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1
Gordon, B. M. "Small induction motor drives". Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599532.
Testo completoAbstract (sommario):
Domestic appliances represent very cost conscious applications for drives where the emphasis is on achieving the optimum compromise between cost and performance. The requirements placed on a domestic appliance drive are so radically different from those demanded of an industrial drive, that a detailed re-evaluation of all the constituent sub-units of the drive must be undertaken. Domestic appliances are produced in large volumes so the use of a special arrangement or custom components can be justified if an overall benefit can be demonstrated. The work presented in this dissertation is concerned with small drives which are suitable for domestic appliances. A study of the optimal number of phases for current and possible future power electronic construction methods is presented and their suitability of domestic appliance drives considered. Comparisons based on material utilisation and the quality of the air gap flux waveform are presented. With the power electronic technology available two and three phase drives were found to be the best compromise between cost and complexity, and several drives of each type were built to provide experimental evidence on the performance of each alternative drive topology proposed. The experimental results obtained from the different drives built are related to the conclusions of work on inverter topology and phases number.
2
Green, T. C. "Scalar controlled induction motor drives". Thesis, Heriot-Watt University, 1990. http://hdl.handle.net/10399/892.
Testo completo
3
Hussein, Ali. "Interface issues in induction motor drives". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ44877.pdf.
Testo completo
4
Armstrong, G. J. "Encoderless vector controlled induction motor drives". Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246112.
Testo completo
5
Smith, Andrew Neil. "Speed Sensorless Induction Motor Drives : A Comparison". Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506428.
Testo completo
6
Chi-Kwong, Luk Patrick. "The transputer control of induction motor drives". Thesis, University of South Wales, 1992. https://pure.southwales.ac.uk/en/studentthesis/the-transputer-control-of-induction-motor-drives(c1a20165-02d4-43d8-b1d8-039cdb1e471e).html.
Testo completoAbstract (sommario):
The inherent advantages of the induction motor in variable speed drive applications can now be realised in a cost-effective manner as a result of recent advances in power electronics and microelectronics. This thesis is devoted to the advancement of the use of induction motors in variable speed applications, and describes the analysis, simulation and implementation of a variable speed induction motor drive. The state-space method lends itself as an ideal approach both for digital computer modelling and design of modem controller and was therefore adopted for the analysis and simulation of the drive system. The simulation was developed by means of a low cost personal computer package called MATLAB that has been designed to facilitate matrix operations. The use of such a specialized software package provided a 'user-friendly' operating environment with error messages identifying problem areas during program development. The resulted computer model of the drive system offers high flexibility and modularity and can be readily incorporated into further analysis and real-time controller design. Experimental results of the drive demonstrated good correlation with the model at both steady and transient states and the validity of the model is therefore confirmed. The experimental drive system was developed by means of transputers and its associated programming language occam. It was a flexible and comprehensive drive system comprising: (i) an on-line user interactive environment facilitated by the Transputer Development System; (ii) a 3-phase inverter bridge as the power conditioning unit; and (iii) a signal processing unit by means of a multi-transputer network system. The adoption of the transputer and occam enabled parallel processing to be achieved cost effectively in the drive system. The specifications of the drive system developed included on-line speed change, dynamic braking and programmable soft-start. Vector-control was also incorporated for good dynamic response. Experimental results of the specified functions of the drive are provided to confirm the proposed specifications of the drive. Further research areas on the present system are proposed, so that a viable industrial implementation may be contemplated.
7
Stefani, Andrea <1976>. "Induction Motor Diagnosis in Variable Speed Drives". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2311/1/Stefani_Andrea_Tesi.pdf.
Testo completoAbstract (sommario):
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.
8
Stefani, Andrea <1976>. "Induction Motor Diagnosis in Variable Speed Drives". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2311/.
Testo completoAbstract (sommario):
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.
9
Healey, Russell Cameron. "Advanced induction motor models for vector controllers". Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337900.
Testo completo
10
Turl, Gary. "A synchronised multi-motor control system using hybrid sensorless induction motor drives". Thesis, University of Nottingham, 2002. http://eprints.nottingham.ac.uk/29510/.
