motor pump for the alternative configuration, performances similar to the imported photovoltaic technology dedicated systems can be obtained. For 30 meters, the alternative configuration pumped only 1% less than the Grundfos system. The cost of pumped volume for 30 meters of manometer total height of the alternative system is 22% cheaper than the system Grundfos and 51% cheaper than the system Solarjack (Sun Pumps).

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Antonopoulos, Antonios. "On the Internal Dynamics and AC-Motor Drive Application of Modular Multilevel Converters." Doctoral thesis, KTH, Elektrisk energiomvandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156200.

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This thesis is an effort to investigate the operation and the performanceof modular multilevel converters (M2Cs). Proven to be the most promisingtopology in high-voltage high-power applications, it is necessary to put aneffort in understanding the physical laws that govern the internal dynamicsof such converters, in order to design appropriate control methods. AlthoughM2Cs belong to the well-studied family of voltage-source converters (VSCs),and claim a modular structure, their control is significantly more complicatedcompared to two- or three-level VSCs, due to the fact that a much highernumber of switches and capacitors are needed in such a topology. This thesishighlights the important parameters that should be considered when designingthe control for an M2C, through analyzing its internal dynamics, and alsosuggests ways to control such converters ensuring stable operation withoutcompromising the performance of the converter.Special focus is given on ac motor-drive applications as they are very demandingand challenging for the converter performance. Interactions betweenthe internal dynamics and the dynamics of the driven motor are experimentallyinvestigated. The problem of operating the converter when connectedto a motor standing still is visited, even under the condition that a greatamount of torque and current are requested, in order to provide an idea forthe converter requirements under such conditions. Finally, an optimization ofthe converter operation is suggested in order to avoid overrating the convertercomponents in certain operation areas that this is possible.All analytical investigations presented in this thesis are confirmed by experimentalresults on a laboratory prototype converter, which was developedfor the purposes of this project. Experimental verification proves the validityof the theoretical investigations, as well as the correct performance of thecontrol methods developed during this project on a real, physical converter,hoping that the results of this thesis will be useful for large-scale implementations,in the mega- or even giga-watt power range.
Denna avhandling är ett försök att undersöka drift och egenskaper avmodulära multinivåomvandlare (M2C:er). Eftersom denna topologi anses varaden mest lovande inom högspänings-högeffekt-tillämpningar är, och somett underlag för att kunna formulera lämpliga styrmetoder, är det nödvändigtatt lägga kraft i att försöka förståde fysikaliska lagar som styr den inredynamiken i sådana omvandlare. Även om M2C:erna tillhör den välstuderadefamiljen av spänningsstyva omvandlare (VSC:er), och har en modulärstruktur, är deras reglering avsevärt mer komplicerad jämfört med två- ellertre-nivåomvandlare, eftersom ett mycket större antal switchar och kondensatorerär nödvändiga i en sådan topologi. Denna avhandling sätter fingretpå de parametrar som måste beaktas när man konstruerar regleringen för enM2C, genom att analysera den interna dynamiken, samt att föreslå sätt attstyra sådana omvandlare såatt stabil drift kan säkerställas utan att negativtpåverka prestanda.Ett speciellt fokus läggs på växelströmsmotordrifter eftersom de är särskiltutmanande vad gäller prestanda. Växelverkan mellan den interna dynamikenoch motorns dynamik undersöks experimentellt. Problemet att driva motornvid stillestånd behandlas även i fallet med hög ström och högt moment för atterhålla kunskap om kraven påomvandlaren i sådana fall. Slutligen föreslås enoptimering av omvandlarens drifttillstånd för att undvika överdimensioneringav omvandlarens komponenter i de fall detta är möjligt.Alla analytiska undersökningar som läggs fram i denna avhandling är bekräftadegenom experimentella resultat från en laboratorieomvandlare, somutvecklats inom ramen för detta arbete. Den experimentella verifieringen bevisargiltigheten av alla teoretiska undersökningar. Den visar också på demycket goda prestanda som de utvecklade styrmetoderna har vid drift aven verklig fysisk omvandlare. Förhoppningen är att resultaten från detta arbetekan komma till använding i storskaliga implementerinar i mega- ellergiga-wattklassen.

QC 20141201

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Narayanan, G. "Synchronised Pulsewidth Modulation Strategies Based On Space Vector Approach For Induction Motor Drives." Thesis, Indian Institute of Science, 1999. http://hdl.handle.net/2005/139.