Testo completoAbstract (sommario):
The main aim of this project was to research, develop and test an induction motor drive not requiring a speed encoder, but which could be considered commercially viable by motor drives manufacturers, and which should aim to meet the follow requirements: • Dynamic torque performance and steady state speed-holding accuracy to be comparable with encodered vector controlled drives • Extensive and highly accurate knowledge of electrical and mechanical parameters of the motor and load not to be required • Extensive commissioning from an expert engineer not to be necessary • Algorithm not to rely on excessive computational capability being available The drive was to operate, in a stable manner, over speed and load ranges at least comparable with commercially available sensorless induction motor drives. The above requirements were set such that the developed sensorless technique may be considered for synchronised multi-motor process applications, where the advantages of a sensorless system could be exploited for hazardous, damp and hot conditions. The solution developed consists of a leading model-based sensorless method augmented with a speed estimator that tracks harmonics, seen in the stator terminal quantities, due to rotor slotting. The model-based scheme facilitates field-orientated control for dynamic performance. The slot harmonic speed estimator tunes the model for speed accuracy. Slot harmonics are identified using a recursive signal processing method termed the Recursive Maximum Likelihood - Adaptive Tracking Filter. This work is the first example of the method being developed into a practical sensorless drive system and the complete speed identifier is described, including set-up, pre-filtering and the minimal parameter considerations. Being recursive the method is computationally efficient, yet has accuracy comparable with that of FFT identifiers used in other work. The developed sensorless strategy was implemented practically on two motor drive systems. The performance of the scheme is shown to give encoder like speed holding accuracy and field-orientated dynamic performance. The two drives were also configured and tested as a speed synchronised pair, using applicable multi-motor control techniques, themselves compared and contrasted. The sensorless performance is demonstrated, alongside an encodered version acting as a benchmark, and the performance of the two schemes is shown to be highly comparable. The author has found no other example of sensorless techniques considered for use in multi-motor applications. The use of such a technique brings established advantages associated with encoder removal and allows multi-axis electronic synchronisation to be considered for parts of a process where an encoder may not be appropriate.
11
Gadoue, Shady Mostafa. "Artificial intelligence applied to speed sensorless induction motor drives". Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/1613.
Testo completoAbstract (sommario):
During the last two decades there has been considerable development of sensorless vector controlled induction motor drives for high performance industrial applications. Such control strategies reduce the drive's cost, size and maintenance requirements while increasing the system's reliability and robustness. Parameter sensitivity, high computational effort and instability at low and zero speed can be the main shortcomings of sensorless control. Sensorless drives have been successfully applied for medium and high speed operation, but low and zero speed operation is still a critical problem. Much recent research effort is focused on extending the operating region of sensorless drives near zero stator frequency. Several strategies have been proposed for rotor speed estimation in sensorless induction motor drives based on the machine fundamental excitation model. Among these techniques Model Reference Adaptive Systems (MRAS) schemes are the most common strategies employed due to their relative simplicity and low computational effort. Rotor flux-MRAS is the most popular MRAS strategy and significant attempts have been made to improve the performance of this scheme at low speed. Artificial Intelligence (AI) techniques have attracted much attention in the past few years as powerful tools to solve many control problems. Common AI strategies include neural networks, fuzzy logic and genetic algorithms. The mam purpose of this work is to show that AI can be used to improve the sensorless performance of the well-established MRAS observers in the critical low and zero speed region of operation. This thesis proposes various novel methods based on AI combined with MRAS observers. These methods have been implemented via simulation but also on an experimental drive based around a commercial induction machine. Detailed simulations and experimental tests are carried out to investigate the performance of the proposed schemes when compared to the conventional rotor fluxMRAS. Various schemes are implemented and tested in real time using a 7.5 kW induction machine and a dSP ACE DS 1103 controller board. The results presented for these new schemes show the great improvement in the performance of the MRAS observer in both open loop and sensorless modes of operation at low and zero speed.
12
Zheng, Libo. "Analysis and control of five-phase induction motor drives". Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501695.
Testo completoAbstract (sommario):
Analysis and control of five-phase induction motor drives are investigated in this thesis. A vector model for five-phase induction motors is derived. Two distinct aspects related to multi-phase induction motor modelling are revealed and determination of the equivalent circuit parameters is explained from theoretical and experimental viewpoints. Modulation techniques for the five-phase voltage source inverter are developed, with both separate and simultaneous space excitation included. The analysis of five-phase induction motor drives is verified using a practical test rig. Indirect vector control applied to the first and third space harmonics, with separate excitation and simultaneous excitation, are experimentally assessed.
13
Blasco, Giménez Ramón. "High performance sensorless vector control of induction motor drives". Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/13038/.
Testo completoAbstract (sommario):
The aim of this research project was to develop a vector controlled induction motor drive operating without a speed or position sensor but having a dynamic performance comparable to a sensored vector drive. The methodology was to detect the motor speed from the machine rotor slot harmonics using digital signal processing and to use this signal to tune a speed estimator and thus reduce or eliminate the estimator’s sensitivity to parameter variations. Derivation of a speed signal from the rotor slot harmonics using a Discrete Fourier Transform-based algorithm has yielded highly accurate and robust speed signals above machine frequencies of about 2 Hz and independent of machine loads. The detection, which has been carried out using an Intel i860 processor in parallel with the main vector controller, has been found to give predictable and consistent results duing speed transient conditions. The speed signal obtained from the rotor slot harmonics has been used to tune a Model Reference Adaptive speed and flux observer, with the resulting sensorless drive operating to steady state speed accuracies down to 0.02 rpm above 2 Hz (i.e. 60 rpm for the 4 pole machine). A significant aspect of the research has been the mathematical derivation of the speed bandwidth limitations for both sensored and sensorless drives, thus allowing for quantitative comparison of their dynamic performance. It has been found that the speed bandwidth limitation for sensorless drives depends on the accuracy to which the machine parameters are known and that for maximum dynamic performance it is necessary to tune the flux and speed estimator against variations in stator resistance in addition to the tuning mechanism deriving from the DFT speed detector. New dynamic stator resistance tuning algorithms have been implemented. The resulting sensorless drive has been found to have a speed bandwidth equivalent to sensored drives fitted with medium resolution encoders (i.e. about 500 ppr), and a zero speed accuracy of ± 8 rpm under speed control. These specifications are superior to any reported in the research literature.