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In high power induction motor drives, the switching frequency of the inverter is quite low due to the high losses in the power devices. Real-time PWM strategies, which result in reduced harmonic distortion under low switching frequencies and have maximum possible DC bus utilisation, are developed for such drives in the present work. The space vector approach is taken up for the generation of synchronised PWM waveforms with 3-Phase Symmetry, Half Wave Symmetry and Quarter Wave Symmetry, required for high-power drives. Rules for synchronisation and the waveform symmetries are brought out. These rules are applied to the conventional and modified forms of space vector modulation, leading to the synchronised conventional space vector strategy and the Basic Bus Clamping Strategy-I, respectively. Further, four new synchronised, bus-clamping PWM strategies, namely Asymmetric Zero-Changing Strategy, Boundary Sampling Strategy-I, Basic Bus Clamping Strategy-II and Boundary Sampling Strategy-II, are proposed. These strategies exploit the flexibilities offered by the space vector approach like double-switching of a phase within a subcycle, clamping of two phases within a subcycle etc. It is shown that the PWM waveforms generated by these strategies cannot be generated by comparing suitable 3-phase modulating waves with a triangular carrier wave. A modified two-zone approach to overmodulation is proposed. This is applied to the six synchronised PWM strategies, dealt with in the present work, to extend the operation of these strategies upto the six-step mode. Linearity is ensured between the magnitude of the reference and the fundamental voltage generated in the whole range of modulation upto the six-step mode. This is verified experimentally. A suitable combination of these strategies leads to a significant reduction in the harmonic distortion of the drive at medium and high speed ranges over the conventional space vector strategy. This reduction in harmonic distortion is demonstrated, theoretically as well as experimentally, on a constant V/F drive of base frequency 50Hz for three values of maximum switching frequency of the inverter, namely 450Hz, 350Hz and 250Hz. Based on the notion of stator flux ripple, analytical closed-form expressions are derived for the harmonic distortion due to the different PWM strategies. The values of harmonic distortion, computed based on these analytical expressions, compare well with those calculated based on Fourier analysis and those measured experimentally.

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McKinnon, Douglas John Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Novel efficiency evaluation methods and analysis for three-phase induction machines." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2005. http://handle.unsw.edu.au/1959.4/21869.

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This thesis describes new methods of evaluating the efficiency of three-phase induction machines using synthetic loading. Synthetic loading causes the induction machine to draw full-load current without the need to connect a mechanical load to the machine's drive shaft. The synthetic loading methods cause the machine to periodically accelerate and decelerate, producing an alternating motor-generator action. This action causes the machine, on average over each synthetic loading cycle, to operate at rated rms current, rated rms voltage and full-load speed, thereby producing rated copper losses, iron loss and friction and windage loss. The excitation voltages are supplied from a PWM inverter with a large capacity DC bus capable of supplying rated rms voltage. The synthetic loading methods of efficiency evaluation are verified in terms of the individual losses in the machine by using a new dynamic model that accounts for iron loss and all parameter variations. The losses are compared with the steady-state loss distribution determined using very accurate induction machine parameters. The parameters were identified using a run-up-to-speed test at rated voltage and the locked rotor and synchronous speed tests conducted with a variable voltage supply. The latter tests were used to synthesise the variations in stator leakage reactance, magnetising reactance and the equivalent iron loss resistance over the induction machine's speed range. The run-up-to-speed test was used to determine the rotor resistance and leakage reactance variations over the same speed range. The test method results showed for the first time that the rotor leakage reactance varied in the same manner as the stator leakage and magnetising reactances with respect to current. When all parameter variations are taken into account there is good agreement between theoretical and measured results for the synthetic loading methods. The synthetic loading methods are applied to three-phase induction machines with both single- and double-cage rotors to assess the effect of rotor parameter variations in the method. Various excitation waveforms for each method were used and the measured and modelled efficiencies compared to conventional efficiency test results. The results verify that it is possible to accurately evaluate the efficiency of three-phase induction machines using synthetic loading.

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Mebarki, A. "Variable speed constant voltage constant frequency generation system." Thesis, University of Bath, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358884.

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Roštek, Martin. "Estimace rychlosti vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378739.

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Rýchlosť vozidla je jednou z kľúčových stavových premenných, ktorej znalosť je potrebná v reálnom čase a s vysokou presnosťou, aby mohla slúžiť ako vstupná veličina pre systémy kontroly dynamiky vozidla. Jej priame meranie vo vozidle je však finančne náročné. Riešením tohoto problému môže byť použitie meraní zo senzorov bežne dostupných na palube vozidla a ich následný prepočet na rýchlosť vozidla. Tieto merania sú však veľmi zaťažené procesným šumom, čo vyplýva z komplexnosti pohybu vozidla. Preto je nutné vyvinúť algoritmus so schopnosťou vysporiadať sa s týmito negatívnymi vplyvmi. Algoritmus prezentovaný v tejto práci odhaduje pozdĺžnu rýchlosť vozidla s použitím meraní uhlových rýchlostí štyroch kolies, pozdĺžnej akcelerácie, momentov motora, rýchlosti otáčania okolo zvislej osi a natočenia volantu. Algoritmus bol testovaný na veľkom počte situácií považovaných za kritické na odhad rýchlosti vozidla, ako napríklad prudká akcelerácia na vozovke s nízkym koeficientom trenia, núdzové brzdenie s aktiváciou ABS, či jazda v kopci s kolesami v preklze, prinášajúc uspokojujúce výsledky.

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Lorenz, Tomáš. "Regulace příkonu přečerpávacích vodních elektráren v čerpadlovém provozu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217583.

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This paper focuses on the Double Fed Induction Machine in the Pumped Storage Power Plants. It includes listing of this plants in the world, where such a technology is used; principle of Double Fed Induction Machine, its usage with variable speed, advantages and disadvantages and also experience of its usage.

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Gerkens, Rick, and David Berg. "Elkvalitéproblem vid varvtalsstyrd motordrift i industrimiljö." Thesis, KTH, Data- och elektroteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122892.

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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.

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Tibola, Jonas Roberto. "Controle e supervisão de fonte ininterrupta de energia híbrida." Universidade Federal de Santa Maria, 2017. http://repositorio.ufsm.br/handle/1/12301.

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This work presents contributions to the modeling, control and management of an hybrid uninterrupted power supply (UPS) based on Otto cycle power generator set and lead acid battery bank. The proposed configuration is called hybrid due to the presence of two energy storage elements: i) the fuel fed the Otto cycle internal combustion engine (ICE) of the generator set and ii) a lead acid battery bank, which can be recharged from the grid or from the generator. With the hybridization it is possible to add up the advantages of UPS’s such as uninterrupted power supply and high output energy quality with the advantages of power generator sets, such as high autonomy and lower installation cost for high autonomy. In addition, with the hybrid topology it is possible to explore degrees of freedom that do not exist in the independent configurations, such as: i) variable speed operation and ii) start-stop operation of the MCI in order to reduce consumption/ emissions in lower loads, (iii) use of Otto cycle engine with lower cost in relation to a Diesel ICE. The hybrid UPS is composed of an Otto cycle internal combustion engine (ICE), a three-phase/three-wire rectifier, which can be connected via contactors to the grid, or to the permanent magnet synchronous generator (PMSG), a battery bank connected to the DC bus through a bi-directional boost converter, and a three-phase/four-wire inverter at the output. Experimental results are provided indicating that variable speed operation can achieve a reduction of up to 32% in specific fuel consumption, depending on the load range. For start-stop operation, the reduction in specific fuel consumption can reach up to 39%, depending on the load range.
Este trabalho apresenta contribuições a modelagem, controle e gerenciamento de uma fonte ininterrupta de energia (UPS) híbrida baseada em grupo motor ciclo Otto e bateria chumbo ácido. A configuração proposta é denominada híbrida devido a presença de dois armazenadores de energia: i) o combustível para alimentar o motor a combustão interna (MCI) ciclo Otto do grupo motor gerador e ii) um banco de baterias chumbo ácido, a qual pode ser recarregado pela rede ou pelo gerador. Com a hibridização é possível agregar as vantagens das UPSs tais como, ininterruptibilidade de fornecimento de energia e alta qualidade de energia da tensão de saída, com as vantagens dos grupos motores geradores, tais como, elevada autonomia e menor custo de instalação para autonomias elevadas. Além disso, com a topologia híbrida é possível explorar graus de liberdade não existentes nas configurações independentes, tais como: i) utilização de velocidade variável e ii) operação em regime start-stop no MCI afim de reduzir consumo/emissões em baixas cargas, iii) utilização de motor ciclo Otto com menor custo em relação a um MCI Diesel. A UPS híbrida é composta por um motor a combustão interna (MCI), um retificador trifásico a três/quatro fios, o qual pode ser conectado através de contatoras à rede, ou ao gerador síncrono de ímãs permanente (PMSG), um banco de baterias conectado ao barramento através de um conversor boost bidirecional, e um inversor a quatro fios na saída. Resultados experimentais são apresentados indicando que a operação em velocidade variável pode alcançar um redução de até 32% no consumo específico de combustível, dependendo a faixa de carga. Já para a operação em regime start-stop a redução no consumo específico de combustível pode alcançar até 39%, dependendo da faixa de carga.

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Magill, Robert Joseph. "Efficiency and loss evaluation of induction motors for variable speed drives." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367160.

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Anyang, Ernest Ohene. "The impact of variable speed drives on energy efficient induction motors." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10028.

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Includes abstract.
Includes bibliographical references.
In an era when the world is faced with diminishing resources and energy security concerns, the slightest energy savings can prove essential in energy conservation. Induction motors and motorised loads consume an estimated 60% of the total energy required in the South African industry. This figure stands at 40% worldwide. Energy Efficient induction motors have proven to be an effective solution in the quest to reduce energy consumption. In South Africa, there have been efforts to replace the standard motors already in operation with energy efficient motors. The South African Utility, ESKOM, through its energy efficiency motor programme, has been providing incentives to its industrial customers to speed up this process.

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Essah, David N. "New modeling techniques for power electronics based systems with application to switched reluctance drives /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9962521.

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Dissertations / Theses on the topic 'VARIABLE-SPEED MOTOR'

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