14
Leong, Chee Yeow. "Evaluation of excitation schemes for small induction motor drives". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611939.
Testo completo
15
Cilia, Joseph. "Sensorless speed and position control of induction motor drives". Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362888.
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16
Zbede, Yaman. "Model predictive MRAS estimator for sensorless induction motor drives". Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3771.
Testo completoAbstract (sommario):
The project presents a novel model predictive reference adaptive system (MRAS) speed observer for sensorless induction motor drives applications. The proposed observer is based on the finite control set-model predictive control principle. The rotor position is calculated using a search-based optimization algorithm which ensures a minimum speed tuning error signal at each sampling period. This eliminates the need for a proportional integral (PI) controller which is conventionally employed in the adaption mechanism of MRAS observers. Extensive simulation and experimental tests have been carried out to evaluate the performance of the proposed observer. Both the simulation and the experimental results show improved performance of the MRAS scheme in both open and closed-loop sensorless modes of operation at low speeds and with different loading conditions including regeneration. The proposed scheme also improves the system robustness against motor parameter variations and increases the maximum bandwidth of the speed loop controller. However, some of the experimental results show oscillations in the estimated rotor speed, especially at light loading conditions. Furthermore, due to the use of the voltage equation in the reference model, the scheme remains sensitive, to a certain extent, to the variations in the machine parameters. Therefore, to reduce rotor speed oscillations at light loading conditions, an adaptive filter is employed in the speed extraction mechanism, where an adaptation mechanism is proposed to adapt the filter time constant depending on the dynamic state of the system. Furthermore, a voltage compensating method is employed in the reference model of the MP-MRAS observer to address the problems associated with sensitivity to motor parameter variation. The performance of the proposed scheme is evaluated both experimentally and by simulation. Results confirm the effectiveness of the proposed scheme for sensorless speed control of IM drives.
17
王化謙 e Huaqian Wang. "A novel sliding mode control method for induction motor drives". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31234495.
Testo completo
18
Wang, Huaqian. "A novel sliding mode control method for induction motor drives /". [Hong Kong] : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B15970073.
Testo completo
19
Gao, Yuan, e 高源. "Control of chaos in advanced motor drives". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45014784.
Testo completo
20
Purcell, Anthony. "New switching techniques for direct torque controlled induction motor drives". Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285275.
Testo completo
21
Shirsavar, S. A. "Parameter and speed estimation for vector controlled induction motor drives". Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263045.
Testo completo
22
Rajamani, 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.
Testo completo
23
Makazaga, Iban Vicente. "Sensorless control of induction motor drives for railway traction applications". Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.712120.
Testo completo
24
Li, Jian. "Implementation and simulation of various vector controlled induction motor drives". Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU083755.
Testo completoAbstract (sommario):
The development of AC drives has gained momentum with the advancement of power electronic devices, control theory and technology of microprocessors. Based on high speed digital signal processing theory and power transistor hardware, two axis machine model and adaptive control techniques, a vector controlled fully digital induction motor drive is a high performance, low cost drive which is becoming increasingly popular in many industrial applications in all power ranges and will succeed the dc drive in the near future. The main goal of the thesis is to investigate the various forms of implementations of vector controlled digital signal processor based high performance induction motor drives. For this purpose, a TMS320C30 digital signal processor board with transducer and interfacing circuits has been designed, manufactured and built. Furthermore a conventional bipolar transistor inverter has been modified and interfaced to the DSP board. The entire hardware has been tested and successfully implemented. The control software is versatile and provides a platform for implementing various control configurations. The first part of the thesis reviews the development of various vector controlled drives; different mathematical models are presented and discussed together with digital simulation results of different vector controlled schemes. Intelligent control algorithms based on neural networks, fuzzy control, self-tuning control are also considered, some of them are tested by using real-time simulation or on a real drive. Different PWM strategies are investigated and compared, and a versatile and reliable real-time PWM algorithm is generated and integrated into the drive control software. Various parameter identification and auto-commissioning techniques are included in the control software. Details of experimentally obtained results for various vector drives are presented.
25
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.
Testo completo
26
Wu, Zhan-Yuan. "Energy efficient PWM induction machine drives for electric vehicles". Thesis, University of Sheffield, 2000. http://etheses.whiterose.ac.uk/14622/.
Testo completoAbstract (sommario):
The viability of any electric vehicle is critically dependent on it having an acceptable range between charges, a feature which is ultimately dictated by the capacity of the battery energy store. Considerable improvements in vehicle range are possible, however, by ensuring the most effective use of this limited energy resource through the minimisation of the losses in the electric drive-train, i.e. the combined machine and power electronic controller. A particular consideration is that, for the majority of the time, the electric drive-train will be operating at part load. The thesis investigates the operation of induction motor based electric traction drive-trains, with a view to minimising the system loss over typical driving cycles. The study is based around a 26kW induction motor and IGBT inverter drive, which is typical of the technology used to power a small urban vehicle. A potential advantage of an induction motor based drive-train is the ability to vary the level of excitation field in the motor, and therefore the balance of iron and copper loss. The control of the supply voltage magnitude necessitates the use of some form of modulation on the output of the power converter. The method of modulation employed will influence the harmonic content of the supply to the motor, the level of parasitic harmonic loss in the machine and the switching losses of the power semiconductors. A theoretical study supported by experimental work on a DSP controlled drive is presented and used to determine the most appropriate modulation strategy at a given operating point to achieve an optimal balance between the motor copper, iron and harmonic loss and inverter switching and conduction loss. It is shown that compared to the established method of constant flux and fixed inverter switching frequency control, a significant reduction in the traction system loss can be achieved. Some different modulation schemes involve varying amounts of computational overhead in a DSP, the implementation of candidate modulation and control schemes has also been investigated to ensure the defined scheme is practically realisable.
27
Yang, Chao. "Speed Sensorless Control for Induction Motor Drives with AI-Based MRAS". Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525087.
Testo completo
28
Giaouris, Damian. "Open loop control and stability of induction motor drives, including wavelets". Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407618.
Testo completo
29
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.
Testo completo
30
Huang, F. "On-line simulation of inverter-induction motor drives for rapid transit". Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292819.
Testo completo
31
Bezanov, Goran. "On-line control of microprocessor-based PWM for A.C. drives". Thesis, Brunel University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280761.
Testo completo
32
Bai, Jiing-Wen, e 白景文. "Optimal Efficiency Control of Induction Motor Drives". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/02744689294772516481.
Testo completoAbstract (sommario):
碩士淡江大學
機械工程學系
87
Since the vector controlled drive for variable speed applications are usually not running with full-load, therefore if the rotor flux can be adjusted according to the load torque then the motor operating losses can be reduced. The purpose of this thesis is to develop a practical optimal efficiency control scheme that is suitable for the vector controlled drives in variable speed applications. The proposed control scheme utilized the power factor as the control variable to modify the motor magnetizing current in order to maintain a minimum loss operation of the motor. In addition to theoretical analysis and computer simulations, various experiments were also performed to verify the proposed control scheme.
33
WU, ZONG-XIAN, e 吳宗憲. "Stability analysis of drives-fed induction motor". Thesis, 1987. http://ndltd.ncl.edu.tw/handle/44553368677852907208.
Testo completo
34
蔡正爵. "Computer-Aided Design of Induction Motor Drives". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/57348451109906511419.
Testo completo
35
Yang, Chia-Hsiang, e 楊家響. "Field Weakening Control of Induction Motor Drives". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/02134530532161859954.
Testo completoAbstract (sommario):
碩士淡江大學
機械工程學系
86
A practical scheme for field weakening control of induction motor drives is proposed. This scheme utilize control of the stator flux to be inversely proportional to the motor speed when in the field weakening region, and at the same time maintain the rotor flux orientation in order to keep the instantaneous control of the motor torque. Stator flux field weakening is more efficiency than rotor flux field weakening control in using fixed power source voltage. A flux observer is also proposed by combing voltage model and current model in compensation way. There is a solution in the switching of field weakening point that torque is unstable. Derivation and analysis of the control law is presentation in the paper including compensation,and the control scheme is verified with simulation and experimental result.
36
Jian, Yun-huah Chang, e 張簡韻桓. "Study on Two-Phase Induction Motor Drives". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/u39ddk.
Testo completoAbstract (sommario):
碩士國立虎尾科技大學
航空與電子科技研究所
101
The electrical fan, based on the induction motor, operate with very low efficiency on the high slip, when the speed control is used by the series inductors or capacitors. In order to improve the efficiency of the induction motor, inverter benefit with Pulse Width Modulation (PWM) methods included the unipolar PWM and the bipolar PWM is discussed. The unipolar method shows the better harmonics performance for the improvement of the noise reduction. The inverter with PWM method also has the advantage of efficiency operation then the induction motor operated on the tradition method. The new type two-phase induction motor speed control with four legs inverter structure compare with the conventional method by using the two-phase theory. The new method has lower switch losses and the better harmonics injection to the motor current. The noise, a kind of electrical noise caused by the current harmonics, is reduced effetely by using the new method. In order to evaluate the performance, include the efficiency, harmonics and noise, the three kinds of tests are included. They are the high voltage (110V) and low voltage (24V) ceiling fan and the new method. The results shows that the PWM inverter with two phase theory has the better efficiency, when that compared with the traditional ceiling fan in the single phase control. The new methods with four legs inverter structure obtain the best efficiency, the power consumptions are reduced for 11W to 6W.
37
Hatua, Kamalesh. "Active Reactive Induction Motor - A New Solution For Load Commutated SCR-CSI Based High Power Drives". Thesis, 2010. https://etd.iisc.ac.in/handle/2005/2009.
Testo completoAbstract (sommario):
This thesis deals with a new solution for medium voltage drives. Load Commutated Inverter (LCI) fed synchronous motor drive is a popular solution for high power drive applications. Though the induction machine is more rugged and cheaper compared to the synchronous machine, LCI fed induction motor drive solution is not available. The basic advantage of a synchronous machine over an induction machine is the fact that the synchronous machine can operate at leading power factor. Due to this property load commutation of SCR switches of the LCI is achievable for synchronous machine. On the contrary an induction machine always draws lagging power factor current; this makes it unsuitable as a drive motor for LCI technology. In this thesis a new LCI fed induction motor drive configuration is developed as an alternative for synchronous motor drives.
A new variant of six phase induction motor is proposed in this context. The machine is named as Active Reactive Induction Machine (ARIM). The ARIM contains two sets of three-phase windings with isolated neutral. Both the windings have a common axis. One winding carries the active power and can be wound for higher voltage (say 11kV). The other winding supplies the total reactive power of the machine and can be wound for lower voltage (say 2.2 kV). The rotor is a standard squirrel cage. High power induction machines usually demand lesser magnitude of reactive power compared to the total power rating of the machine ( 20% ). Therefore excitation winding has a smaller fraction of the total machine rating compared to the power winding.
A VSI with an LC filter supplies reactive power to the ARIM through the excitation winding and ensures leading power factor at the power winding. This is similar to the excitation control of the LCI fed synchronous machine. The direct VSI connection is possible due to the lower voltage rating for the excitation winding. In this way, the VSI voltage rating does not limit the highest motor voltage that can be handled. An LCI supplies the real power into the ARIM from the power winding. The LCI currents are quasi square wave in shape. Therefore they have rich low order harmonic content. They cause 6th and 12th harmonic torque pulsations in the machine. This is a problem for the LCI fed synchronous machine drive. In the proposed drive, the VSI can compensate these low frequency m.m.f. harmonics inside the machine air gap to remove torque pulsation and rotor harmonic losses. The advantage of the proposed topology is that no transformer is required to drive an 11kV machine.
It is always desirable to feed sinusoidal voltage and current to both the power winding and the excitation winding. To address this problem, a second configuration is proposed. A low power three-level VSI is connected in shunt at the power winding with the proposed ARIM drive as discussed above. This VSI compensates the low frequency harmonic currents to achieve sinusoidal motor currents at the motor winding. This VSI acts as a shunt active filter and compensates for the lower order harmonics injected by the LCI.
The proposed topologies have LC filters to maintain sinusoidal motor voltages and currents by absorbing the VSI switching frequency components. But the motor terminal voltage oscillates at system resonant frequency due to the presence of LC filters. These resonant components in the terminal voltages are required to be eliminated for smooth terminal voltages and safe load commutation of the thyristors. In this thesis a simple active damping method is proposed to mitigate these issues.
The proposed topologies are experimentally verified with an ARIM with 415 V power winding and 220 V excitation winding. The control is carried out on a digital platform having a TMS 320LF 2407A DSP processor and an ALTERA CYCLONE FPGA processor. Results from the prototype experimental drive are presented to show the feasibility and performance of the proposed drive configurations.
38
Hatua, Kamalesh. "Active Reactive Induction Motor - A New Solution For Load Commutated SCR-CSI Based High Power Drives". Thesis, 2010. http://hdl.handle.net/2005/2009.
Testo completoAbstract (sommario):
This thesis deals with a new solution for medium voltage drives. Load Commutated Inverter (LCI) fed synchronous motor drive is a popular solution for high power drive applications. Though the induction machine is more rugged and cheaper compared to the synchronous machine, LCI fed induction motor drive solution is not available. The basic advantage of a synchronous machine over an induction machine is the fact that the synchronous machine can operate at leading power factor. Due to this property load commutation of SCR switches of the LCI is achievable for synchronous machine. On the contrary an induction machine always draws lagging power factor current; this makes it unsuitable as a drive motor for LCI technology. In this thesis a new LCI fed induction motor drive configuration is developed as an alternative for synchronous motor drives.
A new variant of six phase induction motor is proposed in this context. The machine is named as Active Reactive Induction Machine (ARIM). The ARIM contains two sets of three-phase windings with isolated neutral. Both the windings have a common axis. One winding carries the active power and can be wound for higher voltage (say 11kV). The other winding supplies the total reactive power of the machine and can be wound for lower voltage (say 2.2 kV). The rotor is a standard squirrel cage. High power induction machines usually demand lesser magnitude of reactive power compared to the total power rating of the machine ( 20% ). Therefore excitation winding has a smaller fraction of the total machine rating compared to the power winding.
A VSI with an LC filter supplies reactive power to the ARIM through the excitation winding and ensures leading power factor at the power winding. This is similar to the excitation control of the LCI fed synchronous machine. The direct VSI connection is possible due to the lower voltage rating for the excitation winding. In this way, the VSI voltage rating does not limit the highest motor voltage that can be handled. An LCI supplies the real power into the ARIM from the power winding. The LCI currents are quasi square wave in shape. Therefore they have rich low order harmonic content. They cause 6th and 12th harmonic torque pulsations in the machine. This is a problem for the LCI fed synchronous machine drive. In the proposed drive, the VSI can compensate these low frequency m.m.f. harmonics inside the machine air gap to remove torque pulsation and rotor harmonic losses. The advantage of the proposed topology is that no transformer is required to drive an 11kV machine.
It is always desirable to feed sinusoidal voltage and current to both the power winding and the excitation winding. To address this problem, a second configuration is proposed. A low power three-level VSI is connected in shunt at the power winding with the proposed ARIM drive as discussed above. This VSI compensates the low frequency harmonic currents to achieve sinusoidal motor currents at the motor winding. This VSI acts as a shunt active filter and compensates for the lower order harmonics injected by the LCI.
The proposed topologies have LC filters to maintain sinusoidal motor voltages and currents by absorbing the VSI switching frequency components. But the motor terminal voltage oscillates at system resonant frequency due to the presence of LC filters. These resonant components in the terminal voltages are required to be eliminated for smooth terminal voltages and safe load commutation of the thyristors. In this thesis a simple active damping method is proposed to mitigate these issues.
The proposed topologies are experimentally verified with an ARIM with 415 V power winding and 220 V excitation winding. The control is carried out on a digital platform having a TMS 320LF 2407A DSP processor and an ALTERA CYCLONE FPGA processor. Results from the prototype experimental drive are presented to show the feasibility and performance of the proposed drive configurations.
39
Kuo, Cheng-Yuan, e 郭政遠. "LOAD SHARING CONTROL FOR PARALLEL INDUCTION MOTOR DRIVES". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/47948606547098413807.
Testo completoAbstract (sommario):
碩士國立清華大學
電機工程學系
93
The major purposes of this thesis are to establish a parallel induction motor drive system and to perform its load sharing control. First, the possible parallel system configurations and their features are explored. In addition, some existing load sharing control strategies and also surveyed. Owing to the features of larger rating, rigid structure, brushless and possession of steep torque-speed characteristic, induction motors have been extensively employed for large equipments with parallel operation. For successfully performing its load sharing control, the basic characteristics, dynamic modeling and driving control of an induction motor are first comprehended. Then its load sharing control principle and methods are explored, and accordingly, the control method is proposed. For convenience of making performance evaluation test, a small parallel induction motor drive system driving a common load is established. Each motor is fed by its specific inverter. The master/slave current sharing approach is adopted for the proposed control method, and a simple disturbance cancellation based robust control is applied to enhance the load sharing control performance. In this thesis, a single-switch three-phase switch-mode rectifier (SMR) is designed and implemented. Circuit operation, design of circuit components and control scheme of this SMR are introduced in detail. Under well-regulated DC-link voltage, the line drawn power quality is much improved. The designed SMR is first verified its effectiveness by some simulation and measured results under resistive load. Then it is employed to serve as the front-end converter of the parallel induction motor drive. Some experimental results are provided to demonstrate the whole drive comparative performance including line drawn power quality, static and dynamic load sharing characteristics, dynamic speed response, DC-link voltage regulation characteristics, etc. Key words: Induction motor, scalar control, parallel load sharing control, master-slave method, disturbance cancellation robust control, three-phase switch-mode rectifier.
40
Wung, Ming-der, e 翁明德. "A current predictive controller for induction motor drives". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/46622462252547685982.
Testo completoAbstract (sommario):
碩士國立中央大學
電機工程研究所
83
The purpose of this paper is to design an excellent digital current controller which is the driver of the three- phase AC induction motor. It is necessary to know the varia- tion of the motor parameters and the information of the back e. m.f. for the conventional current predictive controllers. The controller in this paper is a current predictive control- ler based on the linear prediction. Owing to the pretty short sampling time, we can estimate the back e.m.f. by supposing the deriation of the flux between two neighborhood sampling times be zero. Furthermore, considering the variation of the motor parameters, we can effectively predict the back e.m.f. by linear prediction. The simulation and the experiment illu- strate the results. The prediction coefficients not only effectively estimate the variation of the back e.m.f. but also reflect the variation of the motor parameters, i.e., the controller is adaptive. The controller is simple and robust enough. We need not to estimate the complex flex and the motor parameters. The only information we must know is the stator current. To de- crease the current harmonics and the chopper energy loss, we use the best chopper pattern of the inverter in the space ve- ctor modulation. The effect of the short circuit prevention time is compensated. Furthermore, the simulation illustrate the noise margin is good.
41
Pan, Yi-Cheng, e 潘奕丞. "Hybrid Direct Torque Control for Induction Motor Drives". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/61568632171644115675.
Testo completoAbstract (sommario):
碩士清雲科技大學
電機工程研究所
94
Induction motors have been widely used in industry applications. According to its mechanical structure identities, the induction motor has a lot of advantages such as stable structure, low price, simplicity of maintenance and so on. Recently, direct torque control technique has been well developed. Differently from the field-oriented control (FOC), DTC does not tend to reproduce the electromechanical behavior of a dc motor drive but is aimed at a complete exploitation of the flux and torque-producing capabilities of an induction motor (IM) fed by a pulse width modulation (PWM) inverter. In this case, DTC can be viewed as a novel concept in the control of IM drives. This paper develops a hybrid direct torque control (H-DTC) strategy, which combine the switching-table -based direct torque control (ST-DTC) and the space vector modulation direct torque control (SVM-DTC), for high performance induction motor (IM) drives. A switching logic is designed for choosing either the ST-DTC or SVM-DTC strategy during the drive operation to guaranty transient and steady-state performance. Under transient operating conditions, the fast torque response is preserved by using ST-DTC, while better steady-state performance is achieved by using the SVM-DTC. The effectiveness of the proposed method will be demonstrated by computer simulations and experimental tests.
42
Chin-Liun, Chen, e 陳俊良. "Simulation and analysis of linear induction motor drives". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/85458052891035667979.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
機械工程系
87
Abstract The purpose of this paper is to simulate the vector control of induction motor by using the software MATLAB-SIMULINK. We first expound the formulation of the electric electron element model, which is needed in rotor magnetic field oriented control, and the two kinds of different pulse modulation rules, in order to modulate the order of entering motor driver signal. Then, we use the equal-effect electric circuit of the induction motor to establish a mathematical formula which is to apply to magnetic field oriented control. It is also explained in the paper how to complete indirect vector control, in order to have a fixed speed and fixed position control over the motor. We also analyze the different flux estimation laws, on the purpose of reaching a sensorless control, and discuss the test results as a reference for further practices. Finally, we analyze the equal-effect electric circuit of the linear induction motor. Because of its construction, we make use of the asymmetric effect of its d-q axis and compare its difference to the open route test of a symmetric model. Then, we apply the linear induction motor model to accomplish a speed close loop vector control and discuss the result.
43
Chang, Kuang-Yuan, e 張廣元. "Controller Tuning for Vector-Controlled Induction Motor Drives". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/87765522089398234158.
Testo completoAbstract (sommario):
碩士國立台灣工業技術學院
電機工程技術研究所
85
This thesis investigates the controller parameter tuning method for both a closed-loop vector-controlled and a sensorless vector-controlled induction motor drives. Asystemmatic procedure based on root-locus and frequency renponse techniques is proposed to tune the controller parameters. The thesis also proposes the design of a rotor flux observer for improving the low-speed performance of sensorless vector-controlled drive. In hardware implementation the 80196MC single-chip micro- processor is used for control software development. In estimatingthe rotor flux, the actual stator voltages are not measured, insteadthe stator voltage commands are used. The cost of the system isreduced since no voltage sensor is used for stator voltage sensing.Also, the rotor flux is estimated using the rated flux value and alow-pass filter so as to compensate the deviation caused by theintegrator during low-speed operation. Adeadtime compensationcontrol board is added to the hardware, which results in goodperformance during low speed with loads. The experimental results show good performance for both the closed-loop and the sensorless vector-controlled drives under no-load and loading conditions at various speeds.
44
Yu, Soon-Huang, e 游順煌. "Design and Implementation of Linear Induction Motor Drives". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/07449654371326034691.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
機械工程研究所
84
Owing to the difference between linear motor and rotary motor, like as end-effect, edge effect, skin effect, larger air gap and harmonic, unbalance phenomenon, and the normal force coupling effect , So the paper make the mathematical model and the equivalent circuit, and analysis the static and dynamic thrust-velocity characterictic, and improve the system performance. Using digital signal processor and the IGBT inverter module, with the technologies of vector control and voltage space PWM , design and implement a one-horsepower motor drives, also test the capability in rotary indiction motor. Taking account of the end-effect compensation in linear induction motor drives control law. And the method has control of effective flux, allowing a complicated induction motor to be treated as an ideal one, then a frequency compensation control follows to reduce error, then examines and improves the thrust- velocity performance. Finally, the paper accomplishes the velocity and position control under different loading conditions.
45
蕭霖癸. "An adaptive control strategy for induction motor drives". Thesis, 1989. http://ndltd.ncl.edu.tw/handle/62479842359448860820.
Testo completo
46
Kuang-Yuan, Chang, e 張廣元. "Controller Tuning for Vector-Controlled Induction Motor Drives". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/21287027134531243267.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
電機工程技術研究所
86
This thesis investigates the controller parameter tuning method for both a closed-loop vector-controlled and a sensorless vector-controlled induction motor drives. Asystemmatic procedure based on root-locus and frequency renponse techniques is proposed to tune the controller parameters. The thesis also proposes the design of a rotor flux observer for improving the low-speed performance of sensorless vector-controlled drive. In hardware implementation the 80196MC single-chip micro- processor is used for control software development. In estimatingthe rotor flux, the actual stator voltages are not measured, insteadthe stator voltage commands are used. The cost of the system isreduced since no voltage sensor is used for stator voltage sensing.Also, the rotor flux is estimated using the rated flux value and alow-pass filter so as to compensate the deviation caused by theintegrator during low-speed operation. Adeadtime compensationcontrol board is added to the hardware, which results in goodperformance during low speed with loads. The experimental results show good performance for both the closed-loop and the sensorless vector-controlled drives under no-load and loading conditions at various speeds.
47
Parida, Pragyanshree. "A Sliding Mode Controller for Induction Motor Drives". Thesis, 2009. http://ethesis.nitrkl.ac.in/1435/1/thesis.pragyan.pdf.
Testo completoAbstract (sommario):
Induction motors are being applied today to a wider range of applications requiring variable speed. Generally, variable speed drives for Induction Motor require both wide operating range of speed and fast torque response, regardless of any disturbances and uncertainties (like load variation, parameters variation and un-modeled dynamics). This leads to more advanced control methods to meet the real demand. The recent advances in the area of field-oriented control along with the rapid development and cost reduction of power electronics devices and microprocessors have made variable speed induction motor drives an economical alternative for many industrial applications. These AC drives are nowadays replacing their DC counter part and are becoming a major component in today’s sophisticated industrial manufacturing and process automation. Advent of high switching frequency PWM inverters has made it possible to apply sophisticated control strategies to AC motor drives operating from variable voltage, variable frequency source. The complexity in there mathematical model and the consequent need for the sophisticated algorithms are being handled by the computational power of low cost microprocessors to digital signal processors (DSPs).
In the formulation of any control problem there will typically be discrepancies between the actual plant and the mathematical model developed for controller design. This mismatch may be due to un-modeled dynamics, variation in system parameters or the approximation of complex plant behavior by a straightforward model. The designer must ensure that the resulting controller has the ability to produce required performance levels in practice despite such plant/model mismatches. This has led to an intense interest in the development of robust control methods which seek to solve this problem. One particular approach to robust-control controller design is the so-called sliding mode control methodology.
In this dissertation report, a sliding mode controller is designed for an induction motor drive. The gain and band width of the controller is designed considering rotor resistance variation, model in accuracies and load disturbance, to have an ideal speed tracking. The chattering effect is also taken into account. The controller is simulated under various conditions and a comparative study of the results with that of PI controller has been presented.
48
Panda, Yashobanta. "Analysis Of Cascaded Multilevel Inverter Induction Motor Drives". Thesis, 2010. http://ethesis.nitrkl.ac.in/2928/1/Final_thesis_23-02-11.pdf.
Testo completoAbstract (sommario):
This thesis aims to extend the knowledge about the performance of different cascaded multilevel inverter induction motor drives through harmonic analysis. Large electric drives and utility applications require advanced power electronics converter to meet the high power demands. As a result, multilevel power converter structure has been introduced as an alternative in high power and medium voltage situations. A multilevel converter not only achieves high power ratings, but also improves the performance of the whole system in terms of harmonics, dv/dt stresses, and stresses in the bearings of a motor. Several multilevel converter topologies have been developed; i) diode clamped, ii) flying capacitors, and iii) cascaded or H-bridge. Referring to the literature reviews, the cascaded multilevel inverter (CMI) with separated DC sources is clearly the most feasible topology for use as a power converter for medium & high power applications due to their modularization and extensibility. The H-bridge inverter eliminates the excessively large number of (i) bulky transformers required by conventional multilevel inverters, (ii) clamping diodes required by multilevel diode-clamped inverters, , and (iii) flying capacitors required by multilevel flying-capacitor inverter.
49
Bhatia, Amitpal Singh I. S., Vinit Kumar Gupta e Sourav Anand Sethi. "Simulation and Speed Control of Induction Motor Drives". Thesis, 2012. http://ethesis.nitrkl.ac.in/3382/1/Final_Thesis.pdf.
Testo completoAbstract (sommario):
Induction motors are the most widely used electrical motors due to their reliability, low cost and robustness. However, induction motors do not inherently have the capability of variable speed operation. Due to this reason, earlier dc motors were applied in most of the electrical drives. But the recent developments in speed control methods of the induction motor have led to their large scale use in almost all electrical drives.
Out of the several methods of speed control of an induction such as pole changing, frequency variation, variable rotor resistance, variable stator voltage, constant V/f control, slip recovery method etc., the closed loop constant V/f speed control method is most widely used. In this method, the V/f ratio is kept constant which in turn maintains the magnetizing flux constant so that the maximum torque remains unchanged. Thus, the motor is completely utilized in this method.
During starting of an induction motor, the stator resistance and the motor inductance (both rotor and stator) must be kept low to reduce the steady state time and also to reduce the jerks during starting. On the other hand, higher value of rotor resistance leads to lesser jerks while having no effect on the steady state time.
The vector control analysis of an induction motor allows the decoupled analysis where the torque and the flux components can be independently controlled (just as in dc motor). This makes the analysis easier than the per phase equivalent circuit.
50
Chen, Shaotang. "A new approach to motor condition monitoring in induction motor drives". 1993. http://catalog.hathitrust.org/api/volumes/oclc/32712447.html.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 76-80).